20-101872--TIR Report-2-17-2021-V1AP CONSULTING ENGINEERS PLL4
CIVIL ENGINEERING
FEBRUARY 12,2021
d'i kwim
PREPARED FOR:
KARNAFEL RESIDENCE
PARCEL #6143600450
FEDERAL WAY, WA
I hereby state that these Drainage Calculations have been prepared by me or under my supervision and
meet the standard of care and expertise which is tisual and customary in the community for professional
engineers. I understand that City of Federal Way does not and will not assume liability or the sufficiency,
suitability, or performance of drainage facilities prepared by me.
91MEMOM
TABLE OF CONTENTS
PAGE
1.0 PROJECT OVERVIEW
1
2.0 CONDITIONS AND REQUIREMENTS SUMMARY
3
3.0 OFF -SITE ANALYSIS
5
4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
5
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
8
6.0 SPECIAL REPORTS AND STUDIES
9
7.0 OTHER PERMITS
9
8.0 ESC ANALYSIS AND DESIGN
9
9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT
9
10.0 OPERATIONS AND MAINTENANCE MANUAL
9
TABLE OF APPENDICES
APPENDIX
SOIL INFORMATION
A
DRAINAGE PLAN
B
EROSION AND SEDIMENT CONTROL PLAN
C
OPERATIONS AND MAINTENANCE MANUAL
D
DRAINAGE CALCULATION
E
SPECIAL REPORTS
F
KARNAFEL RESIDENCE TECHNICAL INFORMATION REPORT
1.0 PROJECT OVERVIEW
This report accompanies the drainage review plan prepared for the Karnafel Residence
project on parcel 6143600450 in City of Federal Way, Washington. The site location is
shown in Figure 1, below. The project has been designed to meet the requirements of the
2016 King 1 Countv Surface Water Design Manual (KCSWDM).
FIGURE 1 - Vicinity Map
The existing site is approximately 1.14-acres. It has an existing shared driveway and the
remaining area is in a forested condition. The neighboring parcels are also single-family
residential lots. Historic land cover characteristics are provided below in Table 1.
One wetland was found and delineated on this lot in the previous application for the
Pierson Driveway as described in according to the Technical Information Report
prepared by Edward McCarthy, P.E., dated January 31, 2013. The property slopes
toward the east edge of the property based on topographic information provided Axis
Survey & Mapping on a survey, dated November 16, 2020.
11 Pa g e
TABLE 1 — PREDEVELOPED AREAS
Area I Total
Description I (ft2) I (ft2)
Public Road
3,041
3,041
—Impervious
Pervious
Forest
9,225
9,225
Total � 12,266
The developed site will consist of a new single-family residence, a new sidewalk, a new
driveway, and the required frontage improvements along South 334th Street. The
developed areas are tallied below in Table 2. The developed sub -basin map is included
in Appendix E.
The soils present on the project site are identified as being underlain by Alderwood
gravelly sandy loam (AgB) soils in the geotechnical report provided by GeoResources
LLC, dated February 1, 2021.
The project area is also divided into two threshold discharge areas. The developed areas
draining to these threshold discharge areas are described below.
The northern threshold discharge area will consist of the frontage improvements which
have an estimated area of 460 square feet of impervious surfaces, and a landscaped area
of aproximately 861 square feet. The developed land cover characteristics are tallied
below in Table 2.
Impervious Sidewalk
Drivewai
Pervious
Area (ft2)
Total (ft2)
366
460
94
861
861
1,321
The southern threshold discharge area will consist of the new single-family residence,
which has an estimated roof area of 3,916 square feet, a 75 square -foot sidewalk, and a
1,146 square -foot driveway, and a landscaped area of aproximately 2,767 square feet.
The developed land cover characteristics are tallied below in Table 3.
