LUTC PKT 11-17-1997
~
City of Federal Way
City Council
Land Use/Transportation Committee
November 17, 1997
5:30 pm
City Hall
Council Chambers
AGENDA
1.
CALL TO ORDER
2.
AFPROY AL OF MINUTES
3.
PUBLIC COMMENT (3 minute limit)
4.
BUSINESS ITEMS
A.
Subdivision Code Amendment
Action
Largen/McClung/45 min
B.
Subdivision Signs
Action
Largen/McClung/I5 min
C.
Bob Dahl Request for Sign
Code Amendment
Action
Moore/5 min
D.
Final Acceptance of West Fork
Hylebos Creek Restoration
Project (AG#97-183)
Action
Renstrom/l0 min
F.
Belmor Regional Stormwater Detention Action
Pond Facility/Storm Drainage
Improvements Process III
Application
PrattiBarker/20 min
5.
ADJOURN
Committee Members:
Phil Watkins, Chair
Ron Gintz
Mary Gates
City Staff:
Greg Moore, Director, Community Development Services
Sandy Lyle, Administrative Assistant
253.661.4116
City of Federal Way
City Council
Land Use/Transportation Committee
November 17, 1997
5:30pm
City Ban
Council Chambers
SUMMARY
In attendance: Committee members Phil Watkins (Chair) and Ron Gintz; Mayor Skip Priest; Director of Community
Development Services Greg Moore; Deputy Director of Community Development Services Kathy McClung; Public Works
Director Cary Roe; Assistant City Attorney Bob Sterbank; Surface Water Manager Jeff Pratt; Principal Planner Greg Fewins;
Administrative Assistant Sandy Lyle.
1. CALL TO ORDER
The meeting was called to order at 5:35pm by Cbairman Phil Watkins.
2. APPROVAL OF MINUTES
The minutes of the October 20, 1997, meeting were approved as presented.
3. PUBLIC COMMENT
There was no public comment on items other than those included in the agenda.
4. BUSINESS ITEMS
A. Subdivision Code Amendment - The Committee chose to accept a formula to replace the PRDIPUD ordinance to be
used to calculate density. They required 15% open space and 20% for streets are subtracted from the gross land area
and then divided by the lot size of the underlying zoning district. The Committee required all open space in this
provision to be usable. They adopted a two-acre minimum property area before cluster subdivisions are allowed and
decided not to allow flexibility concerning street standards. The Committee decided to allow zero lot line development
in duplex configuration reducing to one-half the underlying zoning but no smaller than 3600 square feet. Committee
members then requested that staff return to the December 1, 1997, meeting with a final draft of the Subdivision Codes
changes for them to review.
B. Subdivision Si¡¡:ns - As previously reported to the Committee a number of signs at subdivisions are out of compliance
with the Sign Code. illegal wall signs, pedestal signs and pole signs coexist with legal signs. There are no addresses
or addressees to which to send violations. With minor "tweaking" existing subdivision signs would be brought into
compliance with the code. The Committee directed that code language be changed to permit all existing subdivision
signs with the caveat that when the signs are replaced they will be brought up to code. The Committee warned that too
much tweaking would cause businesses to want variances to apply to them, too.
C. Bob Dahl Reqpest for Si p1 Code Amendment - Mr. Bob Dahl approached the Committee with a request to amend the
Sign Code to allow temporary signs to inform the public about periodic blood drives at a local church. The Committee
denied his request, choosing not to rule by exception.
D. Final Acceptance of West Fork l{ylebos Creek Restoration Project (AG#97-183) - The West Fork Hylebos Creek
Rehabilitation Project Contract was accepted by the Committee as complete and forwarded it to the City Council at the
December 2, 1997, meeting. The final cost for construction of the projects was $56,111.01, which was $10,170.18
below the approved construction contract budget of $66,281.19, including the 10% construction contingency.
E. Belmor Re¡:ional Stonnwater Detention Pond Facility/Storm Dra1ns¡:e Improvements Process III Awlication - The
Committee m/s/c recommendation of approval of the Belmor Regional Stormwater Detention Pond Facility/Storm
Drainage Improvements Process III Application. The project would replace three undersized roadway culvert crossings
within the right-of-way, extend a culverted storm drain trunk line and construct a bulkhead (flood wall) for stream
stabilization. The proposal is intended to rehabilitate a section of Hylebos Creek and alleviate flooding of 20th Avenue
South and adjacent private property between SR99 and 23rd Avenue South. The project would lessen the impact of
increased peak flows delivered by future Phase n improvements to the upstream Sea- Tac Mall drainage system. The
Committee requested that staff return to a future meeting to discuss issues and legal aspects associated with pro-rata
cost recovery on regional capital improvement projects and maintenance cost recovery associated with road cuts versus
boring for proposed development projects.
5. FUTURE MEETINGS
The next meeting will be held on December 1, 1997 at 5:30pm in City Council Chambers.
6.
ADJOURN
The meeting was adjourned at 7: IOpm.
I: \LU- TRANS\NOV17LUT.SUM
CITY OF -
~ 13:J~
~~ Fn-'
DATE:
November 25, 1997
TO:
Phil Watkins, Chair
Land Use and Transportation Committee
FROM:
Rick Perez, Traffic Engineer fØ?
SUBJECT:
Sounding Board Ordinance Package to King County Council
Background
This memo is to update the City Council of the development underway with King County
METRO's South County Sounding Board and seek City Council's input on new developments in
the process of implementing a revised transit route structure.
In Federal Way, service changes implemented in September 1997 include the following:
1.
Midday service on Route 181 was increased to 30 minute headways. Route 181 was
realigned between S 336th Street and Federal Way Transit Center from Weyerhaeuser
Way S to S 336th Street, 20th Avenue S, and S 324th Street.
2.
The new route to Kent (Route 183) was implemented. This replaced Route 902 and the
portion of Route 192 south of the Star Lake Park and Ride. This created a gap in transit
service on Military Road S between S 304th Street and S 288th Street, and requires that
commuters now using the portion of Route 192 south of Star Lake transfer at Star Lake
or Federal Way Transit Center to other commuter routes.
3.
Route 194 was realigned from Pacific Highway S and S 348th Street between S 336th
Street and the South Federal Way Park and Ride to S 336th Street and 9th Avenue S.
4.
Route 903 was realigned between S 336th Street and Federal Way Transit Center from
S 336th Street and 20th Avenue S to 1st Avenue S, S 320th Street, and 11th Place S.
This also modifies the DART service area.
It was recognized that other changes would be necessary to more fully implement the Sounding
Board's recommendations. Metro had planned for these changes to occur in February 1998, but
are now planned for June 1998.
Matt Shelden of Metro will present the proposed service revisions with public comment provided
at an Open House in September.
RP:jg
cc: Project File - Day File
K: \LUTC\SBCfYREC.2
Mœo
TO:
Land Use Committee Members
Kathy McClung, Deputy CDS Director tkA
FROM:
DATE:
November 24, 1997
RE:
Subdivision Code and Subdivision Signs
Attached is the revised ordinance with changes discussed at
previous meetings.
ORDINANCE NO.
AN ORDINANCE OF THE CITY COUNCIL OF THE CITY OF
FEDERAL WAY, WASHINGTON, AMENDING CHAPTER 20
OF THE FEDERAL WAY SUBDIVISION CODE, ADOPTING
SPECIFIC AMENDMENTS AND ADDING NEW
REGULATIONS FOR CLUSTER SUBDIVISIONS AND
AMENDING CHAPTER 22 OF THE FEDERAL WAY
ZONING CODE ADDING NEW PROVISIONS FOR
SUBDIVISION SIGNS.
A.
WHEREAS amendments to the Federal Way City Code (FWCC) text are
authorized pursuant to FWCC Sections 22-216 and 22-217 pursuant to Process IV
review; and
B.
WHEREAS the Federal Way City Council has considered proposed changes
to the FWCC regarding specific subdivision regulations; and
C.
WHEREAS the Federal Way City Council, pursuant to FWCC 22-517, having
determined the Proposal to be worthy of legislative consideration, referred the Proposal
to the Federal Way Planning Commission as a priority item for its review and
recommendation; and
D.
WHEREAS the Federal Way Planning Commission, having considered the
Proposal at public hearings during 1997 on June 4, June 18, and August 20 pursuant to
FWCC Section 22-523, and all public notices having been duly given pursuant to FWCC
Section 22-521; and
E.
WHEREAS the public was given opportunities to comment on the Proposal
ORD#
, PAGE 1
during the Planning Commission review; and
F.
WHEREAS the City of Federal Way SEPA responsible official has issued a
Declaration of Nonsignificance on April 27, 1997; and
G.
WHEREAS following the public hearings, the Planning Commission submitted
to the land Use and Transportation Committee of the City Council its recommendation
in favor of proposed subdivision code amendments adding sections to the FWCC as
noted previously; and
H.
WHEREAS the Federal Way land Use and Transportation City Council
Committee met on September 3rd and 15th, October 6th and 20th, November 3rd and
17th and December 1 st, 1997 to consider the recommendation of the Planning
Commission and has moved to forward the Proposal, with amendments, to the full City
Council; and
I.
WHEREAS there was sufficient opportunity for the public to comment on the
Proposal; NOW, THEREFORE,
THE CITY COUNCil OF THE CITY OF FEDERAL WAY, WASHINGTON,
DOES HEREBY ORDAIN AS FOllOWS:
Section 1. FindinQs. After full and careful consideration, the City Council of the
City of Federal Way makes the following findings with respect to the Proposal and the
proposed amendments to the Federal Way City Code ("FWCC"):
1.
The Federal Way City Council adopted the Federal Way Comprehensive
Plan in order to comply with the state's Growth Management Act; and
ORD#
, PAGE 2
2.
The Federal Way Comprehensive Plan contains policies that call for the
amending of subdivision regulations to promote innovative and flexible standards in the
design and development of new residential subdivisions; and
3.
The Federal Way SEPA responsible official has issued a Declaration of
Nonsignificance on April 27, 1997; and
4.
The proposed code amendments would not adversely affect the public
health, safety or welfare; and
5.
The Planning Commission, following notice thereof as required by RCW
35A.63.070, held public hearings on the proposed regulatory amendments and has
considered the testimony, written comments, and material from the public by and through
said hearings.
Section 2. Conclusions. Pursuant to FWCC Section 22-217 and based upon
the Findings set forth in Section 1, the Federal Way City Council makes the following
Conclusions of Law with respect to the decisional criteria necessary for the adoption of
the Proposal:
1.
The Proposal is consistent with the following Comprehensive Plan goals
and policies:
LUP16 Revise existing land use regulations to provide for
innovation and flexibility in the design of new single family
developments and in-fill.
LUP19 Consider special development techniques (e.g. accessory
dwelling units, zero lot lines, lot size averaging, and planned unit
ORD#
, PAGE 3
developments) in single family areas provided they result in
residential development consistent with the quality and character of
existing neighborhoods.
LUP20 Preserve site characteristics that enhance residential
development (trees, watercourses, vistas, and similar features) using
site planning techniques such as clustering, planned unit
developments, and lot size averaging.
HP14 Amend development regulations to encourage superior
design and a greater diversity of housing types and costs through
such techniques as incentives, inclusionary zoning, planned unit
developments, density bonuses, and transfer of development rights.
HP15 Consider zero lot line standards within planned unit
developments to create higher density single family neighborhoods
with large open space areas.
2.
The Proposal bears a substantial relationship to the public health, safety
and welfare because it implements policies aimed at increasing housing diversity
and availability, neighborhood identity and promotes site sensitive development
to protect the environment and neighborhood character.
Section 3. Amendment. The Federal Way Zoning Code, Chapter 20, is amended
to provide as set forth in Attachment A which is attached and by this reference is
incorporated herein.
Section 4. The provisions of this ordinance are declared separate and severable.
The invalidity of any clause, sentence, paragraph, subdivision, section, or portion of this
ordinance or the invalidity of the application thereof to any person or circumstance, shall
not affect the validity of the remainder of the ordinance, or the validity of its application
, PAGE 4
ORD#
to other persons or circumstances.
Section 5. Ratification. Any act consistent with the authority and prior to the
effective date of this ordinance is hereby ratified and affirmed.
Section 6. Effective Date. This ordinance shall take effect and be in force five
(5) days from the time of its final passage, as provided by law.
PASSED by the City Council of the City of Federal Way this
,1995.
day
of
CITY OF FEDERAL WAY
MAYOR, MAHLON S. PRIEST
ATTEST:
CITY CLERK, N. CHRISTINE GREEN, CMC
APPROVED AS TO FORM:
CITY ATTORNEY, LONDI K. LINDELL
FILED WITH THE CITY CLERK:
PASSED BY THE CITY COUNCIL:
PUBLISHED:
ORD#
, PAGE 5
EFFECTIVE DATE:
ORDINANCE NO.
ORD#
PAGE 6
ATTACHMENT A
Article I.
In General
Sec. 20-1.
Definitions
Binding site plan shall mean a plan drawn to scale processed in
accordance with the provisions of this chapter and RCW 58.17.
Binding site plans are divisions of land for sale or qround lease
for commercial ef. industrial. manufactured home parks. and
condominium uses.
Article II Plats
DIVISION 4. BINDING SITE PLANS*
----------
*Cross reference(s)--site plan review procedure, §22-361 et
seq.
State law reference(s)--Binding site plans, RCW 58.17.035.
----------
Sec. 20-61. Subdivisions requiring binding site plan.
Division of any land for sale or lease which is classified
for commercial, business, office, or industrial development, or
which is to be developed as condominiums or manufactured home
park shall be required to obtain an approved binding site plan in
accordance with this and other ordinances of the city.
Sec. 20-68. Alteration of bindina site glan.
Alteration of an approved bindinq site plan shall follow the
same process and requirements set forth in this division for the
approval of a bindinq site plan.
Sec. 20-108.5. Alteration and vacation of short glats.
(a) Alteration of an approved short plat shall follow the same
review process used to create a short plat as set forth in Sec.
20-81: EXCEPT that when an alteration involves a public
dedication, the alteration shall be processed as provided in
Division 9..
(b) Vacation of an approved short plat shall follow the process
established as follows: EXCEPT that, when a vacation involves a
public dedication, the vacation shall be processed as provided in
Division 9.
1
(1) A preapPlication conference between the proponent and
city staff to discuss the circumstances and reasons for
the vacation as set forth in Sec. 20-82.
(2) Review of the short subdivision vacation application to
determine whether or not the application is complete and
acceþtable for filing. An application for vacation shall
include the followinq:
(a) An application for approval of a short subdivision
vacation shall be made to the department of community
development services upon forms furnished by the city.
Applications shall be made by the owner or owners of the
parcel or þarcels of all property encompassed by the
application or by a duly authorized aqent. The owner or
owners of all parcels to be included must ioin in or be
represented in the application.
(3)
(b) The apþlication shall include seven prints of the
approved short subdivision and accompanied by statement
settinq forth the reasons for vacation.
Approval. approval with conditions. or denial of the
short subdivision vacation by the director of the
department of community development services.
Filinq of the short subdivision vacation in the office
of the county division of records and elections.
(4)
Division 6. Preliminary Plat
Sec. 20-110. Content and form of application
(8) Preliminary plat certificate not less
from a licensed title insurance comþany.
~ Additional information as required at
the director of community development services.
than 90 days old
the discretion of
Division 9.
Vacation of Subdivisions
Sec. 20-250. Plat vacation aDDlication.
When any person is interested in the vacation of any subdivision
that person shall submit an application to request the vacation
to the city.
(a) Siqnatories. The application shall contain the
signatures of the majority of those persons having an ownership
interest of lots. tracts. parcels. sites or division in the
subiect subdivision or a portion to be vacated. If the
subdivision is subiect to restrictive covenants which were filed
at the time of approval of the subdivision. and the application
2
for alteration would result in the violation of a covenant. the
application shall contain an aqreement siqned bY all parties
sub;ect to the covenants providinq that the parties agree to
terminate or alter the relevant covenants to accomplish the
purpose of the vacation of the subdivision or portion thereof.
(b) Completed application defined. A completed application
shall be as required for preliminary plats. pursuant to FWCC
Section 20-107.
Sec. 20-251. Acce~tance of a~plication. routina.
(a) Upon submittal of a completed apPlication for vacation of
plat. the department of community development services shall
transmit at least one CoPY of the application for vacation for
review and recommendation to each of the followinq:
(1)
Public works department;
(2) Lakehaven utilitv District and/or city of Tacoma
Public utility Department and/or other utility district.
as appropriate;
(3)
Federal Way Fire Department;
(4) County department of public health. if septic systems
are proQosed for sewage disposal;
(5)
Federal Way School District #210; and
(6)
Building division;
(7) Other individuals or jurisdictions as deemed
appropriate by the director.
(b) An application for plat vacation shall not be accepted for
filinq for the purpose of official processinq until:
The director of community development services
determines that the applicant has paid all fees and
submitted all documents and information as required herein
to permit a full public hearinq on the merits of the
application; and
Sec. 20-252. Process for review and notice of Ðublic hearina.
(1)
(a) Upon confirmation by the director of community development
services that the plat vacation aQPlication is complete the
application shall be processed and reviewed followinq the
procedures defined in section 20-109 et seq.
(b) Notice of the hearinq shall be mailed to the appropriate city
or county officials if their proposed plat vacation lies within
one mile of the adioininq city or county boundary. and to all
3
agencies or private companies pursuant to section 20-251(a)
herein.
(c) All notices required in this section shall clearly describe
in layperson's terms the nature of the request. the location of
the proposal. the date. time and location of the hearing~ and
address and telephone number where additional information may be
obtained relative to the application. .
Sec. 20-253. Report to hearinq examiner: review.
(a) No less than seven days prior to the date of the public
hearinq. the department of community development services shall
submit to the hearinq examiner a written report summarizinq the
application for plat vacation. The report shall contain. in
addition to the requirements in section 20-111, et sea.. the
followinq information:
All communications from other aaencies or individuals
relatinq to the application which were received in time to
be included in the report to the hearinq examiner.
A list of recommendations from the department of
community development services. department of public
works. and other appropriate departments relating to plat
vacation approval.
(b) The hearinq examiner shall review the application in
accordance with the procedures stipulated in Article VII. Process
IV Review.
(1)
(2)
Sec. 20-254. city council review, action.
city council review of hearinq examiner recommendations on
applications for plat alterations shall be limited to the record
of the hearinq examiner. oral comments received at the public
meetinq (so lonq as such comments do not raise new issues or
information not contained in the examiner's record) and the
hearina examiner's report.
ARTICLE III. DESIGN CRITERIA*
Sec. 20-153. Density.
(b) Lots created in under section 20-154 may be below minimum lot
size requirements of chapter 22, provided the total number of
lots created does not exceed the number which would be permitted
in a conventional subdivision on a site 'of the same total area,
after reservation of required open space. The total number of
lots permitted will be calculated by subtractinq the required
open space (15%) and subtractinq 20% for streets from the qross
land available. then dividinq by the minimum lot size of the
underlyinq zoinq district.
Sec 20-154. Cluster subdivision.
(a) In order to promote open space and the protection of natural
4
fatures such as trees, wetlands, and other environmentallY
sensitive areas. lots may be reduced in size and placed in
clusters on the site. The gross land area available for cluster
subdivisions must be a minimum of two acres.
(b) Lots created in a cluster subdiviision may be reduced in size
bbelow the minimum required in chaspter 22, up to 1/2 of the size
of the underlying zoninq requirement but in no case smaller than
3600 square feet. per lot.provided that minimum yard aftà setback
requirements are met except as allowed for in Cd) below.Building
eetbac]c linca for cach lot 3hall bc ahown on thc facc of a
clueter subdivieion plat.
(c) Open space created by cluster subdivisions shall be protected
from surhter subdivision or development by covenants filed and
recorded with the final plat ot the subdivision.
(d) Cluster subidivisons can be constructed with zero-lot lines.
provided that no more than two units may share a common wall.
(e) Any subdivision created by this section must provide all open
space on-site and it must all be usable.
Sec. 20-155. Open Space and recreation.
(b) All residential subdivisions shall be required to provide
open space in the amount of 15 percent of the gross land area of
the subdivision site, or if the site iD five acres or leoo in
aiBc, applicants may acc]c altcrnativc methode of providing the
required open opace aD permitted by eection 19 41 et oeq., if
acccptabic to the city; Except for subdivisions created under
section 20-154, a fee-in-lieu payment may be made to satisfy open
sþace requirements at the discretion of the parks director after
consideration of the city's overall park plan. quality. location.
and service area of the open space that would otherwise be
provided within the project. The fee-in-lieu of open sþace shall
be calculated on fifteen percent (15%) of the most recent
assessed value of the property. In the absence of an assessment.
the market value shall be based on an appraisal conducted by a
MAI certified appraiser or another professional appraiser
approved by the parks director. And except for lots within an
existing subdivision. where open space was already dedicated or a
fee in lieu paid. the percent of open space required will be the
difference between the open space dedicated prior and 15%. Any
fees collected shall be utilized within the Park Comprehensive
Plan Planning Area that the sub;ect property falls within.
(c) Any combination of open space types may be used to
accomplish the total area required to be reserved as follows:
Open Space % of Gross Land
Category Area
Usable 10% minimum
Conservation No maximum or minimum
5
Buffer
Constrained
2% maximum
2% maximum
An administrati ve al teration of the open space category percentaae
requirements within the above categories may be made bY the parks
director on a case-by-case basis. but in no case shall the combination
of cateaories total less than 15% unle3ss otherwise provided for in
section 20. Review and approval of such cases shall be based on the
followina considerations:
1. The chanae in percentaqe requirements would result
in a superior open space plan than could be accomplished
under the standard percentage requirements.
2. The availability and types of open space located
within the immediate area.
3. The presence on-site of environmental features that
are unique or rare or of local importance.
4. The opportunities for the preservation of
sianificant views and creation of public access to points
of interest.
5. The relationship of the proposed open spaces to the
city's park plan.
CHAPTER 22
Zoning
Article XIII. supplementary District Regulations
Division 1. Generally
Sec. 22-955. calculatinq lot coveraqe.
(a) General. Except as specified in subsection (b) of this
section, the area of all structures, pavement and any other
impervious surface on the subject property will be calculated as
a percentage of total lot area. exclusive of the area of any
recorded access easements. in determining compliance with maximum
lot coverage required in this chapter. If the subject property
contains more than one use, the maximum lot coverage requirements
for the predominant use will apply to the entire development.
6
Changes to section 22-335 Nonconforming signs.
(e) Amortization. All legal nonconforming signs except
subdivision siqns installed prior to February 28. 1990 (see
section 22-335 ;) shall be discontinued and remoyed or made
conforming within ten years from the effective date of this code,
on or before February 28, 2000, and all signs which are made
nonconforming by a subsequent amendment to this code shall be
discontinued and removed or made conforming within five years
after the date of such amendment (collectively the "amortization
period"). Upon the expiration of the amortization period, the
sign shall be brought into conformance with this code, with a
permit obtained, or be removed. A sign prohibited pursuant to
section 22-1600 may not be brought into conformance and must
therefore be immediately removed upon the expiration of the
amortization period.
(;) Subdivision signs. All leqal. nonconforming subdivision signs
constructed prior to February 28. 1990 shall be exempt from the
amortization requirement unless they are removed. rebuilt. or
altered beyond customary and routine maintenance. or are
determined to be within the siqht distance trianqle or are in
public riqht of way and interfere with construction. maintenance
or other public improvements. in which case the siqn must be
replaced with a siqn that meets the requirements of section 22-
1600.
Memo
FROM:
Land Use Committee
Kathy McClung, Deputy CDS Director~
TO:
DATE:
November 25, 1997
RE:
Carryover work program
Attached is the schedule for the code amendments and annexations
from the 1997 work program into 1998. At a future meeting we
will provide information regarding other code amendments we will
be required to make in 1998 due to changes to state law as well
as other proposed changes the staff and Planning Commission have
suggested.
11/25197
Projected Timelines for Code
Amendments & Annexations
Draft ... 'SEPA '. 'Planmng. LUTC ...CC
Report Complete Commission
1724 Complete Complete Complete Complete Complete
Downtown
Parking Complete N/A Complete Complete Complete
Essential Public
Facilities Complete Complete Complete Complete Complete
Non-
Confonning Complete 5/15 Complete Complete 12/2
Subdivision Complete 5130 Complete 12/1 12/16, 1/6
Tele-
communications 5/23 7/16 Complete Complete Complete
Sensitive Areas Complete 6/11 October January February
Affordable 11/18
Housing July September October November & 12/2
Shoreline November December Feb/Mar March April
Comprehensive
Plan Update December January January February March
Residential
Design January February April May June
Wellhead
Protection January February May May June
Enchanted
Annexation November November December December December
We have been notified that the Weyerhaeuser Annexation will become active again shortly.
Applewood Annexation will be incorporated in the Comprehensive Plan Update.
Regional Governance is dependent on Suburban Cities Association Committee work.
I: IDOCUMEN'I\CO D EAD MN . C /IT
DATE:
November 23, 1997
TO:
Phil Watkins, Chair
Land U selTransportation C mmittee
FROM:
SUBJECT:
S336th/Kitts Regional Storage Facility Repair - Final Acceptance
Background:
Prior to release of retainage on a Public Works project, the City Council is required to accept the
work as complete to meet State Departments of Revenue and Labor and Industries requirements.
The [mal cost for construction of the S336th/Kitts Regional Storage Facility Repair Project is
$40,986.35, which is $3619.89 below the approved construction contract budget of $44,606.24,
including the 10 % construction contingency.
Recommendation:
Forward the following item to the December 16, 1997 City Council meeting with the
recommendation to approve:
1.
Acceptance of Muck Creek Construction, S336th/Kitts Regional Storage Facility Repair
contract #AG 97-190 as complete.
Attachment
K: \WTC\KI1TSREP. WPD
DATE:
August 26, 1997
TO:
Phil Watkins, Chair
Land Use/Transportation Committee
Jeff Pratt, Surface Water Manager ~
FROM:
SUBJECT:
S336th/Kittts Regional Storage Facility Repair - Bid Award
BACKGROUND:
During the Winter stoms of '96/'97 a slope failure (mud slide) occurred along a portion of slope
within the primary detention cell at the S336th/Kitts Corner regional stormwater storage facility.
The referenced project proposes repair of the failed slope. The design of the proposed repair was
submitted by CH2M Hill, Inc. the City's design consultant on the original project with an
estimated cost of $52,810.01.
The Surface Water Management Division invited five of its small works roster contractors to bid
on the above repair project. On August 26, 1997, the City received two bids. The low-bid
contractor for this project is Muck Creek Construction, with a total bid amount of $40,551.24.
This bid amount is 23 % lower than the engineer's estimated construction cost for this project (see
attached bid tabulation).
Based on the reference checks completed by City staff, there is no known reason why this low
bidder should not be able to successfully complete this project to the City's satisfaction.
Due to the declaration of this storm event as a Major Disaster, the City will recover portion of the
repair costs, approximately $28,000.00, from the State and the Federal Emergency Management
Administration. The balance of the cost will be paid from the Surface Water Minor Capital
Improvement Fund.
RECOMMEl\TDA TION:
Staff recommends the award of this project to the lowest responsive, responsible bidder, Muck
Creek Construction Inc., in the amount of $40,551.24 and that a 10% construction contingency
totaling $4,055.00 be established for this project. In addition, staff recommends that this matter
be placed on the September 16, 1997 City Council meeting consent agenda for their consideration.
K:\LUTC\KIITSREP.LUT
Bid Tabulation
South 336th Regional Storage Facility Repair of primary Detention Cell
BID OPENING
AUGUST 26,1997
IBid 1 IBid 2 Bid 3 Bid 4 ¡Bid 5
Vendor Name ...> Muck Creek Construction Uoyed Enterprises, Inc ENGINEER'S ESTIMATE
Location ____om> Eatonville WA Federal Wav WA
Item Amount Price Total Price Total Price Total PrIce Total Price Total Price Total
1 Mobilization 1 5,150.00 5,150.00 3,000.00 3,000.00 0.00 0.00 0.00 0.00 0.00 0.00 6,343.00 6,343.00
2 Excavation Including Haul 1 6,000.00 6,000.00 19,500.00 19,500.00 0.00 0.00 0.00 0.00 0.00 0.00 10,400.00 10,400.00
3 Low Permeability Soil 360 8.00 2,880.00 15.00 5,400.00 0.00 0.00 0.00 0.00 0.00 0.00 4.00 1,440.00
4 Gravel Backfill for Drain 470 15.00 7,050.00 15.00 7,050.00 0.00 0.00 0.00 0.00 0.00 0.00 20.00 9,400.00
5 Quarry Spalls 360 17.00 6,120.00 20.00 7,200.00 0.00 0.00 0.00 0.00 0.00 0.00 18.00 6,480.00
6 Undefdraln Pipe 6 In. Dia 650 7.50 4,875.00 10.00 6,500.00 0.00 0.00 0.00 0.00 0.00 0.00 2.50 1,625.00
7 Topsoil Type A 120 12.00 1,440.00 15.00 1,800.00 0.00 0.00 0.00 0.00 0.00 0.00 15.00 1,800.00
8 Landscaplng 1 3,825.00 3,825.00 7,SOO.00 7,SOO.00 0.00 0.00 0.00 0.00 0.00 0.00 11,140.00 11,140.00
SUBTOTAL 37340.00 57.950.00 0.00 0.00 0.00
Sales Tax /B) 8.6% 1 3211.24 4 983.70 0.00 0.00 0.00 4 182.01
TOTAL 40.551.24 62.933,f0 U.UU O.OC 0.00 52.810.01
id S¡nnature es es
Bid Bond Yes Yes
Addendums NA NA NA NA NA
.~
~
Bid Tabulation
South 336th Regional Storage Facility Repair of primary Detention Cell
BID OPENING
AUGUST 26,1997
IBid 1 IBid 2 1t:Sld J lid 4 Bid 5
Vendor Name ---> Muck Creek Construction Lloyed Enterprises, Inc ENGINEER'S ESTIMATE
Location ___m_--> Eatonville WA Federal Way. WA
Item Amount Price Total Price Total Price Total PrIce Total Price Total Price Total
1 Mobilization 1 5,150.00 5,150.00 3,000.00 3,000.00 0.00 0.0.0 0.00 0.00 0.00 0.00 6,343.00 6,343.00
2 Excavation Including Haul 1 6,000.00 6,000.00 19,500.00 19,500.00 0.00 0.00 0.00 0.00 0.00 0.00 10,400.00 10,400.00
3 Low Permeability Soil 360 8.00 2,880.00 15.00 5,400.00 0.00 0.00 0.00 0.00 0.00 0.00 4.00 1,440.00
4 Gravel Backfill for Drain 470 15.00 7,050.00 15.00 7,050.00 0.00 0.00 0.00 0.00 0.00 0.00 20.00 9,400.00
5 Ouarry Spells 360 17.00 6,120.00 20.00 7,200.00 0.00 0.00 0.00 0.00 0.00 0.00 18.00 6,480.00
6 Und:!fdraln Pipe 6 In. Dia 650 7.50 4,875.00 10.00 6,500.00 0.00 0.00 0.00 0.00 0.00 0.00 2.50 1,625.00
7 Topsoil Type A 120 12.00 1,440.00 15.00 1,800.00 0.00 0.00 0.00 0.00 0.00 0.00 15.00 1,800.00
8 Landscaping 1 3,825.00 3,825.00 7,500.00 7,500.00 0.00 0.00 0.00 0.00 0.00 0.00 11,140.00 11,140.00
SUBTOTAL .00 o.on 0.00
Sales Tax II'!> 8.6'10 I 3211.24 4 983.70 0.00 0.00 0.00 4 182.01
TOTAL 40.551.24 b:l.!lJJ. U 0.00 0.00 .QQ- 52.810.01
10 Sionature es es
Bid Bond Yes Yes
Addendums NA NA NA NA NA
,,-...,
~
DATE:
November 17, 1997
TO:
Phil Watkins, Chair
Land Use/Transportation Committee
David Rens1rom ~
SWM Water Quality Program Coordinator
FROM:
SUBJECT:
Final Acceptance of the West Fork Hylebos Creek Rehabilitation
Project Contract
Background
Prior to release of retainage on a Public Works project, the City Council is required to accept
the work as complete to meet State Departments of Revenue and Labor and Industries
requirements.
The final cost for construction of the West Fork Hylebos Creek Rehabilitation Project is
$56,111.01, which is $10,170.18 below the approved construction contract budget of
$66,281.19, including the 10% construction contingency.
Recommendation
Forward the following item to the December 2, 1997 City Council meeting with the
recommendation to approve:
1.
Acceptance of Roadway Construction Inc. 's, West Fork Hylebos Creek Rehabilitation
Construction contract #AG 97-184 as complete.
K: \SWM\HYLEBOS . WPD
FEDERAL WAY
MEMORANDUM
DATE:
October 28, 1997
TO:
City Council Land Use & Transportation Committee
Council member Phil Watkins, Chair
~ory Moore, AICP, Director of Community Development Services
FROM:
CONTACT: Deb Barker, Associate Planner
RE:
BELMOR REGIONAL STORMWATER DETENTION POND FACILITY
AND STORM DRAINAGE IMPROVEMENTS PROCESS ill
APPLICATION
Federal Way File No. UPR96-0045
Related File No's UPR 96-0044, SEP 96-0022 and ADM 96-0054
I.
SUMMARY OF APPLICATION
The proposal is to construct a regional stormwater detention pond facility, replace three
undersized roadway culvert crossings within the right-of-way, extend a culverted storm
drain trunk line and construct a bulkhead (flood wall) for stream stabilization. The
proposal is intended to rehabilitate a section of Hylebos Creek and alleviate flooding of
20th Avenue South and adjacent private property between SR 99 and 23rd Avenue South
(Exhibit A). The proposal wi11lessen the impact of increased peak flows delivered by
future Phase II improvements to the upstream (Sea-Tac Mall) drainage system.
Six separate project sites are included in the scope of work. The sites are located within
Residential Multi-Family (RM) zoning districts. Pursuant to Federal Way City Code
(FWCC) section 22-678, Public Utilities are permitted uses in the RM zoning district
subject to Use Process III approval.
ll.
REASON FOR COUNCIL ACTION
This application was filed on July 26, 1996, prior to adoption of the recent code
amendments and procedural changes implementing HB1724, regulatory reform
requirements. The Hearing Examiner may render only a recommendation under the
previous Process III review. The final decision for all such requests rest with the City
Council. Bringing this matter before the City Council Land Use Committee for review and
recommendation prior to the full Council is consistent with how land use matters are
currently processed by the City.
ill.
IV.
HEARING EXAMINER IS RECOMMRNDA TION
To approve the application subject to one condition. Pages one through eight of the
Hearing Examiners recommendation contain findings and conclusions which serve as a
basis for the recommendation. The entire recommendation is attached.
PROCEDURAL SUMMARY
July 26, 1996
SEPA application filed.
October 25, 1996
The application for Use Process III approval filed with the
city.
January 29, 1997
Federal Way State Environmental Policy Act (SEP A)
Responsible Official issued a SEP A Determination of Non-
Significance (DNS).
February 28, 1997
SEP A appeal period expired. No appeals were filed with
the city.
March 11, 1997
Hearing Examiner public hearing.
October 14, 1997
Hearing Examiner issued recommendation to approve the
application.
Pursuant to Chapter 22, Article VIII, Process
III Review of the Federal Way City Code,
the Hearing Examiner shall issue a written
recommendation to the City Council (see
Exhibit A).
October 28, 1997
Hearing Examiner recommendation appeal period expired.
No appeals have been filed with the city to date.
November 3, 1997
City Council Land Use Committee meeting.
Land Use Committee forwards a
recommendation to the full City Council.
November 18, 1997
City Council meeting.
Pursuant to Section 22-490 of Federal Way
City Code, the City Council shall consider
the application at a scheduled meeting.
To date, no challenges to the Hearing Examiner's recommendation have been filed with
2
V.
VI.
the City.
DECISIONAL CRITERIA
City Council's review of the application is limited to the record of the hearing before the
Hearing Examiner, the Examiner's written report, compliance with decisional set forth in
FWCC Section 22-490, and other applicable ordinances and regulations of the Federal
Way City Code. City Council may approve the application only if all three decisional
criteria of FWCC Section 22-490( d), listed below, are met. Specifically, the application
must be consistent with:
a.
The Comprehensive Plan,
Response: The proposed action is consistent with the 1995 City of Federal Way
Comprehensive Plan
b.
All applicable provisions of the Code, including those adopted by reference from
the Comprehensive Plan,
Response: The proposed action is consistent with decisional criteria under FWCC
sections 22-364 Site Plan Approval; 22-394 (b) Process I; 22-490 (d) Process III
approval; 22-1286(b) Geologically hazardous areas; 22-1306 (a) Stream Setbacks;
22-1308 (c & d) Bulkheads; 22-1309 (c, d & e) Culverts; 22-1311 Rehabilitation;
22-1312(a) Intrusion into Setbocks, and 22-1359 (b) Structures, improvements arul
land surface modifications within the setback area from regulated wetlands.
and,
c.
Public health, safety and welfare.
Response: Development of the site in accordance with the comprehensive plan, and
all applicable development codes and regulations would ensure that the interest of
the public's health, safety, and welfare are protected.
COUNCIL ACTION
A draft resolution recommending approval of the application has been prepared for City
Council review based on the Hearing Examiner recommendation. The City Council may,
by action approved by a majority of the total membership, take one of the following
actions after consideration of the record before the Hearing Examiner.
a.
Approve the application request,
b.
Approve the application request with minor modifications,
c.
Deny the application request,
3
d.
Remand the matter back to the Hearing Examiner for further consideration, or,
e.
Schedule a public hearing before the City Council, in order to consider non-minor
modifications to the application request.
The City Council shall not substantially modify the Hearing Examiner recommendation
without first referring the matter back to the Hearing Examiner or conducting its own
public hearing of the application.
Exhibits
A. Hearing Examiner Decision
B. Draft Resolution
C. Staff Report to the Federal Way Hearing Examiner
D. October 27, 1997 Public Process memo
E. September 29, 1997 letter from Moberg Family
S P rIp u b work I belpond llan duse . nun 0
4
CITY OF FEDERAL WAY
RECEIVED
0 C T 1 4 1997
CITY CLERKS OFFICE
CITY OF FEDERAL WAY
OFFICE OF THE HEARING EXAMINER
In re the matter of:
)
)
BELMOR REGIONAL STORMW A TER )
DETENTION POND FACILITY AND STORM )
DRAlNAGEIMPROVEMENTS )
)
)
UPR96-0045, SEP96-0022,
AND ADM 96-0054 ..
PROCESS III
--------------------------------------------------
I. SUMMARY OF APPLICATION
The proposal is to construct a regional stormwater detention pond facility, replace three
undersized roadway culvert crossings within the right-of-way, extend a culverted storm drain trunk
line and construct a bulkhead (flood wall) from stream stabilization. The proposal is intended to
rehabilitate a section of Hylebos Creek and alleviate flooding of 20th Avenue South and adjacent
private property between SR-99 and 23rd Avenue South (Exhibit A). The proposal will lessen the
impact of increased peak flows delivered by future Phase II improvements to the upstream (Sea- Tac
Mall) drainage system.
II. PROCEDURAL INFORMATION
Hearing Date:
Decision Date:
March 11, 1997
October 14, 1997
At the hearing the following presented testimony and evidence:
1. Deb Barker, City of Federal Way
2. Dean Moberg
3. Kenneth Moberg
4. Jeff Pratt, City of Federal Way
5. Greg Fewin, City of Federal Way
6. Dwayne Kochel
EXHIBIT A
P.A G E -'-~ 0 F_~
BELMOR
October 14, 1997
Page - 2
At the hearing the following. exhibits were admitted as part of the official record of these
proceedings:
9.
1.
Staff Report with all attachments
2.
Letter from Dean Moberg dated March 11, 1997
3.
Letter from Kenneth Moberg dated March 10, 1997
4.
Memorandum to Examiner from Deb Barker dated April 3, 1997
5.
Letter to Examiner from Kenneth E. Moberg dated April 7, 1997
6.
Letter to Deb Barker dated April 14, 1997
7.
Letter with attachments from Kenneth Moberg to Examiner dated April 17, 1997
8.
Letter to city clerk from Nonnan A. Moberg dated April 21, 1997
Letter from Bob Sterbank dated May 2, 1997
10.
Letter from Kenneth Lee Moberg to Examiner dated May 5, 1997
11.
Letter from Bob Sterbank to Examiner dated May 12, 1997
12.
Letter to Examiner from Kenneth Lee Moberg dated August 15, 1997
13.
Letter to Examiner signed by Kenneth Lee Moberg and Dean Moberg dated
September 29, 1997
14.
Letter from Deb Barker to Examiner dated September 29, 1997
III. FINDINGS
1.
The Hearing Examiner has heard testimony, admitted documentary evidence into the record,
and taken this matter under advisement.
The Community Development Staff Report sets forth general findings, applicable policies
and provisions in this matter and is hereby marked as Exhibit" 1" and incorporated in its
entirety by this reference.
2.
EXHIBIT Ie
P,AGE~~~OF 1C4
BELMOR
October 14, 1997
Page - 3
3.
4.
5.
6.
B.
C.
All appropriate notices were delivered in accordance with the requirements of the Federal
Way City Code (FWCC).
The applicant, Surface Water Management Division of the City of Federal Way Public
Works Department (City), is proposing to construct regional stonn water improvements
along a section of a Hylebos Creek tributary to alleviate flooding problems on 20th Ave. S.
and private properties adjacent to the tributary between SR-99 and 23rd Ave. S. The project
area is bordered on the north by 324th Street and extends south to an area just north of 336th
Street. According to the project map (Exhibit "A"), stonn water discharging from the
proposed facilities will enter the Kitts Comer regional stonn water detention facility
currently under construction, and from there the S. 336th regionalstonn water detention
facility, also under construction. The three facilities will lessen the impact of increased peak
flows anticipated from development upstream to include the Sea Tac Mall.
The entire project site is located within the Residential Multi-Family (RM) zoning district
of the Federal Way City Code (FWCC). Section 22-678 FWCC allows public utilities within
the RM district subject to Process III approval.
Construction of the facility will occur on six sites which together will include a regional
stonn water detention pond facility, culvert and bulkhead work, and stream rehabilitation.
The proposed work and locations thereof are as follows:
A.
Site I is the northwest portion of the Belmor Mobile Home Park and Country Club
at 2101 S. 324th Street. Improvements include construction of a 7.5 acre foot, above
ground, regional detention pond along the west Hylebos Creek setback area and
partially within the fairway of the ninth hole of the Belmor Golf Course. The City
will lower the west channel bank to fonn an overflow along the alignment of the
existing north/south sanitary sewer. The City will also install approximately 385 feet
of new 84 inch diameter trunk stonn drain between S. 324th St. and the detention
pond. Two sets of 24 inch culverts will connect the stream channel to the detention
pond. Culvert installation will require filling approximately 230 feet of existing
stream channel.
Site II is a private drive crossing located at 32830 20th Ave. S. where improvements
include the installation of a new 48 inch diameter culvert under said driveway as a
replacement for one 12 inch and two 18 inch diameter culverts. Improvements also
include the placement of fill to elevate the bridge roadway section and installation
of rip rap for erosion control.
Site III is the S. 330th St. crossing where improvements include activation of the
existing 48 inch diameter culvert which will replace the 18 inch and 24 inch culverts.
EXHIBIT A
P AGE ~ ~ 0 F._l!i_~,
BELMOR
October 14, 1997
Page - 4
Rip rap will be installed to control erosion and the 18 and 24 inch culverts plugged
and abandoned.
D.
Site IV is the 20th Ave. S. crossing where improvements include the installation of
460 feet of new 48 inch diameter storm drain culvert beneath and along the west
shoulder of 20th Ave. S. The City will install four new catch basins on the west side
of said road and rip rap for erosion control.
E.
Site V is the S. 333rd crossing where improvements will include the installation of
two parallel 42 inch diameter culverts under S. 333M St. as a replacement for the two
existing 18 and 24 inch diameter culverts. The City will move the outlet location
approximately 20 feet west of the existing culverts and install rip rap for erosion
control.