21 Page
TABLE 3 - SOUTHERN THRESHOLD DISCHARGE AREA - DEVELOPED AREAS
Description Area (ft2) Total (ft2)
Roof Area 3,916
Impervious Driveway 1,146 5,137
Sidewalk 75
Pervious Landscaping 2,767 2,767
7,904
2.0 CONDITIONS AND REQUIREMENTS SUMMARY
Within the limits of construction, the predeveloped project site is assumed to have
consisted of 9,225 square feet of forest. The developed site will contain 5,597 square feet
of new impervious surfaces for the new structures and driveways. The developed site
will also contain 3,628 square feet of landscaping area. There are two threshold
discharge areas found within this site.
Since the project proposes 2,000 square feet of new impervious surface, does not qualify
for Simplified Drainage Review, and is not subject to Large Project Drainage Review,
Directed Drainage Review will be required for this project. This report will show how
the project complies with Core Requirements 1 through 9 and Special Requirements 1
through 5, as follows:
Core Requirement #1: Discharge at Natural Location
Under existing conditions, stormwater runoff from the project site is naturally dispersed
toward the east edge of the property. According to the Technical Information Report
prepared by Edward McCarthy, P.E., dated January 31, 2013, the property contains two
threshold discharge areas. A wetland on the northern portion of the property collects
on -site runoff and flows to the north and discharges to a public closed storm system that
continues to flow to the north, discharging to North Lake within 700 feet from the site.
An on -site wetland on the southern portion of the property drains through off -site
forested properties to the south. Adjacent properties to the west contribute minor sheet
flow runoff to the site but no stormwater structures were identified on the property.
Runoff from the east is largely collected in the stormwater system for North Lake Ridge
development and conveyed around the project site.
Core Requirement #2: Off -site Anal
The off -site system analysis is included in Section 3.0 of this report.
Core Requirement #3: Flow Control
Stormwater runoff from the developed site will not increase the 100-year peak flow rate
by more than 0.15 cfs over the predeveloped, 100-year peak flow rate and, therefore
flow control will not be required for this project.
Core Requirement #4: Conveyance System
The conveyance system for this project includes pipes on the property that convey the
stormwater to the rock pad. They are sized appropriately to handle the stormwater that
is anticipated.
Core Requirement #5: Erosion and Sediment Control
Erosion and sediment control requirements will be met for this project as described in
Section 8.0.
Core Requirement #6: Maintenance and Operations
The conveyance system, splashblock, and dispersion trench will be maintained privately
by the property owner. Operations and Maintenance guidance is addressed in Section
10.0.
Core Requirement #7: Financial Guarantees and Liability
Financial guarantees are not expected to be required by the City of Federal Way.
Core Requirement #8: Water Quality
The project will be exempt from the requirement to provide water quality treatment
because less than 5,000 square feet of new or replaced pollution -generating impervious
surface (PGIS) is proposed.
Core Requirement #9: Flow Control BMPs
This project will be constructed on a lot that greater than 22,000 square feet but less than
5 acres in size and inside the Urban Growth Area and will, therefore, be subject to Large
Lot BMP Requirements, as discussed in Section 1.2.9.2.2 of the 2016 KCSWDM. This
project will implement the BMPs found in the list in Section 1.2.9.2.2.
Special Requirement #1: Other Adopted Area -Specific Requirements
There are no known area -specific special requirements that apply to this project site.
4 1 P a g e
Special Requirement #2: Flood Hazard Area Delineations
There are no known flood hazard areas on or adjacent to this project.
Special Requirement #3: Flood Protection Facilities
Flood protection facility special requirements do not apply to this project. The project
does not propose to construct a new or modify an existing flood protection facility.
Special Requirement #4: Source Controls
Since the proposed project is a single-family residence, source control measures are not
expected to be required in conjunction with this project. There is no proposed outside -
use or storage of significant quantities of pollutants.
Special Requirement #5: Oil Control
The proposed project does not require oil control measurements. The site is not
considered high -use since it is a single family residence.