F.
Site VI is the Empire Garden Apartments stream channel located at 33311 18th Lane
South. The City will enlarge the channel around the Southeast apartment building by
widening it within the stream setback area. Improvements also include construction
of a concrete slope retainage and flood wall up to four feet in height along the
relocated west cbannel bank and the maintenance of the earth stream bank: on the east
side. The City will overexcavate the stream channel bed and place rip rap base
overlain by stream gravel.
The entire project is along a tributary of West Hylebos Creek, a major stream based upon the
FWCC definition. Five wetlands within the project site currently providing storm water
functions will not be directly impacted or displaced by the improvements, but approximately
2.02 acres of wetland setback and stream areas will be affected. Mitigation is limited to
wetland setback areas, the stream, and upland setback areas. Replacing a portion of the
stream channel with a culvert and filling portions of the channel (along with associated
stream habitat replacement) conforms to Section 22-1309( c )(2) FWCC as the stream corridor
has previously been degraded and potential soils contamination in the channel identified.
7.
8.
9.
The Federal Way Comprehensive Plan (FWCP) encourages protection and enhancement of
the City's aquifers. The project area has a "low" susceptibility to groundwater contamination
and the project is outside of the RedondolMilton Channel Aquifer and associated aquifer
recharge area. The regional groundwater system is located at least 70 feet below ground
surface, and the City will install a low permeability soil liner or a geosynthetic clay line
within the detention pond to control discharge to groundwater.
The City prepared an Environmental Assessment to evaluate the potential for hazardous
substances or materials. The assessment establishes that elevated levels oC urban type
contaminants are present in the existing drainage ditch at levels which will require special
EXHIBIT A
PAGE~ OF-IL
11.
12.
13.
BELMOR
October 14, 1997
Page - 5
handling, treatment, and disposal.
10.
The project will require filling 230 linear feet of stream channel and excavation ðf a 7.5 acre
permanent pool pond. However, no significant adverse geotechnical impacts related to
construction of improvements are expected, and affected areas will be revegetated. The
applicant will implement all geotechnical recommendations in the clearing, grading, and
construction process.
Fourteen significant trees are located within the project areas, three of which will be removed
to tàcilitate installation of the drainage facilities. Since more than 25% of the significant trees
are retained, replacement is not required and the City will develop a tree protection
management plan in conformance with Section 22-1568 FWCC. The applicant will also
submit revegetation plans for all disturbed areas in accordance with Sections 22-1359(e) and
22-1311 FWCc.
Shapiro and Associates conducted a field investigation to identify animals on the site.
Neither the investigation nor the records of the Washington Natural Heritage Program or the
U.S. Fish and Wildlife service indicate the presence of sensitive, threatened, or endangered
animal species or juvenile salmonids. However, the project includes several measures to
preserve and enhance wildlife to include the creation of a permanent pool, improvements in
water quality, improvement of wetland setbacks and upland habitat, revegetation of disturbed
areas, and protection of downstream regional wetlands and fish habitat resources. Since the
project is located within a residential neighborhood, the applicant will control short tenn
noise impacts by adequately muffling equipment and limiting hours of construction.
Furthennore, traffic will be disrupted at little as possible and one lane maintained at all
times.
Due to the complexity and size of the proposed action and the multiple locations, the
Examiner is evaluating and making findings on the entire proposal as a system rather than
separately considering each of the six locations. The culvert and bulkhead work within
streams requires Process I approval pursuant to Sections 22-1308 and 22-1309 FWCc.
Findings on Process I criteria are hereby made as follows:
A.
The regional storm water facility is consistent with the Multi-Family designation of
the 1995 FWCP. The City has reviewed the proposed facility for confonnance with
all land use, circulation, and natural environmental policy elements of the
comprehensive plan. Staff has found and the Examiner agrees that the project is in
confonnance with the goals and policies of the FWCP.
B.
The project is consistent with the RM zoning district of the -FWCC, the
Environmental Policy Code, and all other development codes and regulations
EXHIBIT Pc
PAGE- ~OF L
BELMOR
October 14, 1997
Page - 6
14.
B.
C.
including the decisional criteria of Section 22-678 FWCC.
C.
The proposed development will implement the 1991 Draft Hylebos Creek and Lower
Puget Sound Basin Plan; is consistent with the FWCP; and will protect adjacent and
downstream properties from flooding hazards, will enhance sensitive areas, and will
protect 20th Ave. S. from flooding. Therefore, construction of the project furthers the
public health, safety, and welfare.
Decisional criteria for Process III review are found in Section 22-490( d) FWCC. Findings
on each criteria are hereby made as follows:
A.
As previously found, the regional stonn water facility is consistent with the Multi-
Family designation of the 1995 FWCP.
As previously found, the project is consistent with all applicable provisions of the
FWCC.
As previously found, the project is consistent and furthers the public, safety, and
welfare.
Constructing the stonn drainage detention pond at the Belmor Mobile Home Park will
encroach into stream setbacks and is regulated by Section 22-1306 FWCC. Section 22-
. 1312(a) FWCC authorizes the Hearing Examiner to recommend approval to the Federal Way
City Council if ...no feasible alternative exists to traversing the setback area based on an
analysis of technology and system efficiency; and the specific location and extent into the
setback constitutes the minimum necessary encroachment to meet the requirements of the
public facility or utility.
15.
The project is an essential public facility, and based on the Montgomery Water Group, Inc.
Technical Memorandum 4-1 (Exhibit F), no feasible alternative exists to traversing the
stream setback area. The specific location and extent of encroachment into the stream setback
constitutes the minimum necessary to allow the City to meet the requirements of the public
utility.
16.
The project requires the City to install rock headwall bulkheads along the stream channel at
all sites. Section 22-1308( c)( d) FWCC authorizes the Examiner to recommend approval of
bulkheads if the decisional criteria set forth therein are met. Findings on each criteria are
hereby made as follows:
A.
The rock bulkheads are needed to prevent significant erosion, and vegetation alone
would not sufficiently stabilize the bank. Native species of vegetation are
EXHIBIT fJr
PAGE~Jt._OF - W
BELMOR
October 14, 1997
Page - 7
incorporated into the bulkhead design, but the Water Group technical memo
establishes that due to high flow rates, vegetation alone will not stabilize the banks.
Bulkheads are also necessary to prevent significant erosion around tlie inlets and
outlets of storm drains due to the high velocity flow of flood water.
B.
The bulkheads are designed to minimize the transmittal of water to other properties,
and changes to horizontal or vertical configuration of the land in or around the stream
will be kept to a minimum. The Water Group Technical Memo establishes that the
bulkheads have been designed to contain the flow within the existing stream channel,
the pond, and new culvert areas. Wider channels and larger culverts should minimize
transmittal of water currents to adjacent properties. No changes to the horizontal
configuration of the land in or around the stream is necessary, and changes to the
vertical configuration are limited to those necessary to accomplish the purpose of
flood control.
Section 22-1309(c)(d) and (e) FWCC authorizes the Hearing Examiner to recommend
approval of culverts to the City Council if the criteria set forth in said section are satisfied.
Findings on each criteria are hereby made as follows:
17.
A.
18.
Culverting the stream will destroy no significant habitat areas and the "reasonable
use" criteria does not apply because the storm water facility is not a development
project.
B.
This criteria requires the culvert be designed and installed to allow passage of fish
inhabitating and using the stream and be large enough to accommodate a 100 year
storm event. Said criteria also requires an applicant to demonstrate by submitting
alternative site plans showing the stream in an open condition that no other
reasonable design exists. The Water Group Technical Memo establishes that no fish
inhabit or use the stream at any of the six project locations, and that the Kitts Comer
storm water detention project creates fish blockage. Therefore, no fish inhabitat or
use the stream, and the proposed storm drain size will accommodate the 100 year
storm event. The technical memo assesses alternatives to culverting the drainage
channel and demonstrates that no other reasonable site design is possible because of
topographic, utility, and contaminated sediment constraints.
C.
This criteria requires a bond to ensure maintenance of the system. Since the
maintenance is the responsibility of the City, bonding is not required. The City
Public Works Department will develop a maintenance plan.
Stream rehabilitation is proposed for areas south and east of the East Empire Garden
Apartments at Site VI in accordance with Section 22-1311 FWCC. Proposed improvements
EXHIBIT 1r
PAGE--1_0F ~'t
20.
BELMOR
October 14, 1997
Page - 8
include providing a larger channel to convey flows which reduces the potential for channel
bed and bank erosion. Planting plans will be submitted with the building permit for review.
19.
Proposed improvements at the inlets and outlets of the new trunk storm drain at Sites IV and
V, and the bulkheads and channel widening at Site VI will be partially within the 100 foot
setbacks from regulated wetlands. Section 22-1359(b) FWCC authorizes the Director of
Community Development Services to recommend approval of the intrusion if no feasible
alternative exists and if the specific location and extent of intrusion constitutes the minimwn
necessary to meet the requirements of the public facility or utility. The Water Group
Technical Memo and a letter from Adolfson and Associates, Inc., the City's wetland
contractor (Exhibit L), establish that the intrusions constitute the minimwn necessary to meet
the requirements of the public utility.
Significant concerns about stream improvements at Site VI were raised by Moberg
Engineering, Dean W. Moberg, and Kenneth Lee Moberg. The record was left open for a
response by the City to the Mobergs' concerns and to allow further discussions between the
Mobergs and the City. Following extension discussions, the Examiner was advised by both
the Mobergs and the City that they had reached agreement. The Mobergs subsequently
withdrew their opposition to the project.
IV. CONCLUSIONS
From the foregoing findings the Hearing Examiner makes the following conclusions:
2.
3.
1.
The Hearing Examiner has jurisdiction to consider and decide the issues presented by this
request.
The request to construct the Belmor Regional Stormwater Detention Pond Facility and Storm
Drainage Improvements satisfies the criteria for Process I and Process III approval as set
forth in the FWCc.
The request also satisfies all FWCC criteria related to intrusion into stream setbacks,
bulkheads, culverts, stream rehabilitation, wetland setback encroachment, groundwater
protection, environmentally sensitive areas, geologically hazardous areas, tree removal, and
wildlife protection. Therefore, the proposed storm water drainage improvements should be
approved by the Federal Way City Council subject to the following condition:
A.
Prior to starting construction, the Surface Water Division of the City of Federal Way
shall pay for the services of a qualified professional selected and retained by the
EXHIBIT
PAGE .~
Pr
0 F- 1c1"
BELMOR
October 14, 1997
Page - 9
Department of Community Development Services to review plans, inspect, and issue
written reports to the Director of Community Development Services specific to
monitoring and protection of sensitive areas stating that the project complies with the
requirements of FWCC sections 22-1286(b) Geologically hazardous areas; 22-
1306(a) Stream Setbacks; 22-1308 (c & d) Bulkheads; 22-1309 (c, d & e) Culverts;
22-1311 Rehabilitation; 22-1312(a) Intrusion into Setbacks, and 22-1359(b)
Structures, improvements and land surface modifications within the setback area
from regulated wetlands.
DECISION:
It is hereby recommended to the Federal Way City Council that the Be1mor Regional
Stormwater Detention Pond Facility and Storm Drainage Improvements be approved subject
to the condition contained in the conclusions above.
DATED THIS / Cf ~A Y OF October, 1997.
ST HEN K. CAUSSEAUX, JR.
Hearing Examiner
TRANSMITTED THIS 14th DAY OF October, 1997, to the following:
APPLICANT:
Marwan Salloum
City of Federal Way Public Works Department
33530 1st Way South
Federal Way, Washington 98003
Dean Moberg
5801 89th Ave. SE
Olympia, WA 98513
Norman Moberg
1802 S. 333rd Street
Federal Way, W A 98003
EXHIBIT It
P A G E_~~__O F~~_~
BELMOR
October 14, 1997
Page - 10
Mrs. Robert Ferguson
2004 S. 333rd St.
Federal Way, WA 98003
Kenneth Moberg
20l5 E. 12Pt St.
Tacoma, W A 98445
City of Federal Way
c/o Bob Baker
33530 1st Way S.
Federal Way, WA 98003
EXHIBITÅ
PAGElfL.OF L
RIGHTS TO RECONSIDERATION AND CHALLENGE
THE BELOW STATED RIGHTS TO RECONSIDERATION AND APPEAL AND DESIGNED
TO
PROVIDE
NOTICE
OF
TIME
LIMITS
AND
A GENERAL
OUTLINE
OF
PROCEDURES.
THE
SPECIFIC
REQUIREMENTS
FOR
REQUE'ST
FOR
RECONSIDERATION ARE FOUND IN SECTION 22-488 OF THE FEDERAL WAY CITY
CODE.
THE SPECIFIC REQUIREMENTS FOR CHALLENGES TO THE HEARING
EXAMINER'S
RECOMMENDATION ARE FOUND
IN SECTION 22-489
OF THE
FEDERAL
WAY
CITY
CODE.
CLARIFICATION
OF
THE
RIGHTS
TO
RECONSIDERATION AND CHALLENGE AND THE NAMES AND ADDRESSES OF
PERSONS WHO HAVE A RIGHT TO CHALLENGE MAY BE OBTAINED FROM THE CITY
CLERK OF THE CITY OF FEDERAL WAY.
RECONSIDERATION
Any person who has a right to challenge a recommendation of the
Hearing Examiner under the Federal Way City Code may request the
Hearing
Examiner
to
reconsider
any
aspect
of
his
or
her
recommendation by delivering a written request for reconsideration
to
the
Department
of
Community
Development
within
seven
(7)
calendar days after the date of issuance of the Hearing Examiner's
recommendation.
The person requesting the reconsideration shall
specify in the request what aspect of the recommendation he or she
wishes to have reconsidered and the reason for the request..
The person requesting the reconsideration shall within seven (7)
calendar days following issuance of the recommendation, mail or
personally deliver a copy of the request for reconsideration along
with a notice of the right to file a written response- to the
EXHIBIT Ir
PAGEJLOF --L
request
to those persons who have a right
to challenge under
Federal Way City Code. Proof of such mailing or personal delivery
shall
be
made
by
an
affidavit
attached
to
the
request
for
reconsideration at
the
time of delivering the
request
to the
Department of Community Development. The notice shall state that
such response must be received by the Department of Community
Development within seven (7) calendar days following the filing of
the request with the department.
Any person filing a response to a response to the reconsideration
request must distribute that response by mail or personal delivery
to those persons having a right to challenge under the Federal Way
City Code.
Proof of such distribution by mail or personal delivery
shall be made by affidavit attached to the response delivered to
the Department of Community Development.
Within
ten
(10 )
working
days
after
expiration
of
the
reconsideration period, the Hearing Examiner shall notify the
persons who have a right to challenge under the Federal Way Zoning
Code, whether or not the recommendation will be reconsidered. The
Hearing Examiner may reconsider the recommendation only if he or
she concludes that there is substantial merit in the request.
The
process of reconsideration will be in accordance with Section 22-
488 of the Federal Way City Code.
CHALLENGE
The recommendation of the Hearing Examiner may be challenged by any
person who is to receive a copy of that recommendation.
The
challenge, in the form of a letter of challenge, must be delivered
EXHIBIT A
PAGEß(.~- OF --1L
to the Department of Community Development within fourteen
(14)
calendar
days
after
the
issuance
of
the
Hearing
Examiner's
recommendation or, if a request for reconsideration is filed, then
within fourteen (14) calendar days of either the recommendation of
..
the Hearing Examiner denying the request for reconsideration or the
reconsidered recommendation.
The letter of challenge must contain
a clear reference to the matter being challenged and a statement of
the
specific
factual
findings
and
conclusions
of
the
Hearing
Examiner disputed by the' person filing the challenge.
The person
filing the challenge shall include, with the letter of challenge,
the
fee
established by the
City.
The
challenge will
not
be
accepted unless it is accompanied by the required fee.
The
person
challenging
the
recommendation
shall
within
said
fourteen (14) calendar day period mail or personally deliver a copy
of the letter of challenge along with a notice of the right to file
a written response to the challenge to those persons who have the
right to file a challenge under Section 22-489 of the Federal WaY
City Code.
The
notice
shall
state
that
such response must be
received by the Department of Community Development within five (5)
working days following the filing of the written challenge with the
department.
Any person filing a response to the reconsideration request must
distribute that response by mail or personal delivery to those
persons having a right to challenge under Section 22-489 of the
Federal
Way City Code.
Proof
of
such distribution by mail
or
EXHIBIT If
PAGEð- OF~-.Fr"
personal
delivery
shall
be
made
by affidavit
attached
to
the
response delivered to the Department of Community Development.
The
recommendation
of
the
Hearing
Examiner may be
challenged
whether or not
there was
a
request
to reconsider the
Hearing
Examiner's recommendation.
Any challenge of the Hearing Examiner's
recommendation will be heard by the Federal Way City Council.
EXHIBIT A
P.A G E _fL 0 F -1Ï-
RESOLUTION NO.
@NMPif
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF
FEDERAL WAY, WASHINGTON, APPROVING WITH CONDITIONS
THE APPLICATION FOR THE BELMOR REGIONAL STORMWATER
DETENTION POND FACILITY AND STORM DRAINAGE
IMPROVEMENTS, FEDERAL WAY FILE NO. UPR96-0045.
WHEREAS, the applicant, the City of Federal Way, applied
to the City of Federal Way for approval of a project to construct
a regional stormwater detention pond facility and associated storm
drainage improvements at six sites in the vicinity of South 324th
Street
and
S.
336th
Street,
adjacent
to
20th
Avenue
S.
(~ApplicationH); and
WHEREAS,
pursuant to
Federal Way City Code
(~FWCCH )
Section
22-678
et
seq. ,
the Application requires
Process
III
review; and
WHEREAS, a determination of non-significance (~DNSH) was
issued for this proposal on January 29, 1997, pursuant to the FWCC
and the State Environmental Policy Act (~SEPAH), and the DNS was
not appealed; and
WHEREAS, FWCC section 22-490(d) contains certain criteria
for the consideration of a Process III application; and
WHEREAS,
all
public
notice
having
duly
been
given
pursuant to FWCC Section 22-480; and
WHEREAS, the Federal Way Land Use Hearing Examiner held
a public hearing on March 11, 1997, concerning the application; and
Res. #
, Page 1
EXHIBIT
PAGE I
~
OF -5-
WHEREAS, at the conclusion of the hearing and subsequent
discussion between the Applicant and adj acent property owners,
Federal
Way
Land, Use
Hearing
Examiner
issued
its
Findings,
Conclusions, Conditions, and Recommendations on October 14, 1997;
and
WHEREAS, the City Council of the City of Federal Way is-
the governmental body now having jurisdiction and authority to pass
upon the approval, denial or modification of the conditions of said
Application pursuant to FWCC Section 22-490; and
WHEREAS,
this
matter
having been
considered by
the
Federal Way City Council Land Use/Transportation Committee at its
meeting on November
3,
1997,
for the purpose
of
issuing its
recommendation for conditional approval of the Application to the
full City Council; and
WHEREAS, the City Council having considered the written
record and the Findings, Conclusions, and Recommendations of the
Hearing Examiner, pursuant to Chapter 22 of the FWCC and all other
applicable City codes; NOW THEREFORE,
THE
CITY COUNCIL OF THE CITY OF FEDERAL WAY HEREBY
RESOLVES AS FOLLOWS:
Section 1.
Findings
of
Facts,
Conditions
and
Conclusions.
The
Findings,
Conclusions,
Conditions
and
Recommendations of the Federal Way Land Use Hearing Examiner issued
on October 14, 1997, following a hearing held on March 11, 1997,
, Page 2
the City of Federal Way's
EXHIBIT ~
PAG E- z., OF ~
which issued a recommendation to approve
Res. #
application
to
construct
a
regional
stormwater detention pond
facility and associated improvements subject to certain conditions,
are hereby adopted as the Findings, Conclusions and Conditions of
the City Council.
Section 2.
Application approval.
Based upon the
Findings,
Conclusions,
Conditions
and
Recommendations
of
the- -
Federal Way Land Use Hearing Examiner, as adopted by reference by
the City Council set forth hereinabove, the application of the City
of Federal Way to construct a regional stormwater detention pond
facility and associated improvements, Federal Way File No. UPR 96-
0045, is hereby approved subject to the conditions contained in the
Recommendation of the Federal Way Land Use Hearing Examiner report
for this matter dated October 14, 1997, attached hereto as Exhibit
A and incorporated by reference.
Section 3.
Conditions
of
Approval
Integral.
The
conditions of approval of the facility are all integral to each
other with resp~ct to the City Council finding that public use and
interest
will
be
served by
the
construction
of
the
regional
stormwater detention pond facility and associated improvements.
Should
any
court
having
jurisdiction over
the
subj ect matter
declare any of the conditions invalid,
then,
in said event,
the
approval granted in this resolution shall be deemed void, and the
Application shall be remanded to the Hearing Examiner for the City
of Federal Way to review the impacts of the invalidation of any
Res. #
, Page 3
additional proceedings as
EXHIBIT ~
PAGE 3 OFt)
condition or conditions and conduct such
are necessary to assure that the Application makes appropriate
provisions for the public health, safety and general welfare and
other
factors
as
required
by
applicable
County
and/or
City
ordinances, rules and regulations and forward such recommendation
to the City Council for further action.
Section 4.
Severability.
I f any section,
sentence, - -
clause or phrase of this resolution should be held to be invalid or
unconstitutional
by
a
court
of
competent
jurisdiction,
such
invalidity or unconstitutionality shall not affect the validity or
constitutionality of any other section, sentence, clause or phrase
of this resolution.
Section 5.
Ratification.
Any act consistent with the
authority and prior to the effective date of the resolution is
hereby ratified and affirmed.
Section 6.
Effective Date.
This resolution shall be
effective immediately upon passage by the Federal Way City Council.
RESOLVED BY THE CITY COUNCIL OF THE CITY OF FEDERAL WAY,
day of
, 19
WASHINGTON, this
CITY OF FEDERAL WAY
MAYOR, MARLON S. PRIEST
ATTEST:
, Page 4
EXHIBIT "8
PAGE~OF ~
CITY CLERK, N. CHRISTINE GREEN, CMC
Res. #
APPROVED AS TO FORM:
CITY ATTORNEY, LONDI K. LINDELL
FILED WITH THE CITY CLERK:
PASSED BY THE CITY COUNCIL:
RESOLUTION NO.
I:\spr\pubwork\belpond\resolutn.txt
K: \RESO\FORM
Rev. 12/23/96
, Page 5
EXHIBIT ~
PAGE~~OF -C
Res. #
CITY OF FEDERAL WAY
DEPARTMENT OF COMMUNiTY DEVELOPMENT SERVICES
REPORT TO THE
FEDERAL WAY HEARING EXAMINER
Public Hearing - March 11, 1997,2:00 p.m.
Delmor Regional Stormwater Detention Pond Facility
and Storm Drainage Improvements
Federal Way File No:
UPR96-0045
Related File Numbers:
SEP96-0022, UPR96-0045, ADM96-0054
Applicant:
Marwan Salloum, Surface Water Mgt Project Engineer
City of Federal Way Public Works Department
Phone: 661-4095
Owner:
City of Federal Way (adjacent site private ownership)
Requests:
City Council review of the:
-Public utilities within RM zoning districts
-Intrusions into stream setbacks
-Stream bulkheads
-Stream culverts
-Stream rehabilitation
- Wetland setback intrusion by essential public facilities
Staff representative:
Deb Barker, Associate Planner, (206) 661-4103
Staff Recommendation:
Conditional Approval
Exhibits
Exhibit A
Exhibit B
Exhibit C
Exhibit D
Vicinity Map
Reduced Scale Site Plan
Full Scale Site Plan of Project Sites 1 Through 6
Determination of Nonsignificance, January 29, 1997
1
EXHIBIT ~
PAGEloF]ll
Exhibit E
Exhibit F
Exhibit G
Exhibit H
Exhibit I
Exhibit J
Exhibit K
Exhibit L
I.
Wetland Delineation and Flagging for the Helmor Mobile Home Park Regional
Storage Facility, Prepared by Sheldon and Associates, Apri118, 1996, and
Memorandum of October 11, 1996
Technical Memorandum 4-1, Prepared by Montgomery Water Group, Inc.,
Revised October 1, 1996.
Geotechncial Data Report, Prepared by CH2M Hill, July 11, 1996
Phase I Environmental Assessment, by Landau Associates, December 15, 1995
SEPA Checklist, July 25, 1996, with Amendment of September 30, 1996
Geotechnical Recommendations Prepared by CH2M Hill, February 28, 1997
Site Plan Approval, March 5, 1997
Letter from Adolfson Associates, Inc. dated February 18, 1997
GENERAL INFORMATION
A.
Project Description/Summary
The proposal is to construct a regional stormwater detention pond facility,
replace three undersized roadway culvert crossings within the right-of-way,
extend a culverted storm drain trunk line and construct a bulkhead (flood wall)
for stream stabilization. The proposal is intended to rehabilitate a section of
Hylebos Creek and alleviate flooding of 20th Avenue South and adjacent private
property between SR 99 and 23rd Avenue South (Exhibit A). The proposal will
lessen the impact of increased peak flows delivered by future Phase II
improvements to the upstream (Sea- Tac Mall) drainage system.
Six separate project sites are included in the scope of work. The sites are located
within Residential Multi-Family (RM) zoning districts. Pursuant to Federal Way
City Code (FWCC) section 22-678, Public Utilities are permitted uses in the
RM zoning district subject to Use Process III approval. The project sites and the
associates improvements are as follows (Exhibit B):
Site....l is located within the northwestern portion of the Belmor Mobile Home
Park at 2101 South 324th Street and includes construction of a 7.5 acre-foot
above ground regional detention pond facility, installation of 385 lineal feet of
84 inch storm drain trunk line, replacement of approximately 200 feet of
existing 48 inch pipe at the outlet of the stream channel and relocation of a
existing asphalt golf cart path. Construction is proposed within the stream
channel and the associated 100 foot wide setback of a tributary of the Hylebos
Creek, a major stream as defined in the Federal Way City Code (FWCC).
These improvements require process I and process III approvals.
2
EXH'B\" ~
PAGE~OF JJU.
Sik2 is located at 32830 and 32856 20th Avenue South and includes
replacement of one 12 inch and two 18 inch culverts with a 48 inch culvert
under a private driveway spanning Hylebos Creek. These improvements require
process I approval.
Si.t.e....3. is located at 32856 and 33018 South 330th Street and includes activation
of an existing 48 inch culvert which replaces one 18 inch and one 24 inch
culverts under South 330th Street spanning Hylebos Creek. The 18 inch and the
24 inch culverts will be abandoned. These improvements require process I
approval.
Site.A is located along 20th Avenue South between South 331st and South 332nd
Streets and includes culverting of a stream with installation of 460 lineal feet of
48 inch diameter pipe on the west side of 20th Avenue South, and four catch
basins for extension of a storm drain trunk line. Two lateral lines will connect
the proposed line to a existing 30 inch line located in the east shoulder of 20th
A venue South. Regulated wetlands are located at each end of the proposed
culvert. Work is proposed within the 100 foot wetland setback area; however,
no improvements are proposed within the wetlands. These improvements
require process I and process III approvals.
Si..tú is located at 1815 and 1816 South 333rd Street and includes replacement
of 18 inch and 24 inch culverts with two 42 inch culvert under South 333rd
Street spanning Hylebos Creek. Regulated wetlands are located at each end of
the existing culverts. Work, consisting of approximately three lineal feet of rip-
rap related to the culvert ends to minimize channel erosion, is proposed within
the 100 foot wetland setback area. No improvements are proposed within the
wetland. These improvements require Process I approval.
Sik..6 is located at the southeastern portion of 33311 - 18th Lane South (East
Empire Garden Apartments) and includes construction of a four foot tall
concrete bulkhead retaining wall (flood containment wall) on the west side of
the stream and the widening of the Hylebos Creek for stream rehabilitation. The
northerly portion of site 6 is within the 100 foot setback area of a wetland.
Work is not proposed within the wetland. Work at this site is intended to
provide flood protection to the apartments. These improvements require process
I approval.
B.
Location
Six improvement sites between South 324th Street and South 336th Street,
adjacent to 20th Avenue South, within the Hylebos Creek, Federal Way, WA,
at 2101 South 324th Street (Belmor Mobile Home Park), 32820 and 32856 -
EXHIBIT C
P AGE 2- 0 Fi81..
3
20th Avenue South, 32856 and 33018 - South 330th Street, the 33100 block of
20th Avenue South, 1815 and 1816 South 333rd Street and the East Empire
Garden Apartments at 33311 18th Lane South.
c.
Scope of Project Elements
The project consists of six sites with three separate elements with distinct siting,
function, and environmental considerations: 1. A regional stormwater detention
pond facility; 2. Culvert and bulkhead work; and 3. Stream rehabilitation. The
specific proposed drainage system improvement elements are described below.
Site No.1 (Belmor Stream Channel), Location: Within Belmor Mobile Home
Park and Country Club Development (Refer to Exhibit C-l)
1.
Construct a 7.5 acre-foot above ground regional detention pond facility
(excavated permanent pool pond) along the west stream setback area and
partially within the fairway of the 9th hole of the Belmor golf course.
Lower the west channel bank to form an overflow section (dike between
stream channel and detention pond) along the alignment of the existing
north-south sanitary sewer alignment.
2.
Install approximately 385 feet of new 84 inch-diameter trunk storm drain
between the south limit of the South 324th Street right-of-way and the
north limit of the regional detention facility (with outlet to the existing
stream channel). This will function as the downstream segment of a phase
II upstream (West Hylebos) WHIO trunk drainage system replacement
through the Sea- Tac Mall area.
3.
Retain the existing stream channel in an undisturbed condition beyond the
limits of the pond excavation and trunk storm drain installation. Provide
two sets of 24 inch culverts to interconnect the stream channel and
detention pond.
4.
Fill approximately 230 feet of the existing stream channel for culvert
installation to meet drainage system grade constraints and to cap stream
bed sediments containing elevated levels of urban contaminants.
5.
Provide temporary connection of the new trunk storm drain to the existing
48 inch-diameter storm drain at the north end of the existing stream
channel.
6.
Reinstall (vertical alignment) approximately 200 feet of the existing 48
inch-diameter stonn drain at the outlet of the Belmor stream channel reach.
4
EXHIBJT-C
PAGE.~OF j81-
7.
Install a new outlet hydraulic control structure with connection to both the
existing stream channel and the regional detention pond facility.
Site No.2 (Private Drive Crossing), Location: 32830 - 20th Avenue South,
(refer to Exhibit C-2)
1.
Install a new 48 inch-diameter culvert under a private driveway across the
stream channel as a replacement for one 12 inch and two 18 inch-diameter
existing culverts.
2.
Place fill to elevate the bridge roadway section to provide required culvert
cover.
3.
Install riprap at each end of culvert within the stream for erosion control.
Site No.3 (South 330th Crossing), Location: 32856 and 33018 South 330th
Street, (Refer to Exhibit C-3)
1.
Install extensions to each end of the existing 48 inch-diameter culvert
within the embankment which are currently inactive. After extension, the
new 48 inch culvert length will equal that of the existing active parallel 18
and 24 inch culverts.
2.
Install rip rap at each end of the culvert to control erosion.
3.
Plug and abandon existing 18 and 24 inch-diameter culverts.
Site No.4 (20th Avenue South Crossing), Location: Along 20th Avenue South
Between South 331st and South 332nd Streets (Refer to Exhibit C-4)
1.
Install approximately 460 feet of new 48 inch-diameter storm drain culvert
across and along the west shoulder of 20th Avenue South to parallel the
existing 30 inch-diameter storm drain culvert along the east side of the
roadway. Install four new catch basins along its alignment on the west side
of 20th Avenue South.
2.
Install a new covered inlet structure (including a vault and manhole)
approximately 20 feet upstream of the existing drop inlet, connect to the
existing and new storm drains, perform localized grading, install riprap and
cover the existing inlet structure.
3.
Connect existing 18 and 24 inch storm drain crossings of 20th Avenue
South at South 332nd Street to new storm drain outlet (at new manhole).
5
EXHIBIT C,
PAGE 5 of--'-8-1
D.
4.
Install rip rap at the outlet within the existing stream channel.
Site No.5 (South 333rd Crossing), Location: 1815 South 333rd Street, (Refer
to Exhibit C-5)
1.
Install two parallel 42 inch-diameter culverts under South 333rd Street as a
replacement for the two existing 18 and 24 inch-diameter culverts. Move
the outlet location approximately 20 feet west of the existing culverts
outlet with graded connection to the stream channel (results in longer
culvert but does not result in stream channel fill).
2.
Install rip rap at each end of the culverts for erosion control.
Site No.6 (Empire Garden Apartments Stream Channel), Location: 33311 -
18th Lane South, (Refer to Exhibit C-6)
1.
Construct an enlarged channel around the existing southeast apartment
building by widening it within the setback area.
2.
Construct a concrete slope retainage and flood wall up to four feet in
height along the relocated west channel bank, maintain an earth stream
bank on the east side.
3.
Over-excavate stream channel bed and place rip-rap base overlain by
stream gravel.
4.
Install perforated sub drain pipe behind the wall with gated outlets to the
stream channel. .
Land Use/Zoning /Comprehensive Plan Designation
The current land uses adjacent to the project site include a mobile home park
and golf course country club, residential multifamily and single family units,
and vacant land. The zoning is Residential Multi-family (RM 3600 and RM
2400). The 1995 Comprehensive Plan designation is Multi-family.
ll.
CONSULTED DEPARTMENTS AND AGENCIES
As part of the Environmental Review by Federal Way staff, site visits were conducted
and the proposal was circulated to the Federal Way Community Development Review
Committee (CDRC) consisting of the following agencies and city departments: -
6
EXHIBIT C,
PAGEJ;LOF .J.BJ
*
*
Federal Way Public Works Department.
Federal Way Building Division.
King County Fire District #39.
Lakehaven Utility District.
Wetland Consultant, Adolfson Associates (Only reviewed wetland impacts.)
*
*
*
Responses from the applicant and Adolfson Associates, Inc. are incorporated into this
staff report.
ID.
ENVIRONMENTAL ANALYSIS
A.
Environmental Assessment
Pursuant to the State Environmental Policy Act (SEPA), RCW 43.21C, the
responsible official of the City of Federal Way issued a Determination of Non-
significance (DNS) for the regional stormwater detention pond facility on
January 29, 1997 (Exhibit D). The determination was based on review of
information in the project me, environmental checklist, and site visits resulting
in the conclusion that the proposal would not have significant adverse impacts
on the environment. Affected agencies and the public were offered the
opportunity to comment on or appeal the determination for 29 days.
The appeal period ended on February 28, 1997. No comments or appeals were
filed with the city.
B.
Physical Features
1.
Surface Water/Groundwater
Surface Water Analysis:
A "Wetland Delineation and Flagging for the Belmor Mobile Home Park
Regional Storage Facility," prepared by Sheldon & Associates, Inc.,
April 18, 1996 ("Wetland Report"), was prepared for the project area
(Exhibit E).
"Technical Memorandum 4-1, prepared by Montgomery Water Group
revision of October 1, 1996" ("Water Group Technical Memo"), was
prepared to address the project scope and provide responses to applicable
city code criteria (Exhibit F)
7
EXHIBIT C.
PAGE '7 OF ~C
A "Geotechnicial Data Report, prepared by CH2M Hill, July 11, 1996"
(uGeotechnical Data Report"), was prepared to describe the site
subsurface conditions (Exhibit G).
A "Phase I Environmental Assessment for the Sea- Tac Regional Storage
Facility, by Landau Associates, December 15, 1995" ("Environmental
Assessment") was prepared (Exhibit H).
The applicant provided a "SEPA Checklist, July 25, 1996" ("Checklist")
prepared with technical assistance from CH2M Hill (Exhibit I).
The Wetland Report confirms that the project courses through a tributary
of the West Hylebos Creek. (West Hylebos Creek tributary oo14C
according to the Hylebos Creek and Lower Puget Sound Basin Plan).
The Hylebos Creek is a major stream based on the city stream definition.
The Checklist states that five wetlands within the project site currently
provide storm water function, and that based on the current FWCC
wetland definition, no wetland would be directly impacted, permanently
or temporarily, or displaced by the proposed development. As proposed,
approximately 2.02 acres of wetland setback and stream areas would be
affected by construction of facility and associated improvements.
Mitigation for indirect and direct potential impacts to wetlands setback
areas, the stream, and upland setback areas vary depending upon the
kind and location of impact. The Water Group Technical Memo states
that in all cases, project design impacts to sensitive areas were avoided
where possible with predesign layout of project improvements. Where
impacts were unavoidable, designs minimized impacts within the
limitations of the project.
According to the Checklist, the detention pond facility is designed to
divert stream flows exceeding 20 cubic feet per second (cfs) for 25-year
storm events. Outflow of the detention facility will be controlled to
approximately 90 cfs for a 25-year storm event.
Pages 7 and 8 of the Water Group Technical Memo state that replacing
the portion of Tributary 00 14C stream channel with an 84 inch culvert,
and filling of the channel, along with associated stream habitat
replacement, conforms to the criteria of FWCC Section 22-1309 (c )(2),
Culverts, because the stream corridor has already been degraded and the
potential soils contamination in the channel has been identified.
8
EXHIBIT C.
PAGE10F -1ß1
An alternative plan for a non-fill option was submitted by the applicant.
Page 8 of the Water Group Technical Memo identifies several
constraints to an open channel alternative, including the proximity of
existing uses and utilities along with hydraulics constraints, and
concludes that the constraints demonstrate that no reasonable alternative
exists.
In the Water Group Technical Memo, the applicant states that a short-
term increase in sediment load delivered to the stream system could
result from construction activities. In page 15 of the Checklist, the
applicant proposes that implementation of Best Management Practices
(BMP) source control measures designed into the project would control
runoff and associated sediment delivered to the downstream drainage
system, in accordance with agency permit conditions.
Groundwater Analysis:
The Federal Way Comprehensive Plan (FWCP) contains policies that
encourage protection and enhancement of the city's aquifers. Aquifer
recharge areas, as defined by FWCC Section 18-28, are considered
environmentally sensitive areas pursuant to FWCC Section 18-141
(a)(I). For areas meeting this defmition, the city is required to preclude
development which is deemed incompatible.
The project area is designated as having a "low" susceptibility to
groundwater contamination (infùtration rating potential) according to the
FWCP map IX -1. In addition, the project site is outside of the Redondo-
Milton Channel Aquifer and associated recharge area according to the
city's environmentally sensitive areas map.
The Geotechncial Data report reported that the regional groundwater
system is located at least 70 feet below the ground surface and was not
encountered in any of the test boring drilled to a maximum depth of
approximately 68 feet. Excavation for the proposal will involve the
upper 20 to 30 feet of soil. It is expected that a "perched" groundwater
systems will be encountered at elevations of five to eight feet below
ground surface. These perched systems are isolated, dependent on
rainwater for recharging, and not hydraulically linked to the regional
aquifer system. Based on these findings, the applicant proposed that a
low permeability soil liner or geosynthetic clay line be installed in the
detention pond to control ex filtration to groundwater and provide for a
permanent pool in the detention facility.
9
EXHIBIT c..
PAG E Cf OF.J.&:z
:'.~ ....
2.
Surface Geology/Topography: The Checklist states that the site generally
consists of flat to rolling terrain with some steeper slope areas near the
southern terminus of the project. The Belmor Mobile Home Park is
relatively flat. Moderate slopes occur to the east and west of the project
sites.
The Geotechnical Data Report was prepared to describe the site
subsurface soils of the project area as a basis for improvement design
(Exhibit G). Geotechnicial recommendations (Exhibit 1) were prepared
to respond to the design and construction of Belmor Park improvements.
Page 6 of the Water Group Technical Memo states that the sides of the
existing stream channel through Belmor Park are steeper than 40 percent
and meet the defmition of geologically hazardous areas.
The Environmental Assessment was prepared to assess the potential for
hazardous substances or materials to exist on the site. Page 9 of the
Environmental Assessment states that elevated levels of urban runoff
type contaminants such as petroleum, hydrocarbons, and polyaromic
hydrocarbons are present in the existing drainage ditch at levels likely to
require special handling and treatment and disposal.
The applicant proposes filling of 230 feet of existing stream channel
from the existing storm drain outlet. A 7.5 acre excavated permanent
pool pond will be created west of the existing stream.
Existing stream corridors and associated stream setbacks would be
impacted by placement of drainage systems. According to the Water
Group Technical memo, no significant adverse geotechnical impacts
related to construction of improvements within environmentally sensitive
areas are expected. Steep slopes would be eliminated with fIll placement
and subsequently revegetated.
The Environmental Assessment states that seismic effects to the soils at
the sites are expected to be negligible. Subsurface materials are believed
to be too dense for liquefaction to be of concern or for any significant
settlement to occur. The Water Group Technical Memo states that slope
stability, landslide hazard, and sloughing, etc, will be considered in the
final design to confirm that the proposed improvements will minimize
risks in geologically hazardous areas.
Based on the Environmental Assessment, the applicant does not
anticipate that there are geologically hEXHfBslTl occe.
10 PAGEBLOF jSJ--
Because development is proposed on and within 25 feet of geologically
hazardous areas, geotechnical recommendations were prepared in
accordance with FWCC section 22-1286 (b & c) (Exhibit 1) and
reviewed by city staff for conformance with criteria. The
recommendations shall be implemented in the grading, clearing and
construction permit process.
3.
Vegetation:
The Wetland Report identifies the existing vegetative conditions for each
of the six project sites. Conditions range from formal residential
landscaping to non-developed areas vegetative with native species.
The Water Group Technical Memo contains a significant tree inventory
and field maps. The inventory identifies 14 significant trees located
within the project area. Three of these trees are to be removed to
facilitate installation of the drainage facilities. As more than 25 percent
of the significant trees within the project area are retained, replacement
trees are not required. A tree protection management plan will be
required with the landscape plan (required to be submitted with the
construction permit application) in conformance with FWCC section 22-
1568(c)(6) Significant trees.
Revegetation plans for all disturbed areas shall be submitted with the
construction permit application to verify conformance with FWCC
section 22-1359(e), Improvements within a wetland setback area, and
FWCC section 22-1311, Stream Rehabilitation. All clearing areas will
be clearly shown on the engineering plans and be approved by the city
prior to commencement of any clearing. In addition, all required
landscaping must be installed before the [mal inspection occurs.
4.
Wildlife
The Checklist identified animals observed on or near the site based on a
1991 study by Shapiro and Associates. The Wetland Report was
prepared to verify and classify wetland areas within the project area. The
wetlands and upland sites provide habitat for a number of wildlife
species, including mallards, herons, songbirds, amphibians, beaver, fish,
and bats.
Neither the field investigations of Shapiro and Associates, nor the
records of the Washington Natural Heritage Program and the U.S. Fish
and Wildlife Service indicate the presence of sensitive, threatened, and
11
EXHIBIT C
PAGEKOF 181
c.
endangered animal species. No evidence exists of the presence of
juvenile salmonids (amphibians or amphibian eggs) throughout the
project area streams and wetlands.
The project includes several measures to preserve and enhance wildlife
habitat including creation of a permanent pool, improvements in existing
water quality resulting from erosion and sedimentation controls,
permanent protection of existing stream, wetland setback and upland
habitats, revegetation of disturbed areas, and protection of downstream
regional wetlands and fish habitat resources. Temporary construction-
related impacts to wetlands and adjacent uplands would be minimized by
restricting the construction period to summer and early fall months,
application of erosion and sedimentation control measures, and
revegetation of disturbed areas.
Significant Social Features
1.
Neighborhood Characteristics
The project is proposed within a residential neighborhood in the eastern
portion of the city. The detention pond will be located within a mobile
home park and golf course. Other improvements are within the public
rights of ways and adjacent to existing single family and multifamily
dwelling units.
The Checklist states although the completed project will not generate
noise, there are short term noise impacts associated with site
construction. Measures to control short term noise impacts include
adequately muffled power driven equipment and use of the heavy
equipment only during hours as required by city code. The hours of
construction activity shall be in compliance with FWCC Section 22-1006
Developmem Activities and Heavy Equipment Operations, which states
that no development activity shall may occur between 8:00 p.m. and
7:00 a.m., Monday through Saturday, Sundays, or holidays which are
observed by the city.
2.
Street System
The installation of replacement culverts beneath roadways would be
accomplished using open cut operations. For the South 330th Street,
South 333rd Street, and 20th Avenue South crossing, open cut would be
required because of potential utility conflicts. Any disturbance to
pavement would be repaired. Mitigation measures included in the project
12
EXHIBIT <:
PAGE~OF :191
design are:
.
Use of cut-and-cover trenching to maintain roadway use during
construction
.
Maintain at least one lane of South 330th Street, South 333rd
Street, and 20th Avenue South to vehicular traffic at all times
.
Use appropriate traffic control to direct traffic during
construction
.
Post temporary signage in advance of proposed road closure
periods (if any) or for alternative (detour) routes
All roadway work within the public right-of-way would be to Washington State
. Department of Transportation and City of Federal Way standards. Surfacing of
the maintenance access roads outside of the public right-of-way is expected to
be asphalt.
3.
Surface Water Facilities
According to the West Hylebos (WH) 08, WHlO and WHll Regional
Drainage Analysis and Detention Predesign Report of June 1994, the
proposed development is consistent with the 1991 ExecUtive Proposed
Basin Plan Hylebos Creek and Lower Puget Sound Basin. The proposed
development would provide enhanced flood control, and control of
existing sources of waste discharge (Le., pollutant washoff, spills) to the
tributary drainage system. The proposed development would not result in
any new sources of waste discharge into surface or ground waters.
IV.
ANALYSIS OF DECISIONAL CRITERIA
Due to the complexity and size of the proposed action, and the wide range of the
decisional criteria to be assessed, this section provides analyses of the conformance of
the proposed action as a system, rather than assessing conformance with decisional
criteria for separate sub-elements of the proposed action.
A.
Site Plan Review
The project requires site plan review because pursuant to FWCC Section 22-
366, if the proposal requires approval through processes I, II, or III, the site
plan review decision prepared under this article will be put in writing and form
13
EXHIBIT C
PAGEAOF --1B1
B.
the basis of, or be an exhibit to, the staff report to the Hearing Examiner. A site
plan review approval letter and findings are attached (Exhibit K).
Process I Review
Culvert and bulkhead work within streams requires Process I approval pursuant
to FWCC Section 22-1308 Bulkheads and FWCC section 22-1309 Culverts.
Pursuant to FWCC Section 22-394 (b), the Director of Community
Development Services (and the Hearing Examiner pursuant to Process III
review) may recommend approval of the proposed action only if the following
decisional criteria are met:
1.
It is consistent with the comprehensive plan.
Response: The Belmor Park Regional Stormwater facility project site
area is designated as Multi-family in the Federal Way 1995
Comprehensive Plan. The proposed development has been reviewed for
conformance with all land use, circulation, and natural environmental
policy elements of the comprehensive plan. If approved as proposed and
as recommended by staff, the project would be in conformance with the
comprehensive plan.
2.
It is consistent with all applicable provisions of the FWCC.
Response: The zoning for the proposed development site area is Multi-
family. The project is required to comply with provisions of the FWCC,
Environmental Policy Code, and all other development codes and
regulations including decisional criteria of sections 22-678, Public
Utility. The proposed development is classified as a public utility and is
an allowed use subject to Site Plan Review and Process III within the
RM zone. The applicant's consultant has designed the proposal in
relation to these development codes and regulations. As proposed and
recommended by city staff, the proposed development would comply
with all applicable codes and regulations.
3.
It is consistent with the public health, safety, and welfare.
Response: The proposed development will implement the 1991 Draft
Hylebos Creek and Lower Puget Sound Basin Plan, and is consistent
with the City of Federal Way Comprehensive Plan, City Code, and other
applicable development codes and regulations. Approval of the proposed
project would protect adjacent and downstream properties from flooding
hazards, protect and enhance sensitive areas, prevent traffic disruptions
14
EXH 18 IT C-
PAGEB-OF jBj
due to flooding across 20th Avenue South and South 336th Street, and
permit development of adjacent properties consistent with the land use
classifications of the city's comprehensive plan. Development of the site
and adjacent properties in accordance with applicable development codes
and regulations would ensure that public health, safety, and welfare is
protected.
c.
Process ill Review
Public utilities within RM zoning districts require Process III approval per
FWCC Section 22-678 Public Utilities.
Pursuant to FWCC Section 22-490 (d), the City Council may approve the
proposed action only if the following decisional criteria are met:
1.
It is consistent with the comprehensive plan.
Response: The Belmor Park Regional Stormwater Pond Facility project
site is designated as Multi-family in the Federal Way 1995
Comprehensive Plan. The proposed development has been reviewed for
conformance with all land use, circulation, and natural environmental
policy elements of the comprehensive plan. If approved as proposed and
as recommended by staff, the project would be in conformance with the
comprehensive plan.
2.
It is consistent with all applicable provisions of the FWCC.
Response: The current zoning for the proposed development site is
Multi-family. The project is required to comply with provisions of the
FWCC, Environmental Policy Code, and all other development codes
and regulations including decisional criteria of FWCC section 22-678.
The proposed development is classified as a public utility and is an
allowed use subject to Site Plan Review and Process III within the RM
zone. The applicant's consultant has designed the proposal in relation to
these development codes and regulations. As proposed and recommended
by city staff, the proposed development would comply with all
applicable codes and regulations.
3.
It is consistent with the public health, safety, and welfare.
Response: The proposed development will implement the 1991 Draft
Hylebos Creek and Lower Puget Sound Basin Plan, and is consistent and
the City of Federal Way Comprehensive Plan, City Code, and oilier
15
EXHIBIT C
PAGE~OF -.1B1.
D.
E.
applicable development codes and regulations. Approval of the proposed
project would protect adjacent and downstream properties from flooding
hazards, protect and enhance sensitive areas, prevent traffic disruptions
due to flooding across 20th Avenue South and South 336th Street, and
permit development of adjacent properties consistent with the land use
classifications of the city's comprehensive plan. Development of the site
and adjacent properties in accordance with applicable development codes
and regulations would ensure that public health, safety, and welfare is
protected.
Intrusion into Stream Setbacks
Grading and clearing in conjunction with the installation of the storm drainage
detention pond facility at Belmor Mobile Home Park (site 1) is proposed to
encroach into stream setbacks as regulated by FWCC Section 22-1306.
Pursuant to FWCC Section 22-1312 (a), Intrusion into Setbacks, the Hearing
Examiner may recommend approval of the proposed action only if no feasible
alternative exists to traversing the setback area based on an analysis of
technology and system efficiency; and the specific location and extent into the
setback constitutes the minimum necessary encroachment to meet the
requirements of the public facility or utility.
Response: The proposed project is an essential public utility, as defmed by
FWCC Section 22-1 and as allowed by FWCC section 22-1312 (a), Intrusion
into Setbacks. Based on the Water Group Technical Memo, no feasible
alternative exists to traversing the stream setback area, and the specific location
and extent of encroachment into the setback constitutes the minimum necessary
encroachment to meet the requirements of the public utility.
Bulkheads
The Water Group Technical Memo states that bulkheads are proposed in the
form of rock head walls and pads for inlet and outlet storm drains located in and
along the stream channel at sites 1, 2, 3, 4, 5, and 6.
Pursuant to FWCC Section 22-1308(c) and (d), Bulkheads, the Hearing
Examiner may recommend approval of the proposed action only if the following
decisional criteria are met:
1.
The bulkhead is needed to prevent significant erosion and the use of
vegetation would not sufficiently stabilize the bank to prevent erosion.
16
EXHIBIT C,
PAGEJlLOF jS,J
Response: Revegetation of the bulkheads with native species has been
incorporated into the proposed development design, but vegetation
plantings alone would not sufficiently stabilize the bank to prevent
erosion due to the high flow rates, according to the Water Group
Technical Memo. The memo states that bulkheads would prevent
significant erosion around the inlet and outlet storm drains resulting from
the high velocity flow of floodwater entering the culverts.
2.
The bulkhead, ifpermitted, would be designed to minimize the
transmittal of water current to other properties and changes to horizontal
or vertical configuration of the land in or around the stream would be
kept to a minimum.
Response: According to the Water Group Technical Memo, the
bulkheads have been designed to contain the flow within the existing
stream channel, excavated detention pond, and new culvert areas. Flow
velocities at the upstream and downstream face of the culverts will be
reduced from existing conditions due to the larger cross sectional areas
provided by the replacement culverts. This should the minimize the
transmittal of water currents to adjacent properties. There would be no
horizontal configuration of the land around the stream. Changes to the
vertical configuration of the land in or around the stream are necessary
to accomplish the purpose of flood control, but have been minimized.
F.
Culverts
The Water Group Technical Memo states that replacement culverts will be
installed at sites 1, 2, 3, 4, and 5 to accommodate design project flows.
Pursuant to FWCC Section 22-1309 (c)(d) and (e), Culverts, the Hearing
Examiner may recommend approval of the proposed action only if the following
decisional criteria are met:
1.
No significant habitat areas would be destroyed and the proposed culvert
is necessary for some reasonable use of the subject property.
Response: The Checklist identified animals observed on or near the site
based on a 1991 study by Shapiro and Associates. The Wetland Report
was prepared to verify and classify wetland areas within the project area.
The wetlands and upland sites provide habitat for a number of wildlife
species, including mallards, herons, songbirds, amphibians, beaver, fish,
and bats.
17
EXHIBIT C,
PAG E12 OF -.1&7
Neither the field investigations of Shapiro and Associates, nor the
records of the Washington Natural Heritage Program and the U.S. Fish
and Wildlife Service indicate the presence of sensitive, threatened, and
endangered animal species. No evidence exists of the presence of
juvenile salmonids (amphibians or amphibian eggs) throughout the
project area streams and wetlands.
Consequently, the proposed culverts would have the least impact on
habitat areas, and no significant habitat areas would be destroyed.
The "reasonable use" criteria does not apply because the Belmor
Stormwater Detention pond facility and associated improvements is not a
development project. Installation of the improvements will provide for
reasonable development within the basin by providing for additional
storm water storage capacity.
2.
The culvert would be designed and installed to allow passage offish
inhabiting or using the stream, and would be large enough to
accommodate a lOO-year storm. The applicant must demonstrate, by
submitting alternative site plans showing the stream in an open
condition, that no other reasonable site design exists.
Response: The Kitts Corner Stormwater Detention facility project,
located downstream of the project site, created fish blockage. According
to the Water Group Technical Memo, no fish are know to inhabit or use
the stream at these locations. Therefore fish passage requirements do not
apply.
Inlet storm drain size is designed to accommodate the estimated 100 year
storm event. Pages 7 and 8 of the Water Group Technical Memo assess
alternatives to culverting the drainage channel at site 1 and demonstrates
that no other reasonable site design exists because of existing
topographic, utility, and contaminated sediment constraints.
3.
The applicant would provide a bond ensuring maintenance, at all times,
of the culverts on the subject property in order to keep them free from
debris and sediment so as to allow free passage of water and, if
applicable, fish.
Response: The maintenance of the proposed development is the
responsibility of the City of Federal Way and is not subject to the
standard bonding requirements. Routine maintenance would be scheduled
and performed by the city's Surface Water Division, which is an -
18
EXHIBIT C
PAGEAOF ,~-,
ongoing responsibility of the Public Works Department. A maintenance
plan will be developed by Public Works Department.
I.
Stream Rehabilitation
Stream rehabilitation is proposed for the stream south and east of the East
Empire Garden Apartments at site 6 in accordance with FWCC section 22-1311,
Rehabilitation. A City of Federal Way interpretation, May 9, 1996, states that
stream rehabilitation shall include, "...alteration of existing stream to improve or
increase its functions and values without degrading other existing functions.
Such implementation shall be performed in accordance with an approved plan
for the design, implementation, maintenance and monitoring of the project."
Response: Page 15 of the Water Group Technical Memo states that the
proposed improvements will minimize the potential for channel bed and bank
erosion by creating a larger channel to convey flows. As negotiations with the
property owner have not been finalized, the applicant has not provided final
planting plans for the project site. These final plans shall be submitted with the
building permit for review. In a February 18, 1997 letter, Adolfson Associates,
(the city's wetland contractor) concurs with the findings for the bulkhead and
associated stream rehabilitation.
J.
Structures, Improvements, and Land Surface Modification Within Setback
Areas from Regulated Wetlands for Essential Public Facilities
The Water Group Technical Memo states that proposed improvements at the
inlet and outlet of the new trunk storm drain at sites 4 and 5, and that bulkheads
and channel widening at site 6, will be partially within 100 foot setbacks from
regulated wetlands.
Pursuant to FWCC Section 22-1359 (b), Structures, Improvements and Land
Surface Modification within setback areas from regulated wetlands, the Director
of Community Development Services may recommend approval of the proposed
action only if no feasible alternative exists to traversing the setback area based
on an analysis of technology and system efficiency; and the specific location and
extent into the setback constitutes the minimum necessary encroachment to meet
the requirements of the publicfacUity or utility.
Response: Alternatives to this proposed development were considered in the
planning process documented in the 1991 Draft Hylebos Creek and Lower Puget
Sound Basin Plan. The Water Group technical Memo documents that the
setback constitutes the minimum necessary encroachment to meet the
requirements of a public utility. The city's wetland contractor, Adolfson
19
EXHIBIT C
PAGEJ![OF --'-Sj
xu.
E.
F.
G.
H.
Associates, Inc. has reviewed this material and concurs with the findings in a
February 18, 1997, letter (Exhibit L).
FINDINGS OF FACT AND CONCLUSION
Based on an analysis of the proposed action, the environmental record, and related
decisional criteria, the Department of Community Development Services finds that:
A.
The site is designated Multi-family according to the 1995 Federal Way
Comprehensive Plan.
B.
The project site is zoned Multi-family (RM). Portions of the site are RM 2400
and RM 3600.
c.
The applicant has made application to construct a regional surface water
conveyance and detention system.
D.
A Determination of Nonsignificance was issued for this proposed action on
January 29, 1997. The comment period for this determination was completed on
February 13, 1997, with no comments received. The appeal period for this
determination was completed 14 days after the comment period deadline, with
no appeal filed. This determination is incorporated by reference as though set
forth in full.
The site is surrounded by a variety of land uses from vacant lots, mobile home
park golf course, multi-family housing, and single family dwelling units. The
proposed use is compatible with the existing land uses and density in this
vicinity.
The proposed surface water facilities have been designed in accordance with
requirements of the 1990 Surface Water Design Manual and the Draft Hylebos
Creek and Lower Puget Sound Basin Plan.
The proposed development is within geologically hazardous area, stream,
stream setback, and wetland setback, all derIDed as environmentally sensitive
areas under the Federal Way City Code.
The applicant has provided an analysis of required decisional criteria for
proposed intrusion on and within 25 feet of geologically hazardous areas
pursuant to FWCC 22-1286, Geologically Hazardous Areas Development, in a
February 28, 1997; memorandum (Exhibit J). This analysis and findings are
incorporated by. reference as though set forth in full.
20
EXHIBIT C
PAGE2(LOF --18-7
N.
1.
The applicant has conducted a determination of whether the proposed action
would adversely impact significant vegetation. The Wetland Report and the
Water Group Technical Memo were prepared by qualified professionals
pursuant to FWCC section 22-1568, Significant Trees (Exhibits E & F). The
analysis and findings are incorporated by reference as though set forth in full.
To the maximum extent feasible, existing natural vegetation would be
maintained on site. Additional supplemental landscaping is proposed and will be
required by the FWCC.
J.
The applicant has provided an analysis of whether a regulated wetland exists on
or within 100 feet of the proposed development. The required Wetland Report
(Exhibit E) was prepared by a qualified professional approved by the city
pursuant to FWCC section 22-1356, Determination of wetland and regulated
wetland. This analysis and [IDdings are incorporated by reference as though set
forth in full.
K.
The applicant has provided an analysis of whether the proposed action would
adversely impact streams. The Water Group Technical Memo (Exhibit F) was
prepared by a qualified professional to respond to FWCC sections 22-1308
Bulkheads, 22-1309 Culverts, and 22-1311 Rehabilitation. This analysis and
findings are incorporated by reference as though set forth in full.
L.
The proposed action is consistent with 1995 City of Federal Way Comprehensive
Plan.
M.
The proposed action is permitted by the Federal Way City Code, subject to
Process ill review. The proposed action is consistent with decisional criteria
under FWCC sections 22-364 Site Plan Approval; 22-394 (b) Process I; 22-490
(d) Process III approval; 22-1286(b) Geologically hazardous areas; 22-1306 (a)
Stream Setbacks; 22-1308 (c & d) Bulkheads; 22-1309 (c, d & e) Culverts; 22-
1311 Rehabilitation; 22-1312(a) Intrusion into Setbacks, and 22-1359 (b)
Structures, improvements and land surface modifications within the setback area
from regulated wetlands.
Development of the site in accordance with the comprehensive plan, and all
applicable development codes and regulations would ensure that the interest of
the public's health, safety, and welfare are protected.
v.
RECOMMENDATIONS
Upon review of this application, the environmental determination of nonsignificance,
and pertinent decisional criteria, the Department of Community Development Services
21
EXHIBIT' C
PAGE-.2l.0F -1S7
recommends approval of the proposed action subject to the following conditions:
A.
Prior to starting construction, the Surface Water Division of the City of Federal
Way shall pay for the services of a qualified professional selected and retained
by the Department of Community Development Services to review plans,
inspect, and issue written reports to the Director of Community Development
Services specific to monitoring and protection of sensitive areas stating that the
project complies with the requirements ofFWCC sections 22-1286(b)
Geologically hazardous areas; 22-1306 (a) Stream Setbacks; 22-1308 (c & d)
Bulkheads; 22-1309 (c, d & e) Culverts; 22-1311 Rehabilitation; 22-1312(a)
Intrusion into Setbacks, and 22-1359 (b) Structures, improvements and land
surface modifications within the setback area from regulated wetlands
Transmitted to parties listed hereafter:
*
Federal Way Hearing Examiner
*
Marwan Salloum
22
EXHIBIT C
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1".10' VERT
WHI0.CIPOI TRUNK STORM DRAINAGE ¡>NO REGIONAl STORAGE FACILITY
IMPROVEMENT PROJECT
~ r ~"rnIO
~......~ PROJECT SITE NNOG' 6CROSS SECTIONS
-=:.L-I BUILDI -
~~ RY' DITCH ALONG APARTMENT 19-JUN'1996 09'02,51
FILE NAME; .epoplO,dlv
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EXHIBIT C,
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(206) 661-4000
FEDERAL WAY, WA 98003-6210
ENVIRONMENTAL DETERMINATION OF NON-SIGNIFICANCE
BELMOR REGIONAL STORMW ATER DETENTION FACILITY A1\TD
STORM DRAIN IMPROVEMENTS
SEP 96-0022
Related File Nos. :UPR 96-0044, UPR 96-0045, ADM 96-0054
Description of
Proposal:
Construct a regional stormwater detention facility, replace three undersized
roadway culvert crossings, extend a storm drain trunk line and construct a
flood wall. The proposal is intended to rehabilitate a section of the Hylebos
Creek, alleviate flooding of South 320th Street and adjacent private
property between SR 99 and 23rd Avenue South adjacent to 20th Avenue
South.
Proponent:
City of Federal Way
Location:
Six improvement sites between South 324th Street and South 336tl1 Street,
adjacent to 20th Avenue South, within the Hylebos Creek
Lead Agency:
City of Federal Way
The responsible Official of the City of Federal Way hereby makes the following decisions based
upon impacts identified in the environmental checklist, the Federal Way Comprehensive Plan, the
final staff evaluation for this action, and other municipal policies, plans, rules, and regulations
designated as a basis for exercise of substantive authority under the Washington State
Environm~nta1 Policy Act Rules pursuant to R.C.W. 43.31C.060.
The lead agency for this proposal has determined that it does not have probable significant adverse
impact on the environment, and an Environmental Impact Statement (EIS) is not required under
RC.W. 43.21C.032(2)(c). This decision was made after review of a completed environmental
checklist and other information on file with the lead agency. This information is available to the
public on request.
This DNS is issued under WAC 197-11-340(2); the lead agency will not act on this proposal for
15 days from the date of issuance. Comments must be submitted by 5:00 p.m. on February 13,
l22L
EXH I B IT - c.. JB1
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Unless modified by the City, this determination will become final following the above comment
deadline. Any person aggrieved of the City's final detennination may file an appeal with the City
within 14 days of the above comment deadline.
Contact Person: Deb Barker, Associate Planner, 661-4103
Responsible Official: Gregory Moore, AICP
Position/Title: Director of Community Development Services
Address: 33530 First Way South, Federal Way W A 98003
Date Issued: January 29, 1997
Signature: 4~
/ f
s epafile \belpo n d \d nstext. ntc
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EXH'B'T C. -
PAGË3'LoF ~--
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Exhibit E is the Wetland Delineation and Flagging for the Be1mor Mobile Home Park
Regional Storage Facility, Prepared by Sheldon and Associates, April 18, 1996, and
Memorandum of October 11, 1996.
The exhibit is 41 pages in length. Pages 1 through 21 are enclosed. Pages 22 of 41, Appendix A -
Data sheets and Appendix B - Maps, are hereby incorporated by reference as though set forth in
full. These documents are on file as part of the full exhibit and are available for review at the
Department of Community Development Services. (The maps are included in Exhibit I, SEP A
checklist).
EXHIBIT C
PAGE35-0F Æ.1
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WETLAND DELINEATION AND FLAGGING
for the .
BELMOR MOBILE HOME. PARK
REGIONAL STORAGE FACILITY
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Prepared for.
City of Federal Way
33530 First Way South
Federal Way, W A 98003-6210
Prepared by.
Sheldon & Associates, Inc.
5031 University Way NE, #208
Seattle, W A 98105-4341
206/522-1214
April 18, 1996
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TABLE OF CONTENTS
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Page
INTRODUCfION......................................................................1
ME'fHOOOLOGY .....................................................................1
Review of Existing Information ..........................ò;..................... 1
WetlandDefinition .......................................'.....................4
Evaluation of Field Conditions ..........................,.......................4
Wetland Delineation and Classification ..........................................4
Vegetation................................................................4
Soils .....................................................................5
Hydrology................................................................6
WetlandDetermination .""""""""""""""""""""""""""'" 6
United States Fish and Wildlife Service Yegetation Classification. . . . . . . . . . . . . . . . . .. 7
WetlandRating................................................................7
Wetland Buffer ....................,...........................................7
Stream Rating """""""""""""""""""""""""""...........7
StreamBuffer ............................................................:.~.. 8
Wetland Functions and Values ..................................................8
WaterQualityImprovement................................................8
Flood/StormwaterControl.................................................9
GroundwaterExchange ....................................................9
Natural Biological Support .................................................9
Erosion/Shoreline Protection ...............................................9
Cultural/Recreational Value .............................................. 10
FINDINGS ...........................................................................10
General Site Characteristics .................................................... 10
StreamandWetlandCharacteristics """""""""""""""""""""" 11
Wildlife Observed or Expected .................................................16
REGULATORYISSUES................................................................16
REFERENCES ........................................................................18
LiteratureCited ..............................................................18
APPENDIX A - DATA SHEETS
APPENDIX B WETLAND/STREAM MAPS
APPENDV' C - KING COUNTY SENSITIVE AREAS MAP FOLIO
EXHIBIT C
P A GE...31 0 F III
EXH
PAGE
Fed<rd W.y/Belmo<
W<lt.nd Ddi"".tion.rod r-unctionol Volues A.ss.ssm<nt
by SIo<ld"" '" ÆssodaJ<s
ÆpriJ 18. 1996
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LIST OF FIGURES AND TABLES
Figures
Page
1. YicinityandSoilMap......................................."~'.""""""""."'. 2
2. Site Map ...........................................................................3
....~
Tables
1. Wetland Plant Indicator Status................................... .....................5
2. Summary of Wetland and Stream Locations................................ ...........10
EXHIBIT C
PAGE..3iOF .1B2-
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¡;,. ~nl W.y/B.,1mor
W<tl...d DeUnaHon and Functional Valu<s Ass=ment
11
fry Sh<1dtm & A=d4Ic:s
ApriI!8,1996
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WETLAND DELINEATION AND FUNCTIONAL VALUES ASSESSMENT
INTRODUCfION
The City of Federal Way is proposing the upgrade of five culvert crossings and two stream
realignments in Federal Way, Washington. The northern extent of.. the study area is in the
Belmor Mobile Home Park, south of South 324th Street. The southernmost site is a stream
channel behind the East Empire Apartments. See Figure 1: Vicinity and Soils Map and
Figure 2: Site Map.
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Sensitive areas located within the project area include a stream and associated wetlands.
Sheldon & Associates conducted stream and wetland delineations within the project area
in November 1995. The purpose of this report is to characterize the stream and wetlands,
assess functional values of the wetlands, and describe and rate the stream within the
project area.
METHODOLOGY
Review of Existing Information
Existing documents were reviewed to gain specific background knowledge of the site.
Literature reviewed as part of the study included:
. City of Federal Way Environmentally Sensitive Areas Code, Article XIV Zoning
Code (1991);
. Soil Survey, King County Area, Washington, Sheet Number 15, Poverty Bay
Quadrangle (Synder et al. 1973);
. Sensitive Areas Map Folio, King County, Washington, Sheet Number 6. (King
County, 1990).
. USFWS National Wetland Inventory Map: Poverty Bay Quadrangle (U.S. Fish
and Wildlife Service 1973); and
. The Catalog of Washington Stream' and Salmon Utilization, Volume 1
(Washington State Department of Fisheries, 1975).
EXHIBIT
Fed.nIWay/~1mor
Wrtland o.Un6Ilion and functional Valu.. Ass.ss"",nl
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Scale:
1 inch = 2,400 feet
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Wcll.nd o"Unotion and FunaionaJ VaJucs
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Wetland Definition
The 1989 Unified Federal Methodology for Identifying and Delineating Jurisdictional
Wetlands (FICWD 1989) defines wetlands as follows:
Those areas that are inundated or saturated by surface or groundw(lJer at a frequency
and duration sufficient to support, and that under nonnal circumstances do support,
a prevalence of vegetation typiœlly adapted for life in saturated soil conditions.
Wetlands generally include swamps, marshes, bogs, and similar areas.
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Evaluation of Field Conditions
The wetland delineations were conducted by Pesha Klein and Esther Howard of Sheldon
& Associates on November 13 and 21, 1995. Wetlands were delineated using the 1989
Unified Federal Methodology for Identifying and Delineating Jurisdictional Wetlands
(FICWD 1989) and the Army Corps of Engineers 1987 Wetland Delineation Manual
(Environmental Laboratory 1987).
At each culvert or stream segment within the study area, data on vegetation, soils, and
hydrology were collected. Each end of the culvert was treated as a separate site for the
purposes of this study. At each location, the wetland boundary or top of bank of the
. stream was marked with pink and black striped plastic flagging affixed to vegetation. The
stream bank and/or associated wetland within a SO-foot radius of each culvert was
flagged.
Wetland Delineation and Classification
The 1989 Federal Manual requires examination of three parameters: vegetation, soils, and
hydrology. For an area to be classified as wetland, hydrophytic vegetation, hydric soils,
and wetland hydrology must be exhibited. Each parameter is discussed further in the
sections below. Data were recorded on field data sheets, which are presented in
Appendix A. The flag number for the wetland plot appears in the upper left-hand corner
of the data sheet. This flag number corresponds to the plot shown on the surveyed
wetlands map as the area where the data was collected. Refer to Appendix A for the data
forms.
Vegetation . EXHI8~
Hydrophytic vegetation consists of those plant species grow~Q~ , on
substrate that at least periodíælly lacks oxygen. For each ~~~!B)! :~e;..,
f"d."..IW'y/Bdmor 4 ~
Wcll.nd Odi"".tion.nd [-undion.1 V.lu<s ~""'nt """-;118,1996
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estimated for each plant species present, and dominant species were determined. Per the
1989 manual, the hydrophytic vegetation criterion is met when more than 50 percent of the
dominant species are hydrophytic, based on the wetland plant species indicator status
from the U.S. Fish and Wildlife Service rating (Reed 1988). The wetland plant rating list
separates vascular plants into four basic groups by their wetland indicator status. A plant
species indicator status is based on that species frequency of occurrence in a wetland. The
indicator status rating is summarized in Table 1. Plant species ar~ identified using Flora
of the Pacific Northwest (Hitchcock and Cronquist 1973). .
Table 1. Wetland Plant Indicator Status
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Iiulicator Status , : " Definition ..
Obligate Wetland Plants (OBL) Plants that occur almost always in
wetlands: estimated probability in
wetlands greater than 99% under natural
conditions.
Facultative Wetland Plants (FACW) Plants that have an estimated probability
of 67% - 99% to be found in wetlands.
Facultative Plants (PAC) Plants that are equally likely to occur in
wetlands or nonwetlands: estimated
probability of 34% - 66% to be found in
wetlands.
Facultative Upland Plants (FACU) Plants that usually occur in non wetlands,
estimated probability of 1 % - 33% to be
found in wetlands.
Obligate Upland (UPL) Plants that occur almost always in
nonwetlands under natural conditions,
estimated probability greater that 99%.
Soils
Soils were sampled in each plot using a soil auger and evaluated for hydric indicators.
Soils were sampled to a depth of 18 inches where possible, and were observed for soil
indicators between 12 and 18 inches. Hydric indicators include mottling and/or gleyed
soils. Mottles are spots or blotches of contrasting color occurring within the soil matrix.
Gleyed soils are predominantly neutral gray in color. Soil chroma, or color, was
determined using a Munsell color chart (Kollmorgen Corporation 1975). - Soil
characteristics observed in the field were compared to Soil Conservation Ser' SCS)
EXHIBIT _c. E 1=
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descriptions of mapped soils to confirm the mapping or to determine if an inclusion of
another soil type was present. Refer to Figure 1 for SCS soils mapping.
Hydrology
Direct observations of hydrology are often limited during the .dry season. However,
indicators may be present throughout the year that confinn the occurrence of saturation
or inundation for periods of time adequate to satisfy criteria designated in the 1989
man ual.
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Hydrology indicators for the 1989 methodology include recorded data, aerial photographs,
and field indicators such as visual observation of inundation or saturation, oxidized root
channels, water marks, drift lines, visible sediment deposits on substrate and plant
surfaces, water-stained leaves, surface scoured areas, wetland drainage patterns,
morphological plant adaptations, and/ or hydric soil characteristics. In cases where both
hydrophytic vegetation and hydric soils are present, wetland hydrology is assu:r:n~d to
occur per the Unified Federal Methodology (FICWD 1989).
To determine if the wetland meets hydrology criteria, inundation or saturation field
indicators, natural drainage class, water table, and permeability must be considE;:!red. In
addition, inundation for one week or more during the growing season must be observed.
Wetland Determination
Sampling results for the three parameters were analyzed to make a wetland determination
for each plot. Based on the results of plot determinations and visual observation of site
characteristics, an overall assessment of the area was conducted and wetland boundaries
were located. The boundaries were identified by attaching flagging to vegetation at
approximately 20-foot intervals within a SO-foot radius of each culvert or stream segment.
For most wetland plots identified, data for a corresponding upland plot was collected to
confirm the edge of the wetland.
The survey for this site was completed by CH2MHill. A map showing the surveyed
wetlands and stream is presented in presented in this report. In some areas, the wetland
and stream flagging was removed prior to the survey. Wetland and stream areas that were
not surveyed, were sketched onto the map and then digitized by CH2MHill. Each map
indicates whether or not a survey was completed. Refer to Appendix B for the
wetland/stream maps. Refer to Figure 2 for a map of the site locations.
The Anny Corps of Engineers uses the 1987 Anny Corps of Engineers Wetland Delineation
Manual (Environmental Laboratory 1987) to identify and delineate wetlands.- The
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wetlands on this site meet the wetland criteria for both the 1987 and 1989 methodologies,
and did not require two separate flaggeå boundaries.
United States Fish and Wildlife Service Vegetation Classification
Vegetation communities in the wetland were classified using a system developed by the
United States Fish and Wildlife Service called Classification of Wetlands and Deep Water
Habitats of the United States (Cowardin et alI979). This system is hierarchical and
structa.red around biologicat hydrological, and substrate characteristics.
Wetland Rating
At this time, City of Federal Way zoning pertaining to environmentally sensitive- areas
does not include a rating system for wetlands.
Wetland Buffer
Wetland buffers are considered to be one of the richest zones for mammals and birds.
Vegetated upland buffers provide essential life needs for birds and animals that are
considered to be wetland-dependent species (Washington Department of Ecology 1992).
Functions which may be provided by wetland buffers include protecting wetland
functional values, water quality improvement, wildlife habitat, and human impact
deterrence. Vegetated wetland buffers may reduce impacts to ~ater quality by controlling
soil erosion, reduce pollutants, and can reduce water velocities, and may moderate water
level fluctuations.
The City of Federal Way Environmentally Sensitive Areas Code (Article XIV, Section 22-
1357) requires a IOO-foot buffer on all wetlands. Buffers are measured from the wetland
edge as delineated in the field.
Stream Rating
Streams were rated using the criteria described in Section 22 of the City of FederalWay
Zoning Code. Federal Way uses the following definitions of Major and Minor streams:
EXHIBIT C. E~-
l'M<rolW'y/(k!moc ~ -:,
W<il.nd D<li"".tion.nd r-unction.! V"¡u<s ^",="",nt 7 April 18. 1996
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"Major stream shall mean any stream, and the tributaries of any stream, which contains or
supports, or under normal circumstances contains or supports a local or migratory fish
popula tion."
"Minor stream shall mean any stream that does not meet the definition of major stream."
Stream Buffer
. The CJty .of Federal Way code includes minimum buffer requirements for streams. All
buffers are measured from the top of any bank of a stream. The minimum buffer
requirements are:
Major stream
Minor stream
lOO-foot buffer
50-foot buffer
This stream is a tributary to Hylebos Creek, which has been documented as habitat for
salmonid fishes. Therefore, it would be considered a Major Stream, requiring a lOO-foot
buffer.
Wetland Functions and Values
Wetlands have the ability to reduce flooding, purify water, and provide wildlife habitat,
shoreline protection, groundwater exchange, and offer cultural and recreational values.
A wetland functional value assessment was conducted for the wetland in the project area.
Each of the functions described below were rated high, moderate, or low.
It should be noted that wetland boundaries continued beyond those flagged for the study
area. Although biologists investigated as much of the wetlands off-site as was feasible, the
entire systems were not studied. As a result, functions and values discussed in this report
represent only the portions of the wetlands in the project area. A brief summary
discussion of functional values for the wetland are discussed in the Findings Section of this
report.
Water Quality Improvement
Wetlands can improve water quality by filtering out sediments, excess nutrients, and toxic
chemicals. This can occur through settling, which happens when water velocity is slowed
in a wetland, and through uptake of materials by vegetation. A wetland's ability to purify
water is based on a number of factors, induding the residence time, and type and density
of vegetation. Wetlands do not function as bottomless sinks for the treatment of degraded
EXH..~.~....;~...IT ~
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r-MmI W.y/lklmor ~ ^G .
Wdland o.,li~atlon.nd functional Values r,-,
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surface water or the deposition of large quantities of sediments. All wetlands have a
threshold limit; input exceeding the limit will result in the collapse of the wetland system.
Flood/Stormwater Control
Wetlands can play an important role in flood reduction because of their ability to slow and
store flood waters. During high rainfall events, water can be stored in wetlands and
released slowly over a few days, thereby reducing the volume. of water available at the
time of peak flooding. This is especially important in urbanizing areas. The ability of a
. partiCJ:¥ar.wetland to reduce flooding is dependent on a number of factors, including the
wetland's position in the watershed, size, shape, and association with other aquatic
systems.
Groundwater Exchange
Wetlands can act as groundwater recharge sites, or groundwater discharge sites.
Groundwater recharge occurs when water from the land surface percolates slowly into the
ground to replenish aquifers, which are sometimes used as municipal or private water
supplies. Wetlands may recharge shallow or perched lenses of water which in turn
discharge into streams. Groundwater discharge, which is more common in the Pacific
Northwest, occurs when groundwater emerges from the ground as a seep or a spring, thus
helping to maintain stream flows. The penneability of underlying soils and the location
of the water table detennine a wetland's groundwater exchange.
Natural Biological Support
A number of wildlife speåes are dependent upon wetlands for all or part of their life cycle.
The wildlife habitat is dependent, in part, on the structural and species diversity of plant
communities, the proximity of upland habitat, and surrounding land uses. The structural
complexity of a tree canopy layer, shrub layer, and ground layer provide feeding, resting,
and nesting habitat for a wide variety of species.
Erosion/Shoreline Protection
Freshwater wetlands help protect lakeshores and banks of rivers and streams. Wetland
vegetation greatly reduces erosion, primarily by dampening and absorbing wave and
current energy and by binding and stabilizing the soil with roots.
r-ed~...1 W.y/lklmoc
Weiland Ddi""a¡;on and Functional Valu.. Assðsm<nt
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Cultural/Recreational Value
Wetlands have value as scenic and recreational areas. Recreational opportunities include
hiking, bird watching, or fislùng. Some wetlands are important archeological or historical
sites, while others have been utilized for scientific study, education, and the protection of
aquatic and terrestrial habitats.
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FINDINGS
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General Site Characteristics
The proposed project site is consists of seven culverts and two longer stream segments of
a creek which is an unnamed tributary to Hylebos Creek. Land use is primarily single
family residential. A mobile home park is at the north end of the project area, and an
apartment complex is located at the southern extent -- .
According to the King County Soil Survey, one soil series is mapped in the project area.
Alderwood gravelly sandy loam, 15-30 percent slopes (AgC) is a series made up of
moderately well-drained soils in upland areas. They formed in glacial deposits. A
representative profile shows a surface layer and subsoil consisting of very dark brown,
dark brown, and grayish brown gravelly sandy loam about 27 inches tlùck. Grayish brown
weakly consolidated to strongly consolidated glacial till to depths of 60 inches and farther
characterize the substratum. Soils in the Alderwood series are not identified as hydric
(USDA SCS 1990), but include up to 2 percent areas of hydric soils.
Wetland inventories for the area, ,including the Federal Way and National Wetland
Inventories, do not indicate wetlands within the study area.
Table 2 below summarizes our findings.
Table 2. Summary of Wetland and Stream Locations
. :: Sitc~;\> ~':<:'!~"V~iI~ll'd\~"i~ 50' teet radius'of
" h. . ,. ., . , ".'. ,
, ...~~',,:",..~ /:~,;/':;' "'.'. :""~';":"'culvei1 ' "
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, Stream.
1 no
2 no
3 no
4
yes
yes
yes
r""¡.n.1 Way/lklmo<
Wetland Ddin.atlon and functional Valu« Ass<ssm<nt
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~_m___..._- ____m_.__._.__.___m_- ... m I mm . .. .
. Site \Vèn¡Ü1,d ..;.vIiI' 50'iect~radius of Slrcall1
" ""cÜ'lvért '
. --..-- --.......- .-...--
5 no yes
6 yes, wetland starts - 32 feet northeast yes
of the culvert at the fence.
.
7 yes, wetland starts - 27 feet west of yes
the culvert
8 yes, wetland starts at the culvert yes, stream is
within the
wetland
9 yes, wetland starts - 50 feet west of yes
the culvert
10 yes, the southwest boundary of the yes
wetland starts - at the culvert and the
southeast boundary starts at the
northern edge of the fence and
continues north.
Stream and Wetland Characteristics
Site 1 (Belmor Mobile Home Park)
There were no wetlands identified in this area. The top of bank of the stream channel was
flagged and surveyed.
The stream is located in the western portion of the site. The channel is steep sided and 15-
20 feet wide. Several inches of water were present in the channel at the time of the site
visit The channel supports hydrophytic vegetation, although no wetlands were present.
Dominant vegetation in the stream channel is reed canary grass (Phalaris arundinacea) and
Pacific willow (Salix lasúmdra). Common species in this area are creeping buttercup
(Ranunculus repens), soft rush (funcus effusus) and hardhack (Spirea douglasil). Several
patches of common cattail (Typ1ul futifolia) are also present Soils were not examined within
the stream channel. See Data Form Number 1.
Buffer to the east of the stream has houses to the top of the slope, and a golf course lies to
the west.
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W«I...d IXUnatlon and FundlonoJ Vatu.. Ms<ssm<nt
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Site 2 (Johnson Property, 32830 20th Ave S.)
NQ wetlands were identifed within a 50-foot radius of the culvert. The top of bank of the
stream channel was flagged but not surveyed.
This part of the site is a landscaped yard. Ornamental ivy grows to the edge of the water
within the study area. The stream is shaded by ornamental weeping willow. The stream
channel is approximately 5 feet wide, and 4-5 inches of water were present at the time of
the site visit. The substrate is gravel.
Site 3 (Valles Property, 32856 20th Ave S.)
No wetlands were identifed within a 50-foot radius of the culvert. The top of bank of the
stream channel was flagged but not surveyed.
The stream channel is contained within a narrow artificial channel on this property. It is
approximately 14 iriches wide. Vegetation consists of ornamental ivy growing to the edge
of the retaining walls. The soils were not examined in this area.
Upland on both sides of the stream is landscaped.
Site 4 (Hanks Property, 32856 20th Ave S.)
No wetlands were identifed within a 50-foot radius of the culvert. The top of bank of the
stream channel was flagged and surveyed.
The stream channel is about 8 feet wide at the north end of the delineated area, and
narrows to 2 feet wide at the culvert. The substrate is gravel, and the water was 2 inches
deep at the time of the site visit.
Upland vegetation consists of red alder and western red cedar (Thuja plicata) with 'an
understory of Robert geranium (Geranium robertianum) and creeping buttercup. Soils in
the uplands adjacent to the stream are dark yellowish brown (10YR 3/4) gravelly sandy
loams. Himalayan blackberry (Rubus discolor) grows next to the culvert. See Data Form
Number 2.
Site 5 (Griffith Property, 33018 20th Ave S.)
No wetlands were identified witlún a 50-foot radius of the culvert. The top of bank of the
stream channel was flagged and surveyed. The upland vegetation consists of red alder
and black cottonwood (Populus balsamifera), with an unde tory of blackb r Ý and
EXHIBJ1r,. C
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F<d.ral Way/lJclmoc
W<iland DcU...ation and r-unctional Value; Ass.ssmont
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salmonberry (Rubus spectabiIis). Soils are very dark grayish brown (10YR 3/2) sandy loams
with no mottles. See Data Form Number 3.
The stream channel was approximately 2 feet wide and 3 inches deep when the fieldwork
was conducted. The stream has a gravel substrate. Where the culvert enters the property,
a 1.5 foot deep pool has formed.
Site 6 (East of 20 Avenue)
A wetland is present approximately 32 feet northeast of the culvert at the fence. A steep
sided stream channel is present starting at the culvert to the wetland. The wetland and the
stream banks were not flagged or surveyed.
The site is located east of 20th A venue South behind a house. The wetland is a palustrine
forest which forms a narrow band along the stream. Dominant vegetation includes red
alder, salmonberry and reed canarygrass. Other commonly occurring species include
Himalayan blackberry and pig-a-back plant (Tolmiea menziesÏl). Access to the wetland was
not available so data was not collected.
The stream is steep sided from the culvert and then the gradient flattens out at the fence
where wetland is present The stream channel"is approximately four feet wide. The banks
of the stream and adjacent buffer area are vegetated by red alder and Himalayan
blackberry.
Since the wetland was not accessed, a functional value assessment was not conducted.
Site 7 (G. Moberg Property, East)
A wetland was flagged approximately 27 feet west of the culvert The wetland and stream
channel were not surveyed.