3.0 OFF -SITE ANALYSIS
Downstream Basin of Threshold Discharge Area:
A Level 1 downstream analysis was completed by Edward McCarthy, P.E., that is dated
January 31, 2013. The same downstream analysis is applied in this project and included
in Appendix F. In summary, runoff leaves the north basin through a conveyance
connected in a public closed storm system and it flows north, to an open channel and
ultimately discharges to North Lake approximately 740 feet from the site. Runoff leaves
the south basin in an open channel and it enters to the large forest wetland. At about
1,500 feet from the site, it enters a public closed storm system.
Upstream Tributary Basin:
There are no known concentrated sources of stormwater discharge to this property.
4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
Flow Control
A WWHM analysis of the historic and developed surfaces has been completed and
included with this report. This analysis shows that the 15-minute, 100-year peak flow
5 1 Pegs
rate under historic conditions (forest on type C soils) from the areas that will be
disturbed by this project will not be surpassed by the 100-year peak flow rate under
developed conditions by more than 0.15 cfs. This project is, therefore, exempt from
providing flow control facilities. Credits from Table 1.2.9.A of the KCSWDM were
applied to the analysis.
The runoff from all of the project areas will be modeled in two separate threshold
discharge areas (TDA). The northern TDA includes all the frontage improvements. The
southern TDA includes the roof area, driveway, sidewalk, and the landscaping area
around the house. The runoff from southern TDA areas will be collected in a system of
catch basin before it discharges to the proposed rock pad located to the east of the
shared driveway. The model inputs for these TDAs are summarized below.
Under developed conditions, in the northern TDA, the portion of the property that will
be disturbed for construction will be covered by 366 square feet of sidewalk (0.008 acres,
modeled as impervious, flat), 94 square feet of driveway (0.002 acres, modeled as
impervious, flat), and 861 square feet of lawn and landscaping (0.020 acres, modeled as
lawn on type C soils, moderate slope). The public road is not new or replaced, but
because of existing topography, it will discharge to the same existing catch basin that it
did before the development.
In the southern TDA, the portion of the property that will be disturbed for construction
will be covered by 3,916 square feet of roof (0.090 acres, modeled as impervious, flat), 75
square feet of sidewalk (0.002 acres, modeled as impervious, flat),1,146 square feet of
driveway (0.026 acres, modeled as impervious, flat), and 2,767 square feet of lawn and
landscaping (0.064 acres, modeled as lawn on type C soils, moderate slope). The table
below summarizes the inputs to the WWHM model for this project.
Developed
Modeled as
Impervious
Lawn
Pasture
Forest
Sidewalk
0.008 acres
0.008acres
0.000 acres
0.000 acres
0.000 acres
Driveway
0.002 acres
0.002 acres
0.000 acres
0.000 acres
0.000 acres
Landscaping
0.020 acres
0.000 acres
0.020 acres
0.000 acres
0.000 acres
Totals
0.030 acres
0.010 acres
0.020acres
0.000 acres
0.000 acres
The results of the analysis of the northern threshold discharge area indicates a 15-
minute,100-year peak flow of 0.003 cfs. This is less than a 0.15 cfs increase over the
predeveloped 15-minute,100-year peak of 0.016 cfs. Therefore, this TDA will be exempt
from providing flow control facilities.
6 1 P a
WWHM MODEL SUMMARY SOUTHERN TDA)
Developed
Modeled as
Impervious
Lawn
Pasture
Forest
Roof
0.090 acres
0.089 acres
0.001 acres
0.000 acres
0.000 acres
Sidewalk
0.002 acres
0.002 acres
0.000 acres
0.000 acres
0.000 acres
Driveway
0.026 acres
0.024 acres
0.002 acres
0.000 acres
0.000 acres
Landscaping
0.064 acres
0.000 acres
0.064 acres
0.000 acres
0.000 acres
Totals
0.182 acres
0.115 acres
0.067 acres
0.000 acres
0.000 acres
The results of the analysis of the northern threshold discharge area indicates a 15-
minute,100-year peak flow of 0.017 cfs. This is less than a 0.15 cfs increase over the
predeveloped 15-minute,100-year peak of 0.113 cfs. Therefore, the northern threshold
discharge area is exempt from providing additional flow control facilities.