This site.is located west of the intersection of 20th Ave South and South 332nd St. The
depth of the water in the stream channel was approximately 4 inches. The stream flows
into a forested wetland approximately 27 feet west of the culvert.
The wetland is dominated by red alder with an understory of salmonberry. Manna grass
(Glyceria elata) dominates the herb layer. Soils in the wetland are black (lOYR 2/1) silt
loams from the surface to a depth of 18 inches. Soils were saturated to the surface during
the site visit. See Data Form Number 4. The wetland would be classified as Palustrine
Forested Broad Leaf Deciduous. It appears to be part of the same wetland as that on Site
7, described below.
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This wetland appears to be of moderate value overall. Water quality improvement is
probably low to moderate due to the small amount of emergent vegetation and short
residence time of water. However, roots of the woody vegetation may trap sediment and
pollutants. Floodflow moderation is probably moderate to good, as the trees and shrubs
would reduce velocities. Groundwater exchange is likely to be low, with most occuring
along the wetland edge at boundaries between soils of different permeabilities. Biological
support is moderate due to species and structural diversity. The.wetland is surrounded
by roads which limit the movement of wildlife. Therefore, it wóuld probably be more
suitable for small mammals and songbirds. The cultural and recreational values of this
wetland are limited, as it is on private property.
Big leäf maple with a ground cover of dewberry and sword fern comprises the upland
vegetation. The soils are dark brown (10YR 3/3) and dark yellowish brown (lOYR 3/4)
sandy loarns, with a layer of hard pan at 12 inches. See Data Form Number 5.
Site 8 (G. Moberg Property, South)
A wetland was flagged atthe culvert but was not surveyed.
The stream at this site is' associated with a forested wetland. The wetland overstory is
dominated by black cottonwood, with a shrub layer of sparse salmonberry. A dense patch
of Himalayan blackberry is present near the culvert. The soil was saturated to the surface
and is made up of black (l0YR2/l) silt loarns. Water in the stream channel was 12 to 18
inches deep at the time of the site visit. The wetland would be classified as Palustrine
Forested Broad Leaf Deciduous. See Data Form Number 6.
Upland adjacent to the wetland is characterized by red alder, with occasional Douglas fir.
The understory is made up of sparse salmonberry, dewberry (Rubus ursinus), and sword
fern. Big leaf maple (Acer macrophyllum) and western red cedar were observed in the
general vicinity. Soils are made up of dark brown (lOYR 3/3) and dark yellowish brown.
(lOYR 3/4) sandy loarns. See Data Form Number 7.
r
The functions and values of this wetland are discussed with Siteßas they are probably
part of the same wetland.
Site 9 (A. Moberg Property)
A wetland is present approximately 50 west of the culvert (or 22 feet southwest of the
manhole). Stream channel is present from the culvert west to the wetland. The wetland
and the stream channel were not surveyed.
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a coating of sediment. The stream flows into a forested wetland immediately west of the
50-foot radius from the culvert.
The wetland is characterized by forested vegetation, dominated by black cottonwood and
Oregon ash (Fraxinus latifolia). The shrub layer is primarily made up of salmonberry, with
hardhack as the subordinate species. Herbaceous vegetation occurs in nearly monotypic
patches, including manna grass, creeping buttercup, and slough sedge (Carex obnupta).
Soils in the wetland are very dark gray (lOYR3/1) silt loarns from the surface to a depth
of 18 inches. Soils were saturated at the surface at the time of the field visit. The wetland
would be classified as Palustrine Forested Broad Leaf Deciduous Forested. See Data Form
Number 8.
The upland is characterized by red alder with occasional Douglas fir. The shrub layer is
sparse salmonberry, and dewberry and sword fern make up the understory. The soils
were observed to be dark brown (10YR 3/3) gravelly sandy loarns. See Data Form 9.
This large, forested wetland could be considered of moderate to high value, due to its
being in an urbanizing watershed. Water quality improvement is probably modérate.
There was little emergent vegetation observed, although woody plants uptake pollutants
and nutrients for longer storage. Groundwater exchange is expected to occur near the
wetland edges. Biological support is good in this wetland. Mallard ducks were observed
in the wetland at the time of the site visit. Standing water is likely present year round,
providing a source of water for birds and mammals. Structural diversity was fairly high,
and part of the wetland is buffered by upland forest, making the wetland good habitat for
a variety of mammals and birds commonly found in the area.
Site 10 ( East Empire Garden Apartments)
A wetland is present at the north end of the site. The southern boundary of the wetland
is the culvert and the north end of the wood fence. South of the wetland, stream channel
is present to the south property boundary. The stream channel was flagged and surveyed.
The wetland was not surveyed.
The stream in this part of the study area has been artificially channelized. Approximately
12 inches of water was present at the time of the site visit. Vegetation in the channel
includes water starwort (Ozllitriche stagnalis) and foxtail grass (Alopecurus sp.). The banks
of the stream are maintained as lawn, and are planted with ornamental shrubs.
A forested wetland extends outside the study area to the east towards Site 8. Black
cottonwood and Oregon ash are the dominant trees. The shrub layer is characterized by
Sitka willow. The herb layer covers approximately 10 percent of the soil, the remainder
being 6 inches o(stánding water. Water marks on the trees indicate higher water levels.
Soils in the wetland are very dark gray (10YR 3/1) silt loarns, with mottles at 12 inches.
See Data Form Number 10.
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W",tland Delineation and Functio I u
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The functions and values of this wetland are discussed as part of Site 8, as both sites are
part of the same wetland system.
Stream
The stream in the study area is an unnamed tributary to HylebosCreek. Sections of it are
piped underground. It joins another unnamed tributary to Hyleb6s Creek approximately
1 mile southwest of the southern extent of the study area. It is shown in the King County
Sensitive Areas Map Folio as an unclassified stream. See Appendix C: King County
- Sensitive Areas Map Folio. The Catalog of Washington Streams and Salmon Utilization
(Washington State Department of Fisheries 1975) does not identify this stream. It would
be considered a Major stream according to City of Federal Way criteria. A formal study
to detennine fish usage in this stream segment was not part of the scope of this project.
Wildlife Observed or Expected
A fonnal wildlife study was not part of this scope, however, wildlife use of the wetlands
in this project area are limited because of the development in the area. A number of
passerine birds were observed within, above, and adjacent to the wetlands and stream.
Other birds and small mammals such as rabbits, moles, opossum, mice, raccoon, shrews,
and deer would be expected to USe the upland forest adjacent to the wetlands and stream
for food, nesting, and cover.
Although no amphibians or amphibian egg clutches were observed during the field visit,
amphibians may be present in small numbers in the area. A formal amphibian study was
not conducted for this project.
REGULATORY ISSUES
Several federal, state, and local regulations affect the development of wetland areas.
Agencies that have jurisdiction over development impacts associated with on-site wetlands
include, but may not be limited to, the City of Federal Way and the U.S. Army Corps of
Engineers (ACOE).
Prior to permitting any activities in wetlands, Federal Way requires wetland boundaries
to be delineated and surveyed by qualified personnel. Wetlands are subject to verification
and approval by the City of Federal Way.
The ACOE administers Section 404 of the Clean Water Act, which regulates the discharge
of dredged or fill materials into waters of the United States, including wetlands. For this
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project, if any wetland fill is proposed, the Corps would have to be notified so they could
verify the wetland edges and make their jurisdictional determination on which type of
pennit is required.
The Washington State Department of Fish and Wildlife administers the Hydraulic Project
Approval (HP A) permit. If the project proposes any work in the stream, a HP A permit
will be necessary.
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Wttl.nd o.,ü"".tion.nd Functionl.l Vl.lues Assess~nt
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ITy Sht/don & AssòciaItS
ÆprlI IS, 1996
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REFERENCES
Literature Cited
Cowardin, L.M., V. Carter, Ee. Golet, and E.T. La Roe. 1979. Classification of wetlands
and deepwater habitats of the United States. Office of Biological Services, Fish and
Wildlife Service, U.S. Department of the Interior, FWS 1035-79/81. 103 pp.
, Hitch.s:oc~, C.L. and A. Cronquist. 1973. Flora of .the Pacific Northwest. University of
Washington Press. 730 pp.
Kollmorgen Corporation. 1975. Munsell soil color chart Macbeth Division of Kollmorgen
Corporation. Baltimore, Maryland.
Reed, P.B., Jr. 1988. National list of plant species that occur in wetlands: Northwest
(Region 9). U.S. Fish and Wildlife Service Biological Report. 88 (26.9). 89 pp:- -
Snyder, Dale E., Phillip S. Gale, and Russell E Pringle. 1973. Soil survey, King County
area, Washington, sheet number 15. United States Department of Agriculture, Soil
Conservation Service.
U.S. Department of Agriculture, Soil Conservation Service. 1990. Washington hydric soil
list.
Washington Department of Ecology. 1992. Wetland buffers: use and effectiveness.
Publication #92-10. Washington State Department of Ecology. Olympia, Washington.
Williams R. Walter, Richard M. Laramie, and James J. Ames. 1975. A catalog of
Washington streams and salmon utilization. Volume 1, Puget Sound Region.
Washington Department of Fisheries, Olympia, Washington.
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Apri/IS,1996
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MONTGOMERY WATER GROUP, iNC.
Water Resources. Environmental. Civil Engineering
RECEIVED
0 C T 1 1 1996
TECHNICAL MEMORANDUM 4-1
FEJ};~~.::,\).. \r.\Y?:JBLIC'WORKS
ADMj.i:~ lBTRATION DIVISION
TO:
Jeff Pratt, City of Federal Way, Surface Water Management
Marwan Salloum, City of Federal Way, Surface Water Management
Greg Fewins, City of Federal Way, Community Development
COPIES:
Steve Wasson, CH2M HILL
@( JJ(,U4Jð' 1) ¡.;(..~(.~ (.!)N eF
. /tPPl..-\..cl}ßw cc:>oe-
7e;c.:-'.!QÑ S.
FROM:
Jeny Bibee, Montgomery Water Group
DATE:
Revised October 1, 1996
RE:
WHlO-CIPOl, Sea-Tac Trunk Stonn Drainage and Regional Storage
Facility Improvement Project - FWCC Compliance Review Memorandum
PROJECT:
96-119.4
This memorandum provides a revised assessment of the proposed WHIO-CIPOI stonn drainage
capital improvementS project to identify applicable Federal Way City Code (FWCC) compliance
requirementS including process approval needs. It incorporates response to a Department of
Community Development Memorandum (Planning, Item 5) from Bill IGngman, dated September
13, 1996. It also provi~s.--!:~.~.E9.~~s__tQ~ppl~~~Þ!~J3y'Ç~_çQmQliaI].cesriteria and the required
supporting technical infonnation as the basis for development of a City staff report evaluation of
the project for required process review and approvals. It is intended to support the draft
environmental checklist for the project submitted for City review in July.
Project Site Locations and Components Description
The project is located within the West Branch Hylebos Creek watershed subbasin, along tributary
stream 0014C, between the South limit of South 324th Street and approximately 400 feet north of
South 336th Street. The six drainage system improvement site areas affected by the project along
this tributary stream reach are as follows:
.
Site No.1 - The open stream reach through the BelMor Mobile Home Park and Country Club
(golf course)
Site No.2 - An existing private driveway culvert crossing approximately 300 feet north of
South 330th Street
Site No.3 - The existing culvert crossing of South 330th Street r"\"~ ~
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620 K¡F?AG,ESS:l02.Ç)F~KLAND,WA 98083-2
206-827-3243 FAX 206-827-3509
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Site No.4 - An existing stonn drain system along 20th Avenue South between approximately
South 332nd Street and its inlet north of South 331st Street
Site No.5 - The existing culvert crossing of South 333rd Street
Site No.6 - An existing open stream reach through the Empire Gardens Apartments complex
extending from approximately 250 feet south of South 333rd Street to 400 feet north of South
336th Street.
.
.
The proposed drainage system improvement components are described below. For drawings that
illustrate the proposed improvements, refer to the SEPA environmental checklist prepared for this
project.
Site No.1 (BelMor Stream Channel) Improvements Description
Location: Within BelMor Mobile Home Park and Country Club Development
1. Construct a 7.5 acre-foot regional detention facility (excavated pennanent pool pond) along
the west stream setback area and partially within the fairway of the 9th hole of the BelMor
golf course. Lower the west channel bank to fonn an overflow section (dike between stream
channel and detention pond) along the alignment of the existing north-south sanitary sewer
alignment
2. Install approximately 385 feet of new 84 inch-diameter trunk stonn drain between the south
limit of the South 324th Street right-of-way and the north limit of the regional detention
facility (with outlet to the existing stream channel). This will function as the downstream
segment of a future upstream WHlO trunk drainage system replacement through the Sea-Tac
Mall area.
3. Retain the existing stream channel in an undisturbed condition beyond the limits of the pond.
excavation and trunk stonn drain installation. Provide two sets of culverts to interconnect the'
stream channel and detention pond.
4. Fill approximately 230 feet of the existing stream channel for pipeline installation to meet r
drainage system grade constraints.
5. Provide temporary connection of the new trunk stonn drain to the existing 48 inch-diameter
stonn drain at the north end of the existing stream channel.
6. Re-Iay (vertical alignment) approximately 200 feet of the existing 48-inch diameter stonn
drain at the outlet of the BelMor stream channel reach.
7. Install a new outlet hydraulic control structure with connection to both the existing stream
channel and the regional detention pond.
Site No.2 (Private Drive Crossing) Improvements Description
Location: 32830 20th Avenue South
1. Install a new 48 inch-diameter culvert under a private driveway access across the stream
channel as a replacement for three existing 12 and 18 inch-diameter culverts.
2. Place fill to elevate the road section to provide required pipeline cover (results in longer
culvert and minimal stream channel fill).
3. Install rock head walls and pads at each end of culvert for erosion control.
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Site No.3 (South 330th Cro,'iising) Improvements Description
Location: 32856 and 33018 South 33Oth Street
1. Install extensions to each end of the existing 48-inch diameter culvert within the embankment
(currently plugged at each end). Mter extension, the new 48 inch culvert length will equal
that of the existing parallel 18 and 24 inch culverts (currently active).
2. Install rock headwalls and pads at each end of the culvert to control erosion.
3. Plug and abandon existing 18 and 24 inch-diameter culverts.
Site No.4 (20th Ave. South Crossing) Improvements Description
Location: Along 20th Avenue South Between South 331st and South 332nd Street
1. Install approximately 460 feet of new 48 inch-diameter storm drain across and along the west
shoulder 0~20th Avenue South to parallel the existing 30 inch-diameter storm drain along the
east side of the roadway. Install four new catch basins along its alignment on the west side of
20th A venue South.
2. Install a new inlet structure approximately 20 feet upstream of the existing drop inlet, connect
to the existing and new storm drains, perform some localized (minor) grading, install a rock
blanket, and cover the existing inlet structure.
3. Connect the existing 18 and 24-inch storm drain crossings of 20th Avenue South at South
332nd Street to the new storm drain outlet (at new catch basin)
4. Install a rock headwall and pad at the outlet within the existing stream channel.
Site No.5 (South 333rd Crossing) Improvements Description
Location: 1815 South 333rd Street
1. Install two parallel 42 inch-diameter culverts under South 333rd Street as a replacement for
the two existing 18 and 24 inch-diameter culverts. Move the outlet location approximately 20
feet west of the existing culverts outlet with graded connection to the stream channel (results
in longer culvert but does not result in stream channel fill).
2. Install rock headwalls and pads at each end of the culverts for erosion control.
Site No.6 (Empire Garden Apartments Stream Channel) Improvements Description
Location: 3331118th úme South
1. Construct an enlarged stream channel around the existing southeast apartment building by
widening it within the setback area.
2. Construct a concrete slope retainage and flood wall up to four feet in height along the
relocated west channel bank.
3. Over-excavate stream channel bed and place rip-rap base overlain by stream graveL
4. Install perforated subdrain pipe behind the wall with gated outlet to the stream channel.
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Applicable FWCC Sections
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FWCC sections applicable to proposed improvements at each project site are identified below
based on code review and Department of Community Development process approval
requirements review (reference September 13, 1996 memorandum).
Site No.1 (BelMor Regional Detention Basin and Trunk Storm Drain Improvements)
. 84 inch inlet stonn drain,
stream channel grading
and fill, rock pad
/. Detention pond facility
. Outlet structure and 48 inch
outlet storm drain, stream
channel grading, rock pad
22-1286
22-1308
22-1309
~2-1312(a)
:/22-678
~2-1312(a)
1z2-1308
:(22-1309
22-1312(a)
All improvements within stream 22-1313
and setbacks
All improvement areas 22-1568
.
.
Geologically hazardous areas
Bulkheads (Process I)
CulvertS (Process I)
Intrusions into setbacks, essential
public facilities and utilities
Land use/public facility in an
RM zone (Process III)
Intrusions into setbacks, essential
public facilities and utilities
Bulkheads (Process I)
CulvertS (Process I)
Intrusions into setbacks, essential
public facilities and utilities
Additional requirements for land
surface modification
Significant trees
Site No.2 (Private Driveway Culvert Improvement)
. 48 inch replacement culvert,
stream channel grading, rock
pads
22-1308
v22-1309
22-1312(a)
22-1313
22-1568
Bulkheads (Process I)
Culverts (process I)
Intrusions into setbacks, essential
public facilities and utilities
Additional requirements for land
surface modification
Significant trees
Site No.3 (South 33Oth Street Culvert Improvement)
. 48 inch culvert extensions,
stream channel grading, rock
pads
22-1308
22-1312(a)
22-1313
Bulkheads (Process I)
Intrusions into setbacks, essential
public facilities and utilities
Additional requirements for land
surface modification
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Site No.4 (20th Avenue SE Trunk Storm Drain Improvement)
~2-678
. 48 inch stann drain inlet
and outlet, stream channel
grading, rock pads
22-1308
22-1312( a)
22-1313
v,22-1359(b)
22-1568
Land use/public facility in an
RM zone (Process III)
Bulkheads (Process I)
Intrusions into setbacks, essential
public facilities and utilities
Additional requirementS for land
smface modification
Structures, improvements, and land
surface modification within the
setback areas from regulated
wetlands, essential public facilities or
utility
Significant trees
Site No.5 (South 333rd Street Culvert Improvement)
. 2 - 42 inch culvert replacement, 22-1308
stream channel grading, "'22-1309
rock pads 22-1312(a)
22-1313
~2-1359(b)
Bulkheads (Process I)
Culverts (process I)
Intrusions into setbacks, essential
public facilities and utilities
Additional requirementS for land 0
surface modification
Structures, improvementS, and land
surface modification within the
setback areas from regulated
wetlands, essential public facilities or
u ti1i ty
Site No.6 (Empire Garden Apartments Stream Channel Improvements)
. Stream channel widening and
restoration including flood
wall, rock pads, revegetation
-/22-1308
v22-1311
22-1312(a)
22-1313
v22-1359(b)
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Bulkheads (Process I)
Rehabilitation
Intrusions into setbacks, essential
public facilities and utilities
Additional requirements for land
surface modification
Structures, improvements, and land
surface modification within the
setback areas from regulated
wetlands, essential public facility or
u ti1i ty
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FWCC Compliance Response
This sections describes how the project complies with the applicable sections of the FWCc. It is
intended to provide the required information for City staff report responses to decisional criteria
as the basis for Department of Community Development process approval review (where
applicable as noted). The project sites are evaluated independently; multiple improvement
components within a particular site are evaluated collectively (i.e., within BelMor site).
Site No.1 (BelMor Regional Detention Basin and Stream Channel Improvements)
Section 22-678 - Land UselPublic Facility in an RM Zone (Criteria from Section 22-490(d))
(1),(2) The project proposal is consistent with the comprehensive plan permitted uses within the
multifamily residential (RM) zoning for this site area. The proposed multi-use, pennanent
pool detention pond with access trail, and the appertenant trunk stOrm drain pipelines and
hydraulic control structures will serve the existing site and .tributary upstream drainage areas
stonnwater control needs. It is compatible with the existing uses of the site (retirement
community mobile homes, golf course, and community center). It will also provide
stOrmwater public facility infrastructure improvements consistent with potential requirements
for redevelopment of the site to permitted uses. It will meet the applicable RM use zone
chart criteria for lot size, setbacks, lot coverage, structure height, landscape requirements,
signage, and parking. Overall, it is consistent with the FWCC and City policies for
prospective site uses.
(3) The project proposal considers the public health, safety, and welfare by providing flooding
protection and water quality improvement for existing and prospective site and downstream
land uses. It provides stream and wetland habitat protection and enhancement through
regulation (detention) of stream flows promoting settling of urban runoff pollutants. It also
allows solutions to be implemented for existing upstream flooding problems within public and
private right-of-ways and properties that protect the public health, safety, and welfare.
Section 22-1286 - Geologically hazardous areas, Limitations
(b) The side slopes of the existing stream channel through the BelMor park area are typically
steeper than 2.5: 1 (40 percent) and range to greater than 10 feet in depth. Therefore, those
slopes have been designated as potential geologically hazardous areas based on the FWCC
definition of steep slope hazard areas. Proposed improvements for the new inlet 84 inch
stonn drain will encroach with those steep slope area and within 25 feet of their top and toe.
~ After installation of the new storm drain, the channel beyond the pipe zone would be
\ backfilled with excess excavation from the proposed detention pond to the top of bank thus
) eliminating the steep slope hazard area from this channel reach. Approximately 230 feet of
, stream channel downstream from the existing stonn drain outlet will be affected by this
improvement.
(c) A draft geotechnical data report has been prepared for this project to describe the site
subsurface soils as the basis for design of improvements. Piezometers have been installed in
selected bore holes completed with that field investigation to allow follow-on monitoring of
groundwater levels. One of the piezometers is located near the channel reach affected by the
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inlet storm drain improvement. Data from its monitoring are being collected by City staff,
and will provide information to assist in the geotechnical design assessment. Slope stability,
landslide hazard and slouglùng, seismic hazards, groundwater effects, seep conditions, and
bank vegetation will be considered in final design to confinn that the improvements will
minimize risks of occurrence of geologic hazards within the site area.
22-1308 - Bulkheads
(a) The proposed bulkheads for this site (rock headwalls and pads for inlet and outlet storm
drains) will be located in or along the stream channel.
(b) Process I review will be required in accordance with Section 22-386.
(c) The new storm drains will convey flows up to the 1O0-year design event without overbank
flooding within the stream reach between the inlet and outlet storm drains. The use of rock
headwalls and pads is proposed to prevent significant erosion around the inlet and outlet
storm drains. Entrance and exit flow velocities could otherwise cause slope embankment or
channel bed erosion if only vegetative treatments are used. This is of particular concern for
this site given the environmental site assessment (ESA) characterization of existing channel
sediment quality (refer to ESA report appended to the SEP A checklist). Scour and transport
of potentially contaminated sediments could be detrimental to downstream stream and
wetland habitat. For additional area of construction disturbance beyond the limits of rock
headwalls and pads, revegetation will be consistent with the native plants materials found in
the existing channel.
(d) All improvements will be located on a single property ownership and within the limits of
easement to be established and acquired by the City for the improvements. Flows will be
contained within the existing stream channel and excavated detention pond between the inlet
and outlet stonn drains. Beyond the immediate area of the inlet and outlet storm drains, the
stream channel will remain in its existing condition with a lowered west bank to allow
overflow to the proposed detention facility at high flow stages.
22-1309 - Culverts
(a) Installation of the proposed 84 inch inlet stonn drain will require filling of approximately 230
feet of the existing stream channel downstream from the existing storm drain outlet. Refer
to the SEP A checklist drawings for the proposed limits of the stream channel fill.
(b) Process I review will be required in accordance with Section 22-386.
(c) (1) The habitat value of the existing stream channel segment proposed for fill for inlet storm
drain installation is culTently degraded. No fisheries are known to exist in tlùs stream reach
based on prior downstream assessment by King County SWM and the Washington
Department of Fish and Wildlife. Wildlife habitat has not been documented, but its functions
and values are likely degraded considering the lack of stream buffer and its sulTounding uses
(golf course and mobile home development). The documented presence of contaminated
sediments in the channel bed (refer to environmental site assessment) also degrades existing
wildlife habitat uses of this stream reach. Therefore, closure of this stream reach should not
destroy any significant habitat area.
(2) The proposed fill of the identified stream channel segment is necessary for the proper
hydraulic function of proposed improvements and their interface with future upstream trunk
drainage system improvements. Site constraints and existing site features limit the tial
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for an alternative approach that would leave the affected segment of stream as an open
channel. Those constraints include:
. The need lower the grade of the stream channel at the existing stonn drain outlet by
approximately 3 feet
. An existing sanitary sewer line that is aligned partially under the stream channel and
its west slope embankment (with minimum cover)
. The golf course facilities in close proximity (green, sand trap, and cart path)
. The potentially contaminated stream channel sediments
. Topographic constraints (high area along west channel bank) that would result in
fUI1her encroachment impacts for a lowered channel alignment
An alternative site plan is appended that identifies the impacts of channel regrading to meet
those site constraints and leave the affected channel in an open condition. The resulting
impacts to golf course and utilities demonstrate that no other reasonable site design exists.
(d) The inlet storm drain size is designed to accommodate the estimated lOG-year storm event
runoff from conditions of an unrestricted upstream trunk drainage system (future proposed
capital improvement project). Since no fIsh are known to inhabit or use the stream at this
location, no fIsh passage requirements should apply.
22-1312( a) Intrusions into setbacks, essential public facilities and utilities
(a) All proposed improvements at this site will be within the stream or its 100 foot setback. It is
not technically feasible to locate the detention pond and stonn drain improvements at an
alternate location beyond the stream setback since they require placement at the location of'
the natural stream channel. The physical constraints of the site and its recreational uses (golf
course) limit the facilities placement to that shown (reference the SEPA environmental
checklist drawings). Based on basin plan analysis, no other downstream site exists that meets
the required design criteria for the facilities required function. The improvement is necessary
to meet project needs to reduce flooding, erosion and downstream habitat degradation and to
improve public safety. The improvements result in the minimum stream setback
encroachment to meet the design criteria established for this project.
22 -1313 - Additional requirements for land surface modification
(1) Placement of fIll within the stream or its setback will be limited to that required for the inlet
and outlet storm drain installation and for the detention pond surface lining materials. The fill
material for those applications will be a combination of native materials excavated from the
existing detention pond excavation, low penneability glacial till and topsoil (on-site or
impOI1ed as suitable) for the de$ntion pond soil liner, and impoI1ed select granular fill
materials for pipe bedding/zone and for maintenance access roadway surfacing. Unsuitable
organic materials and excess excavation from the detention pond excavation will be disposed
of at the designated earthwork disposal area for this project. Special handling and disposal
requirements from the minimal excavations of potentially contaminated channel sediments for
rock headwall and pads placement will be adhered to (proposal is to encapsulate with the
stream channel backfIll for the inlet stonn drain).
(2) No dredge spoils are proposed Dor deposit on this site.
(3) Disturbed project site areas beyond the limits of other surface treatments (i.e., rock
headwalls/pads, roadway surfacing) will be planted (along stream banks) native plant
EXH I BIT C '¡. T .
PAGE-.uLOF --181. 8 t'/,. '~ '
(
(
or hydroseeded with a native gra,ss seed mix consistent with that normally associated with
local streams and setback areas. I Within the restored golf course area, landscape treatments
for disturbed areas will be consi$tent with the golf course functional requirements based on
agreement to be developed with, the property owner.
22-1568 - Significant trees
(c) Based on field reconnaissance ~ review of field surveyed base maps, a total of nine
significant trees (Douglas Fir anqI Pine with circumference greater than 36 inches) have been
identified within the anticipated construction corridor for this project site. In addition several
other small coniferous and deciduous (cedar and ornamental) trees were inventoried within
the project construction corridor~ but are not significant trees by definition. Their type, size,
and location, along with a preliminary assessment of the potential to preserve them or their
removal needs are shown on the :appended field inventory maps. Of the significant trees, the
two most northerly pines and a centrally located pine will definitively require removal for the
inlet storm drain and detention p<>nd construction respectively. The four pines along the AC
cart path at the south site limits wd the Douglas Fir near the outlet stonn drain will be
reviewed further in design to confirm their preservation potential. If preservation is possible,
the landscape plan for the improvements will identify any special measures required during
construction consistent with FWCC requirements. If anticipated construction measures are
not able to adequately preserve those significant trees, they will be shown for removal and a
plan for their replacement will be developed with final design of improvements consistent
with property owner input. Other non-significant trees will be shown for preservation on the
contract drawings where not in qirect conflict with construction limits.
Site No.2 (Private Driveway Culve~t Improvements)
Section 22-1308 - Bulkheads
(a) The proposed bulkhead (rock he~dwa1l and pad) will be located in or along the stream.
(b) Process I review will be required: in accordance with Section 22-386.
(c) The new culvert will convey estitnated peak flows up to a l00-year event without roadway
overtopping. The use of a rock ~eadwall is proposed to prevent significant erosion around
the inlet and outlet of the new culvert. Entrance and exit flow velocities could otherwise
cause slope embankment or chaqnel bed erosion if only vegetative treatments are used.
Revegetation of disturbed streani. channel and setback areas beyond the limits of the rock
headwall and pad will be by hydfoseed with a native grass seed mix in accordance with
Section 22-1313.
(d) The proposed culvert improvement and associated bulkhead will minimize the potential for
water CUITent damages (erosion Øue to high flows overtopping roadway) to the private
property on which it is located. 11'0 accomplish this, a larger culvert is required that results in
the need to elevate the drivewayiin the area of the culvert. This results is some (minor)
I
additional fill encroachment into! the stream channel to the minimum extent required to
provide adequate backfill cover 9ver the new culvert. Flow velocities at the upstream and
downstream face of the culvert Will be reduced from existing conditions due to the larger
cross-sectional area of the replaqement culvert.
t! ~
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EXHIBIT C~ . I
PAGE~OF ~f[,
9
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I
22-1309 - Culverts i
(a) Installation of the proposed 48 ipch culvert will require filling of approximately 20 feet of the
existing stream channel (10 feet each at the culvert inlet and outlet). Refer to the SEPA
checklist drawings for the prop~sed limits of the stream channel fill.
(b) Process I review will be requir~ in accordance with Section 22-386.
(c) (1) The habitat value of the exi$ting stream channel segment proposed for fill for inlet stonn
drain installation is currently d~graded. No fisheries are known to exist in this stream reach
based on prior downstream ass4ssment by King County SWM and the Washington
Deparunent of Fish and Wildlifþ. Wildlife habitat has not been documented, but is likely
degraded due to the urban uses ¡in close proximity. Therefore, closure of this stream reach
should not destroy any signific~t habitat area.
(2) The proposed minor fill of .he identified stream channel segment is necessary to install a
larger culvert through the private driveway crossing as part of removal of an existing stream
channel hydraulic restriction. ~ite constraints and existing site features limit the potential for
an alternative approach that woþld leave the exisiting stream segment as an open channel.
An alternative site plan is not ptovided since no other reasonable site design exists.
(d) The culvert size is designed to ~ccommodate the estimated lOa-year stonn event runoff from
conditions of an unrestricted u~tream trunk drainage system with the BelMor regional
storage facility (Site No. 1 imp~ovements). Since no fish are known to inhabit or use the
stream at this location, no fish ~assage requirements should apply.
I
Section 22-1312( a) - Intrusions intq setbacks, essential public facilities and utilities
(a) All proposed improvements at ~is site will be within the 100 foot stream setback. It is not
technically feasible to locate th~ culvert and rock headwall at an alternate location beyond the
stream setback since they requJe placement at the location of the natural stream channel.
The culvert improvement is ne~essary to meet project needs to reduce flooding, erosion and
downstream habitat degradatio~ and to improve public safety. The improvements result in
the minimum stream setback enþroachment to meet the design criteria established for this
project. I
I
I
I
Section 22 -1313 - Additional requir'(!ments for land surface modification
(1) The fill material for this project :mprovement will be a combination of native materials
excavated from the existing roa way fill, "imported select granular fill materials for pipe
bedding/zone and roadway surf cing, and supplemental select backfill to elevate the roadway
to the design grades. Unsuitabl~ organic materials from the excavation will be disposed of at
the designated earthwork dispo~al area for this project. Fill materials on the embankment
face will be covered with geote*tile and rock slope protection to minimize erosion and water
qualitylhabitat degradation. I
(2) No dredge spoils are proposed fpr deposit on this site.
(3) Disturbed project site areas beyønd the limits of other surface treatments (i.e., rock
headwalls/pads, roadway surfacing) will be hydroseeded with a native grass seed mix
consistent with that nonnally as~ociated with local streams and setback areas.
I
I
1
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EXHIBIT
PAGEJdLOF__1 L
c
10
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~.
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Section 22-1568 - Significant trees I
(c) Based on field reconnaissance ~ reviev.' of field surveyed base maps, only one significant
tree (60-inch circumference We tern Red Cedar) has been identified within the anticipated
construction area required for t s improvement. It's location is shown on the appended field
inventory maps (approximately 0 feet east of culvert centerline at downstream face of
culvert). Preservation of this tre will be dependent on the final design finish grade
requirements. If the tree cannot be preserved, replacement is proposed to meet code and
property owner requirements. addition, an existing smaller (30 inch circumference) willow
tree (not a significant tree due to size) located above the existing culvert will be removed and
replaced beyond the trenching lif1its of the new culvert to meet property owner requirements.
I
Site No.3 (South 330th Street Culv rt Improvements)
(
(
Section 22-1308 - Bulkheads
(a) Same response as for Site No.2.
(b) Same response as for Site No. 2.1
(c) The proposed culvert improveme t will extend each end of an existing 48 inch culvert
installed within the roadway em ankment with a recent sewer line improvement project. The
culvert ends will daylight throug the existing slope embankment and be made operational to
replace the existing parallel 18 d 24-inch culverts. It will convey estimated peak flows up
to the loo-year event without su stantial surcharge of the inlet. A bulkhead (rock headwall
and pad extending within the exi ting stream channel and setback) is proposed to prevent
significant erosion around the in et and outlet of the new culvert. Entrance and exit velocities
could otherwise cause slope emb ent or channel bed erosion if only vegetative treatments
are used. Revegetation of distur ed stream channel and setback areas beyond the limits of
the rock headwall and pad will b by hydro seed with a native grass seed mix in accordance
with Section 22-1313.
(d) The proposed culvert improveme t and bulkhead will reduce flow velocities at the upstream
and downstream face of the culvfrt due to the larger cross-sectional area of the replacement
culvert (existing culverts to be plpgged). The improvement will also result in reduced
upstream water depths for comp¥able flows with less risk of creating eddy CUlTents under
high head conditions that could rþsult in embankment erosion. For adjacent properties
beyond the culvert limits (at the ~oad right-of-way), no significant changes in flow velocities
are anticipated for the improved fulvert condition. No changes in the embankment finish
grade are proposed for this impr<þvement.
I
Section 22-1312(a) - Intrusions into tetbacks, essential publicfacílities and utilities
(a) Same response as for Site No.2. ]
Section 22-1313 - Additional requirefents for land surface modification
(1) Same response as for Site No.2, xcept that only the roadway embankments slopes will be
excavated and restored in a simil fashion for extensions to the culvert.
(2) Same response as for Site No.2.
1
(3) Same response as for Site No. 2.1
I
EXHIBIT C. I
PAGE-'1-0F ~
11
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Site No.4 (20th Avenue SE Trunk þtorm Drain Improvements)
Section 22-678 - Land Use/Public ÁCility in an RM Zone (Criteria from Section 22-490(d))
(1),(2) The project proposal is con~~tent with the comprehensive plan permitted uses within the
multifamily residential (RM) zo ing for this site area. The proposed trunk stann drain
pipelines and inlet hydraulic st ctures will serve the existing site and uibutary upstream
drainage areas stormwater contr I needs. It is compatible with the existing uses of the site
(single and multifamily residen . al, preschool). It will also provide stormwater public facility
infrastructure improvements co sistent with potential requirements for redevelopment of the
site to permitted uses. It will m et the applicable RM use zone chart criteria for lot size,
setbacks, lot coverage, structure height, landscape requirements, signage, and parking.
Overall, it is consistent with the CC and City policies for prospective site uses.
(3) The project proposal considers e public health, safety, and welfare by providing flooding
protection for existing and pros ective site and downstream land uses. It also allows
solutions to be implemented for xisting upstream flooding problems within public and
private right-of-ways and prope ies that protect the public health, safety, and welfare.
(
(
Section 22-1308 - Bulkheads
(a) Same response as for Site No.2.
(b) Same response as for Site No.2.
(c) Same response as for Site No.2, except that rock headwalls and pads will be placed at the
inlet and outlet of the improved torm drain as shown on the SErA checklist drawings. The
parallel storm drain will functio with the existing storm drain to convey flows up to the
estimated l00-year storm event eak flow without overtopping of the channel banks (within
private property) or the roadwa embankment at its inlet.
(d) Same as response for Site No.3, except that the proposed bulkheads will reduce the risk of
transmittal of flows to private pr perty surrounding the inlet structure (currently a frequent
flooded area). Reduction in outl t velocities due to the enlarged pipe cross-sectional area
combined with the rock headw and energy dissipation pad will minimize the potential for
downstream scour beyond the ro dway right-of-way limits. The proposed changes in finish
grade within the stream or setba k for construction of this improvement are limited to minor
regrading for relocation of the i et structure (approximately 20 feet northeast of its current
location), piping backfill to inter onnect it with the existing inlet structure, and minor grading
beyond the road right-of-way at he outlet for rock pad placement.
Section 22-1312( a) - Intrusions into etbacks, essential public facilities and utilities
(a) Same response as for Site No.2, except that only a portion of the trunk storm drain
improvement is located within t e 100 foot stream setback.
ents for land surface modification
xcept that no change in roadway finish grades will occur.
Section 22-1313 -Additional requir
(1) Same response as for Site No.2,
(2) Same as response for Site No.2.
(3) Same as response for Site No.2, xcept that finish grade surface treatments within the
roadway corridor will be AC pa ement with crushed rock surfacing on the road shoulders (as
currently exists). EXHIBIT ~
~:~ ~~ 0 F 12 PAJ E_- f f-: OF J~i:~
(
("
Section 22-1359(b) - Structures, im rovements and land swface nwdifications within the
setback areas if regulated wetlands, essential public facilities and
utility
(b) Proposed improvements at the "nlet and outlet of the new trunk storm drain will be within the
100 foot setback areas of delin ated wetlands limits shown on the SEP A checklist drawings. -
Those limits have not yet been erified as regulatory through the Corps of Engineers. It is
not technically feasible to loca the storm drain, inlet structure, and rock headwalls and pads
at an alternate location beyond e wetland setback since they require placement at the
location of the natural'stream cannel. The storm drain improvement is necessary to meet
project needs to reduce floodin , erosion, and downstream habitat degradation and to
improve public safety. The im rovements result in the minimum wetland setback
encroachment to meet the desi n criteria established for this project.
Section 22-1568 - Significant trees
(c) Based on field reconnaissance d review of field surveyed base maps, a total of four
significant trees (Douglas Fir w th circumference greater than 27 inches) have been identified
within the anticipated construe ion conidor for this project site. In addition various other
small coniferous and larger dec duous (red alder, cottonwood) trees were inventoried within
the project construction conido , but are not significant trees by definition. Their type, size,
and location, along with a prel' inary assessment of the potential to preserve them or their
removal needs are shown on th appended field inventory maps. The four significant trees
are located along the west side f 20th Avenue South within approximately 11 to 14 feet
(west) of the proposed centerli e alignment of the new 48 inch-diameter storm drain. They
can potentially be preserved (w th trench box construction) although excavation would
encroach within the drip line 0 those trees. If anticipated construction measures are not able
to adequately preserve those si nificant trees, they will be shown for removal and a plan for
their replacement will be de vel ped with final design of improvements. Other non-significant
trees will be shown for preserv~tion on the contract drawings where not in direct conflict
with construction limits.
Site No.5 (South 333rd Street Cut ert Improvements)
Section 22-1308 - Bulkheads
(a) Same response as for Site No.
(b) Same response as for Site No.
(c) Same response as for Site No.
(d) The proposed dual 42 inch culv rt and bulkhead improvement will carry estimated discharges
up to the 1oo-year event witho t overtopping of the roadway embankment (freeboard less
than 0.5 feet). The improveme t will reduce velocities at the upstream and downstream faces
of the culverts due to their larg r cross-sectional area of the replacement culverts (existing
culvertS to be cut and plugged) Since the overflow over the existing roadway that occurs for
high flows with the existing culverts should not occur for the improved project conditions, a
reduction in the potential for fl oding and erosion damage to adjacent private properties will
result. No significant changes' the finish grade within or adjacent to the stream will occur.
'E"
EXHIBIT C
PAGE-'10F
13
r
C'
Some minor grading within the tream channel and setback area will be required for
relocation of the new culverts 0 tlet approximately 20 feet west of the existing culverts
outlet. This will provide a more hydraulically efficient condition more closely following the
existing stream channel alignm nt, and will control stream channel erosion that has resulted at
the existing culverts outlet.
22-1309 - Culverts
(a) Installation of the proposed 42 i ch culverts will not require filling of the existing stream
channel. The length of culverts will increase, but only because they will be installed along a
skewed alignment closer to that of the stream as it crosses the roadway. No reduction in
stream length will result since e existing stream channel at the outlet will be preserved.
Refer to the SEP A checklist dra ings for the proposed culvert and stream channel limits.
(b) Process I review will be require in accordance with Section 22-386.
(c) (1) The habitat value of the exis 'ng stream channel segment will not be diminished since it
will not be filled.
(2) The proposed culvert replac ment is necessary to remove an existing stream channel
hydraulic restriction. Site const aints and existing site features limit the potential for an
alternative approach. An altern tive site plan is not provided since no other reasonable site
design exists.
(d) The culvert size is designed to a commodate the estimated 1O0-year stonn event runoff from
conditions of an unrestricted up tream trunk drainage system with the BelMor regional
storage facility (Site No.1 impr vements). Since no fish are known to inhabit or use the
stream at this location, no fish P. sage requirements should apply.
I
Section 22-1312( a) - Intrusions into ~etbacks, essential public facilities and utilities
(a) Same response as for Site No.2.,
I
Section 22-1313 - Additional requirJmentsfor land surface modification
(a) Same response as for Site No.2, except that no change in the roadway fmish grade will result.
(b) Same response as for Site No. 2.1
(c) Same response as for Site No. 2.¡
Section 22-1359(b) - Structures, imPtovements and land surface modifications within the
, se tback areas 0 regulated wetlands, essential public facilities and
utility
(b) Same response as for Site No.4. i
I
SUe No.6 (Empire Garden APartm1nts Stream Channel Improvements)
Section 22-1308 - Bulkheads J
(a) The proposed bulkhead (cast-in- lace concrete flood wall) will be located along the west side
of the existing (disturbed) strea channel (within the existing stream setback area) and will
extend approximately 180 feet i length and 4 feet in height above the existing stream channel
flow line elevations (it will projdct up to 2 feet above adjacent grade of landscaped lawn
along west channel bank). The 4nproved channel width will range between approximately 18
~~~~~1 O~ 1871 14 ;:a~£1
c
(
to 24 feet. For the preliminary design layout of the flood wall, reference the SEP A checklist
plan 8.nd sections drawings).
(b) Process I review will be requir d in accordance with Section 22-386
(c) The expanded stream channel proposed will convey estimated peak flows from a 100 year
design stonn event without flo ing of the adjacent apartment complex buildings. A flood
wall is proposed as a result of si e constraints that limit alternative approaches to providing
the required flood protection an controlling channel erosion. Those constraints include site
and grade constraints due to ali nments of existing sanitary sewer lines, property lines,
topography limitations, and the ocation of the apartment complex buildings. The alternatives
L'l1provements considered are d cumented by technical memorandum and supporting drawings
previously submitted to the City The flood wall will minimize the potential for channel bed
and bank erosion by creating a 1 rger channel cross-sectional area to convey flood flows. Use
of a vegetated slope embankme t along the west channel bank is not possible due to site space
constraints. The protection of etlands 9A and 9B, located immediately downstream of the
site, from sedimentation due to otential stream bank erosion was a primary consideration
(benefit) in selection of the floo wall improvement alternative.
(d) Flow velocities for design sto discharges should not increase as compared to existing
conditions due to the larger ch nel cross-sectional area. Channel water surface elevations
for comparable discharge will crease for the wider channel section resulting in reduction in
potential for flooding and erosi n damage to private property within the apartment complex
and on adjacent properties. No ignificant changes in finish grade beyond the flood wall will
result for this alternative. A su -drainage system is proposed behind the flood wall with
gated discharge to the improve stream channel to accommodate local site runoff.
Section 22 -1311 - Rehabilitation
Administrative approval for str am rehabilitation (excavation, widening, and revegetation) to
provide an increased level of fl oding protection of adjacent multifamily development in this
site area will be required pursu nt to zoning code interpretation issued by the City
(Department of Community De elopment) May 9, 1996. No FWCC criteria response
requirements apply.
Section 22-1312(a) - Intrusions int setbacks, essential public facilities and utilities
(a) All proposed improvements wil be within the stream or its 100 foot setback. It is not
technically feasible to locate th improvements at an alternate location beyond the stream and
setback since they require place ent at the location of the natural stream channel. The flood
wall and channel widening imp ovements are necessary to meet project needs to reduce
flooding, erosion, and downstre habitat degradation, and to improve public safety. The
improvements result in the mini urn stream setback encroachment to meet the design criteria
established for this project.
Section 22-1313 - Additional requir ments for land surface modification
(1) The only backfill materials to b placed within stream channel or setback area will be rock
(rip-rap and stream gravel) with n the improved stream channel. and imported drain gravel
and native backfill materials be ind the flood wall. Unsuitable organic materials from the
excavation will be disposed of t the designated earthwork disposal area for this project.
EXHIBIT C
PAGE.:(LOF A7
15
"
(
(-
(2) No dredge spoils are proposed t be deposited on this site. Excess materials from the channel
excavation will be disposed of t the design3.ted earthwork disposal area.
(3) Disturbed site areas beyond the imits of the stream channel will be revegetated with
landscaping treatments similar t those that currently exists (lawn area). A landscape
restoration plan will be develop d with final design that considers the use of native plant
materials nonnally associated' th local streams and their setback areas for use behind the
flood wall. Concurrence of the esired landscape restoration treatments with the apartment
property owners will be needed.
Section 22-1359(b) - Structures, im rovements, and land surface modification with the
setback areas om regulated wetlands, essential public facility or
utility
(b) Proposed improvements for the ood wall and channel widening will be partially within the
100 foot setback area of the del' eated wetlands limits shown on the SEPA checklist
drawings. Those limits have no yet been verified as regulatory through the Corps of
Engineers. It is not technically easible to locate those improvements at an alternate location
beyond the wetland setback sin they require placement at the location of the natural stream
channel and need to begin whe~ shown adjacent to the upstream wetland area to provide the
required flooding and stream ch nnel erosion protection. The section of stream channel to be
improved has been previously g aded (disturbed) and does not currently support wetland or
native stream vegetation. The s ream channel improvement is necessary to meet project
needs to reduce flooding, erosio , and downstream habitat degradation and to improve public
safety. The improvements resul in the minimum wetland setback encroachment to meet the
design criteria established for th s project.
Conclusions
Based on the above responses to sec. ons of the FWCC applicable to this project, Process lIT
approvals will be required for Site N s. 1 and 4 for public facility improvements consistency with
comprehensive plan land use (RM z ne). Process I approvals will be required to address
improvement items for installation 0 culverts and bulkheads. No other process approval
requirements are anticipated. The D partment of Community Development will prepare a staff
report to respond to decisional crite . a in support of the process reviews and required approvals.
Infonnation presented in this memor ndum will be the basis for development of that staff report.
EXHIBIT C,
PAGE~OF j{2
16
E
PAGE
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Attachments
('
. Significant Trees Fi Id Inventory Maps
. Alternative Stream bannel Restoration Layout - Site No.1 (BeIMor)
EXHIBIT C
PAGE~OF .-l!2
17
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Exhibit G is the Geotechncìal D ta Report, Prepared by CH2M Hill, July 11, 1996
The exhibit is 89 pages in length. ages 1 through 26 are enclosed. Pages 27 of89, Appendix A-
Subsurface exploration data shee and Appendix B - Laboratory testing program and data sheets,
are hereby incorporated by refere ce as though set forth in full. These documents are on file as
part of the full exhibit and are av lable for review at the Department of Community Development
Services.
EXHIBIT <:
PAGE.r[OF JJJ
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EXPIRES
This Repo Has Been Prepared Under the Direction
of Registered Professional Engineer
opyright 199' by CH2M HILL
Reproducti n in Whole or in Part Without the Written
Co sent of CH2M HilL is Prohibited
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EXHIBIT C-
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Contents
1 Introduction """"""""""'"
1.1 Site Location and
1.2 Purpose and Scop
.... """"""""" ................... ...... ............. .......................................1-1
roject Description .., ...............................................................1-1
of Work ........... """"""'" """"""""" ......................................1-4
_I
2 Existing Geotechnical Co ditions ......................................................................................2-1
2.1 Geologic Setting.. ................ ............. ...... .................................................................2-1
2.2 Near-Surface Soil onditions """"""""""""""""""""""""""""""....................2-2
Alderwood G avelly Sandy Loam.................................................................2-3
Arents, AIde ood Material..........................................................................2-3
2.3 Previous Subsurf ce Explorations ........................................................................2-4
Geolabs- W as . ngton, Inc. (1974) ...................................................................2-4
CH2M HILL 1994) """""""""""""""""""""""""""""""""........................2-5
CH2M HILL 1995)....... ................... ......... ................ .......................................2-6
2.4 Groundwater Co ditions """"""""""""""""""""""""""""""""""""'"............2-6
2.5 Seismicity............. """""""""""""""""""""""""""'"...........................................2-8
... ........... ................................. ............. .......... .............................3-1
s ............. """"'" ..... ... ......... ..... ........... ..................... ..................3-1
. toring Wells ... ...... .............. ........... .... .....................................3-3
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3 Field Exploration Progra
3.1 Exploratory Bori
3.2 Groundwater Mo
]
4 Laboratory Testing Progr
. ............ """"""""'" ""'" ..... """""" ........................................4-1
]
5 Interpretation of Field Ex loration Data ...........................................................................5-1
5.1 Subsurface Condi . ons........... ......... .............. ....... """""" .......................................5-1
5.2 Groundwater Loc tions """"""""""""""""""""""""""""""""""'"..................5-2
]
6 Limitations """""""""""'" """"""""""""""""""""""""""""""""....................................6-1
7 References....................;...... """""""""""""""""""""""""""""""""""""""""""""""""" 7-1
]
Appendixes
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A.
B.
C.
Logs of Testing Borl gs ............................... ..... """""""""" ........ .............. ................ A-1
Laboratory Testing P ogram ...................................................................................... B-1
Previous Subsurface xploration..... .......... """""" ...... ........... ................................... C-1
1
Tables
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2
3
Summary of Sub surf ce Exploration Program .........................................................3-1
Summary of Ground ater Monitoring Well Installation and Initial Readings ..3-3
Summary of Laborat ry Test Results .........................................................................4-2
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Figures
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1
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Vicinity Map......... .... ..... """"""""""""""""""""""""""""""'" .....'.......................... .1-2
Boring Locations....... ..... """"""""""""""""" ............................ ............ .............. ...3-2
]
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1 Introduction
The scope of engineering se ices described in this geotechnical data report is authorized
under the terms of contract d scribed in Exhibit A of the Professional Services Agreement
between CH2M HILL and th City of Federal Way, dated November 6, 1995.
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1.1 Site Location an
Project Description
The project area extends sou from approximately South 324th Streetto north of South
336th Street, in the City of Fe eral Way, Washington (see Figure 1). The project site area is
located within Sections 16 an 17 of Township 21 North, Range 4 East.
The proposed project will im rove the trunk drainage system in the City of Federal Way
Drainage Subbasin WHIO (u per and lower) south of South 324th Street (north limit) and
north of South 336th Street (s e Figure 1). The proposed project is the first component of the
second phase of a storm drai age improvement project to alleviate the potential for
frequent flooding of South 3 Oth Street and adjacent private ownerships between SR 99 and
23rd Avenue South.
The proposed project would ttenuate the impact of increased peak flows delivered through
the improved drainage syste through construction of a regional stormwater detention
basin at the South 324th Stre t outfall (within Belmor Park Golf and Country Club) and the
replacement of undersized d wnstream roadway culvert crossings leading to the Kitts
Corner and South 336th regi nal detention facilities.
The proposed project would eplace the existing detention facility located on SeaTac Mall
property with the Belmor Re ional Stormwater Detention Facility located along the western
edge of the Belmor Mobile H me and Golf Course near the intersection of South 324th
Street and Pebble Beach Circ e.
South of Belmor Regional St rmwater Detention Facility, the proposed project would also
replace a set of culverts cros "ng underneath a private drive, as well as replace a set of cul-
verts crossing underneath S
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09'17'08
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11t-lTRODUCTION
The proposed project would Iso include storm drain trunk improvements crossing under-
n~ath and bordering 20th Av nue South, and culvert improvements crossing underneath
South 333rd Street. In additio to culvert and storm drain trunk improvements the pro-
posed project would provide floodwall along the East Empire Garden Apartments south
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of South 333rd'Street.
1.2 Purpose and Seo e of Work
This geotechnical data report ummarizes the results of a geotechnical evaluation con-
ducted by CH2M HILL for th proposed trunk drainage system improvement in the City of
Federal Way Drainage Subba in WHIO (upper and lower) between approximately South
324th Street and South 336th treet. The evaluation includes review of existing information
relevant to the geotechnical aracteristics of the project area, actual subsurface exploration,
and laboratory testing on sel ted samples recovered from the field exploration. The scope
of work for the geotechnical t sk is summarized below.
.
Evaluation of existing co
itions at the project site based on review of regional geology
and seismicity, near-surfa e soil characteristics, and reports from previous subsurface
investigation conducted ithin the vicinity of the project area. Field boring and test pit
logs from previous subsu face explorations are given in Appendix C.
Conduct a field subsurfac exploration and soil sampling program to characterize the
soil conditions at the pro osed site. The exploration program consisted of drilling four
exploratory borings. Fiel logs of these test borings are contained in Appendix A.
.
Installation of three gro dwater monitoring wells (or piezometers) to allow for peri-
odic monitoring of groun water table location by the City.
Laboratory testing on sel cted soil samples for soil classification and evaluation of rele-
vant soil properties. Proc dures and results of laboratory tests are presented in Appen-
dixB.
.
.
.
Preparation of this geotec
SEA 1 0O2co32.DOC PI ^G E-','
7/11/96 J-\'
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2 Existing Geot chnical Conditions
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This section provides an ove iew of existing geotechnical conditions along the general area
between South 324th to Sout 336th Streets and Interstate Highway 5 (1-5) to State Route 99
(SR 99). The overview is base on information published in geology and soil publications
for the King County area (Liv ngston, 1971; Snyder et aL, 1973) and on previous subsurface
exploration work conducted ithin the vicinity of the project site. Information covered in
this review includes regional eology and seismicity, near-surface soil conditions, general
subsurface profile from previ us geotechnical exploration, and groundwater conditions.
2.1 Geologic Setting
The soil deposits at the prop ed project area are mainly the result of sediments deposited
by three or more continental laciers that advanced into Washington from the north during
the Pleistocene Epoch (about 0,000 to 1.2 million years ago). The most recent of this
glaciation is the Fraser Glacia . on, which occurred about 10,000 to 20,000 years ago and
included three major glacial dvances known as the Sumas, Everson, and Vashon Stades.
Each glacier episode deposit assortments of till, outwash sand and gravel, and glacial
lake sediments. As glaciers a vanced and receded, meltwater stream deposits consisting of
coarse-grained materials wer deposited in front of the glacial ice. Material that was depos-
ited from these meltwater str ams as the glacier advanced is referred to as advance outwash
while material deposited as e glacier receded is termed recessional outwash. As the
glacier advanced and moved over these materials, till was deposited at the base of the
glacial ice. The till material, c mmonly termed Vashon till, is typically characterized as hard
blue-gray to gray dense mix re of clay, silt, sand, and gravel. The glacial outwash, on the
other hand, is characterized y lenses of sand and gravel with interbeds of silt and fine
sand.
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After the recession of the last ice sheet, sediments have been deposited in the area by vari-
ous geologic processes. Som were deposited within active stream channels (alluvium)
while others were formed,wi hill kettle depressions (peat and organic silts). Sediments were
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2 EXISTING GEOTECHNICAL CONDITIONS
also deposited in drainages a d former outwash channels through landslide processes.
Post-glacial deposits of this s rt occur in various isolated areas and may occupy the upper
few feet of the soil in some ar as along the project site. Because of the nature of their deposi-
tion, post-glacial deposits are not as dense as those deposited during periods of glaciation.
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Within the project alignment f the proposed Trunk Storm Drainage Improvement, the
most prevalent geologic unit s the Vashon till (Q,) (Minard and Booth, 1988). The till is a
hard, blue-gray to gray concr te-like mixture of clay, silt, sand, and gravel. Other geologic
units that can be found in iso ated areas of the project boundary are the Vashon outwash
(Q) and Peat (Qp): The outw sh material is a remnant of the advance and recessional out-
wash, stratified drift, and ass ciated deposits. This material is made up primarily of silt,
sand, and gravel with some ay. Peat (Qp) is chiefly decomposed vegetal matter that
contains thin clay, diatomite, and pumice beds.
Given the geologic conditio described in this section, it is expected that the till deposits
that underlie most of the proj ct area consist of a very dense and compact mixture of
cobbles, gravel, sand, silt an clay, with occasional boulders. Though in some places the till
may contain a high percenta e of silt and clay, the deposits are very incompressible because
of the overconsolidation and recompression that occurred from being overridden by as
much as 10,000 feet of ice du . g past periods of glaciation. Because of the typical well-
graded characteristics of thes soils and the presence of fine-grained soils within the soil
matrix, these deposits typica y have low permeabilities and allow only minimal percolation
of water. Also because of the e characteristics, the soil is often very moisture sensitive for
use in construction.
2.2 Near-Surface So I Conditions
Subsurface conditions for th top 5 feet of soil at the project site were reviewed based on the
publication by the u.S. Soil onservation Service (SCS) entitled, Soil Survey of King County
Area, Washington (Snyder et 1.,1973). In the Federal Way area, the dominant soil units are
the Alderwood Gravelly San y Loam (0 to 6 percent slopes, AgB and 6 to 15 percent slopes,
Age) and the Arents, AIde ood Material (0 to 6 percent slopes, AmB).
EXHIBIT
SEA1002CD3ß^G E Q,
7/11/96 r M. --11..
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2 EXISTING GEOTECHNICAL CONDITIONS
Alderwood Gravelly Sand Loam
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The Alderwood series is gene ally made up of moderately well-drained soils that have a
weakly consolidated to stron ly consolidated substratum at a depth of 24 to 40 inches.
These soils are predominant i the upland areas and formed under conifers in glacial
deposits. In a representative rofile, the surface layer and subsoil are very dark brown to
dark brown gravelly sandy 10 m about 27 inches thick. The substratum is grayish-brown,
weakly consolidated to stron ly consolidated glacial till that extends to a depth of 60 inches
and more.
The Alderwood soil unit, will h underlies most of the project alignment, is classified to be
silty sand (SM) by uses, gra elly sandy loam (0 to 27 inches) and weakly to strongly con-
solidated till (27 inches or mo e) by USDA, and A-lor A-2 by AASHO. The permeability of
this soil unit is typically mod rately rapid in the upper surface layer and very slow in the
substratum. Typical grain siz distribution data indicate particle sizes that are predomi-
nantly smaller than 3 inches d fines content of about 20 to 30 percent. The depth to
groundwater table is typicall about 2 to 3.5 feet. Erosion hazard is slight to moderate,
shrink-swell potential is low, d corrosivity is moderate to illgh (for both uncoated steel
and concrete). In addition, th soil type associated with the Alderwood series is a fair source
of road fill material. Due to t e seasonal high water table, the degree of limitations for
shallow excavations in this ki d of material is moderate.
Arents, Alderwood Materi I
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This soil unit consists of AId ood soils that have been so disturbed through urbanization
that they no longer can be cla~sified with the Alderwood series. The upper 20 to 40 inches of
this material consists of bro+ to dark-brown gravelly sandy loam, willch is slightly hard
and nonplastic. This material lis underlain by a grayish-brown, weakly to strongly consoli-
dated and impervious substrftum of glacial till. Typical gradation data indicate particle
sizes that are predominantly ~maller than 3 inches with fines content of about 20 to 30
I
The permeability of the upper' disturbed soil is moderately rapid to moderately slow (2 to
6.3 inches per hour), depend' g on its compaction during construction, whil hat of the
-C:~n~ ~~~~~
substratum is very slow « O. 6 inch per hour). The rwsi . ~ sligh
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percent.
SEA1002CD32,o£XH I B IT]
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2 EXISTING GEOTECHNICAL CONDITIONS
1
shrink-swell potential and co osivity characteristics are similar to that of the Alderwood
Gravelly Sandy Loam. Due t the seasonal high water table, the degree of limitations for
shallow excavations is severe.
2.3 Previous Subsur ace Explorations
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Supplemental information on subsurface conditions at the site was provided by reviews of
three previous geotechnical e plorations that were conducted within the general area of the
project site. These studies are ummarized and presented in this section. Location of the
study area and logs of the bo holes and test pit excavations are given in Appendix C.
Geolabs-Washington, Inc. 1974)
A geotechnical investigation as conducted by Geolabs-Washington, Inc., in 1974 to
provide foundation and cons uction recommendations for the water storage tank in
Belmor Park. The tank is 100 et high by 90 feet in diameter, for a total reservoir volume of
approximately 5 million gallo of water. The geotechnical investigation consisted of
drilling three exploratory soil orings around the periphery of the water tank (Figure C1 of
Appendix C). Ground surface elevation for the tank location is estimated to be about 30 to
40 feet higher than the presen ground surface at Belmor Park. The depths of these borings
varied between 23 feet and 47 8 feet. In addition, a piezometer was installed in one of these
borings at a depth of 47.8 feet to monitor the groundwater table elevation. Appendix C
contains the logs of these test ormgs.
Results of this geotechnical in estigation indicate that the site is underlain by a considerable
thickness of very dense, mois , gray, silty sand with gravel, which is believed to be glacial
till. A thin surficial layer (abo t 1.5 to 2. feet) of topsoil material overlays the till. This layer
mainly consists of the weathe ed till, forest duff, plant roots, and organic debris. Standard
Penetration Test blowcounts ange from about 3 to 30 in the upper 4 feet of soil, to essen-
tially greater than 50 at 5 feet nd below. Water was encountered at 34 feet deep in one of
the borings but not in other brings.
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7/11/96 PAGE--L..:J! F
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2 EXISTING GEOTECHNICAL CONDITIONS
A field exploration and labor tory testing program was conducted by CH2M HILL (1994) to
obtain geotechnical informati n necessary to develop preliminary geotechnical design cri-
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teria at 20 special crossings al ng the proposed alignment of the City of Tacoma's Second
Water Supply Pipeline (Taco a P5 Pipeline). The Tacoma Second Supply Pipeline align-
ment runs from east of Palme , through Black Diamond, Auburn and Federal Way, into the
City of Tacoma (Figure C2 of ppendix C). The field exploration program included drilling
test borings and installing pie ometers. The logs of test borings drilled for this project are
attached in Appendix C.
Geotechnical information reI ant to tlùs project involves test borings drilled on both sides
of 1-5 along SE 320th Street in ersection (B23-1 and B23-2), and test borings drilled on both
sides of SR 99 (Pacific Highw y South) at the SE 324th Street intersection (B24-1 and B24-2).
Figures C3 and C4 show the I cations of these test borings.
Test borings B23-1 and B23- 2 ere drilled on the east and west sides of 1-5/ SE 320th Street
interchange, respectively (Fig re C5). Subsurface conditions at test boring B23-1 indicate
very dense Yashon till consis .ng of silty, gravelly sand, which extended from the ground
surface down to a depth of a ut 26 feet. The till was underlain by a very dense, slightly
silty to silty, sandy gravel an gravelly sand, which extended down to 67.6 feet deep
(bottom of the borehole). No et soils were encountered during drilling.
Slightly different subsurface onditions were encountered at boring B23-2. At this test bor-
ing, medium dense granular 11 (for a parking lot) extending from the ground surface down
to about 5 feet was encounter d. Yery dense weathered till (silty gravelly sand) then con-
tinued to a depth of about 30 eet. Below the till were alternating layers of silty, gravelly
sand and sandy gravel to ap oximately 45 feet deep (advance outwash). Underlying this
advance outwash was a layer of older till that extended down to the bottom of the drill hole
(57.7 feet).
The approximate locations of the test borings drilled near the SR 99jSE 324th Street inter-
section are shown in Figures 4 and C6. Both borings were drilled to a depth of about
30 feet. Test boring B24-1 wa drilled on the east side of SR 99 and is characterized by a
10.5-foot fill that had been pI ced for the construction of the parking lot for the SeaTac Mall.
~~t1EcXH I BIT
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The fill is underlain by a ve
boring (30.6 feet). At the we
bank) as shown by the logs
depth of about 11 feet. Thes
which may either be the res
part of the fill material that
gravelly sand (Yashon till),
CH2M HILL (1995)
)
2 EXISTING GEOTECHNICAL CONDITIONS
dense, silty gravelly sand (Vashon till) to the bottom of the
side of SR 99, the fill was about 55-feet thick (parking lot for a
f B24-2. The fill is underlain by organic soils that extended to a
organic soils had N-values that were higher than normal,
It of compaction during the construction of the parking lot or
as used. Underlying this organic soil is the very dense, silty
hich extended to the bottom of the hole (30.5 feet).
CH2M HILL also conducted a geotechnical exploration program for the Kitts Comer /South
336th WH08-CIPOI project der authorization from the City of Federal Way. The compo-
nents of the project generall consist of West Hylebos Tributaries 0014C, 0014A, and 0014
trunk drainage system conv yance and regional detention/ treatment facility improve-
ments. These improvements xtend from north of South 336th Street to east of South 340th
Street (west of SR 99) as sho n on Figure C7. Except for some isolated areas, the soil
encountered during the expl ration was primarily granular consisting of mixtures of sand
and gravel with some silt co tent. Materials are classified under the Unified Soil
Classification System as GP- M, SW-SM, GP, GW, SF, SW, SM, and GM. These materials
are in a dense to very dense tate with SPT blowcounts of 25 to greater than 100.
Test pits excavated in proxi .ty to wetland areas (TP4, TP5, and TPI2) encountered brown,
soft, wet organic soil (OL) w th abundant root and plant material and brown, soft, wet silt
(ML) up to 12 to 12 feet in d th, the total depth of the test pits. A test boring drilled
approximately 600 feet sou east of SR 99/SE 336th Street intersection encountered silt with
gravel (ML) to a depth of ab ut 7 feet. Below this depth, the soil is primarily granular.
2.4 Groundwater Co ditions
The groundwater condition t the project site is characterized by a shallow, perched
groundwater system within he weathered upper layer of Yashon till and a deep regional
groundwater system within he advance outwash.
SEA1~IBIT
7/11/9PAGE~O
2.6
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2 EXISTING GEOTECHNICAL CONDmONS
The perched groundwater sy em is recharged by direct precipitation. Due to the very low
permeability of the unweathe ed Vashon till, rainfall that infiltrates into the more perme-
'¡
able weathered till layer mov s laterally by gravity along the interface of the weath-
ered/unweathered zone. The round water movement is relatively slow due to high silt
content of the weathered till a d the low gradients of the till surface.
"I
Piezometers were installed d ring field exploration for the Tacoma Second Water Supply
Project (CH2M HILL, 1994). t boring B23-1 (1-5 east), the piezometer hydrotip was
installed at a depth of 61.6 to 7.6 feet. The groundwater level measured at this location on
May 1994 was at 67.1 feet bel w the ground surface (bgs). At B23-2, piezometers were
installed at different levels (4 -53 feet and 25-40 feet deep). For the deeper piezometer
(hydrotip at 48-53 feet), the undwater table varied between 23.6 and 24.9 feet bgs while
for the shallow piezometer, e groundwater table varied between 18.0 and 20.4 feet bgs.
These groundwater level dat were taken for the period between May and August of 1994.
At B24-1 (SR 99 east), the mea ured groundwater level was about 16.7 feet bgs for a
piezometer with hydrotip ins aIled at 25-30 feet.
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For the subsurface exploratio conducted by Geolabs-Washington, Inc., at Belmor Park in
1974, the groundwater level as measured at 34 feet deep in one of the borings but was not
encountered in the other two orings located less than 90 feet away. This anomaly was
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During the 1995 geotechnical xploration for Kitts Comer/South 336th project, CH2M HILL
installed piezometers (observ tion wells) at three of the test borings. The groundwater level
monitored at these three loca . ons ranged from approximately 6 to 35 feet below the ground
surface, depending on the sp cific location within the project area and depending on the
time of the year recordings w re made. Furthermore, the groundwater levels do not appear
to represent the regional gro ndwater aquifer but, rather, are indicative of localized,
perched groundwater lenses, as evidenced by the significant changes in groundwater
elevation for relatively simila ground surface elevations. The seasonal fluctuation in
groundwater table during th period of monitoring Oanuary to June of 1995) was less than 5
to 10 feet.
attributed to the possibility
lens in glacial till.
at the water occurs in an isolated zone centered on a sandier
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7/11/PAGEJL
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2 EXISTING GEOTECHNICAL CONDITlONS
-¡
The perched groundwater s stem is recharged by direct precipitation. Due to the very low
permeability of the unweath red Vashon till, rainfall that infiltrates into the more perme-
able weathered till layer mo es laterally by gravity along the interface of the weath-
ered/unweathered zone. Th groundwater movement is relatively slow due to high silt
content of the weathered till nd the low gradients of the till surface.
- ]
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Piezometers were installed ring field exploration for the Tacoma Second Water Supply
Project (CH2M HILL, 1994). t boring B23-1 (1-5 east), the piezometer hydrotip was
installed at a depth of 61.6 t 67.6 feet. The groundwater level measured at this location on
May 1994 was at 67.1 feet be w the ground surface (bgs). At B23-2, piezometers. were
installed at different levels ( 8-53 feet and 25-40 feet deep). For the deeper piezometer
(hydrotip at 48-53 feet), the oundwater table varied between 23.6 and 24.9 feet bgs while
for the shallow piezometer, e groundwater table varied between 18.0 and 20.4 feet bgs.
These groundwater level dat were taken for the period between May and August of 1994.
At B24-1 (SR 99 east), the me sured groundwater level was about 16.7 feet bgs for a
piezometer with hydrotip in taIled at 25-30 feet.
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For the subsurface explorati n conducted by Geolabs-Washington, Inc., at Belmor Park in
1974, the groundwater level as measured at 34 feet deep in one of the borings but was not
encountered in the other tw borings located less than 90 feet away. This anomaly was
attributed to the possibility t at the water occurs in an isolated zone centered on a sandier
lens in glacial till.
During the 1995 geotechnica exploration for Kitts Corner /South 336th project, CH2M HILL
installed piezometers (obse ation wells) at three of the test borings. The groundwater level
morútored at these three loe . ons ranged from approximately 6 to 35 feet below the ground
surface, depending on the sp cific location within the project area and depending on the
time of the year recordings ere made. Furthermore, the groundwater levels do not appear
to represent the regional gro ndwater aquifer but, rather, are indicative of localized,
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perched groundwater lenses as evidenced by the significant changes in groundwater
elevation for relatively simil r ground surface elevations. The seasonal fluctuation in
groundwater table during th period of morútoring Oanuary to June of 1995) was less than 5
".
to 10 feet.
III
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SEA1EXH I BIT
7/11/ÞAGE '7
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2 EXISTING GEOTECHNICAL CONOITlONS
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Based on the existing inform tion discussed in the preceding paragraph, it appears that the
regional groundwater syste is located at least 70 feet below the ground surface and was
not encountered in any of the previous test borings drilled to a maximum depth of about 68
feet. This deep groundwater ystem flows within the permeable advance outwash deposit
that underlies the Vashon till
Since the excavations for this roject will mostly involve the upper 20 to 30 feet of soil, it is
expected that a "perched" gro dwater system will be likely encountered rather than the
regional aquifer. As describe in this section, water that infiltrates the ground is generally
found in perched lenses of m re permeable material within the low permeability-matrix or
in the weathered upper porti n of the till. As this system is recharged by direct precipita-
tion only, the amount of grou dwater flow due to perched groundwater system is not as
abundant as that of the regio al groundwater system.
2.5 Seismicity
Another important considera 'on from the standpoint of regional geology is the seismicity
of the general area. Estimates of seismicity within the Federal Way area are based partly on
historic events that occurred' the Puget Sound region. These recorded earthquake events
include the magnitude 7.1 ea thquake in Olympia in 1949, the magnitude 6.5 earthquake
between Seattle and Tacoma 1965, and the magnitude 5.0 Maury Island earthquake in
1995. These earthquakes wer associated with deep subcrustal activity that takes place
within the Juan de Fuca plate Based on evaluation of earthquake return rates, earthquakes
of magnitude between 5.5 an 6.0 will likely occur within the next 8 to 12 years. These seis-
mic events will result in grou d shaking at the site. According to thes'eismic maps devel-
oped by the u.S. Geological S rvey (USGS) (Algermissen et aL, 1990), the design
acceleration level at the proje site should approximately be 0.3 g, where g is the accelera-
tion due to gravity. The accel ration level has a 10 percent probability of being exceeded in
50 years with an average re period of approximately 475 years.
The design acceleration level etermined by USGS is consistent with that suggested by the
). Under its own classification, UBC classifies the Federal Way
area as seismically active un r Zone 3 of the seismic zoning map with a design accelera-
tion level of 0.3 g. The appro riate site coefficient (S2) for conditions at the site is 1.2.
~~1~~~2EXHIBIT C,
PAGE~l/'(c t
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2 EXISTING GEOTECHNICAL CONDITIONS
- !
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\
Given the geologic condition iscussed in this geotechnical report, it is our opinion that
seismic effects to soils at the si e are expected to be negligible. In general, the subsurface
Ì
materials are believed to be to dense for liquefaction to be of a concern or for any signifi-
cant dynamic settlement to oc ur. Except for some relatively loose fill, slopes and excava-
tions within the project ali ent generally appear to be sufficiently strong to resist seismic
loading. Bearing capacity of e soil is also more than sufficient to resist increased lateral
and vertical loads from the in rtialresponse of structural facilities at the site.
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3 Field Exploraf on Program
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This section discusses the fiel exploration program for the proposed Trunk Storm Drain-
age Improvement Project in e City of Federal Way. The field program consisted of drilling
four test borings and installin three monitoring wells (piezometers) for follow-on moni-
toring by the City.
3
3.1 Exploratory Bori 9s
1,
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Four test borings were drilled to identify the subsurface conditions at the proposed loca-
tions of the project facilities. e test borings were drilled on January 17 and 18, 1996, at the
approximate locations shown 'n Figure 2. Geoboring and Development, Inc., of Puyallup,
Washington, was subcontract d by CH2M HILL to provide the drilling services. The test
borings were drilled to dep ranging from about 16 feet to 42.9 feet for a total footage of
about 120 feet. The test borin were drilled using an Acker Soil Max drill rig equipped
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with 4-inch-diarneter hollow tern auger. This drilling technique entails drilling a hole with
an auger and periodically obt ining soil samples through the hollow center of the auger.
The auger remains in the hole and stabilizes the hole sidewalls. Table 1 gives a summary of
the exploratory borings and t e maximum depth penetrated for each boring.
TABLE 1 I
Summary of Subsurface Exploration Pr ram
B-1
B-3
Estimated Depth of Water Table
Below the Ground Surface
(feet)
5.0-5.5
11.0
Test Boring
Number
B-7
10.5
B-8
3 .9
5.0-5.5
SEA1002crmMH'IBIT
7/11/96 ""I;;^
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19'JUN.1996
08'13'54
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3 FIELD EXPLORATION PROGRAM
. ~
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Representative disturbed soil samples of material encountered in the soil borings were
o~tained at 5-foot intervals u ing a 2-inch-diameter standard split-spoon sampler following
the requirements of the Stand rd Penetration Test (ASTM 01586). A brief description of the
!
i
Standard Penetration Test is iven in Appendix A. Samples retrieved from boreholes were
classified visually in the field 'n accordance with ASTM 02488, Visual-Manual Procedure
for Description and Identifica . on of Soils. The visual classifications were then noted and
recorded on the field boring I gs and were later revised as necessary based on the results of
laboratory testing.
oj.
Following completion of drill ng, test borings requiring piezometer installation (B-1, B-3,
and B7) were backfilled with ppropriate materials, as discussed in Section 3.2 of this
-1
J
geotechnical data report. The est boring without a piezometer (B-8) was backfilled with a
mixture of bentonite chips an drill cuttings. Excess cuttings not used in backfilling the
boreholes were hauled offsite and were disposed accordingly. The logs of exploratory bor-
ings are given in Appendix A
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3.2 Groundwater Mo itoring Wells
Groundwater monitoring we s are used to allow periodic monitoring of the groundwater
table elevation. Three monito ing wells, designated as PI, P2, and P4, were installed for this
project at the locations of test orings B-1, B3, and B-7, respectively (see Figure4.Z-
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The monitoring wells general y consist of about 2 feet of slotted PVC hydrotip (1.5 inch in
diameter) installed at desired depths into the hole. The hydrotip is connected to the I-inch-
diameter PVC riser pipe, whi h was extended to the ground surface. Colorado sand was
used to backfill the hole and/ r areas around the monitoring well pipes up to a depth of
about 3 feet below the groun surface. A 2-foot-thick bentonite seal was used above the
Colorado sand. A concrete m nument with access cover was then installed flush to the
existing ground surface to pr vide a protective cover for the monitoring well.
ation depths of the monitoring wells and the measured
e of installation or shortly thereafter. Periodic readings of the
by the City.
Table 2 summarizes the insta
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groundwater depths at the ti
monitoring wells will be take
EXHIBIT
SEA1002co32.DOC
7/11/96 PAGE IIJ
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3 FIELD EXPLORATION PROGRAM
l
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TABLE 2
Summary of Groundwater Monitoring ell Installation and Initial Readings
1
t
Depth of Hydrotip Measured Depth of Water Below
Below Ground Surface Ground Surface (feet)
Pieozmeter No. Date Install d (feet) 01/18/96 01/22/96
P-1 01/17/96 20.0 7.85 5.52
P-2 01/17/96 22.9 8.50 8.56
P-4 01/18/96 15.3 5.80 5.95
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4 Laboratory T~sting Program
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Representative samples COlleEd from the subsurface exploration were chosen for labora-
tory testing to confirm our fie d visual classification of soils as well as to obtain engineering
properties required for geote. . cal design and construction. These samples were delivered
for testing to Geo-Engineers i Redmond, Washington, under subcontract to CH2M HILL.
The testing program consiste of:
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. Grain Size Analyses (AS D-422)
. Atterberg Limits (ASTM
. Moisture Contents (AST
.
Percent Passing Sieve No. 200 (ASTM D-1140)
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Modified Proctor Compac . on (ASTM D-1557)
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Organic Content Determi ation (ASTM D-2974)
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A brief description of the pr edure to perform each of these tests is presented in Appen-
dix B. Table 3 gives a summa of the laboratory test results. Plots and test data from labora-
tory tests are attached in APPlndix B. Results of these tests are also incorporated in the field
boring logs where approPriatr (Appendix A).
EXHIBIT
~~1f!iÃr3 E.œL 0 F
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T A~LE 3
Summary of Laboratory Test Results
~m Grain Size Distribution Atterberg LImits Moisture-Density ,Relationship
Sample Water LIquid Plastic Plasticity Maximum Optimum
(j)~ Boring Sample Depth Content Percent Percent Percent limit Limit Index Dry Density Moisture Content
m- No. No. (teet) (%) Gravel Sand Fines (%) (%) (%) (pet) (%)
--OJ B-1 SS1 2.5 - 4.0 9 NT NT NT NT NT NT NT NT
C)- B-1 SS2 7.5 - 8.4 13 NT NT NT NT NT NT NT NT
Utl-l B-1 SS3 12.5 - 13.4 9 46 34 20 NT NT NT NT NT '-..J
0 B-1 SS5 22.5 - 23.0 15 NT NT 61 NT NT NT NT NT
:-n I~
B-1 SS8 37.5 - 37.9 19 NT 'NT 18 NT NT NT NT NT
~~~~~---
~--~----- -
B-1 SS9 42.5 - 42.9 17 NT NT NT NT NT NT NT NT
B-3 SS1 2.5 - 4.0 12 19 58 23 NT NT NT NT NT
B-3 SS3 12.5 - 14.0 13 19 58 23 NT NT NT NT NT
B-3 SS5 22.5 - 22.9 9 NT NT 25 NT NT NT NT NT
B-7 SS1 2.5 - 4.0 8 NT NT 14 NT NT NT NT NT
B-7 SS2' 7.5 - 9.0 31 20 45 35 47 38 9 NT NT
B-7 SS3 12.5 - 14.0 20 NT NT NT NT NT NT NT NT
B-7 SS4 15.0 - 16.0 13 NT NT NT NT NT NT NT NT .-.....J
B-8 SS1 2.5 - 4.0 7 NT NT 11 NT NT NT NT NT
B-8 SS2 7.5 - 8.9 9 NT NT NT NT NT NT NT NT
B-8 SS3 12.5 - 13.0 14 21 41 38 NT NT NT NT NT
B-8 SS4 17.5 - 17.8 8 NT NT NT NT NT NT NT NT
B-8 SS8 37.5 - 37.9 18 NT NT NT NT NT NT NT NT
B-1 Bulk 7,5-12.5 NT NT NT NT NT NT NT 136 8
Sample
'Organic content determination for this sample indicated organic content of 8 percent.
NT = not tested.
SEÞJ1002co3E,DOC
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Table 3
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4 LABORATORY TESTING PROGRAM
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5 Interpretation
f Field Exploration Data
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Results of the field exploratioJ, laboratory soil testing, and piezometer installation are pre-
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sented and discussed in this se tion to provide a general description of the project area, the
geotechnical characteristics of e soils encountered during the exploration program, and
groundwater conditions existi g at the site at the time of and shortly after the explorations.
5.1 Subsurface Condi ions
ï
The soil encountered during t s exploration program generally consisted of very dense
granular material that extende to the maximum boring depth of 43 feet. At the north end
of Belmor Park golf course, w ch is the potential site of the proposed regional stormwater
detention basin at the South 32 th Street outfall (within Belmor Park Golf and Country
Club), the upper 5 to 7 feet con ist of very dense silty sand and gravel with about 5 to
,
15 percent fines. Field classific tion of this material indicated predominance of poorly
graded sand with silt and grav I (SP-SM), silty sand with gravel (SM), and poorly graded
gravel with silt and sand (GP- M). At test boring B-3, the fill material is underlain by very
dense silty gravel with sand ( M, GP-GM, SP-SM, and SM) to a depth of 38 feet (the total
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boring depth) with silt content ~s high as 38 percent. SPT blowcounts were essentially
higher than 100. At test boring -1, very similar material as that in boring B-8 (GM, SM, SP-
SM) was encountered between:7 feet and 17.5 feet. From 17.5 feet to 30 feet deep, a hard
layer of sandy silt with gravel I L) and silt content of at least 60 percent was encountered.
This material was fairly dry to: oist and contained thin interbeds of very fine sand and
isolated mottled zones. Underl ing this silt layer is a very de~se layer of SP-SM and SM
with about 10 to 18 percent- silt:extending to the total boring depth of 43 feet. Modified
Proctor compaction test perfo , ed on a bulk sample obtained from the hole cuttings be-
tween 7.5 and 12.5 feet in bori B-1 indicates a maximum dry density of 136 pounds per
cubic foot (pcf) and an optimu
moisture content of 8 percent.
~2XttIBIT
PAGEHLOF :
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5 INTERPRETATION OF FIELD EXPLORATION DATA
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At the south end of Belmor P rk golf course (test boring B-3), the boring encountered about
10 feet of medium dense sur ' ce fill (N-value of 15 to 17), which consisted of silty sand (SM)
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with silt content of up to 23 ercent. Between 10 feet and 23 feet, the soil encountered was
predominantly very dense S -SM and SM with thin lenses of sandy silt (ML) and similar
silt content as the upper 10 f t. A trace of organic materials was also noticed in the upper
10 to 15 feet of the soil.
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The test boring (B-7) drilled 'ear the intersection of 20th Ave. South and South 333rd Street,
,
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adjacent to the existing culve t crossing, encountered an approximately lO-foot-thick fill
layer consisting of medium ~nse GP-GM and SM in the upper 7 feet with about 14 percent
silt and trace of organics. Be een 7 and 9 feet was a thin layer of loose (N-value of 9) dark
brown to black silty sand (S ) with about 8 percent organics and 35 perèent silt. Atterberg
,
limits test conducted on a sa pIe of this material indicated a liquid limit of 47 percent and
plasticity index of 9 percent. e natural moisture content of this material was determined
to be 31 percent. From about feet to 16 feet deep (bottom of hole), the material was essen-
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tially very dense granular soi with less than 10 percent fines. Field visual classification of
this material indicated well- ,aded sand (SW), poorly graded sand (SP), poorly graded
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gravel (GP), and SF-SM.
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5.2 Groundwater Lo ations
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Groundwater was encounter: d in all of the test borings drilled for this project. Approximate
groundwater levels recorded during drilling are given in the appropriate boring logs of
Appendix A.
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In addition to identifying ap roximate groundwater levels during field exploration, moni-
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toring wells (or piezometers) were installed in borings B-1, B-3, and B-7 for follow-on moni-
,
toring by City staff. Prelimin I ry readings taken shortly after installation of the piezometers
,
are summarized in Table 2. T ese readings indicate that the groundwater level at the
piezometer locations ranged om approximately 5 to 9 feet below the ground surface,
depending on the specific loc tion within the project area. Also from these results, it is quite
evident that the groundwate ,levels being monitored are part of the localized, perched
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groundwater lenses develop d on the upper weathered layer of the Vashon till.
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7/11/9þ A G E.M (,-, B<~lf1
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6 Limitations
)
This geotechnical data report as been prepared for the exclusive use of The City of Federal
I
Way for specific application t the design of the South 324th/South 336th Street WHIO-
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CIPOl and 02 project in accor ance with generally accepted geotechnical engineering prac-
tice. No other warranty, expr ~s or implied, is made. The data and interpretation contained
in this geotechnical data repo it are based on information obtained from four soil borings
and three groundwater monit ring wells at the project site. Soil borings and monitoring
wells indicate soil and ground ater conditions only at specific locations and times and only to
the depths penetrated. If signi cant variations in subsurface conditions from those described
are noted during construction, !geotechnical design criteria for the project should be
reevaluated.
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EXHIBIT
SEA100~2 DOC ---, ~
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7 References
Algermissen, S. T. 1990. Pro - bilistic Earthquake Acceleration and Velocity Maps for the United
I
States and Puerto Rico. Miscel aneous Field Studies Map No. MF-2120, u.S. Geological
Survey.
CH2M HILL. 1994. Tacoma S cond Water Supply Project Special Crossings. Draft Geotechnical
Data Report Prepared for th City of Tacoma, Washington.
i/I;-
.-<)
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CH2M HILL. 1995. Geote
'cal Exploration Program, Contract AG-204, Phase 1 Design
336th-WH08-CIPO1. Technical Memorandum 4-2 Prepared for
Services, Kitts Comer/Sou
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Geolabs-Washington, Inc. 1 74. Soil and Foundation Investigation for the Proposed Five
Million Gallon Storage Ta I King County Water District No. 124, Federal Way,
Washington.