Section 1.2.9.2.2 of the KCSWDM requires that a project that must comply with Core
Requirement #9 and which is on a lot that has a size greater than 22,000 square feet and
less than 5 acres either demonstrate compliance with the LID Performance Standard or
implement BMPs on the property in the order identified in the Large Lot BMPs list in
Section 1.2.9.2.2. This project will implement BMPs from the list in Section 1.2.9.2.2.
Mitigation of New and Replaced Impervious Surface:
Full Dispersion: Full Dispersion BMPs are not feasible. There is no 100-foot long native
vegetated flowpath available on this project site with slopes of less than 15%. Therefore,
Full Dispersion BMPs are not feasible.
Full and limited infiltration: It is infeasible to apply infiltration BMPs as detailed in
Appendix C, Section C.2.2. of the 2016 KCSWDM. A stormwater feasibility evaluation
for infiltration was provided in the geotechnical report provided by GeoResources LLC,
dated February 1, 2021, and is included in Appendix A. The soil type determined by the
GeoResources LLC for the stormwater management facility is loamy sand. A high
groundwater was found on -site which was about 2 feet below the existing surface while
1 foot of cover over the facility and 1 foot of separation from groundwater is required
for an infiltration facility. Therefore, it is not feasible to provide an infiltration facility
that complies with Section C2.2 of the KCSWM.
Bioretention: Bioretention BMPs are not feasible. The test pits investigated by
GeoResources LLC indicate that the subsoils were silty loamy sand. It became dense and
cemented at depths of about 3 to 4 feet below the surface. The groundwater elevation
71
was approximately 2 feet below the existing surface. For these reasons, Bioretention
BMPs are not feasible per Section C.2.6 of the KCSWDM.
Permeable Pavement: Permeable Pavement BMPs are not feasible. The test pits
investigated by GeoResources LLC indicate that the subsoils were silty loamy sand. It
became dense and cemented at depths of about 3 to 4 feet below the surface. The
groundwater elevation was approximately 2 feet below the existing surface. For these
reasons, Permeable Pavement BMPs are not feasible per Section C.2.6 of the KCSWDM.
Basic Dispersion: Basic Dispersion BMPs are feasible. In the southern threshold discharge
area, the new roof (700 square feet; 0.016 acres) will be mitigated in accordance with
Section C.2.4.2 of the KCSWDM. The proposed driveway (776 square feet; 0.018 acres)
will be mitigated by sheet flow dispersion in accordance with Section C.2.4.5 of the
KCSWDM.
According to Section 1.2.9.2.2 of the KCSWDM requires that BMPs must be
implemented, at a minimum, to mitigate an impervious area equal to 50% of the
impervious surface coverage when less than 45% of the site will be covered by
impervious surface. The proposed site has a buildable area of 17,262 square feet. The
total proposed impervious area is approximately 5,597 square feet and which equates to
a coverage of about 32%. Therefore, 2799 square feet of the proposed impervious surface
(50%) must be mitigated. The total proposed impervious area being mitigated by the
proposed BMPs will be 1,476 square feet. The remaining area that is required to be
mitigated,1,323 square feet, will be mitigated with the Native Growth Retention Credit.
4,631 square feet of native growth retention area will be set aside on -site incompliance
with Section C.2.10 of the KCSWDM.
The impervious area of the northern TDA cannot be collected and mitigated. It will be
bypassed.
Water Qual&i
This project is exempt from providing water quality treatment because less than 5,000
square feet of PGIS is proposed as part of this project.
5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Conveyance pipes for this project will consist of 6-inch pipes to the rock pad. These
pipes are adequately sized to handle the flows that are anticipated from this project.