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Minard, J. P. and Booth, D. . 1988. Geologic Map of the Redmond Quadrangle, King County,
Washington. Miscellaneous eld Studies Map No. MF-2016, U.s. Geological Survey.
Snyder, D. E., Gale, P. S., an, Pringle, R. F. 1973. Soil Survey of King County Area, Washington.
U.S. Department of Agricul re, Soil Conservation Service.
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Draft Report
Phase I Envi onmental Site Assessment
SeaTac Mal Regional Storage Facility
Fede : al Way, Washington
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December 15, 1995
Prepared for
ity of Federal Way
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! Federal Way, WA
Prepared by
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LA DAU ASSOCIATES, INC.
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World Trade Center. 3600 Port 0 ITacoma Road, SUIte 209 . Tacoma, WA 98424 . (206) 926-2493
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EXHIBIT C,
PtßEllLOF . ....~
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ABLE OF CONTENTS
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INTRODUCTION
SCOPE OF SERVICES
SITE DESCRIPTION AND SE
Site Description
Drainage and Topograph
Geologic Setting I
SITE HISTORY
Historical Site Uses
Historical Adjacent Site U es
AGENCY INFORMATION REVIE
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Washington State Depar ent of Ecqlogy
Seattle-King County Heal Depar~e*.t \
Federal Way Fire District 39 ¡ \ \ \,
Federal Way Planning De artment \ \ \ \
Federal Way Public Wor DepartmepV /, \
!\ ¡ / \ /
SITE RECONNAISSANCE //, ! \ \¡ ~ '.
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SUMMARY OF FINDINGS AND ONCLUSIONS
\ \/: \
NON-SCOPE CONSIDERATI~N1 :"\ \
USE OF THIS REPORJ' \ \! \)
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-REFERENCES\ \ \ \ ~ "I
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EXHIBIT C
PAGE IIU)F
12/14/95 C:\WPDOCS\LAI\BELMOR.ESA
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Figure
Title
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Yicinity Map
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i LIST OF FIGURES
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Observed Conditions Ma
1ST OF APPENDICES
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IDSTORICAL TITLE RE aRT
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EDR REPORT
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INTRODUCTION
This report presents the reslùts of a Phase I environmental site assessment (ESA)
performed for the proposed SeaTac Mall Regional Storage Facility to be located near the
intersection of S. 324th Street and Pebble Beach Circle in the City of Federal Way, Washington.
This ESA was conducted in general accordance with guidelines of th~';American Society
/ \
for Testing & Materials (ASTM), as identified in their Standard Practice fòr Fnvironmental Site
/7
Assessment Process, E 1527-94, and as currently applied in the Pu~et-\Sbund region. This
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standard, while subject to change as all standards are, is recognized as g~rifrally meeting the
"due diligence" requirements of the Superfund Arne~dments/~d Reauthot:{z\"tion Act (SARA)
of 1986 [42 USC 9601(35)(A)(i)] and the Washington Stat~M~del Toxies C~n'~ol Act (MTCA)
\ / ';)
[RCW 70.105D]. \; /\ '.
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SCOPE OF SERVICES ,\ (
This ESA was conducted by Landau ~~~iates, Inc. ~o\ the City of Federal Way (City)
to assess the potential for hazardous substances, oJ.: materials \tçi exist on the site. The scope of
\ 1'. '. ." .
services performed, as established in an Octob~r\jO, '1.995 proposal to the City, included a revIew
¡ ; , '.
of site history, review of agency informatiox{ k( site\reconnaïssance, and preparation of this
report. Authorization to proce~~~ these s~ryk~1-,~as provided by Mr. Marwan Salloum of
/ F' " 1 !
the City on November IS, 19~5( ) J l/
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SITE DESCRIPTION A~ ~~~G
SITE DESCRIPTIOft'--, " \ \ \)
/ " \ \ '
The su91e7tS~e\fs 10cated\d)1e south of SeaTac Mall near the northwest corner of the 63-
\ \ " v
acre Belmor Nfdfile \ ~ome Park and golf course. The subject site consists of an area
approximately ~o\md~d by South 324th Street on the north, the Belmor Mobile Home Park
, \ \ ! ¡
property line or\ t~;/1est, an open charmel drainage ditch on the east, and a fenced area
containing satellif~ djshes, a small building, and the road on the south. The site includes a golf
course fairway and~een, a small gravel parking lot, a non-permanent recycling storage facility,
and the drainage ditch. For the purposes of this study, the remainder of the Belmor Mobile
Home Park was treated as an adjacent site. The area surrounding the subject site includes
SeaTac Mall to the north, residential developments to the south, the 1-5 corridor to the east, and
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a mix of commercial and residential activity to the west. The site location and surrounding area
are il1ústrated on the Vicinity Map, Figure 1.
DRAINAGE AND TOPOGRAPHY
The site and surrounding area are situated within the West Hyleb95 Creek drainage,
/ ".
which drains to the south and ultimately into Commencement Bay. A UI).Ìted'States Geological
. //
Survey map of the area shows West Hylebos Creek as an intermittent strea)n\ In general, surface
water runoff flows onto the site from the north and west. . Runoff is ch~efed into the open
drainage ditch on the east boundary of the site, and flows so~~ to the south~rn site boundary,
/ ' : ,
where it enters a section of underground storm drainagepystèm though'?- 18-inch diameter
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storm drain pipe. According to USGS maps, the original 'Fnn7~ for West H;yìebos Creek was
near the current ditch aligmnent. \. \, / )
\ /
Site topography is that of a gently rolling golf cour~,e ~ith an overall downward slope
to the southeast. The site is generally 4-12 ft,Jô\,er in elev~ti~n than the adjacent property to
the north and west. Grading activity, (both dlf;þÌ1g and fillirigŸ~ associated with nearby streets,
, ;\ " ; / .
commercial and public works developments r~\m~dified the pre-existing natural terrain. A
uniform cut slope is apparent on the north an;d (~est\,ides of the site.
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GEOLOGIC SETTING ( /F\ ¡ . !
The site and surroun~~ aJiis underlkfu by consolidated and unconsolidated deposits
\ \/ \
of the Quaternary Period. Gla:ç:Ûil Jill., ~ mixture of compacted silt, sand, gravel, and cobbles is
¡ / \ \
present througho~t.~e study a~eà\ (Wf/äron 1961), and according to Belmor Mobile Home Park
property man~r/,~~cy EvanS.¡ <\995), is about 8 inches below the soil surface throughout the
property. The\a{t b~\ along th~11Orth and west sides of the subject site suggests that cutting
and filling has \Òfifiri near snrface soil conditions:
SITE mSTORY\/ J
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The review\øf site history included research of aerial photographs, topographic and other
maps, real estate atlases, local history information, historical title information, and other
resources to assess past uses of the site and adjacent properties relative to the potential for
contaminants of concern to exist on or near the site. Specific information used to evaluate
historical site and adjacent site uses included:
EXHt8f17~ßELMOR.~e
PAGE "S OF--18.2
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. Aerial photographs (Walker & Associates 1936, Pacific Aerial Surveys 1961 and
1965, and Washington Department of Natural Resources 1936, 1965, 1970,
1978, 1985, and 1989)
. Topographic Maps (U.s. Geological Survey 1949, 1961, 1968, 1973, and 1981)
. Survey Plats (US. General Land Office 1868)
. Recorded title documents (All Lands Title).
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Information sources contacted or reviewed but which did notpr:,ovide pertinent data
regarding the site and adjacent properties included historical fire insur~cè, maps, city street
directories, county real estate atlases, and the City of Feder~l~ay Librari(. \Several attempts
were made to acquire historical maps of theoBelmor Mobile)1o~ Park from i,ts\manager, Nancy
, / \ /
Evans, without success. ': \ . /; , .
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Historical uses of the site and surrounf\. area can b~\ d\"ced back to 1868 when the area
was originally surveyed by the General L~~ 'Office. Ai\ .that time the site consisted of
¡ \, '. ~
undeveloped land. Documentation of site use~ ib ~oheadily ascertainable between 1868 and the
¡ ¡ ;. ~
early 1930s. However, aerial photographs t~1tn ~~tr'een 1936 and 1989 show that the site
consisted of undeveloped for~s(í~od until 1þ6¡(/~en the Belrnor Mobile Home Park was
/ /' ; i j
established. The Wilson Brotþ~s togging Co. ;o"o/ned the site in the mid 1950s and it is possible
0 ,\ 1: 1/
that they logged the site. The ~\it~}lPp'èfrs to ha~e retained its original development features and
continues to be used prirnarilY\ asl'~oì{ course fairway and drainage ditch.
A historic~rîèview of titÍ'~ ~ctiv.~,tý for the period 1945-1995 was requested from All Lands
/ '. \ \ . 0
Title (their Hi~forica~ Title Repo# 10s presented in Appendix A). The review, which traced title
\ ( \ \ \ /
activity on the \e~tire \B~lmor Mobile Home Park parcel ba~k to 1942, shows that there were 6
recorded real es~at~ coi1tracts or deeds transferring ownership since 1941, when the property was
\ \ ¡!
part of a land gt~t ~¿ ~e State of Washington. Wilson Btothers Logging Company acquired
\ \/ ¡
the property fro~ tI;e/State in 1954 and sold it to a development partnership in 1966. The
property passed thiough several development companies before being sold to Belmor Mobile
Home Park, Ltd. in 1972.
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HISTORICAL SITE USES
The title search also revealed a number of utility easements, including one for the
drainage ditch and a right-of-way to Olympic Pipe Line Company for petroleum pipeline
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construction. It was also noted that the State of Washington reserved all oil, gas, mineral, and
ore rights when it sold the property to Wilson Brothers Logging Company in 1954.
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HISTORICAL ADJACENT SITE USES
Historical uses of the area surrounding the site can be traced back to J868 when the area
/ ,
was fist surveyed by the General Land Office. A that time, the s~9ùnding area was
'/ .
undeveloped. The nearest activity focused on Telegraph Road, whicl1 ~as., located east of the
site in the area where the Weyerhaeuser campus is located today. Afea\u\,es are not readily
ascertainable between 1868 and the early 1930s. However, aeyi,al photogr~pþs taken, between
1936 and 1989 show that the surrounding area was primariíy 1ndevelope~ ~etween the mid
'/ '/ \ ~
1930s and early 1970s. In the mid to late 1970s, the surro~dfg ,fea develop~.¿ at a faster pace,
with the establishment of South 324th Street and SeaTac MðJl\rc6r!h of the site, single family and
\ '/
residential apartments to the south, the Belmor Mobile Ho\rtPark and the 1-5 corridor to the
éast, and single family and residential aparÌD}en.~s and busi11e~es to the west.
, .
, .. \)
AGENCY INFORMATION REVIEW \ '\\\.
. ,., '
Environmental Data Resources, Inc. (~QR) .W~s subcontracted to conduct a search (as
-', ,/, "
prescribed by ASTM) of U.S. 1Jrfvir~nmental Prpteèti6n Agency (EP A) and Washington State
Department of Ecology (E{o~iY:)'j enviroru\nental databases for known and suspected
contaminated sites within a 1\n\p7)r~~ius of ili~ site, potentially including the site. Appendix
B presents the results of that $fã~ch\as\ well as a map illustrating the locations of. known and
suspected contan;nat~d s~tes ir\ ~latieÞ to the subject site. The report shows that the subject
site is not liste9'~ )U1);"'?f the EP 4 4atabases searched by EDR. However, the EDR report shows
, '/ ' , ¡ /
that the'Belmo\ ~obi'e~ome Patk appears on Ecology's Leaking Underground Storage Tank L~st.
In addition, Ecd~o~ hfS¡ documented four small-quantity generators of dangerous waste within
a 1/8-nùle radi~ d! tHe þubject site. As with most database searches, EDR found that some sites
, , I :
were not mappabJe\.{fy.è to incomplete address information. However, by comparing theEDR
\ '/
list of "orphan sites" to the required radius search requirements and a county map, we
determined that seven of the orphan sites fell within the designated radius triggering a need for
further inquiry. All seven sites are small- or large-quantity generators of dangerous waste.
These sites, as well as the four listed dangerous waste generator sites, are discussed below.
12/1EXffIBIT:°R.~A ~-
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WASHINGTON STATE DEPARTMENT OF ECOLOGY
-The Belmor Mobile Home Park property appears on Ecology's Leaking Underground Storage
Tank List. Ecology's file indicates that a 300-gallon underground storage tank was removed in
1990, and that 35 cubic yards of petroleum-impacted soil was excavated and land farmed on the
property. None of Ecology's file documentation included a map showing th~tank location with
/ "
respect to the subject site, but a sketch found in that file supports theJocation indicated by
/ /
grounds keeper Carl Cooper (1995), adjacent to the maintenance shed(il\-the southwest comer
of the property (south of the subject. site). According to Mr. Cooþerr excavated soil was
landfarmed at the maintenance facility and then used for variouJ\projects throughout t~e Belmor
Mobile Home Park. Mr. Cooper also indicated that a 1l0-gaIíori above-grolU1d diesel tank was
/ / '. "
removed at the same time. This was confirmed by the loca', ~Ie <)~partment (IÌ)gham 1995). Due
to the geographic distance involved, apparent sma~ \y6hþme of impacted soil, and
\ /
topographically lower elevation, it is lU1likely that petrole~product from these tanks could
have migrated to the subject site. ( '\ \ \
The other leaking undergrolU1d storage ,~~ sites are\g~nerally more than Vz mile from
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the subject site. A review of associated file~ 8,h?~ed that those sites involved localized soil
contamination, which in most cases, was exca.v~JJd àpd landfarmed onsite. Accordingly, it is
our opirúon that the risk of co~;.aIÍÙI1ants from t1¡é~~_sftes having migrated to the subject site is
low. ' / //'\ i, , ,
The four listed and se~eh ojphan sites identified in the EDR report are small- or large-
\ \ / '-:
quantity generators of dangerd,u$V\;:a;:¡tè. A review of associated files from Ecology's Northwest
" / '. "
regional office sho~s they cor\ta'~ d,niy waste notification fOnI1S. Therefore, environmental
/ '. \ \ \/ . . .
conditions at ~és)-ß,~tè\~ or their\p?tential impact to the subject site cannot be deterinined.
, \\ \\ ~/ .
SEATTLE-KlNC\ ~O~ HEALTII DEPARTMENT
Re~iew 6( ~~.ttl~-King COlU1ty Health Department information consisted of telephone
interviews with \ sMut~rian David Koperski (1995) and environmental specialist Carsten
\ ./
Thompson (1995).\ ßécording to Mr. Koperski, the county has not documented any septic or
sewerage problems with the subject site or immediately adjacent parcels. Similarly, Mr.
Thompson stated that the county has not documented any environmental problems with the
subject site or immediately adjacent properties.
EXHIBIT e
12/14/9PÃGËIii..Õ F -1 r2
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FEDERAL WAY FIRE DISTRICf # 39
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-According to Chris Ingham (1995) the department has no record of fire or hazardous
material calls made to the site or to the adjacent Belmor Mobile Home Park. He is aware of the
underground storage tank that was removed from the park in 1990.
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FEDERAL WAY PLANNING DEPARTMENT /.
Department records show that the site and surrounding area is cun:eh~y zoned RIM 3600
/ .
as multi-family residential. In addition it is located within the West Hyléb9;s ~urface water basin.
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FEDERAL WAY PUBLIC WORKS DEPARTMENT . \ \
No pertinent land use information was obtained from ~s departIri~rlr
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SITE RECO NNAISSAN CE
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Landau Associates conducted a reconnaissance of the site oh November 21,1995 to assess
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current land use activities and environmental conditions. T~e(reconnaissance was documented
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with notes, a checklist, and photographs. Al p,~rt of the frt?nnaissance, Landau Associates
interviewed Ms. Nancy Evans and Mr. Cad ~ò\per, Behrt~j Mobile Home Park property
manager and grounds keeper, respectively. AfcO~:~~g to Ms. Evans, the site has been under its
current use since 1968, and, before that, was oeli"eved, to be either an orchard or undeveloped
-, i /....
forest. Features of the site and lp:unediah~ly/~cÌjatent property, as observed during the
. /, , '
reconnaissance, are illustrate{ ~~~1 Observef J:onditions Map, Figure 2.
The subject site is a pòr\~Y oT\the Belnì:or Mobile Home Park, located just south of the
SeaTac Mall at 2101 South 324tþ St(è~t\jn Federal Way, Washington. The site is currently used
\ ( \ "
as part of a golf c9ur~~ and inclV~es a\~irway, putting green, a small gravel parking lot, a non-
permanent recycl41g\s~rage faci~~, and an open channel drainage ditch. An asphalt~paved golf
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cart path runnf~ no~tl\-south trkverses the site adjacent to the drainage ditch. .The recycling
facility is a fen\e9: enfl9sure containing receptacles labeled for yard waste, glass, cardboard,
metal, and newspaper? ;Known underground utilities on the site include an automatic sprinkler
, . , . .
system for the fainVa~! and a sanitary sewer line just west of the drainage ditch. No evidence
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of the Olympic Pip'eÌine Company petroleum pipeline was observed onsite.
Site topography is gently rolling, with a slight overall slope to the southeast. The subject
site is from 4 to 12 ft lower in elevation than the property to the north and west, where uniform
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12/14/95 cEXHISJ¡A C 6
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Site runoff flows into the drainage ditch on the eastern site boundary, then south until
it enters a 48-inch stonn drain pipe at the south end of the site. The drainage ditch is about 720
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ft long, 15-20 ft wide, about 8-10 ft below the adjacent ground surface, contains about 2-3 ft of
accumulated sediment and soft organic material, and is overgrown with several types of wetÏand
vegetation. /
Flow enters the drainage ditch from a 48-inch pipe that drains a çlé't;Rtion structure on
/
SeaTac Mall property to the north; from a 6-inch concrete pipe located aboÙt 120 feet south of
; /", ,
the north end of the ditch; and from an 8-inch concrete pipe at the south è14 of the ditch. The
origins of the flows from the 6- and 8-inch pipes could not bY;,ascertaine& Additio~al ronon
may also enter the site from the property to the west, whiq(¡s 1. local topoW~phic high.
/ / ' ,
Fertilizers, herbicides, and fungicides are applieâ t6 the site as p¥t of golf course
\ \ /\
maintenance. These chemical, along with small quantities òf'gáso)ine and diesel fuel (estimated
\ /
at less than 60 gallons, stored in 5-gallon containers) are st~r~ in the maintenance shop south
of the site. Three 55-gallon drums labele<vI~r waste oí\ ~torage were also noted at the
maintenance facility. Two of these drums wereßt~red inside\a \shed, and the third was located
, '\ ", ;, /
outside the front of the shed. \ \,\\ '\'
In addition to the maintenance facility, Þi þrimb,~r of mobile homes, a recreational vehicle
, /,',
parking area, and paved roadw~ys~!th under~9,11Ii'~)Ìtilities are located on the property to the
south of the site. / /\ ; .
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To the east of the sû.blect) s~te are thé' Belmor Mobile Home Park Clubhouse and
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additional mobile homes on l~dscjlp;e~ lots. All of the buil~gs within the mobile home park
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are reported to h/Y~, electric O{ ~a~~ gas heat. There are no known oil or propane heat
systems wifull;,Ah;.-pdrk, nor ai~ '~ere any septic systems. The entire park is ~erved by city
sanitary sewer\C~v~ 1995). \/
Directly\n~rth, o~ the site is South 324th Street, and north of that is the SeaTac Mall
parking lot (ind\~? ~e storm water detention structure that discharges'into the drainage
ditch). A power ~ans~ssion main approximately follows South 324th Street but does not cross
the subject site. r-q9->bbvious environmental hazards were observed on the subject site.
,
A Lakehaven Utility District water tower is located on the property to the west of the
subject site. This property is a local topographic high, and is partially covered by grass near
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South 324th Street. A fence encloses the water tower and a storage yard for water system
construction materials. No environmental hazards were observed on the water tower property.
12EXRmrr~ OUSA C
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South of the water tower and west of the subject site is an undeveloped parcel.covered
with trees and brush too thick to allow access. Evidence of historical logging was visible, as well
as filling activity along 17th Avenue South. Other than small amount of urban debris (grocery
carts, tires, and plastics), no environmental hazards were observed from the accessible portions
of that property. /.
South of the undeveloped parcel and adjacent to the west edge o~the)subject site is the
/ /
Lexington Downs apartment complex. This development appears to pe)Q-15 years old, with
electric heat and underground utility services, and is separated from th\{ S~b\~ct site by a fence.
The only potential environmental hazard observed on this /property cq~isted of, garbage
dumpsters, which are located in wooden enclosures inAarkus locati;~\ throughout the
/ / ; ;,
development. It is unlikely that improper disposal of haza1'dFs )\ubstances vi~these dumpsters
would impact the subject site. \ \/ )
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Landau Associates collected samples of sediment fr~nrthe drainage ditch for chemical
analysis on November 21, 1995, as part of a se~:xÍì:,~te investig~ti~n. The results of those analyses
indicates that ditch sediment contains elevated"lè.yels of me~al$, petroleum hydrocarbons and
i ., ... ;/
polyaromatic hydrocarbon compounds. Wa~~~n currently has no quality standards for
freshwater sediment; however, the levels of th~~to~pounds are high enough so that once the
sediment is disturbed (e.g. excavaféäJor constr\uqrÒrvJspecial handling and treatment/disposal
/; : ( - '
methods will be needed. {<d9iti?nal inf°m:-aþon on this subject is contained in Landau
Associates' letter report on se\iÙ;ner\t!~amplingldated , 1995.
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SUMMARY O~,I(~ING$ t-Ni?}:ONCLUSIONS
A revieyl of-s!té\ history s~o\vs that the site consisted of undeveloped forest land until the
Belmor MObil~\ ~om\ ~ark was ~~tablished in 1968. Since that time the site appears to have
retained its ori~f d~v:lopment features ,and use as a drainage ditch and golf course fairway.
The area surro~d;in~ tfe site was relatively undeveloped until the mid- to late-1970s when
numerous busin~sis ~ere established north and west of the site in addition to single-family
; /
residences and ap~J'tment units to the south and west.
A review of federal, state, county, and local information shows that the site does not
appear as a confirmed or suspected contaminated site. However, there are several sites of
concern within a 1-mile radius of the subject site. These include the Belmor Mobile Home Park,
. EXttlBIT"'wo",^ C
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which appears on Ecology's Leaking Underground Storage Tank List, and eleven small- and large-
quantity generators of dangerous waste within a 1-mile radius of the subject site.
Field observations, sediment testing, and other data regarding the subject site and
. .
immediately adjacent properties, revealed the following:
. Sampling and testing of ditch sediment confirmed the presence J',f elevated
levels of urban runoff-type contallÚnants. Several metalg/, petroleum
hydrocarbons, and polyaromatic hydrocarbons are present ay(e~els likely to
require special handling and treatment/disposal if excavated{ ~e.dlment along
the entire 720 ft of open ditch appears to have been similarl:rilnpacted. The
presence of these compounds in ditch sediment represents an e~Vironmental
liability which should be assessed by the City prior t9-,purchase/ d,e~elopme~t.
See Landau Associates y 1995 letter for additional informati'on on this
. I~ / / \ '.
subject. ~"". I ~ / / \ \
. Fertilizers, herbicides, and fungicid~s are used, oj gqlf course ~¡intenance
personnel at the site. Since runoff from the golf çoþfse)likely enters the ditch,
some of these materials may reach the creek, an:~ either accumulate in ditch
sediment or get transported downstream. TestÏ1ig (or these compounds was
not performed and there is no eviden,ce which sùggests that they have been
misused. Also, since ditch sediment is '~own to h~v~ been impacted by other
contaminants, and since any remov~l \md treatrr\~Ìu/ disposal of sediment
because of these other contaminéU1¡ts\ \vò~d also Ilkely mitigate these lawn
chemicals, we see no reason to Purs~E7 itU~)ssue at this time. However, if the
City purchases or gains control ov~r ;,portio,ns of the site which continues to
have these chemicals ,áPNied, an a'greeri\ent with the golf course owner to
address this subjec~xf'7x, b~ approp*i~te. .
\ / \: "
. Past grading of th~\ PFophtr appeai.( to have resulted in cutting and filling.
We were not able 'to\6btaí:n' historical records regarding this activity and;
therefore, the magni~d/e/~ ti;üs grading work represents an unknown. Within
cut areas/_such as thà,t ~xpè~téd along the west boundary, few environmental
or ge9~~cal prob1eÏps týpically arise. However, within fill areas the
possibility o~ past dtripping of contallÚnated material increases, as does the
poteptí'al fçr \finding bVried organic zones, piles of stumps, etc. A Phase II
inve~tigatidr,\ (probably performed using a backhoe), would be needed to
asses~ tþ.is ~s~ue in greater detail. The City's future use of the property, its
ownerpl\ip ~<:9ntrol status, and tolerance for risk of such unknowns should be
considyr~9'ï1 deciding if a Phase II s.tudy is required.
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NON-SCOPE CONSIDERATIONS
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As noted in our proposal, ASTM has identified several non-scope considerations in the
ESA process; wetlan~s, asbestos, radon, lead in paint, and ¡ead in drinking water. Although
these issues are beyond the scope of this ESA we provide the foHowing general information.
12/1EXRIBITOR.ESA C,
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The drainage ditch on the eastern portion of the site is a constructed stormwater
conveyance facility, which, by design, contains water much of the time. Sediment has
accumulated in the bottom of the ditch and vegetation characteristic of wetlands has developed
there. A wetland assessment by Sheldon & Associates, dated November 30, 1995, prepared for
the City, should be referenced for additional information on tlús subject. /
Because there are no buildings or structures on the site, it is unlikely that asbestos or lead
. / /
in paint exits, except that which could be buried in fill or at backgr~únßlevels in the native
soil/ fill, or minor amounts associated with th~ recycling containers. V '; \
Lead in drinking water and the presence of radon are npt discernable without sampling
and analysis; however, the EP A (1993) and the U.S. Geologj~ ~urvey (1993) conside; the area
/ / ; ';
where the parcels are located to have a low potential for r~d(n. ).ead in drir4<fug water should
not be an issue because the area is currently serviced by dtY/ ira}er.
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USE OF THIS REPORT / \ \ \
This Phase I ESA has been undertake~ <4:~o.this repod,¡}epared for the exclusive use of
, '00 00 ;.
the City of Federal Way for specific applicati°r 'tò, ~e subject site. It is intended to provide the
City with an understanding of the potential en~o~ental liabilities associated with the site
, evaluated. Reliance o~ this rey6~i '9Y third péll(tí:i\ó~ others who do not have a contractual
relationship with Landau As(o)iá'tè,s 'for this proJect is at their sole risk.
This report is based on\obseivo~pons and'Wormation obtained during one visit to the site
, 0, / ., 0
and is based solely on the co'\èl~tio\ ~f the site on ~e day of the visit, supplemented with
information obt~?y Landa~, ~soo\ijtes and described herein. In evaluating the site, Landau
Associates has Jé'lißd" ~ good faith~ on representations and information abstracted from sources
, / \ \ \ )
noted in this r~p~rt t~ ~e extentÆhey have not been contradicted by site observations or data
obtained from drfr srui-ces. Accordingly, Landau Associates accepts no responsibility for any
deficiency, miss~t~mjnits, omissions, or misrepresentations in the information provided to us.
Determin~i~¡{ether site conditions defined in this report represent contamination at
levels of concern 'o/.~ matter of judgement. Liabilities associated with contaminated sites are
defined in part by the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) and, for property located in Washington State, by the Model Toxics Control Act
(MTCA). The MTCA cleanup regulation, WAC 173-340, defines the administrative process for
identification, investigation, and cleanup of hazardous waste sites. It also includes detailed
12Ex:RiBffLMORoESA Co.
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requirements for establishing cleanup levels, selecting cleanup actions, and detennining
compliance. Cleanup levels developed in accordance with regulations may provide some
guidance as to the level of concentration of a hazardous substance that may pose a threat to
human health and the environment. However, MTCA regulations'make it clear that exceedances
of the specified cleanup levels "do not necessarily trigger requirements for ;:,leanup activities"
(WAC 173-340-704). In assessing the need for cleanup action, the natur~/~f :release, exposure
/ /
pathways, and the nature of receptors must also be considered. De~e~g whether a site
poses a threat to human health and the' environment, and therefore pMe~ti~lly needs cleanup
action under MTCA, requires an evaluation of these factor~,\ in the con'~e~t of the. cleanup
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regulations and exercise of professional judgement. The ~9in?S and conc1Ìi\si?ns of this report
are based on Landau ~sociates' evaluation'of infonnation ~bfin.7,d and revie~éd for this project
and reflect our professional judgement with respect to that iÌ)forjnation.
. \ /
Within the limitations of scope, budget, and schedul~, fndau Associates has perfonned
the services and made the findings in accordrè~ with gene\a~y accepted practices for Phase I
ESAs in effect in King County at the time thir Ke~ice were ~,formed. This warranty stands
in lieu of all others warranties, express or imP\li~'4. \y&ile thiš report Can be used as a guide, it
r ; ; " "
is neither a rejection nor an endorsement of ü1e &te. \~t must also be understood that changing'
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circumstances in the environm;n1:ard use of¡ ~'sttè 'can alter the conclusions and findings
contained in this report. / /'\ \ ! ¡
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\ \;~\ l/ ~AU ASSOCIATES, INe.
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WDE/MLM/ mjp \ ):'
No. 238009.10 \ \ / ¡
12/14/95 D:\ WPDOCS\PR~JEIþ'S\~WAY\BELMORESA
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William D. Evans, CPG
Associate
EXHIBIT C
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12/\4/95 C:\WPDOCS\LAI\ßELMORESA
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REFERENCES
Cooper,' Carl. 21 November 1995. Personal communication (interview with Ken Chaput, Landau
Associates, Inc. regarding Belmor Mobile Home Park maintenance practices and tank removal).
Belmor Mobile Home Park.
Evans, Nancy. 21 November 1995. Personal communication (interview ;yith Ken Chaput,
Landau Associates, Inc. regarding current and past uses and background infoþnation about the
Belmor Mobile Home Park property). Belmor Mobile Home Park. / / /
!- ;
" /, \
Ingham, Chris. 21 November 1995. ,Personal communication (inteme-t.y 'iWith Ken Chaput,
Landau Associates, Inc. regarding environmental conditions of the site an~ ~urrounding area).
Federal Way Fire District #39. /\" \
/ ;, ' '
Koperski, David. 20 November 1995. Personal communic,at1or(telephone iAtà~iew with Dale
Stirling, Landau Associates, Inc. regarding environrnent~l (on~ition of the\site and adjacent
properties). Seattle-King County Health Department. \ \ // \
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. 1995. ~tter Reporti\\sediment sampling and chemical
,/ ': \ \
M.~ey, Bill. 11 Dec~mber 1995. p~rsonal kq\~~~atioA gelephone interview w~th I?ale
StirlIng, Landau AsSocIates, Inc. regardIng the Çnym.pIa PIpelIne easement across the subject site).
Olympia Pipeline. \ \ \. \"
¡ V' \
Thompson, Carsten. 20 Novemger,\1995. Per¥òr;.ai\cdmmunication (telephone interview with
Dale Stirling, Landau Associate;5~Inc. '.regarding\envir~ental conditions of the site and adjacent
properties). Seattle-King Co~~~e¥th Deparqnent.
\ \ ! j j
Young, Don. 30 November 1$9;5/' Pe¡rsonal éommunication (telephone interview with Dale
Stirling, Landau Associates, In~. rega,r<\ing uses of Lakehaven Utility District's adjacent storage
yard). Director of Water Resoqrc(es, t<it<ehaven Utility District.
/"'. \ \ \/
u.S. Environm~tc;J-P.rqtection A~èpcy: 1993. EP As Milp of Radon Zones: Washington. EP A Report
402/R-93/067.\ ( \ \ \ )
\ \ \ \ Y ,
u.S. Geological ~~e~¡, \~993. Geologic Radon Potential of EP A Region 10. Open File Report 93-292-
J. \ \ j!
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Waldron, H.H. 1~6í ßeology of the Poverty Bay Quadrangle, Washington. U.S. Geological Survey
Map GQ-158. ;, /
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Landau Associates, Inc.
analyses.
EXHIBIT C,
PAG E.us..OF ~
12/15/95 c:\ WPDOCS\LAJ\BELMOR.ESA
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SeaTac Moll
SeaTac Mall
SeaTac Moll
Stormwater
Sand Detention
Stockpile Parking Facility
Area
/
S 324th St.
Materials
'/ Storage
/ lowater
Tower
Yl
Recycle l
.Station
Lake Hoven
Utility District
Soil
t Stockpile
Storage
N Undeveloped
Property
SeoToc Moll
Regional
Storage
Facility
(Selmar
Mobile Home
Pork)
Open
Ditch
Fairway
Pipe
Fairway
~
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200
1
Scale in Feet
400
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EXHIBIT
PAGE.Li10F. I..
SeaTac Moll Regional Storag~ Facility (Selmor Mobile
Observed Conditions Mop, November 21 1
Figure 2
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South 324th to South
336th Streets Trunk
Storm. Drainage
and Belll1or Regional
Storage Facility
JIll provelllen ts Proj ect
Environmental Checklist
(SEP A Chapter 43.21C RC.W)
Submitted by:
City of Federal Way
Prepared for
City of Federal Way
Technical Assistance Provided by CH2M Hill, Inc,
JULY 1996
CHM HIll.
EXHIBIT C
sea1002cEsJã?AGEm ~ -111
7/23/96
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Environmental Checklist
July 1996
South 316th to South 336th Streets
Trunk Storm Drainage and Belmor Regional Storage Facility
Improvements Project
A.
1.
BACKGROUND
Name of proposed project, if applicable:
South 324th to South 336 Streets Trunk Storm Drainage and Belmor Regional Stor-
age Facility Improvements Project
2.
Name of applicant:
City of Federal Way, Surface Water Management Department
3.
Address and phone number of applicant and contact person:
Mr. Jeff Pratt, P.E.
City of Federal Way
33530 1st Way South
Federal Way, Washington 98003
(206) 661-4135
4.
Date checklist prepared:
July 1996
5.
Agency requesting checklist:
City of Federal Way, Department of Community Development
6.
. Proposed timing or schedule (including phasing, if applicable):
Construction schedule June through September 1997.
7.
Do you have any plans for future additions, expansion, or further activity related
to or connected with this proposal? If yes, explain.
Yes. In order to alleviate the potential for frequent flooding of South 320th Street,
and adjacent private ownership between SR 99 and 23rd A venue South, the storm
drain conveyance system to the north of the project limits will be enlarged at a
future date. A regional water quality treatment facility will also be constructed at
the location of the existing Sea-Tac Mall stormwater detention facility.
wJ,5~H I 8 IT Srt
7/23/PAGEl6iOF
EXHf&,~r
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ENVIRONMENTAL CHECKLIST
8.
List any environmental information you know about that has been prepared, or
will be prepared, directly related to this proposal.
.
Other available environmental reference information for the project includes:
King County Surface Water Management Division, 1991. Executive Proposed Basin
Plan, Hylebos Creek and Lawer Puget Sound, Prepared in association with the City of
Federal Way, July 1991.
CH2M HILL, 1994. WHO8, WHlO, and WHll Regional Drainage Analysis and WHO8-
CIPOl Project Predesign Report, Prepared for the City of Federal Way,
Contract 93-284, December, 1994.
Sheldon & Associates, 1996. Wetland Delineation and Flaggingfor the Belmor Mobile
Home Park Regional Storage Facility. Prepared for the City of Federal Way. April 1996.
Landau Associates, Inc., 1995. Draft Phase 1 Environmental Site Assessment, SeaTac
Mall Regional Facility. Prepared for the City of Federal Way. December 19, 1995.
Landau Associates, Inc., 1995. Technical Memorandum: Results of Sediment Sampling
and Testing SeaTac Mall Regional Storage Facility. Federal Way. Prepared for the City of
Federal Way. December 15, 1995.
CH2M HILL, 1996. South 324th to South 336th Street and Belmor Regional Storage
Facility Improvement Project. Geotechnical Data Report. Prepared for the City of Federal
Way. Contact AG 95-265, Draft, July 1996.
9.
Do you know whether applications are pending for governmental approvals of
other proposals directly affecting the property covered by your proposal? If yes,
explain.
No other related applications are pending for governmental approvaL
10.
List any government approvals or permits that will be needed for your proposal,
if known.
The approvals and permits anticipated for the project consist of the following:
.
U.S. Army Corps of Engineers Nationwide Permit 26 letter authorizing direct
and indirect impacts of jurisdictional wetlands or waters of the U.S. (for com-
bined impact area up to 1.0 acre)
Washington State Department of Fish and Wildlife, Hydraulic Project Approval
.
.
Washington State Department of Ecology, Short-Term Modification of Water
Quality Standards
.
City of Federal Way zoning code compliance or process approvals (Divi-
sion 5-Streams, and Division 7-Regulated Wetlands). Land Surface Modification
Approval (issued as grade and fill permit)
EXHIBIT e
SEAlFEDWAY.DOC
7I2p AGE J.30 0 F --.LB.L
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ENVIRONMENTAL CHECKLIST
11.
Give brief, complete description of your proposal, including the proposed uses
and the size. of the project and site. There are several questions later in this
checklist that ask you to describe certain aspects of your proposal. You do not
need to repeat those answers on this page. (Lead agencies may modify this form
to include additional specific information on project description.)
The proposed project would improve the trunk drainage system, within Drainage
Sub-basin WH10, in the City of Federal Way. For the stream reach extending south
of South 324th Street (north limit) and north of South 336th Street (see Figures 1 and
2.). The proposed project is the first phase of a storm drainage improvement project
to alleviate frequent flooding of South 320th Street and adjacent private ownerships
between SR 99 and 23rd Avenue South.
The proposed project would attenuate the impact of increased peak flows delivered
through future (Phase 2) improvements to the upstream (Sea-Tac mall) trunk
drainage system, through construction of a regional stormwater detention basin at
the South 324th Street outfall (within Belmor Park Golf and Country Club).
Existing undersized downstream roadway culvert crossings and storm drainage
facilities will also be improved (to 100-year flood protection level) leading to the
Kitts Comer and South 336th regional detention facilities (currently under
construction).
The proposed project would specifically add the Belmor Regional Stormwater De-
tention Facility located along the western edge (on 9th/18th hole fairway) of the
Belmor Mobile Home and Golf Course, near the intersection of South 324th Street
and Pebble Beach Circle (Site 1, see Figures 3 and 4)
Construction at site 1 will also include installation of 385 feet of 84 inch trunk storm
drain for connection to future upstream storm drainage trunk improvements to re-
lieve flooding in the vicinity of 320th A venue South.
Installation of the 84 inch trunk storm drain will include filling approximately
280 feet of existing stream channel. Filling of the channel in this area is proposed to
cap streambed sediments with elevated levels of urban contaminants as identified
in previous site assessments (Landau Associates 1995).
South of the Belmor Regional Stormwater Detention Facility, the proposed project
would also replace a set of culverts crossing underneath a private drive (Site 2, see
Figure 5), as well as replace a set of culverts crossing underneath South 330th Street
(Site 3, see Figure 6)
The proposed project would also include installation of a parallel trunk storm drain
trunk along 20th Avenue South (Site 4, see Figure 7), and culvert improvements
crossing underneath South 333rd Street (Site 5, see Figure 8). The proposed project
would also widen the Tributary 0014A stream channel and provide a slope
retainage, flood protection wall along the East Empire Garden Aparhnents (Site 6,
see Figure 9).
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IN FEET
WHI0-CIPOI TRUNK STORM DRAINAGE AND REGIONAl STORAGE FACILITY
IMPROVEMENT PROJECT
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Figure 2
SITE PLAN
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ENVIRONMENTAL CHECKLIST
12. Location of the proposal. Give sufficient information for a person to
understand the precise location of your proposed project, including a street
address, if any, and section, township, and range, if known. If a proposal would
occur over a range of area, provide the range or boundaries of the site(s). Provide
a legal description, site plan, vicinity map, and plans required by the agency, you
are not required to duplicate maps or detailed plans submitted with any permit
applications related to this checklist.
The project area extends south from approximately South 324th Street to north of
South 336th Street along the Tributary 0O14A stream channel, in the City of Federal
Way, Washington (see Figure 1). The project site area is located within Sections 16
and 17 of Township 21 North, Range 4 East. The project improvements are pro-
posed to be sited on portions of 7 parcels within this area. The affected parcels' tax
assessment numbers are listed in Table 1. The City proposes to acquire easements
on certain sections of these parcels as part of project implementation.
Table 1: Parcels Affected by the Proposed Improvements
797880-0521 ~j¡I~~Ù
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B.
1.
ENVIRONMENTAL ELEMENTS
Earth
a.
General description of the site (circle one): Flat, rolling, hilly, steep slopes,
mountainous, other (see below)
The site generally consists of a flat to rolling terrain with some steeper areas near the
southern terminus of the project near South 336th Street. The Northern portion of
the project area (Belmor Park area) is relatively flat. Moderate slopes occur to the
east and west of the project sites.
b.
What is the steepest slope on the site (approximate percent slope)?
The steeper slopes within the project site typically range from 10 to 50 percent. The
steepest areas are the roadway embankment fill slopes (with typically 2 to 1 slopes).
What general types of soils are found on the site (for example, clay, sand, gravel,
peat, muck)? If you know the classification of agricultural soils, specify them and
note any prime farmland.
According to the King County Soil Survey, only Alderwood gravelly sand loç¡m
(AgC) is mapped in the project area. Alderwood gravelly sand loam, with 15 to 30
percent slopes, is made Ut of ~o~¡y well-drair><~.j ",' < f¥ - a reé!f"
EXHIBIT . '~~'~""'d
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ENVIRONMENTAL CHECKUST
d.
representative profile shows a surface layer and subsoil consisting of very dark
brown, dark brown, and grayish brown gravelly sandy loam averaging about
27 inches thick. Grayish brown weakly consolidated to strongly consolidated glacial
till to depths of 60 inches and farther characterize the substratum. Soils in the
Alderwood series are not identified as hydric (USDA SCS 1990), but include up to
2 percent areas of hydric soils (Sheldon & Associates, 1996).
Are there surface indications or history of unstable soils in the immediate
vicinity? If so, describe.
No indicators of unstable soils are evident for the project sites. The Soil
Conservation Service (SCS) characterizes the Alderwood soils from zero to
16 percent slopes as having only slight-to-moderate slippage potential due to water
movement over their dense till substrata.
e.
Describe the purpose, type, and approximate quantities of any filling or grading
proposed. Indicate source of fill.
Various excavations, embankments, and other fills will be needed to construct the
proposed project improvements. These will include:
.
Major excavation and limited stream channel fill for construction of the Belmor
Regional Stormwater Detention Facility (Site 1).
Minor excavations and backfill for the replacement of undersized roadway cul-
vert crossings (Sites 2, 3, and 5).
.
.
Trench excavations and selected backfill for trunk storm drain improvements
installation (Site 4).
Minor channel excavation and stabilized fill placement for stream channel
improvements
For the Belmor Regional Stormwater Detention Facility construction and other pro-
posed improvements, the total excavation is estimated to be 22,000 cubic yards
(c.y.). Fill volumes using either select on site or imported material is estimated to be
approximately 7,100 cubic yards, with the majority approximately bein~ native back
fill. Approximately 16,000 c.y. of excess excavation material will be exported to an
. off site earthwork disposal area. The location of one potential earthwork disposal
area is depicted in Figure 1.
.
In addition, approximately 1,200 c.y. of select imported trench backfill and rip rap
would be required for the proposed project. The source of any imported fill mate-
rials is unknown at present, but likely would be from existing local quarry
operations.
Could erosion occur as a result of clearing, construction or use? If so, generally
describe.
f.