81e
6.0 SPECIAL REPORTS AND STUDIES
The geotechnical assessment prepared by GeoResources LLC, dated February 1, 2021 is
included in Appendix A.
The Technical Information Report prepared by Edward McCarthy, P.E., dated January
31, 2013 is included in Appendix F.
7.0 OTHER PERMITS
Building, water and sewer permits for the proposed home will be required in
conjunction with this project.
8.0 ESC ANALYSIS AND DESIGN
Erosion and sediment control requirements will include the delineation of clearing
limits via flagging, proper cover measures for the protection of disturbed areas,
perimeter protection with silt fencing on an as -needed basis, and a stabilized
construction entrance per the City of Federal Way standards. The Erosion and Sediment
Control Plan has been included as part of the construction plans and is included in
Appendix C.
9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT
A bond is not expected to be required by the City for this single-family project.
10.0 OPERATIONS AND MAINTENANCE MANUAL
The on -site dispersion systems and associated elements will be maintained privately by
the property owner. The operations and maintenance guidelines for the private facilities
are provided in the Operations and Maintenance Manual found in Appendix D.
APPENDIX A:
11111111111111111
Mr. DmitriyKamafe|
136-24mStreet Southeast, Apt A
Auburn, Washington 9O002
Drnitriy_2004@hotrnai|.corn
(253)736-5256
February 1, 2021
StorrnvvoterFeosibi|hx Soils Report
Proposed Single -Family Residence
xxx-South 334thStreet
Federal Way, Washington
PN:6143600450
Doc ID: Karnafe|.53341hSL5R
INTRODUCTION
This stormwater soils report addresses the feasibility of the site soils to support infiltration
of collected runoff from the proposed single-family residence to be constructed on the parcel
referenced above. The site is located adjacent and north of3633 South 334!^ Street in Federal
Way, Washington. The general location ofthe site is shown on the attached Site Location Map,
Figure 1.
Our understanding of the project is based on our conversations with you, our
understanding of the City of Federal Way development codes, and our experience in the area. We
understand that you propose to construct single-family residence at the site. We anticipate that
the proposed construction will consist of 1 to 2 story wood -framed structures, founded on
conventional shallow foundations. We understand that the site will be developed with typical
underground residential utilities, concrete driveway, and landscaping areas. A copy of the
proposed site plan isattached asFigure 2.
We understand that the City of Federal Way uses the 2016 version of the King County
Surface Water Design Manual (2016 K[SVVDk4)vvith addendum that requires the confirmation of
subsurface conditions to address the feasibility of the onsi1e infiltration of storrnvvater runoff
generated bythe proposed development.
SCOPE
The purpose of our services was to evaluate the surface and subsurface conditions across
the site, as a basis for providing geotechnica| recommendations and design criteria for the
proposed single-family residential development. Specifically, the scope of services included the
1. Reviewing the available geologic, hvdrogeo| ic,andgeotechnica|datafor1heske
Karnafe|.B34thSt.Se
February 1.2021
Page 2
2. Exploring subsurface conditions across the site by excavating 2 test pits at select
locations onthe site;
3. Describing surface and subsurface conditions, including soil type, depth to
groundwater, and anestimate ofseasonal high groundwater levels;
4. Providing our opinion about the feasibility of onsite infiltration, including a preliminary
design infiltration rate based on grain size data per the 2016 King County Stormwater
Design Manual, ifapplicable;
5. Preparing this written Stonnwoter Feasibility Soils Report summarizing our site
observations and conclusions, and our geotechnical recommendations and design
criteria' along with the supporting data.
The above scope of work was completed in accordance with our Contracting Agreement
dated January 12, 2021. We received written notification to proceed January 13, 2021.
Surface Conditions
The site consists of single tax parcel that is generally "L" shaped. The parcel measures
approximately 100 to 290 feet wide (east to west) by about 100 to 310 feet deep (north to south)
and encompasses about 1.14acres. The site bounded isbvsingle-family development tothe west,
northwest, and south, bvundeveloped land and wetlands tothe east, and bvSouth 3]4 Ih Street to
the northeast.