Erosion could occur as a result of project construction from clearing and grading
activities. The potential erosion hazard will be greatest in areas of the mass
excavation and filling for construction of the Belmor Regional Stormwater Detention
(' EX "', ~
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ENVIRONMENTAL CHECKU:>T
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Facility and at the site of the excess earthwork disposal area. Construction will be
staged to minimize the interface of stream channel flows and disturbed surficial
soils. Erosion and sedimentation measures using accepted best management prac-
tices (BMPs) will be used to minimize site area erosion potential and to control sedi-
mentation where erosion results until the site can be permanently stabilized through
revegetation. Provision for adequate control measures will be particularly focused
on earthwork interface areas with sensitive stream and wetland areas. A detailed
erosion and sedimentation control plan will be developed with final design of proj-
ect improvements.
About what percent of the site will be covered with impervious surfaces after
project construction (for example, asphalt or buildings)?
g.
h.
No significant changes in impervious surface area would result from the proposed
project. Approximately .41 acres of impervious surface area would be created by
construction of the Behnor Regional Stormwater Detention Facility (permanent
pool). Another approximately .04 acres of impervious surface area would result
from roadway crossing culvert improvements.
Proposed measures to reduce or control erosion, or other impacts to the earth, if
any:
Specific BMPs that will be considered for construction period implementation with
project design to control erosion, sedimentation, or other impacts to the earth will
include:
.
Limiting earthwork activities to the summer months to minimize exposure of
exposed soil surfaces to precipitation
.
Designating clearing limits to limit vegetative and land area disturbance re-
quired for project construction; existing vegetation and significant trees will be
preserved wherever possible
Diverting stream flows around or through the construction site area using tem-
porary measures (i.e., cofferdams, pipelines, channels) to limit the interface of
stream flows and earthwork activities
.
Providing appropriate BMP erosion/ sedimentation controls within the construc-
tion area potentially including, but not limited to, filter fabric fences, diversion
and filter berms, hay bale barriers, check structures, grassed swales, stabilized
construction entrances, mulching, matting, seeding, and temporary plastic
sheeting covers
Permanent soil stabilization measures will consist of seeding, planting, and perma-
nent revegetation of cleared areas not limited to other project functions (see
Item B.4.d).
.
2.
Air
a.
What types of emissions to the air would result from the proposal (i.e., dust, auto-
mobile, odors, industrial wood smoke) during construction and when the project
SENFEXHIBIT ~
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ENVIRONMENTAL CHECKUST
is completed? If any, generally describe and give approximate quantities if
known.
The completed project would not result in operational air quality impacts. During
construction, there would be a temporary increase in fugitive dust,suspended par-
ticulates, carbon monoxide, and other emissions from construction vehicles and
equipment. Since a portion of the proposed project is adjacent to 20th A venue
South, and intersects South 330th and 333rd Street, ambient air quality is already
affected by vehicle emissions. Additional temporary emissions during construction
are expected to be minimal and will likely disperse rapidly.
b.
Are there any off-site sources of emissions or odor that may affect your proposal?
If so, generally describe.
No.
c.
Proposed measures to reduce or control emissions or other impacts to air, if any:
Mitigation measures to be considered for temporary construction period air impacts
include:
.
Spraying areas of exposed soils with water to reduce dust
Washing down equipment before leaving the site
.
.
Periodic cleaning of roadways adjacent to the points of site access
3.
Water
a.
Surface:
1)
Is there any surface water body on or in the immediate vicinity of the site
(including year-round and seasonal streams, saltwater, lakes, ponds, wet-
lands)? If yes, describe type and provide names. If appropriate, state what
stream or river it flows into.
Several small lakes, including Steel Lake to the north and North Lake to the
east, are within a mile of the project area, but would not be impacted. The
proposed project would provide drainage improvements for
Tributary 0O14A (King County Surface Water Management, 1991) to Hylebos
Creek. It joins another tributary (OO14C) to Hylebos Creek approximately 1
mile southwest of the southern extent of the project area. It is shown in the
King County Sensitive Areas Map Folio as an unclassified stream. The
Catalog of Washington Streams and Salmon Utilization (Washington State
Department of Fisheries 1975) does not identify this stream. Tributary 0O14A
is considered a major stream according to City of Federal Way zoning code
criteria (Sheldon & Associates, 1996).
During summer months, stream flow is intermittent in reaches of the stream
system. The stream system discharges downstream (south of South 348th
Street) to the regionally significant West Hylebos Wetland and eventually to
Hylebos Creek and Commencement Bay, Puget Sound. For a more detailed
description of the basin wide stream system and its function, please refer to
'~'8>N^,~XHIBnL uC ffPr EX'NJsIT j:. Jß
7/23/96 ,-JAGElflO': 10-1- PA~ O. t¡i!
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ENVIRONMENTAL CHECKUST
Chapter 4 of the Executive Proposed Basin Plan, Hylebos Creek and Laroer Pu-
get Sound (King County Surface Water Management, 1991).
The five wetlands within the project site areas currently provide a storm-
water storage function within the stream system. The locations of the wet-
lands are described in section BAa. For a more detailed desêription of the
size, type, and functions and values of wetlands, please refer to the above-
referenced documents and the WHOB, WHlO, and WHll Regional Drainage
Analysis and WHOB-ClPOl Project Predesign Report, Section 3 and Appendix 0,
Technical Memorandum 3-1 (CH2M HILL, December 1994).
2)
Will the project require any work over, in, or adjacent to (within 200 feet)
the described waters? If yes, please describe and attach available plans. .
Yes, because of the nature of the project, it will require construction within
segments of the Tributary 0014A stream channel and within the 100-foot
setback areas of the stream and identified wetlands. Table 2 identifies
stream, wetland, and setback impacts for project improvement
encroachments where avoidance is not possible. With the exception of Site 4,
all temporary construction impacts would occur within 100 feet of the
wetlands and streams located within the project area. For all project sites
combined, approximately 2.10 acres within 200 feet of a wetland and/or
stream would be temporarily impacted by the proposed project.
Table 2. Project Permanent and Temporary Direct Impact Areas
ADDITIONAL
IMPACT AREA
WITHIN 200'
STREAM 100' SETBACK SETBACK
PROJECT PROJECT WETLAND CHANNEL AREA AREA
SITE NO. DESCRIPTION AREA (SQ. FT.) (SQ. FT.) (SQ. FT.) (SQ. FT.)
BELMOR REGIONAL 0 5,410 74,950
STORMWATER DETENTION
FACILITY
2 PRIVATE DRIVE CULVERT 0 430 1,520
3 SOUTH 330TH STREET 0 240 1,720
CULVERT
4 20TH AVENUE SOUTH 90 190 6,200 3,400
STORM DRAIN TRUNK
5 SOUTH 333RD STREET 30 300 1,080
CULVERT
6 EAST EMPIRE GARDENS APT 0 720 2,720
DITCH IMPROVEMENTS
TOTALS 120 7,290 88,190 3,400 SQ. FT.
0.003 0.17 2.02 0.08 ACRES
EXH I BIT C__.~...
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ENVIRONMENTAL CHECKUST
Within the regulated 100-foot wetland/stream setback area, the project will
potentially impact approximately 2.02 acres. This includes grading for
replacement of undersized culverts, stream channel restoration, and
construction of the Belmor Regional Stormwater Detention Facility.
Mitigation for wetland and stream setback area impacts will consist of d.is-
turbed setback area revegetation with nature grass and plant species in ac-
cordance with City code requirements. In addition, .41 acres of additional
vegetated and open water habitat area will be created within the Belmor
Regional Detention Facility as mitigation for stream channel fill impacts.
3)
The revegetation plan for the area around the Belmor Regional Drainage
Facility has three primary components. The aquatic bench area created
around the permanent pool within the storage facility will be revegetated
with native water tolerant emergent species arranged in an ornamental
pattern to provide visual appeal. Disturbed fairway areas will be restored
with mowed turf grasses within the main fairway area, while the areas
immediately adjacent to the banks of the storage facility will be left as an
unmowed IIroughll area to catch rolling balls and provide a visual distinction
around the edge of the facility. Disturbed areas along the east bank of the
stream channel will be restored with native aquatic vegetation which may
include shrubs and small trees planted in a natural random scheme.
Estimate the amount of fill and dredge material that would be placed in or
removed from surface water or wetlands and indicate the area of the site
that would be affected. Indicate the source of fill material.
4)
Approximately 1,900 cubic yards (c.y.) of fill would placed in the existing
stream channel adjacent to the Belmor Regional Detention Facility. Filling of
the channel is proposed to cap streambed sediment with elevated levels of
urban contaminants as identified in previous site assessments (Landau)1995).
In addition, approximately 220 c.y. of rip rap would be used to line the
stream areas with culvert improvements.
Will the proposal require surface water withdrawals or diversions? Give
general descriptions, purpose, and approximate quantities if known.
When completed, the project will require off-channel diversion and tempo-
rary storage of stream flows in excess of target base-flow conditions at the
Belmor Regional Stormwater Detention Facility. Runoff beyond base flows
would enter the detention storage area via two sets of culverts under an
access path separating the existing stream channel and the detention pond.
Flows would be released from the detention pond at the outlet work's
through a sluice gate. The project as currently envisioned would begin to
divert flows to the detention basin at or above stream flows of approximately
20 cubic feet per second (cfs). The 25-year estimated diversion flow to the
detention basin (future unrestricted conditions) is approximately 162 cfs.
Outflows from the detention basin back to the stream system (based on pre-
design outlet controls and operation assumptions) would be controlled to
EXHIBIT C,
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ENVIRONMENTAL CHECKUST
approximately 90 cis for a 25-year recurrence interval event under future
land use conditions.
No permanent stream flow diversions are required for other project features.
Temporary stream diversions will be required for project construction; these
will be designed to mininúze downstream impacts. The speCific require-
ments and extent of these diversions will be addressed with the project
design. No surface water withdrawals are anticipated to be required for
project construction or operation.
5)
Does the proposal lie within a lOo-year floodplain? If so, note location on
the site plan.
The floodplain of the West Hylebos stream system has not been formally de-
lineated (by FEMA or others). The project improvements are partially located
within the stream corridor. Therefore, they are partially within the
frequently flooded area as defined by Federal Way City Code.
6)
Does the proposal involve any discharges of waste materials to surface
waters? If so, describe the type of waste and anticipated volume of
discharge.
No.
Ground:
1)
Will groundwater be withdrawn, or will water be discharged to ground-
water? Give general description, purpose, and approximate quantities if
known.
The completed project will not result in groundwater withdrawals or dis-
charge other than temporary withdrawals from shallow perched ground-
water lenses as required for project construction. However, infiltration that
naturally occurs between interfaces of the streams, wetlands, and detention
areas will result.
The bottom elevation of the Belmor detention facility is at or below the sea-
sonally high shallow (perched) groundwater elevations based on ongoing
monitoring of piezometers installed with the geotechnical program. In order
to effectively control direct exfiltration to groundwater and to provide for a
permanent pool in the detention facility, a low permeability soil liner or
geosynthetic clay liner will be provided. Considering the available
groundwater data, construction activities (during late summer) for the
Belmor Regional Stormwater Detention Facility should not intercept the local
groundwater table, or measurably impact shallow groundwater quality.
Describe waste material that will be discharged into the ground from sep-
tic tanks or others sources, if any (for example: Domestic sewage; indus-
trial, containing the following chemicals. . .; agricultural; etc.). Describe
, the general size of the system, the number of such systems, the number of
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ENVIRONMENTAL CHECKLIST
(
houses to be served (if applicable), or the number of animals or humans
the system(s) are ,,-xpected to serve.
None are anticipated.
c.
Water Runoff (including stormwater):
1)
Describe the source of runoff (including stormwater) and method of col-
lection and disposal, if any (include quantities, if known). Where will this
water flow? Will this water flow into other waters? If so, describe.
The source of runoff to the project site area is primarily stormwater runoff
from drainage subbasins WH10, within the City of Federal Way, as shown in
Figure 1. The subbasin WH10 (upper portion) headwater drainage area in-
cludes the highly impervious SeaTac Mall area and surrounding developed
land uses. Collection of stormwater runoff in these areas is principally by a
network of trunk and lateral storm drains. Less intensely developed areas
south of SeaTac Mall (lower WH10 subbasin area) also collect and convey
runoff in open ditches and storm drains that intertie to the open stream
system through this area. Other sources of runoff include dry-weather wash-
off from impervious areas and base flow.contributions from shallow ground-
water interfaces with the stream system.
Total estimated average annual runoff at the south limit of the project sites is
less than 3 cfs. Estimated peak flows at this location under existing land use
conditions are anticipated to be less than 64 cfs for the 25-year recurrence
interval event.
Stream flows conveyed through the project site ultimately discharge
downstream of South 348th Street to the West Hylebos Wetland, then into
Hylebos Creek. For more detailed information regarding the overall
drainage basin runoff potential and downstream elements, please refer to the
WHO8, WHl0, and WHll Regional Drainage Analysis and WHO8-CIPOl Project
Predesign Report, Section 2 and Appendix D, Technical Memoranda 1-1 and
2-1 (CH2M HILL, December 1994), and The Executive Proposed Basin Plan,
Chapter 4, Hylebos Creek and Lawer Puget Sound (King County Surface Water
Management, 1991).
2)
Could waste materials enter ground or surface waters? If so, generally
describe.
The completed project would not result in any new sources of waste dis-
charge into ground or surface waters. The project will help control existing
sources of waste discharge (i.e., pollutant washoff, spills) to the tributary
drainage system. A short-term increase in sediment load delivered to the
stream system could result from construction activities. However, BMP
source control measures, as described in Item B.1.h, would be implemented,
and control of runoff and associated sediment delivered to the downstream
drainage system would be in accordance with agency permit conditions. See
response to Item B.3.b.2 also.
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4.
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ENVIRONMENTAL CHECKLIST
d.
Proposed measures to reduce or control surface, ground, and runoff water im-
pacts, if any:
The proposed project will provide enhanced flood control, water quality benefits,
and stream habitat enhancements. In order to achieve these objectives, temporary
and permanent impacts to the stream system will be required. Project wetland
impact areas are not significant (less than 0.01 acre). Those habitats that will see the
greatest impact from construction generally are those that are currently most
degraded. The project will be designed and constructed to avoid sensitive areas,
where possible, and to minimize impacts where not possible. Construction period
measures to control impacts to surface water and groundwater, in addition to those
BMPs described in Item B.1.h, include:
.
Construction activities compliance with an approved erosion and sedimentation
control plan
Restriction of construction equipment to outside of streams, wetlands, and their
setback areas, except where essential to construct project iInprovements
.
Monitoring and treatment of construction area runoff and dewatering flows
prior to release to receiving waters
When completed, the project will provide long-term (operational) control of inter-
cepted runoff through flow attenuation (detention with controlled release) and wa-
ter quality enhancement (sedimentation and biological treatment).
.
Plants
Check or circle types of vegetation found on the site:
_X- deciduous tree: alder, maple, aspen, other: (see below)
_X- evergreen tree: fir, cedar, pine, other: (see below)
_X- shrubs: (see below)
_X- grass (see below)
- pasture
- crop or grain
_X- wet soil plants: cattail, buttercup, bulrush, skunk cabbage, other (see below)
_X- water plants: water lily, eelgrass, milfoil, other
- other types of vegetation
Habitat types present within and adjacent to the proposed project sites include both
wetland and upland vegetation communities. Wetland community types include
freshwater emergent marsh, and palustrine forested wetlands. Upland types include
coniferous forest, mixed coniferous forest, and grassland! shrubland. The following
is a breakdown of the existing vegetative cover by site:
E~SIT C
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ENVIRONMENTAL CHõCKLIST
Site 1. The stream channel within this site supports hydrophytic vegetation al-
though no wetlands were present. Dominant vegetation in the stream channel is
reed canary grass (Phalaris arundinacea) and Pacific willow (Salix lasiandra). Common
species in this area are creeping buttercup (Ranunculus repens), soft rush Uuncu$
effusus) and hardhack (Spirea douglasii). Several patches of common cattail (Typha
latifolia) are also present (Sheldon & Associates, 1996).
Site 2. North of the culverts, along an existing private access road, is a landscaped
yard. Ornamental ivy grows to the edge of the stream channel. The stream is shaded
by ornamental weeping willow. The vegetation south of the set of culverts consists
of ornamental ivy growing to the edge of the retaining walls. Uplands on both sides
of the stream are landscaped.
Site 3. North of the existing culvert, the upland vegetation consists of red alder and
western red cedar (Thuja plicata) with an understory of Robert geranium (Geranium
robertianum) and creeping buttercup. Himalayan blackberry (Rubus discolor) grows
next to the culverts. South of the culverts the upland vegetation consists of red alder
and black cottonwood (Populus balsamifera), with an understory of blackberry and
salmonberry (Rubus spectabilis).
Site 4. A palustrine forested wetland forms a narrow band along the stream channel
north of the existing storm drain inlet. Dominant vegetation includes red alder, sal-
monberry, and reed canarygrass. Other commonly occurring species include Hima-
layan blackberry and a piggy-back plant (Tolmiea menziesii). The banks of the stream
and adjacent buffer area are vegetated by red alder and Himalayan blackberry. A
wetland exists approximately 27 feet to the southwest of the storm drain outlet west
of 20th Avenue South. The wetland is dominated by red alder with an understory of
salmonberry. Manna grass (Glyceria elata) dominates the herb layer. The wetland
would be classified as Palustrine Forested Broad Leaf Deciduous. Big leaf maple
with a groundcover of dewberry and sword fern comprises the majority of the up-
land vegetation.
Site 5. The stream channel north of the existing culverts is located within a palus-
trine forested wetland. The wetland overstory is dominated by black cottonwood,
with a shrub layer of sparse salmonberry. A dense patch of Himalayan blackberry is
present near the culvert. Upland adjacent to the wetland is characterized by red al-
der, with occasional Douglas fir. The understory is made up of sparse salmonberry,
dewberry (Rubus ursinus), and sword fern. Big leaf maple (Acer macrophyllum) and
western red cedar were observed in the general vicinity.
A palustrine forested wetland is also located approximately 50 feet southwest of the
existing culverts outlet. An open stream channel is present between the culvert and
the wetland. The wetland is characterized by forested vegetation, dominated by
black cottonwood and Oregon ash (Fraxinus latifolia). The shrub layer is primarily
made up of salmonberry, with hardhack as the subordinate species. Herbaceous
vegetation occurs in nearly monotypic patches, including manna grass, creeping
buttercup, and slough sedge (Carex obnupta). The upland is characterized by red
alder with occasional Douglas fir. The shrub layer is sparse salmonberry, and dew-
berry and sword fern make up the undiEtX.' ,¡ ¡ c<,' r .. ~ ~ .
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Site 6. A wetland is present north of the site. South of the wetland, an open stream
channel is present through the project improvement area. South of the project area,
Palustrine forested and shrub wetland communities exist.
The stream in the project improvement area has been artificially channelized. Yege-
tation in the channel includes water starwort (Callitriche stagnalis) and foxtail grass
(Alopecurus sp.). The banks of the stream are maintained as lawn, and are planted
with ornamental shrubs. A forested wetland extends outside the project area to the
east towards Site 8. Black cottonwood and Oregon ash are the dominant trees. The
shrub layer is characterized by Sitka willow.
What kind and amount of vegetation will be removed or altered?
b.
The project will potentially impact a total of approximately 2.3 acres of wetland,
stream, and upland vegetation. Approximately .2 acres of wetland and stream vege-
tation would be permanently impacted. Approximately 2.1 acres of vegetation
would be impacted on a temporary basis.
List threatened or endangered species known to be on or near the site.
c.
The Washington Natural Heritage Program and the Washington Department of Fish
and Wildlife (WDFW) maintain records of sensitive, threatened, and endangered
plant species occurring in the state. These agencies were previously contacted re-
garding the status of these critical resources in the project drainage basin area. The
response letters did not identify any documented sensitive, threatened, or endan-
gered plant species within the project site area. Tne Washington Department of
Fisheries and Wildlife Inventory does identify wetlands downstream from the
project sites in their priority habitat and species inventory and recommends their
protection. The reason for this classification as stated in a July 1994 data report is
that the wetlands in the general vicinity of the project have been heavily impacted
by filling.
d.
Proposed landscaping, use of native plants, or other measures to preserve or en-
hance vegetation on the site, if any:
After construction of project improvements, the disturbed portions of the project site
would be revegetated, using native trees, shrubs, and groundcovers. The areas and
types of vegetative restoration are described below.
Belmor Regional Stormwater Detention Facility (Site 1)
Side slopes within the Belmor Regional Stormwater Detention Facility will be re-
vegetated with a mixture of native upland shrub species and with native upland,
meadow species.
The revegetation plan for the area around the Belmor Regional Drainage Facility has
three primary components. The aquatic bench area created around the permanent
pool within the storage facility will be revegetated with native water tolerant
emergent species arranged in an ornamental pattern to provide visual appeal.
Disturbed fairway areas will be restored with mowed turf grasses within the main
fairway area, while the areas immediately adjacent to the banks of the storage
facility will be left as an unmowed "rough" area to catch rolling balls and provide a
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ENVIRONMENTAL CHECKLIST
visual distinction around the edge of the facility. Disturbed areas along the east
bank of the stream channel will be restored with native aquatic vegetation which
may include shrubs and small trees planted in a natural random scheme.
Trunk Storm Drain (Site 4)
Vegetative restoration over the trunk storm drain outside of the improved roadway
corridor, will be hydro seeded with an upland native grass mixture.
Additional Measures
Additional measures to be taken to minimize construction-phase disruption of exist-
ing native vegetation and associated habitat include:
.
Definition of clearing limits to minimize construction area vegetation removal
.
Controlling erosion through accepted BMPs (see Item B.1.h) and stabilizing ex-
posed soil surfaces during construction through covering, mulching, and/ or
seeding
Locate construction staging or temporary access roads outside wetlands, buffers,
or other sensitive areas; avoid heavily vegetated upland areas where possible
.
5.
Animals
a.
Circle any birds and animals which have been observed on or near the site
or are known to be on or near the site:
birds: hawk, heron, eagle, songbirds, other: (see below)
mammals: deer, bear, elk, beaver, other. (see below)
fish: bass, salmon, trout, herring, shellfish, other
Wetlands support a wide variety of wildlife and typically have a higher
wildlife use associated with them than do terrestrial habitats. Shrub and
forested swamps associated with open water provide dense and complex
habitats. Based on prior studies (Shapiro and Associates, 1991), wildlife that
have been observed or are thought to exist within the project site area are
described below. Within the wetlands in the vicinity of the project site
wildlife include mallards, winter wren, robin, song sparrow, red-winged
blackbird, and green heron. Common warblers, vireos, and sparrows that
commonly nest and feed near marshes are expected. Several species cf
diving and dabbling ducks, including mallards, mergansers, and wood
ducks, are expected to use the wetlands.
Upland forest provides cover, nesting, and feeding habitat for a number of
wildlife species including breeding and year-round resident birds. Species
that have been observed in these areas include robins, bush tits, black-capped
chickadee, winter wren, and song sparrow. Spring-summer residents should
include numerous species of warblers, vireos, thrushes, flycatchers, and
finches.
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Signs of the following mammal species have been observed within neighbor-
ing wetlands: mountain beaver, Douglas squirrels, and deer mice. Other
mammal species may be present. The forest leaf litter and ground cover pro-
vide foraging habitat for small mammals that should include shrews, voles,
and jumping mice. The forest's upper canopy layer should support several
species of bats along with Douglas squirrels. Small mammalian predators
such as long-tailed weasel, striped skunk, and opossums are expected to
exist in the forest, while raccoons are expected to hunt along the edge of the
wetland.
A variety of amphibians and reptiles is expected to inhabit the wetlands in
the project vicinity. These include Pacific tree frogs, red-legged frogs, North-
western salamanders, Western red-backed salamanders, and rubber boas.
Use of fish habitat in the project area reaches of West Hylebos Creek is n<?t
fully documented; however, no evidence exists that shows the presence of
juvenile salmonids throughout the project area streams and wetlands. Pres-
ence of salmon in the lower reaches of Hylebos Creek (below the West
Hylebos Wetland area) and associated good habitat has been documented
(King County, 1987). Culverts in this downstream area are, however, cur-
rently impassable for upstream fish migration. The project area streams
contain only intermittent flow during the summer low-flow period. These
factors render the project area streams inhospitable to resident fish. During
prior field investigation (Shapiro Associates and King County) no fish were
observed within the project area wetlands or tributary streams (Sheldon and
Associates, 1996).
b.
List any threatened or endangered species known to be on or near the site.
The Washington Natural Heritage Program and the USFWS maintain
records of sensitive, threatened, and endangered animal species occurring in
the state. These agencies were previously contacted (1989 and 1994) for
another project in the vicinity of this proposal and did not have information
in their files regarding the presence of sensitive, threatened, or endangered
species of animals in or near the project site. No sensitive, threatened, or
endangered species were identified near the project sites.
Is the site part of a migration route? If so, explain.
c.
Migrating passerine birds and small mammals may use the site during
migration, but the site is not considered a significant migration route.
Proposed measures to preserve or enhance wildlife, if any:
d.
The disturbed portions of the project sites will be revegetated with native
species to provide requirements for food, cover, and breeding sites for a
variety of wildlife species. The native plants proposed for revegetation
should add habitat diversity to the site.
Proposed project elements and measures to preserve and enhance wil~life
will include:
sEXHIBIT <:
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.
Belmor Regional Stormwater Detention Facility permanent pool and
perimeter aquatic vegetation will provide additional habitat for produc-
tion of a variety of macroinvertebrate species; upon movement down-
stream, this food source should help enhance the overall productivity of
fisheries resources downstream from the project area.
Project erosion and sediment control BMPs (temporary and permanent)
that will minimize downstream sediment transport to protect valuable
downstream biological resources.
.
.
Protection of existing wetland and upland aniInal vegetation habitats,
where possible, near the construction area through the use of clearing
limit fences; revegetate disturbed areas in accordance with proposed
revegetation plans.
The enhanced stormwater detention function of the added Behnor
Regional Stormwater Detention Facility will help preserve valuable
downstream regional wetlands and fish habitat resources not well
protected under existing conditions.
.
Impacts on the stream system, adjacent wetlands and uplands, and
associated wildlife habitats will be minimized by restricting the con-
struction period to summer, and early fall months.
Energy and Natural Resources
.
What kinds of energy (electrical, natural gas, oil, wood stove, solar) will be used
to meet the completed project's energy needs? Describe whether it will be used
for heating, manufacturing, etc.
The only energy needed for the project's post construction operation will be small
amounts of electrical energy to power instrumentation controls, and maintenance
lighting (if desired) of stormwater flow control structures. Diesel and gasoline fuel
would also be required to power vehicles used in the period; i.e., maintenance of
project facilities.
Would your project affect the potential use of solar energy by adjacent properties?
If so, generally describe.
, No.
What kinds of energy conservation features are included in the plans of this
proposal? List other proposed measures to reduce or control energy impacts, if
any:
Because of the minimal periodic energy requirements for project operation and
maintenance, no conservation features are proposed.
7.
Environmental Health
Are there any environmental health hazards, including exposure to toxic chemi-
cals, risk of fire and explosion, spill, or hazardous waste, that could occur as a
result of this proposal? If so, describe.
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a.
b.
c.
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ENVIRONMENTAL CHECKLIST
No environmental health hazards are expected to occur as a result of the proposed
project, based on environmental site assessment as described below. The project is
designed to help control potential toxic pollutants or hazardous material that could
enter the West Hylebos drainage system at upstream locations.
A Phase I environmental site assessment (ESA) was performed at the proposed loca-
tion of the Belmor Regional Stormwater Detention Facility; the results of that study
are contained in an October 1995 report prepared by Landau Associates, Inc. That
study concluded that sampling and testing of ditch sediment confirmed the
presence of elevated levels of urban runoff-type contaminants. Several metals,
petroleum hydrocarbons, and polyaromatic hydrocarbons are present at levels
likely to require special handling and treahnentj disposal if excavated. Sediment
along the entire 720 feet of open ditch appears to have been similarly impacted. (See
Attachment 1: Phase 1: Environmental Site Assessment, SeaTac Regional Storage
Facility). 0
1)
Describe special emergency services that might be required.
No additional special emergency services will be required.
2)
Proposed measures to reduce or control environmental health hazards, if any:
The proposed stormwater detention systems will reduce the risk of downstream
drainage system contamination from upstream developed land use runoff. Control
measures will include installation of sluice gates at flow control structures to pro-
vide positive shutoff and containment of runoff (dry weather or low flow only) in
the event of a spill within the upstream tributary drainage basin area.
Small amounts of contaminated stream channel sediments, excavated for project
construction, are proposed to be buried in the stream channel backfill for installation
of the 84-inch thick storm drain upstream of the detention facility.
b.
1)
Noise
What types of noise exist in the area which may affect your project (for example:
traffic, equipment, operation, other)?
None.
2)
What types and levels of noise would be created by or associated with the project
on a short-term or a long-term basis (for example: traffic, construction, operation,
other)? Indicate what hours noise would come from the site.
The completed project would not generate noise. Maintenance vehicles that would
periodically visit the site would be the only source of noise subsequent to project
construction. Maintenance would occur during daytime hours on weekdays, except
in the case of an emergency.
Short-term increases in noise would occur at the site during construction. Noise
would come from construction equipment and vehicles used by workers to travel to
and from the site. Short-term noise impacts may occasionally exceed daytime L-25
of 65 dba at adjacent properties (the state standard is stated in terms of the L-25
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ENVIRONMENTAL CHECKU:iT
statistical level). Potential noise impacts during construction will normally be
limited to weekday normal working hours.
3)
Proposed measures to reduce or control noise impacts, if any:
Proposed measures to control short-term noise impacts will be included with the
construction contract specifications and will include:
.
Requiring that power-driven equipment be adequately muffled
Limiting the use of heavy equipment during project construction to the more
stringent of the hours as required by the Washington Administrative Code
(YV AC 173-60) and the Federal Way City Code .
.
8.
Land and Shoreline Use
a.
What is the current use of the site and adjacent properties?
The majority of the site is currently located within single and multifamily residential
neighborhoods.
The current uses for the site range from recreational (a golf course) to single and
multifamily residential).
b.
Has the site been used for agriculture? If so, describe.
The site area is not known to have been used for agriculture in the recent past.
c.
Describe any stru.ctures on the site.
Residential structures do exist within close proximity to the project sites. Mobile
homes exist adjacent to the stream channel (east side) at the Belmor project site. An
apartment complex (Empire Gardens) exists on the west side of the Site 6 project
area.
d.
Will any stru.ctures be demolished? If so, what?
No.
e.
What is the current zoning classification of the site?
The majority of Site 1 is designated by the City of Federal Way Zoning Code as
Multifamily, with the very northern edge of the site designated as Yacant. Sites 2
and 3 are zoned Multifamily. Site 4 is zoned Single Family. Site 5 is zoned Yacant,
and Site 6 is zoned Multifamily.
f.
What is the current comprehensive plan designation of the site?
The entire project area is designated as Business by the Federal Way 1990
Comprehensive Plan.
g.
If applicable, what is the current shoreline master program designation of the
site?
The site is not within 200 feet of a shoreline; therefore, it has no shoreline master
program designation.
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h.
Has any part of the site been classified as an "environmentally sensitive" area? If
so, specify. .
Yes, strèam channels and wetlands in the project site areas classify as "environmen-
tally sensitive" areas under Federal Way City Code. For a description of affected
stream channels and wetlands, see sections B.3.a.1) and B.4.a..
Wetland Rating. At this time, City of Federal Way zoning pertaining to environ-
mentally sensitive areas does not include a rating system for wetlands.
Wetland Setback. The City of Federal Way Code (Article XIV, Section 22-1357)
requires a lOa-foot setback on all wetlands. Setbacks are measured from the wetland
edge as delineated in the field.
Stream Buffer. The City of Federal Way code includes minimum setback require-
ments for streams. All setbacks are measured from the top of any bank of a stream.
The minimum setback requirements are: .
Major stream 100-foot setback
Minor stream 50-foot setback
Stream Rating. Streams were rated using the criteria described in Section 22 of the
City of Federal Way Zoning Code. Federal Way uses the following definitions of
Major and Minor streams.
"Major stream shall mean any stream, and the tributaries of any stream, which
contains or supports, or under normal circumstances contains or supports a local or
migratory fish population."
"Minor stream shall mean any stream that does not meet the definition of major
stream. "
i.
The stream affected by the proposed project is a tributary to Hylebos Creek, which
has been documented as habitat for salrnonid fishes. Therefore, it would be
considered a Major Stream, requiring a lOa-foot buffer.
Approximately how many people would reside or work in the completed project?
j.
None would reside within the site area for the completed project. Periodically, City
personnel would visit the site for maintenance.
Approximately how many people would the completed project displace?
None.
k.
Proposed measures to avoid or reduce displacement impacts, if any:
Not applicable.
1.
Proposed measures to ensure the proposal is compatible with existing and pro-
jected land uses and plans, if any:
Although the site area is designated for Business in the Comprehensive Plan, its
physical characteristics (i.e., wetlands, streams) will limit and partially preclude
future development potential. The proposed stormwater control facilities will be
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b.
c.
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ENVIRONMENTAL CHECKUST
9.
designed with consideration of adjacent development potential and in coordination
with those development interests to maintain land use compatibility.
Housing
a.
Approximately how many units would be provided, if any? Indicate whether
high, middle, or low-income housing.
Not applicable.
b.
Approximately how many units, if any, would be eliminated? Indicate whether
high, middle, or low income housing.
Not applicable.
c.
Proposed measures to reduce or control housing impacts, if any:
10.
Not applicable.
Aesthetics
a.
What is the tallest height of any proposed structure(s), not including antennas?
What is the principal exterior building material(s) proposed?
No above ground structures are proposed.
b.
What views in the immediate vicinity would be altered or obstructed?
Yiews within the project area would be altered temporarily by construction activi-
ties including some removal of vegetation, excavation of earth, and placement of fill.
The Behnor Regional Detention Facility will be designed with vegetative and open
water enhancements that will improve views from residences located adjacent to the
facility .
c.
Proposed measures to reduce or control aesthetic impacts, if any:
Revegetation and screening with landscaping will be provided as discussed in
Item B.4.d.
11.
Light and Glare
What type of light or glare will the proposal produce? What time of day would it
mainly occur?
a.
Light and glare are not anticipated to result from the project. Maintenance lighting
(if provided) for detention area outlet flow controls will be directional and will be
used only periodically for emergency night maintenance.
Could light or glare from the finished project be a safety hazard or interfere with
views?
No.
What existing off-site sources of light or glare may affect your proposal?
None.
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ENVIRONMENTAL CHECKUST
d.
Proposed measures to reduce or control light and glare impacts, if any:
None, since no light and glare impacts are expected to result.
12.
Recreation
a.
What designated and informal recreational opportunities are in the immediate
vicinity?
For the Belmor project site, a private retirement community golf course exists in the
area of project improvements.
b.
Would the proposed project displace any existing recreational uses? If so,
describe.
c.
The project would not displace any current informal recreational use of the Belmor
Park golf course; however, site access would be restricted during construction.
Proposed measures to reduce or control impacts to recreation, including recreation
opportunities to be provided by the project or applicant, if any:
13.
A temporary (short) golf tee would be provided on the 9th hole to maintain play on
the Belmor Park golf course during construction. .
Histonc and Cultural Preservation
a.
Are there any places or objects listed on, or proposed for, national, state, or local
preservation registers known to be on or next to the site? If so, generally describe.
No.
b.
Generally describe any landmarks or evidence of historic, archaeological, scienti-
fic, or cultural importance known to be on or next to the site.
None.
c.
Proposed measures to reduce or control impacts, if any:
None.
Transportation
Identify public streets and highways serving the site, and describe proposed ac-
cess to the existing street system. Show on site plans, if any.
The site area is served by South 324th Street to the north, SR 99 (Pacific Highway
South) to the west, Interstate 5 to the east, and South 336th Street near the proposed
project's southern terminus. South 336th Street is classified as a collector arterial
with connection to the east (beyond the city limits) to the SR 18 highway (see
Figure 1).
Site 1 would be accessible by South 324th Street. Sites 2 would be accessible from
20th Avenue South. Sites 3 would be accessible by South 330 Street. Site 4 would be
accessible by 20th Ave South. Sites 5 and 6 would be accessible from South 333rd
Street.
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ENVIRONMENTAL CHECKUST
b.
Is the site currently served by public transit? If not, what is the approximate
distance to the nearest transit stoP.?
The proposed project will not create any need for public transit services. Metro bus
service is available, however, on SR 99.
c.
How many parking spaces would the completed project have? How many would
the project eliminate?
None.
d.
Will the proposal require any new roads or streets, or improvements to existing
roads or streets, not including driveways? If so, generally describe (indicate
whether public or private).
South 330th Street, 20th Avenue SE, and South 333rd Street will undergo temporary
construction impacts for installation of the proposed trunk storm drainage improve-
ments. The roadways are proposed to be open cut for culvert and storm drain
installation. For the South 20th Street crossing, open cut will be required because of
potential utility conflicts. Any disturbance of pavement will be repaired. All
roadway work within the public right-of-way will be to Washington State
Department of Transportation and City of Federal Way standards. Surfacing of the
maintenance access roads at the Belmor Regional Storage Facility (outside the public
right-of-way) is expected to be asphalt.
e.
Will the project use (or occur in the immediate vicinity of) water, rail, Qr air trans-
portation? If so, generally describe.
No.
How many vehicular trips per day would be generated by the completed project?
If known, indicate when peak volumes would occur.
The completed project will result in only periodic vehicle trips to the site for inspec-
tion and maintenance. No measurable impact on traffic would result.
Proposed measures to reduce or control transportation impacts, if any:
Mitigation measures to be considered to reduce or control transportation impacts
. . where roadway open cut approach is used include:
.
Use cut-and-cover trenching to maintain roadway use during construction
Maintain at least one lane of South 333rd Street, South 330th Street, and
20th Avenue South at all times
.
.
Use appropriate traffic control to direct traffic during construction
Post temporary signage in advance of proposed road closure periods (if any) or
for alternative (detour) routes
.
Public Services
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ENVIRONMENTAL CHECKUST
a.
Would the project result in an increased need for public services (for example: fire
protection, police protection, heal~h care, schools, other)? H so, generally describe.
No.
b.
Proposed measures to reduce or control direct impacts on public services, if any.
No direct impacts to public services are anticipated from the completed project.
During construction, police, fire, and medical aid units would be notified in advance
if lane restrictions are anticipated.
16.
Utilities
a.
Circle utilities currently available at the site:
electricity, natural gas, water, refuse service,
telephone, sanitarv sewer, septic system, other.
The above utilities are currently located in the project area (road right-of-way).
Temporary electrical and water service will be required for construction activities.
b.
Describe the utilities that are proposed for the project, the utility providing the
service, and the general construction activities on the site or .in the immediate
vicinity which might be needed.
Electrical service for project operations will be required for the Belmor Regional
Stormwater Detention Facility's detention cell outlet flow control structure.
Electricity will be provided to these area via extension from existing electrical-lines
adjacent to the site. In addition, some existing utilities may require relocation
during project construction. Utility relocation needs in the immediate vicinity of the
proposed drainage culvert crossing at South 33rd Street and for the storm drainage
along 20th A venue South are being evaluated with the final design.
s are true and complete to the best of my knowledge. I
e lead a ncy is relying on them to make its decision.
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co..
Attachment 1
Phase 1 Environmental Site Assessment
SeaTac Mall Regional Storage Facility
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MEMORANDUM
CHMHILL
Amendments to SEP A Checklist
South 324th to South 336th Streets Trunk Storm
Drainage and Helmor Regional Storage Facility
1m provemen ts Proj eet
TO:
Bill Kingman/Federal Way - Department of Community
Development
Marwan Salloum/Federal Way - Surface Water Management
Steven Wasson/ CH2M HILL
September 30,1996
COPIES:
FROM:
DATE:
Introduction
This addendum addresses comments and information requested in a comment letter from
Community Development (Bill Kingman, September 13, 1996) during the initial review of
the Environmental Checklist subnútted for the subject project in July 1996. Comments were
received from the City of Federal Way Community Development and Public Works
Departments on the proposal to improve the trunk storm drain and construct a regional
storage facility between south 324th and South 336th Streets along the West Hylebos
Tributary 0O14A. The comment letter requested this information prior to continued review
and approval of the Environmental Checklist.
The information provided here has been developed as an addendum to the previously
submitted SEP A Checklist. All information provided here revises that which was
previously subnútted with the checklist. Copies of this addendum should be distributed to
all recipients of the project Environmental Checklist dated July, 1996.
Response to Community Development Comments
Comments from the Department of Community Development covered two general areas,
clarifications to SEP A items, and comments to land use approvals for each of the project
sites. Responses to these items are addressed in the following sections.
SEP A Comments
1. Comment - Provide the address of site 5, (A. Moberg property).
Response - There are two property addresses at Site 5. The address on the north side of
north side of 333rd Street is 1816 S 333rd Street. The address on the south is 1815 S
333rd Street.
EXHIBIT ~
f1Ã~ E ,s " 0 F .J.B:l
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( (" AMENOI.BlE-o~
SOUTH 324 TH TO SOUTH 336TH STREETS TRUNK STORM DRAINAGE AND BaMOR REGIONAL STORAGE FACtUTY I~
".
/ 2. Comment (summarized) - Work is proposed within a wetland abutting SiteS- ~a
OV wetland mitigation plan must be supplied or the improvements must be re!o~
-r ~ outside the wetland. Is this the 435 sf of wetland impact discussed in item OF page 2ï of
\";\~,yí' the SEP A checklist? ,
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Response - A more detailed wetland delineation has been prepared for the SÏì2 (~
Attachment 1). This reanalysis of the identified wetland area north of the CtJ!Wert
crossing notes the prese~ce of both stream channel areas and wetland areas.. ~ an
this dry season analysis the area immediately abutting the north end of the ~
culverts is classified as stream channel area
Regarding the wetland impact area discussed on page 21 of the SEP A checkJ!h.4: P==--~ 21
refers to a wetland impact area of less than 0.01 acres. As shown in Table 2 m:I. ~ 3.7
of the SEP A checklist the actual impact area at Site 5 (S 333rd St.) was origirtally
estimated at 30 sf (less than 1/1000th of an acre). Based on this reanalysis no ~~
wetland vegetation will be impacted by the proposed construction.
A correction to Table 2 is also required in the wetland/ stream impact area tisiëd iLlrSñe
4. Table 2 incorrectly lists 90 sf of wetland impact at Site 4. The referenced 90 sf ~-wnln
correctly be associated with a stream channel impact area at the north end of the
proposed storm drain in 20th Avenue South. A revision to Table 2 which pu.nrïd::sh=>
correction at Site 4 plus the results of the re-delineation at Site 5 is included m
Attachment 2.
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3. Comment - Revise the boundary of the wetland at Site 5, north of South 33&d ~ jn
either the wetland delineation or the SEP A drawing so they match.
Response - Revisions to the wetland delineation map and the SEP A drawing w ;:,-=, - :53
the modified wetland and stream channel delineation at Site 5 are included m
Attachment 3.
/4. Comment (summarized) - Provide a list of observed wildlife species to supp~ ~
wetland delineation report.
~esponse - A list of wildlife species has been prepared and is included with -~tr-c';;T"-:"~~
1.
5. Land use approvals are discussed in the following section.
Land Use Approvals
Community Development's comments included a discussion of the land use aWnn dE;
necessary for construction at the individual project sites. The following sections ~
clarifications to Community Development's site assessments. Additionally, a reD5êë >U..'i-,y
of the Code Compliance Review Memorandum has been included in Attachme.rn: ~ ~
revised memorandum address~s the code compliance issues as discussed in the i....L" ¡,. .~
received from Community Development.
EXHIBIT C,
PÃ~sE 151 0 FJ.B:l
2
\~
c C AMENDMENTS TO SEPA CHECKUST
SOUTH 324TH TO SOUTH 336TH STREETS TRUNK STORM ORAINAGEAND BElMOR REGIONAL STORAGE FACIUTY IMPROVEMENTS PROJECT
330th Street, not a private driveway as referenced in the comment letter from Community
Development. Also the new culvert will be an extension of an existing culvert which is
currently capped under the roadway portion of South 330th Street. Extension of this capped
culvert will not result in any additional stream channel encroachment.