Based on topographic information obtained from the Site Plan by Architects Northwest
dated April 13, 2020 and generally confirmed during our site visit, the ground surface of the parcel
is relatively flat at an elevation of about 410 feet. The existing site configuration is shown on the
Site Vicinity Map, Figure3.
The subject site is generally well vegetated with second growth forest with a moderate
understnry ofsa|a|' ferns' and evergreen huckleberries. No evidence of soil erosion or movement
was observed atthe time ofour site visit.
Site Soils
The Natural Resource Conservation Service (NR[S) Web Soil Survey maps the site as
underlain bvA|denwood gravelly sandy loam (Ag8) soils. A|denwood soils are derived from are a
glacial drift and/or glacial outwash over dense g|acinnnarine deposits' form on slopes of to 8
percent, have a^s|ighi"erosion hazard when exposed, and are included in hydrologic soils group
B. Acopy ofthe NR[Ssoils map isincluded asFigure 4.
Site Geology
The Lidar-revisedgeologic map of the Poverty bay 75' quadrangle, King and Pierce Counties,
Washington by R.W. Tabor, D.B. Booth, and K.G. Troost (2014) indicates that the site is underlain by
ice -contact ((}vi)deposits. The ice -contact and advance outwashdeposits are glacially derived soils
that were deposited during the Vashon S1ade of the Fraser Glaciation, approximately 12'000 to
15,000 years ago. Typically, the ice -contact deposits consist of poorly sorted, unstratified mixtures
of silt, sand, gravel, cobbles, and boulders. The deposits are commonly encountered in a similar
texture to recessional outwash soils but contain lenses of till. These glacial sediments were
ManIkokold
in"=
Karnafel.S334thSt.SR
February 1, 2021
Page 3
originally deposited through fluvial processes on or within the continental ice mass, then lost
support and slumped as the ice receded, causing mixing of the material and disturbance of the
stratification. The ice -contact deposits generally were not overridden by the continental ice mass
and are considered normally consolidated. Infiltration feasibility is dependent on the gradation of
the soils, and can be highly variably in ice contact deposits. An excerpt of the above reference
geologic map is attached as Figure 5.
Subsurface Explorations
On January 19, 2021 we visited the site and monitored the excavation of two test pits to
depths of approximately 4 feet below the existing ground surface in the upper, northern portion
of the site. Our representative logged the subsurface conditions encountered in each test pit, and
obtained representative soil samples. Our test pits were excavated by a small track -mounted
excavator operated by you.
The specific number, locations, and depths of our explorations were selected based on the
configuration of the proposed development and were adjusted in the field based on consideration
for underground utilities, existing site conditions, site access limitations, and encountered
stratigraphy. Representative soil samples obtained from the test pits were placed in sealed plastic
bags then taken to a laboratory for further examination and testing as deemed necessary. The
test pits were then backfilled with the excavated soils and bucket tamped, but not otherwise
compacted.
The subsurface explorations excavated as part of this evaluation indicate the subsurface
conditions at specific locations only, as actual subsurface conditions can vary across the site.
Furthermore, the nature and extent of such variation would not become evident until additional
explorations are performed or until construction activities have begun.
The approximate locations and numbers of our test pits are shown on the attached Site &
Exploration Plan, Figure 2. The soils encountered were visually classified in accordance with the
Unified Soil Classification System (USCS) and ASTM D2488. The USCS is included in Appendix A as
Figure A-1, while the descriptive logs of our test pits are included as Figure A-2 and A-3.
Subsurface Conditions
Our explorations encountered subsurface conditions that generally confirmed the mapped
stratigraphy. Our test pits on site generally encountered about half a foot of topsoil/duff mantling
about 3 feet of brown to black silty sand with gravel in a loose to medium dense, moist to wet
condition. Underlying these surficial soils, we encountered grey with some mottling cemented silty
sand with gravel in a dense to very dense, moist condition. We interpret these soils to be consistent
with weathered ice -contact overlaying undisturbed ice -contact deposits.