Site 5 - The commentary notes that approximatèly 3 feet of rip rap will be located within an
adjacent wetland and that the new culverts are longer than the existing culverts. Based on
the reanalysis of the wetland area discussed earlier, the area around the 3 feet of rip rap is
predominately classified as stream charmel with less than 9 sf wetland impact. As noted in
the commentary the proposed culverts will be longer than the existing culverts. The
proposed culverts will be longer because they will be placed on a skew to the roadway
centerline, where as the existing culverts cross perpendicular to the centerline. The
proposed culverts will not extend beyond the existing roadway embankment, and thus will
not enclose any additional stream charmel area.
Response to Public Works Comments
1. Comment - What types of easements need to be obtained for construction of the project.
Will any easements be negated?
Response - Surface Water Management has a plan set showing proposed temporary
construction, and permanent easement locations. Surface Water Management is
currently negotiating with affected property owners to obtain the needed easements.
No easements will be negated.
2. Comment (summarized) - Clarify the status of the ground water monitoring wells
discussed in the geotech report. Will the soils at the Belmor Park detention facility
support a permanent pool?
Response - Piezometer wells were installed at three locations during the preliminary
geotechnical analysis for the project. These piezometers were capped and covered to
allow the City to monitor the ground water levels prior to construction. After
construction is completed the wells would be abandoned in place, thus they would not
be considered a permanent facility.
Regarding the soils at the proposed detention site; Section b. 1) on page 19 of the
checklist describes that a low permeability soil liner or geosynthetic clay liner will likely
be needed to assure that a permanent pool can be maintained at the proposed detention
pond site. Analysis of the test boring data indicates layers of sandy gravely material
exist within the vicinity of the proposed permanent pool. These layers may not retain
water sufficiently to maintain a permanent pool without some for of additional lining.
3. Comment (summarized) - Clarify the locations and quantities of grading and filling.
.J Response - A follow up memo on the cut and fill quantities for the project was prepared
to address questions raised by the Community Development and was submitted to the
City on August 19, 1996 and is included in Attachment 5. More detailed information on
excavation quantities and locations is also available in the preliminary cost a inion
available from Surface Water Management. E'.'
J~
EXHIBIT ~ .
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PA
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- AMENDMENTS TO SEPA CHECKlIST
SOUTH 324TH TO SOUTH 336TH STREETS TRUNK STORM DRAINAGE AND BElMOR REGIONAL STORAGE FACIU1Y IMPROVEMENTS PROJECT
4. Comment - Item B.3.d (page 21)of the checklist discusses monitoring and treatment of
construction area runoff and dewateririg flows prior to release to the receiving waters.
Clarification is needed as to who will be doing the monitoring.
Response - Monitoring and treatment of construction area runoff would be conducted
based on the requirements of theWSDOT standard speåfications. Monitoring would
typically consist of visual inspections to assure that turbid discharges are controlled.
Treatment to remove sediment would typically be provided by temp ora
sedimentation ponds, or by running the flows through bioswales and straw bales. -(
Monitoring of the activities would be the joint responsibility of the con -actor an the
City's construction representative.
EXHIBIT .c,
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ATTACHMENT 1
SITE 5
WETLAND REANALYSIS and
WilDLIFE SPECIES LIST
EXHIBIT C
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JtIand Analysis 8
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MEMO
To:
From:
Subject:
Date:
Marwan Salloum 'òW\./
Dyanne Sheldon
SEP96-0022: Stream Location South 333 rd Avenue
October 11, 1996
Steve Wassen from CH2MHill called last week to discuss my memo on the South 333rd Stre~t
culvert, and I realized that I had done all of my field analysis on the south side of the roadway,
when your questions focused on the north side of the road. So...to put the issue to rest I re-
visited the site this morning to confirm my notes on the conditions on the north side of the road.
The conditions on the north side of South 333rd from this second field visit are as follows.
The stream which flows through the wetland located north of the roadway has an alignment as
indicated on the Federal Way plan sheet labeled drawing (dwg) 2 (See Attached). The area in the
immediate vicinity of the inlet to the culverts contains some large pieces of concrete rubble and
rip-rap, bare dirt~ and the gravel of the channel bottom, a small patch (approximately 1.5 it X 2
ft.) of reed canary grass, and overhanging Himalayan blackberries. The area immediately
upstream of the culvert openings, in the zone identified on the plan sheets as the wetland impact
zone, is primarily bare dirt and gravel with only that one small patch of reed canary grass present.
During site visits in the spring Pesha Klein, of our staff, observed the entire area upstream of the
culverts was underwater and they appropriately flagged the wetland edge up to the edge of the
culvert and to the edge of the toe of the road shoulder at the culvert. My field observations
noted that the inlet of the stream to the culvert is approximately three feet wide at the culverts,
the channel has no vegetation present within it except the stand of reed canary grass which is
growing on a small gravel "bar" located to the west of the culvert openings. The other vegetation
in this area is an impenetrable stand of Hirnalayan blackberry which is rooted on the shoulders of
the gravel road fill and arches into the wetland area to the north. Although the area immediately
north of the road shoulder back-floods in high water, it does not have rooted vegetation present
within the area of "proposed construction limits".
In reviewing the plan sheets for the proposed culvert placement in relation to the proposed
temporary construction impacts, it appears that the only vegetated zone (i.e. wetlands) to be
impacted is the small patch of reed canary grass near the culvert openings. It is unclear where the
estimate of 435 sq. feet of wetland impact was derived: if one were to consider the small patch of
reed canary grass as wetland, the wetland "impact" would be less thE.~~, , nll1t-
calculations, Technically, the only wetland "impact" would he the removal te iI}) oW _..~-
EXHIBIT c..", PAG OF ~
~06:522J?A.GE&OF ~_._, 5031 UniversityWayN.E. Seattle, WA 981054;41
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Marwan Salloum
Page 2
October 11, 1996
patch of reed canary grass and some overhanging blackberry (which is rooted outside of the
wetland). I would assume with great confidence that both the reed canary grass and the adjacent
invasive blackberry will both grow back within 1-2 years of the project installation. I would
submit that the proposed culvert replacement would not technically impact vegetated wetland as
.the majority of the work is within the unvegetated stream channel and within the portion of the
road shoulder which either has rip-rap already in place and/or blackberry. The wetland edge
begins at the toe of the road fill and in the inunediate vicinity of the culvert replacement, that zone
is characterized by overhanging blackberry which is rooted above the wetland surface.
The September 13, 1996 memo from Bill Kingman noted in Item 3 a discrepency between the
wetland boundary south of 333 rd as mapped in the Wetland Delineation Report and that within
the SEP A checklist. The map has been revised to accurately reflect the correct alignments which
reflect the additional surveying work which was incorporated into the drawings of the SEP A
submittal.
Item 4 of Mr. Kingman's memo requested a listing of observed wildlife species in the wetlands.
Provided below is a list of the conunon birds which are found in these types of urban forested
wetlands in the winter when the original field work was conducted: note that our field staff did
not observed these species during their field visits but this is listing of common wintering species
expected to be found. (The two times I was on-site in September and October of 1996 it was
raining heavily and any bird with any common sense was not vocalizing).
Black-capped chickadee
Bushtit
Common crow
House sparrow
White-crowned sparrow
Fox sparrow
Winter wren
Oregon junco
House fmch
Parus atricapillus
Psaltriparus minimus
Corvus brachyrhynchos
Passer domesticus
Zonotrichia leucophrys
Passerella iliaca
Troglodytes troglodytes
Junco oreganus
CGlpod.acus mexicanus
I hope that this additional information will answer the questions raised by the Planning
Departmetn for their SEPA review. Please let me know if I can clarify any of these issues further.
EXHIBIT C,
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ATTACHMENT 2
TABLE 2 REVISIONS
EXHIBIT C,
PAGEM.OF -LS:I
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REVISED
(October 1, 1996)
Table 2. Project Permanent and Temporary Direct Impact Areas
ADDITIONAL
IMPACT AREA
WITHIN 200'
STREAM 100' SETBACK SETBACK
PROJECT PROJECT WETLAND CHANNEL AREA AREA
SITE NO. DESCRIPTION AREA (SQ. FT.) (SQ. FT.) (SQ. FT.) (SQ. FT.)
BELMOR REGIONAL 0 5,410 74,950
STORMWATER DETENTION
FACILITY
2 PRIVATE DRIVE CULVERT 0 430 1,520
3 SOUTH 330TH STREET 0 240 1,720
CULVERT
4 20TH AVENUE SOUTH 00 400 6,200 3,400
STORM DRAIN TRUNK 0 280
5 SOUTH 333RD STREET æ aae 1,080
CULVERT 0 330
6 EAST EMPIRE GARDENS APT 0 720 2,720
DITCH IMPROVEMENTS
TOTALS 4-2G 0 -7;200 7410 88,190 3,400 SO. FT.
~O ~ 0.17 2.02 0.08 ACRES
EXHIBIT C
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ATTACHMENT 3
WETLAND DELINEATION MAP
- REVISIONS
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ATTACHMENT 4
REVISIONS TO
COMPLIANCE REVIEW MEMORANDUM
(Provided under separate cover)
EXHIBIT C
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ATTACHMENT 5
SEPA CHECKLIST
FILL VOLUME CLARIFICATION MEMO
EXHIBIT C
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MEMORANDUM
CHMHlll
SEPA Checklist Fill Volumes
TO:
FROM:
Marwan Salloum P.E.! City of Federal Way
Steven Wasson
DATE:
August 16, 1996
This memo is in response to the Planning Department request for a clarifications on the fill
and grading quantities discussed in the South 324th to South 336th Streets Trunk Storm
Drainage and Belmor Regional Storage Facility Improvements Project Environmental Checklist
submitted to the City in July 1996. .
I have reviewed the quantities discussed in Section B.1.e (pp.14) and B.3.a.3) (pp. 18), and
have the following clarifications.
At the BeIrnor Regional Storage site the fill and grading quantities are as follows:
Pond Excavation
14,400 CY
7,300 CY
Pipe Excavation
Total Cut 22,000 CY (rounded)
Channel Embankment Fill
Pipe Trench Native Backfill
1,900 CY
6,100 CY
Total Fill 8,000 CY (rounded)
There is a discrepancy of 900 CY yards of pipe trench backfill not accounted for in the
figures on pp. 14 of the Checklist.
In addition to .the BeIrnor site, additional excavation ànd fill will occur at the proposed
culvert crossings and for the channel widening at the Empire Garden Apartments. These
volumes were not included in the checklist but are outlined below. The Embankment
volumes will be limited to the backfilling of the pipe and culvert trenches, and the manhole
excavations.
Excavation (pipe, MH, ret. wall)
Embankment/ Native Backfill
2,700 CY
1,300 CY
As stated on pp. 14 of the checklist approximately 1,200 CY of select imported IIÚIleral
aggregate material will be used for the project. '. (~-¡;.
EXHIBIT C ::d~F £,-'-_..
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SEPA CHECKUST ALL VOLUMES
Included in the table above are the quantities of excavation and backfill associated with the
Empire East Garden Apartments. The specific volumes associated with the channel
widening are as follows, 500 CY excavatiop, and 150 CY of native backfill behind the
proposed wall. Additionally 640 CY of streambed gravel and rip rap would be placed
adjacent to the existing channel within the proposed widening area.
EXHIBIT C
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TECHNICAL MEMORANDUM
CHMHlll
Belmor Regional Storage Facility
Geotechnical Recommendations
PREPARED FOR:
J eXPIRES 1 /29 1'(6"
Marwan Salloum/Federal Way Surface Water Management
King Sampaco
Ken Green P.E.
PREPARED BY:
COPIES:
Deb Barker/ Federal Way Community Development
February 28~ 1997
DATE:
INTRODUCTION
This technical memorandum summari:æs geotechnical recommendations for the Belrnor
Park Regional Storage Facility and Stream Channel Improvements. These improvements
are a part of the proposed project to improve the trunk drainage system in the City of
Federal Way Drainage Subbasin WHi0 (upper and lower) south of South 324th Street
(north limit) and north of South 336th Street. The proposed project would attenuate the
impact of increased peak flows delivered through the improved drainage system through
construction of a regional stormwater detention basin within the Belmor Park Golf and
Country Club near the intersectiOn of South 324:th Street and Pebble Beach Circle. "The
project also includes the replacement of undersized downstream roadway culvert crossings
leading to the Kitts Corner and South 336th regional detention facilities.
The sèope of this technical memorandum includes geotechnical recommendations related to
the design and construction of the Betmor Park improvements (8elmor Park site). The
geotechnical design criteria include requirements for stability of cut slopes and retaining
walls under both gravity and seismic loading. Criteria addressed under earthwork
construction include material excavation, handling, and placement.
The technical memorandum also addresses the occurrence of geological hazards in the area
of development, as required by Divisioll 4, Geologically Hazardous Areas Development, Section
22-1286, Limitations, of the Federal Way City Code (FWCC). This section regulates
development activities and land-surface modifications on or within 25 feet of a geologically
hazardous area. As discussed in the subsequent sections of this technical memorandum,
the development activity or land-surface modification associated with the Belmor Park
Improvements will not lead to or create any increased slide, seismic, or erosion hazard on
adjacent properties. . ~
EXHIBIT C . ~~~~OF L
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9EI.J.40R fiECIONAl STORAGE FACIU1Y
QEOTI;CHNICAI. RECOWÆNDA.T1ONS
SUBSURFACE AND GROUNDWATER CONDITIONS
Results of the fidd explorations, laboratory soil testing, and installation of groundwater
observation w~l\s Me presented and discussed in a geotechnical data report prepared by
CH2M HILL, entitled "Geotechnical Data Report: South 324th to South 336th Streets Trunk
Storm Drainage and ßelmor Regional Storage Facility Improvements Project" dated July
1996. The soil encountered at the Belmor Park site generally consisted of very dense
granular material that extended to the maximum boring depth explored of 43 feet. At the
north end of the site, the soils recovered to a depth of 38 feet were very dense mixture of
silt, sand, and gravel with fines content ranging between 5 to 38 percent. Standard
Penetration Test (SPT) blow counts were essentially higher than 100. A layer of hard sandy
sUt with gravel having a silt content of up to 60 percent was encountered in one of the
borings between 17.5 feet to 30 feet. This layer is underlain by a very dense silt and sand
(SP-SM and SM) with about 10 to 18 percent silt to a depth of 43 feet. At the south end of.
Belmor Park golf course, the test boring encountered about 10 feet of medium dense sand
with silt content of about 23 percent which was iÎ\terpreted to be fill (SPT blow count of 15
to 17). Very dense sand (SP~SM) and silty sand (SM) with thin lenses of sandy silt (ML) was
encountered between 10 fect and 23 feet. The upper 10 to 15 feet at this location also
contain a trace of organic materials in the rE.'Covercd samples.
Groundwater was encountered in all of the test borings drilled duri[\g the subsurface
exploration program. Readings taken shortly after the installation of grounl.i:water
observation wells at the Belmor Park site indicate that groundwater is located about 5.5 feet
to 8.5 feet below the existing ground surface. These levels of groundwater being monitored
from the observation wells or encountered during drilling are most likely part of the
localized, perched groundwater lenses developed atop the very dense o.r hard impermeable
silty layer.
GEOLOGICALLY HAZARDOUS AREAS
The side slopes of the existing stream channel through the BeIrnor Park area are typically
steeper than 2.5H:l V (40 percent) with heights of greater than 10 feet. These slopes are
classified under the category of potential geologically hazardous ¡:\ceas based on the FWCC
definition of steep slope hazard areas.
The proposed improvements for the new inlet 84-inch storm drain, located immediately
north of the proposed detention pond, will encroach within these slope areas and within 25
feet of their top and toe. After installation of this new storm drain, the channel beyond the
pipe zone will be backfilled with excess excavation from the proposed detention pond to
the top of bank, thus eliminating the steep slope hazard area from this channel reach.
Approximately 230 feet of stream channel downstream from the existing storm drain outlet
will be affected by this improvement.
EXHIBIT C
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IJEUoIOA ReGIOH/.I. STORAGE FACIliTY
GeOTECHNICAl RECOI.IMa<OA"nONS
these slopes will meet normally accepted factors of safety for slope stability under gravity
loading.
The seismic potcntial for the project area is moderate. Ground accelerations associated with
lOO-year and SOO-year earthquakes could range from 0.15 to O.JOg, respectively. As
recommended in the following sections, this potential will be considered in the design of
retaining walls and underground structures. As indicated in the geotechnical data report
prepared by CH2M HILL (1996), :>oils at the site of Belmor Park, except for the upper 10 feet.
are generally dense to very dense in consistency, which precludes seismic-related geological
hazards such as liquefaction and lateral spreading.
EXCA V A TION
Excavations into the slopes west of the existing stream channel will be required during
construction of the region~l detention facility. These excavations are anticipated to be about
10 to 22 feet below the existing ground surface. The excavated material is anticipated to be
a mixture of silt, snnd, gravel, and possibly some smaller cobbles in variable proportions.
This material is typically moisture sensitive, especially with increasing fines content (i.e.,
percent passing Sieve No. 200). It is further anticipated that localized pockets of perched
water will be encountered during excavations which will affect the stability of excavation
walls, particularly in the zones where dean, poorly-graded ~i<\nd and gravel can be found.
To minirrùze this problem, it is recommended that all construction operations should be
scheduled to take place during dry summer months.
All excavations should be performed in accordance with the applicable sections of the
WSDOT Standard Specificatiqns. Temporary cut slopes should not be steeper than l.SH:l V.
Control of groundwater and diversion of surface water dming construction will be left to
the responsibility of the Contractor. AU excavated materials which are free from organics,
wood debris, and other deleterious material may be stockpiled on-site, as approved by the
Engineer, for future use as select backfill for the retaining walls.
RETAINING WALLS
Stepped retaining walls will be required to retain the excavated cuts at the western portion
of the Belrnor Park detention pond. The lower walt will have a maximum height of 6.S feet
while the upper wall will have a maximum height of about 12 feet. A lO-foot wide aquatic
bench wiH be provided between the upper and lower wall. The top layer of the bench will
have a minimum of 12 inches of topsoil and should be kept saturated in order for aquatic
plants to grow. Båckslopes above the upper wall will be graded at 2H:IV and will be
planted with ground cover to prevent erosion. .
The retaini~g walls will be constructed using gabions with a rock facing and battered at
6V:IH. A major portion of the lower wall will be submerged in the summer months by a
permanent pool and during major winter storms. In order to maintain él permanent pool in
the pond, the lower wall will need to be watertight. This ca('\ be achieved by using a low
permeability, bentonite-amended backfill behind the gab ions and below the wall. With this
partì.cular b<3ckfill, the lower wall should be designed for full hydrostatic pressure. Due to
EXHIBIT C. E~--;J
PAGE:fl!OF.J.S:1 ' p~ OF ~:í
[CZ~g ON ni:/Y~]
G'C:9T NON
LB/CO/CO
BEWOA REGIONAL STOIW>E FACIUTY
(l1Z0 r£cHNICAL R£CO~GIOA TIONS
the possibility that the walls will be submerged in water (especially the lower wall), it- is
recommended that Terramesh units be used. The Terramesh system consists of gabions
with geogrid reinforcements attached integrally to the gabion units. A similar system is
recommended for the upper wall, except that the backfill material within the reinforced
zone of the wall should be select excavated on-site materials subject to the approval of the
- Engineer.
The design of this type of wall system is provided and certified by the wall manufacturer in -
accordance with the normal retaining wall requirements to meet the project conditions.
Shallow organic materials below the base of the wall should be removed before
construction. The backfill material to be used for the wall should be as described above and
should -be free from organic or other deleterious materials. All retaining walls must be
designed for a factor of safety of at least 1.5 against global stability. It is expected this
requirement can be met based on the dense to very dense nature of the soil at the site. The
wall should be designed using the following parameters: -'
.
Angle of Internal FcicÜon:
32 degrees (Upper Wall)
28 degrees (Lower WaU)
120 lb. per cubic foot
30 degrees
32 degrees
10 percent of height
or a minimum of 2 feet
.
Unit Weight of W.ùl Backtm Material:
Friction Angle of Soils at Wall Base:
Friction Angle for Active Soils: .
Minimum Embedment of Wall Toe:
.
.
.
The backfill material must be compacted to a minimum of 95 percent of the modified
Proctor maximum dry density as determined by ASTM D1557 and at water çontent- within 2
percent of optimum.
The walls should be analyzed for both external and internal stability. For external stability,
the following factors of safety should be satisfied: -
. Sliding: FS ~ 1.5
. Bearing Capacity: FS ~ 2.0
. Overturning: FS ~ 2.0
. Global Stability: FS ~ 1.5
For external stability against seismic Loading, the factors of safety should be greater than or
equal to 75 percent of the above st'atic factors of safety. For internal stability, the following
criteria must be satisfied:
.
RuptUre Strength (5r):
Pullout:
Seismic:
Sr ~ Allowable Tension in Reinforcement
FS ~ 1.5
FS ~ l.l against Pullout
.
.
The retaining walls will be founded on dense to very dense glacial deposits. The allowable
bearing pre$$urc for these soils are typically in the range of 4,000 psf. For this bearing
pressure, total and differential settlements are expected to be less than 1 inch and O.5-inch,
EXHfBïT~.. .
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CITY OF IT
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~ ~ AY" 33530 1 ST WAY SOUTH
(206) 661-4000
FEDERAL WAY, WA 98003-6210
March 5, 1997
- Mr. Marwan Salloum, Surface Water Management Project Engineer
City of Federal Way, Department of Public Works
33530 First Way South
Federal Way, WA 98003
RE:
SPR96-0039 - SITE PLAN REVIEW AND ADMINISTRATIVE DECISIONS
Wetland Setback Intrusions by Essential Public Facilities and GeologicaUy
Hazardous Areas Development, Belmor Regional Stormwater Detention Pond
Facility And Storm Drainage Improvements
Dear Mr. Salloum:
The City of Federal Way has completed the administrative review ofBelmor Regional Stormwater
Detention Pond Facility and Storm Drainage Improvements, which includes construction of a
regional stormwater detention pond facility, replacement of three undersized roadway culvert
crossings within the right-of-way, extension of a culverted storm drain trunk line and construction
a bulkhead flood wall for stream stabilization. The proposal is intended to rehabilitate a section of
Hylebos Creek and alleviate flooding of 20th Avenue South and adjacent private property
between SR 99 and 23rd Avenue South. The proposal wilnessen the impact of increased peak
flows delivered by future Phase IT improvements to the upstream (Sea- Tac Mall) drainage system.
The site plan application for the facility submitted on October 25, 1996, is hereby approved per
the attached Findings of Fact. Administrative decisions for wetland setback intrusions by essential
public facilities and geologically hazardous areas development are also provided. The remainder
of this letter outlines the review processes, gives a brief summary of the process under the State
Environmental Policy Act (SEP A) to date, a partial list of building permit requirements and
outlines procedure relating to appeals, and approval periods as they relate to site plan approval.
REVIEW PROCESSES
Six separate project sites are included in the scope of work. The sites are located within
Residential multi-family (RM) zoning districts. Pursuant to Federal Way City Code (FWCC)
section 22-678, Public Utilities are permitted uses in the RM zoning district subject to Use
Process III approval. This site plan review decision is administrative, and does not grant license to
EXHIBIT <: E~~ t. .
PAGErIJOF -1E1 PA~ OF -9-.1
Mr. Marwan SaUoum
March 5, 1997
Page 2
begin any type of site work. It will be incorporated into and become a basis for the process ill
review by the Federal Way Hearing Examiner and the Federal Way City Council pursuant to
FWCC section 22-366.
ENVIRONMENTAL REVIEW PROCESS
The responsible official of the City of Federal Way issued a Detennination of Non-significance
(DNS) for the regional stormwater detention pond facility on January 29, 1997, pursuant to WAC
197-11-630 (Federal Way File No: SEP95-0021) to satisfy the city's compliance with the State
Environmental Policy Act (SEPA). The appeal period ended on February 28, 1997. No comments
or appeals were filed with the city.
PARTIAL LIST OF BUILDING PERMIT REQUIREMENTS
Based on the application information submitted to date, the city has identified the following items
that must be provided to constitute a complete construction permit application. This items must
be addressed prior to issuance of any permits in conjunction with the project. (please be advised
that when review of the construction permit commences, additional review items may be
identified. )
1.
A Technical Information Report (TIR) is required to be submitted with the
construction permit application.
2. A final landscape plan that meets the requirements ofFWCC Article xvll,
. Landscaping, must be submitted with the construction permit application. The
landscape plan must be approved before construction permits may be issued. All
required landscaping must be installed based on the approved plans before final
inspection occurs.
PROCEDURAL INFORMATION
Unless modified or appealed, this site plan approval is valid for a period of one year from the date
of the decision. If no further action is taken within one year of the decision, the decision will
expire. A six month extension may be granted only if a written request is submitted to the city's
Department of Community Development Services, 33530 First Way South, Federal Way, WA
98003, at least 30 days prior to the expiration of the decision.
EXHIBIT c:
PAG E11JOF -.l.8:1
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-
Mr. Marwan Salloum
March 5, 1997
Page 3
This decision may be appealed by the applicant. The appeal must be in the form of a letter
delivered to the Department of Community Pevelopment Services, 33530 First Way South,
Federal Way, W~ and be accompanied by the established fee, within 14 calendar days after
- issuance of the decision. The appeal letter must contain a clear reference to the matter being
appealed and a statement of the factual findings and conclusions of the Director of Community
Development Services disputed by the person filing the appeal.
This decision shall not waive compliance with future City of Federal Way codes, policies, and
standards relating to this development.
If you have any questions regarding this decision, please contact Deb Barker, Associate Planner,
at 661-4103.
Sincerely,
~~p
Director of Community Development Services
enc: Findings for Site Plan Approval
Approved Site Plan
c:
Greg Fewins, Principal Planner
Deb Barker, Associate Planner
Dick Mumma, Building Official
Stephen Clifton, Public Works Develøpment Services Manager
Julie :Venn, Public Works Engineering Plans Reviewer
Greg Brozek, King County Fire District #39
Mary Young, Lakehaven Utility District
File
Sptlpub.. orklbelpond\opnpprovol.11r
~Iarr~
p~ OF ~~I
EXHIBIT e
P AGE -11.90 F JÆ1
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City of Federal Way
Department of Community Development Services
SITE PLAN REVIEW
Findings of Fact and
Administrative Decisions for
Wetland Setback Intrusions by Essential Public Facility and
Geologically Hazardous Areas Development
Belmor Regional Stormwater Detention Pond Facility
and Storm Drainage Improvements
SPR 96-0039
The following are fIndings of fact for Site Plan Review for the Belmor Regional Stormwater
Detention Pond Facility and Storm Drainage Improvements.
1.
The City of Federal Way Public Works Department proposes to construct a regional
stormwater detention pond facility, replace three undersized roadway culvert crossings
within the right-of-way, extend a culverted stonn dnün trunk line and construct a bulkhead
flood wall for stream stabilization. The work is intended to rehabilitate a section of
Hylebos Creek and alleviate flooding of 20th Avenue South and adjacent private property
between SR 99 and 23rd Avenue South (Exhibit A). The proposal is intended to lessen the
impact of increased peak flows delivered by future Phase IT improvements to the upstream
(Sea- Tac Mall) drainage system.
2.
The zoning for the subject site is Residential Multifamily (RM 2400 and RM 3600).
3.
The 1995 Federal Way Comprehensive Plan designation for the site is Multifamily.
4.
Regional stormwater detention pond facilities are permitted uses within RM zoning
districts pursuant to Federal Way City Code (FWCC) section 22-678, Public Utilities. Use
Process ill approval by the Federal Way City Council is required.
5.
Note #2 of FWCC Section 22"'()78, states that facilities "may be permitted only if locating
this use in the immediate area of the subject property is necessary to permit effective
service to the area to be served." In response, the applicant has stated on page 6 of the
Montgomery Water Group technical memorandum dated October 1, 1996 that the
proposed multi-use, pennanent pool detention pond with access trail, and the appurtenant
trunk stonn drain pipelines and hydraulic control structure will serve the existing site and
tributary upstream drainage areas storm water control needs.
6. There are six improvement sites between South 324th Street and South 3,~~ ~treet,
EXH I ;;t to ê ;;:;Ufu' wifuffi fue Hylebos ~~y~ ~Ol
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Belmor Regional Stormwater Dctention Pond/Improvements
Findings of Fact
page 2
South 324th Street (Belmor Mobile Home Park), 32820 and 32856 - 20th Avenue South,
32856 and 33018 - South 330th Street, the 33100 block of 20th Avenue South, 1815 and
1816 South 333rd Street and the East Empire Garden Apartments at 33311 18th Lane
South (Exhibit B).
7.
Access to the project sites will be provided by South 324th Street, South 330 Street, South
333rd Street, and 20th Avenue South. The 1995 FWCP classifies 20st Avenue South and
South 330th Street as principal arterial streets while South 333rd Street is unclassified.
8.
The project sites generally consist of flat to rolling terrain with some steeper slope areas
near the southern tenninus of the project. The Belmor Mobile Home Park is relatively flat,
with steep slopes in the stream area. Moderate slopes occur to the east and west of the
project sites.
Approximately .41 acres of impervious surfaces will be created by the construction of the
Belmor Regional Stormwater Detention pond facility (permanent pool). Another .04 acres
if impervious surface area will result from roadway crossing culvert improvements.
10.
Portions of the proposed development åre within areas designated as geologically
hazardous steep slope, stream, stream setback, and wetland setback, all defined as
environmentally sensitive areas under the Federal Way City Code. The project courses
through a tributary OOl4C of the West Hylebos Creek. The Hylebos Creek is a major
stream based on the city stream definition. Grading, fill, culverts, bulkheads and stream
rehabilitation work is proposed within the stream~ These intrusions must be reviewed in
accordance with FWCC Article XIV, Environmentally Sensitive Areas. The City Council
will decide upon the proposal using process III.
11.
Thè SEP A checklist states that five wetlands within the project site currently provide storm
water function, and that based on the current FWCC wetland definition, no wetland would
be directly impacted, permanently or temporarily, or displaced by the proposed
development.
The Water Group Technical Memo dated October 1, 1996, states that proposed
improvements at the inlet and outlet of the new trunk storm drain at sites 4 and 5, and that
bulkheads and channel widening at site 6 will be partially within 100 foot setbacks from
regulated wetlands. These intrusions must be reviewed in accordance with FWCC Section
22-1359, Structures, improvements and land surface modifications within the setback areas
from regulated wetlands. No wetland intrusion is proposed.
Pursuan,t to ,FW CC, see,tio,n 22-1359(b), &sentia1public~t. . '~i~t"director
of community development 'may permit the placeme p~
EXH I Br¡r_~..~ PAG OF 't ,I
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12.
Belmor Regional Stormwater Detention Pond/Improvements
Findings of Fact
page 3
13.
14.
utility in a setback area from a regulated wetland if he or she determines that the
improvement must traverse the setback area because no feasible or alternative location
exists based on an analysis of technology and system efficiency. The specific location and
extent of the intrusion into the setback area must constitute the minimum necessary
, encroachment to meet the requirements of the public facility. II
In response, the applicant has stated on pages 13 and 16 of the M~ntgomery Water Group
technical memorandum dated October 1, 1996 that the facility improvements constitutes
the minimum necessary encroachment to meet the requirements of a public utility. The
city's wetland contractor, Adolfson Associates, Inc. has reviewed this material and concurs'
with the fIDdings in a February 18, 1997 letter (Exhibit C). This analysis is hereby
incorporated by reference as though set forth in full. The essential public facility intrusions
into the wetland setback area are approved based on satisfactory documentation of the
decisional criteria.
The applicant proposes to excavate approximately 22,000 cubic yards of material and fill
7,100 cubic yards of materiøl. Approximately 16,000 cubic yards of excess excavation
. material will be exported to an off site earthwork disposal area. In addition approximately
1,200 cubic yards of select imported trench backfill and rip-rap would be required for the
project. The soils for the area are listed in the 1973 King County area soils survey as
Alderwood gravelly sandy loam (AgC) with 6 to 15 percent slopes.
The October 1, 1996 Montgomery Water Group technical memorandum states that slopes
which meet the definition of geologically hazardous are within the existing stream channel
at site 1. 230 feet of stream channel will be filled following installation of a 84 inch
culvert at this location. Development on or within 25 feet of geologically hazardous areas
is administratively reviewed pursuant to FWCC Section 22-1286(c), and requires a soils
report which describes how proposed development impacts the subject property. A
Geotechnicial Recommendation memo prepared by CH2M Hill dated February 28, 1997
(Exhibit D) was submitted. It satisfies the criteria of FWCC Section 22-1286(c)(2) and
(3), and contains recommendations for grading and filling at site #1. The proposed grading
and filling of steep slope geologically hazardous areas at site 1 is approved. The
recommendations contained in the memo will be implemented in the grading and clearing
and construction permits process.
Based on 70 foot depths of the regional groundwater system and the low infiltration rating
of the subject site, the applicant has proposed that a low permeability soil liner be installed
in the detention pond to control exfiltration to the groundwater and provide for a
permanent pool in the detention facility.
E~H I ~T leVC;f urban runoff type conmminan~ such ~d .
CA"-t: It' .11"\t: 10.., . - . I
15.
Belmor Regional Stormwater Detention Pond/Improvements
Findings of Fact
page 4
17.
18.
19.
20.
21.
22.
polyaromic hydrocarbons are present in the existing stream corridor at site 81 at levels
lilœly to require special handling and treatment and disposal according to an Environmental
Assessment report.
The responsible official of the City of Federal Way issued a Determination of Non-
significance (DNS) for the project on January 29, 1997 pursuant to WAC 197-11-630
(Federal Way File No: SEP 96-0022) to satisfy the city's compliance with the State
Environmental Policy Act (SEPA). The appeal period ended on February 28, 1997. No
comments or appeals were filed with the City. This determination is incorporated by
reference as though set forth in full.
Any erosion related impacts during clearing and construction will be mitigated by
implementing a Temporary Erosion/Sedimentation Control (TESC) plan to be reviewed
and approved by the City of Federal Way in conjunction with construction pennits as
required by FWCC Section 22-948.
According to the West Hylebos (WH) 08, WHI0 and WHll Regional Drainage Analysis
and Detention Predesign Report dated June, 1994, the proposed development is consistent
with the 1991 Executive Prpposed Basin Plan Hylebos Creek and Lower Puget Sound
Basin. The proposed development would provide enhanced flood control, and control of
existing sources of waste discbarge (i.e., pollutant washoff, spills) to the tributary drainage
system.
A technical information report (TIR) containing a level one analysis and additional data
as necessary shall be submitted with the construction permit application.
All disturbed areas will be required to be landscaped according to FWCC Article xvll,
Landscaping. A final landscape plan based on the approved site plan must be approved
before the construction permits may be issued.
There are fourteen (14) trees'on the site that meet the defmition of significant tree under
FWCC section 22-1568(b). Tb.ree (3) significant conifer trees are proposed to be removed
to facilitate installation of the drainage facility and culvert improvements. A tree protection
management plan will be required with the landscape plan in conformance with FWCC
section 22-1568(c)(6).
The project includes several measures to preserve and enhance wildlife habitat including
creation of a permanent pool, improvements in existing water quality resulting from
erosion and sedimentation controls, permanent protection of existing stream, wetland and
upland habitats, revegetation of disturbed areas, and protection of downstrearnt1gional
EX H I B I rtlandC fish habitat resources. Temporary constru~íf'~dS
PAGE 113DFJØ1 ' PA~ ~,
23.
Belmor Regional Stormwater Detention Pond/Improvements
Findings of Fact
page 5
and adjacent uplands would be minimized by restricting the construction period to summer
and early fall months, appli,Cation of erosion and sedimentation control measures, and
revegetation of disturbed areas.
24. . The installation of replacement culverts beneath roadways would be accomplished using
open cut operations. Mitigation measures include the use of cut-and-cover trenching to
maintain roadway use during construction; maintain at least one lane of South 330th Street,
South 333rd Street and 20th Avenue South to vehicular traffic at all times; use of
appropriate traffic control to direct traffic during construction; and posting of temporary
signage for detour routes in advance of proposed road closures if any. All roadway work
witlùn the public right-of-way would be to Washington State Department of Transportation
and City of Federal Way standards.
25.
26.
27.
28.
29.
30.
A METRO bus stop on 20th Avenue South will be relocated during construction activities
in coordination with King County/METRO.
The proposed site plan was reviewed to ensure optimal location and configuration of access
to the subject property.
The site is surrounded by a variety of land uses from vacant lots, mobile home park golf
course, multifamily housing, and single family dwelling units. The proposed use is
compatible with the existing land uses and density in this vicinity.
The proposal embodies design principles such as vegetation replacement and protection,
stream restoration, and wetland protection that do not conflict with adjacent uses in the
immediate area.
Thè proposed site plan application and application attachments have been reviewed for
compliance with the Federal Way Comprehensive Plan, pertinent zoning regulations and
all other applicable city regulations. .
The proposed development is consistent with Site Plan Review decisional criteria required
under section 22-364, Purposes of review, of the Federal Way City Code.
Conclusions: The proposed site plan and application for intrusions of essential government
facilities into regulated wetland setback areas and geologically hazardous area development have
been reviewed for compliance with Federal Way Comprehensive Plan, pertinent zoning
. regulations and all other applicable City regulations. Final construction drawings will be reviewed
for compliance with specific regulations, conditions of approval and applicable City requirements.
TIùs recommen?ation shall not waive compliance with future City of Federal Way codes, P.)~cieS
E~Hi;diTlatic. this decision. ~~---~r;' ~
M^""" IOU~ PA~ =
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Belmor Regional Stormwater Detention Pond/Improvements
Findings of Fact
page 6
Recommendation prepared by Deb Barker, Associate Planner, March 5, 1997
Exluòits:
A:
B:
c:
D:
Reduced scale site plan
Vicinity Map
Adolfson letter dated V18/97
Geotechnicial recommendation letter dated 2/28/97
spr\pub work\belpond\findings . txt
EXHIBIT ~
PAGElJS.OF --LSJ.
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18 February 1997
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ADOLFSON> ,
AS~OClATES; INC
Deb Barker
Federal Way Department of Community Development Services
33530 ~ 1st Way South'
Federal Way, Washington 98003-6210
RE:
UPR 96-0044, UPR 96-0045, ADM 96-0054
Belmor Regional Porid
Dear Ms. Barker:
..
Adolfson Associates, Inc. (AAI):ispleasedto provide the following c~mmentsreg~dirig,' ','
the above-referenced project. As you requested inyour,letterof12 FebruaryJ997;we' ': ,
examined the proposed projecttø détermineif it was in compliance with FWCC Section' ,
22.: 135 9(b). The project propos4s to construct a r~gionalstonnwater pond, replace. thr.ee-:, .'
, culverts (two in public rightS-òf-way, one on priVé;\tèø~pêrty), extend as~oriÍ14rain'~ ,.","
line, and construct a ,tIood walL Each of these projectelements was ex~iried '" '
independently with re~pectto FWCCSèction22-1359(b). ' , , , .' '
Three of the project elements arø proposed in areas which do not co~fiûn wetlands;"
consequently, these lòcations,doIiot contain wetland buffers., The three eleIIients..;. the '
regional stormwater pond, the cillverton privatè' property, and the culvert under South '
330th Street - therefore will not intrude into wetland buffers and conformance with
FWCC Section 22-1359(b) doesnot apply. '
"
..
The storm drain line extension ~d South 333rd Street culvert replacement elements
would require constructionadiyities within wetland buffers. However, a technical
. memorandum prepared by the Montgomery Water Group, mc, (dated 1 October 1996) .
states that it would be technically infeasible to locate inlet structure, headwa~ls, pa~s;ét.c~; "
at alternate locations that would result in lesser wetland buffer impacts. Further, although ,
the design does ,not app~ar to be finaliied;'the 1.:,Q9toD¡;o,r'l996 memorandwnc<?mmitStheo, ,,' .
project team to limiting buffer iropácts to themÜ¿jmurn q.ecessatyto meet the proj~c~ '
elements' respective design criteria. , Accordingly, th~§~ tWo prôject e~einéntsâppeaÌ"tÞ:';'
confol1}l to F~CCSection 22:1~~9(b).', ' " '
The final project elelIlentehtailsstreamchannelimprovements'. As'þartofthe .,.', '
improvements, a cast-in-place flood wåII (bulkhead) wouid~be located åIongth~~~st side
of the 'stream channel, and would intrude into a wetland buffer. The flood wallis' ' ,
necessary to achieve thegol!Ù of this project element, and its construction at an alternative
location would compromise the ~eed to reduce flooding, erosion, and downstream' hab~tit.
degradation. Based on information provided by the project's technical team, it appears ' ,
that the impacts associated with the flood wall would be the minimum necessaryto,meet .
design criteria, Therefore, this project element àlso appears to ..:t:~o F~{éò<¡;iW:~!3y
22-135 9(b ). ~ .:, UNIW DEVELOPM ENT.D EPARTMENT
EXHIBIT C. PA~ OF ~ FEB 12 1 1997
En~iron.mePa1ÂGE~QF~tle, WA 98107 f~one(206J789-9658 FaX(2~6J789-9684 0
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'We vêrymuch appreciate the oppK>rtunityto pro~idê.thes~comnientsto you. l(youhave '
any'questions, or if you receive additional or revisedtecÏiíiicaliIiformationregardipg any
, of the project elements, please call me at 789-965'8:' Thank you. ",
, Sincerely,'
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EXHIBIT C,
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MEMO
Subject:
City Council Land Use & Transportation Committee
Deb Barker, Associate Planner \)lÞ
Public process of the Belmor Regional Stormwater Detention Pond Process ill
application request
October 27, 1997
To:
From:
Date:
On March 11, 1997, the Federal Way Hearing Examiner convened a public hearing for the Belmor
Regional Stormwater Detention Pond facility and storm drainage improvements. Representative
of the Moberg family presented testimony about their adjacent property at the hearing. The
Hearing Examiner kept the public record open to ascertain his authority of the project and provide
the Moberg family an opportunity to evaluate the project.
Additional information was provided to the Hearing Examiner by the applicant, city staff and the
Moberg family. The family met at length with the applicant to negotiate easements and to
ascertain that the project would not impact their property.
On September 29, 1997, the Moberg family sent the Hearing Examiner a letter which stated that
their issues were resolved and requested that the hearing record be closed (Exhibit E). The City
requested that the record be closed on that same date.
The Hearing Examiner issued his recommendation for the application on October 14, 1997
(Exhibit A).
The complete written record, which includes technical report data, letters and memorandum, has
been incorporated by reference as though set forth in full and is available for viewing at the
Department of Community Development Services. Contact Deb Barker, Associate Planner at
661-4103 for additional information.
EXHIBIT 'D
PAGE-LOF --Ì-
..
.
I
MOBERG ENGINEERING
RECEIVED
SfP 2 9 1997
COY CtERt(S Of FreE
QTVOf ÆOERAL WAY
TACOMA, WASHINGTON
September 29, 1997
Consulting Engineers
Way Hearing Examiner
Stephen K. Causseaux, Jr., Federal
c/o Deb Barker, Associate Planner
City of Federal Way
33530 First Way South
Federal Way, washington 98003-6210
Reference: Belmore Stormwater Detention Facility and
Storm Drain Improvements t7:%~~~~~~~~~)
To clarify any confusion from my previous letter, the agreement
which we have signed, and is to become a contract between the
Moberg Brothers and the City of Federal Way which includes
modification to the project elements and easement of the 100 year
flood plain to the City, does completely resolve our objections
to the proposed project. All of the issues regarding the
property and the stormwater drainage have been resolved. We now
agree with the City that the hearing record may be closed, and
you may proceed to issue your determination and recommendations.
I am sorry, and do apologize, for any confusion that my other
statements, of opinion, may have created.
~4~ }/;1 ~~?
~:~: Lee Moberg, P. E.
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, EXHIBIT E
PAGELOF --'
1111:
2015 East 121st Street, Tacoma, Washington 98445
(206) 537-4375