Laboratory Testing
Geotechnical laboratory tests were performed on a select sample retrieved during test pit
explorations to determine soil index and engineering properties encountered. Laboratory testing
included visual soil classification per ASTM D2487 and ASTM D2488, moisture content
determinations per ASTM D2216, grain size analyses per ASTM D6913, and No. 200 wash per ASTM
D1140 standard procedures. Test results are included in Appendix B.
GORGES
earth m n€.e,,v.;.�;�.7t��,7',9ts.
Karnafe|.B34thSt.Se
February 1.2021
Page 4
Groundwater Conditions
Nngroundwater seepage was observed intest pit TP-1 atthe time ofexcavation; however,
iron -oxide staining, a form of soil mottling, was observed at about 3.5 to 4feet below the existing
ground surface. At test pit explorations TP'2 we observed rapid groundwater seepage at
approxirnabe|y3.5 feet below the existing grade. Similarly, iron -oxide staining was also observed in
test pitTP'I as shallow as 2feet from the existing ground surface. Based on these observations
made during our subsurface explorations, we interpret that the site is prone to perched
groundwater during periods ofprolonged wet weather. Perched groundwater develops when the
vertical infiltration of precipitation through a sha||uvv, more permeable soil is slowed at depth by
deeper' less permeable material, such as the encountered ice -contact deposits. We anticipate
fluctuations in the local groundwater levels will likely occur in response to precipitation patterns, off
site construction activities, and site utilization. Analysis or modeling of anticipated groundwater
levels during construction isbeyond the scope ofthis report.
CONCLUSIONS
Based on our site reconnaissance and subsurface explorations, it is our opinion that the
onsitoinfiltration ofs1nrrnvva1errunoff generated bvthe proposed residential development isnot
feasible given the shallow depth to evidence of seasonal high groundwater.
Infiltration Recommendations
Per the 2016 K[SVVOM Appendix C, Section [.2.2.2, a nnininnunn vertical separation of3feet
is required from the bottom of an infiltration facility to seasonal groundwater and a nninirnunn of
feet ofpermeable soil is required below the facility bottom. Additionally, infiltration facility bottoms
must be located within native soils in accordance with Chapter 5' Section 52 and Appendix [.
Section [.2.2.2. Groundwater seepage was encountered at2.5feet be|nvv existing grade in test pit
TP-2 and evidence of seasonal high groundwater was observed at 2 feet below existing grade.
Based on the above rnininnurn vertical separation requirements and the observed
subsurface conditions, Infiltration is not feasible at the site. We recommend that alternative
storrnvvater management BMPs be implemented to manage the roof runoff from the proposed
residential development. All rninirnurn setback requirements and infeasibility criteria should be
considered prior to the selection of any stornnvvaterfacility for the proposed development. All
stormwater facilities should be designed and constructed in accordance with the 2016 KCSWIDM. If
there is insufficient room at the site to meet the nninirnunn setback requirements or if onsite
storrnvvater management is not feasible for the proposed development, the proposed storrnvvater
system should be connected directly to the existing municipal stormwater system, as appropriate.
LIMITATIONS
We have prepared this report for Mr. Drnitri Kornafe[ and other members of the design
team for use inevaluating aportion ofthis project. The data used inpreparing this report and this
report should be provided to prospective contractors. Our report, conclusions and interpretations
are based ondata from others and limited site reconnaissance, and should not beconstrued as
warranty ofthe subsurface conditions.
Variations in subsurface conditions are possible between the explorations and may also
occur with time. A contingency for unanticipated conditions should be included in the budget and
Karnafe|.B34thSt.Se
February 1.2021
Page 5
schedule. Sufficient monitoring, testing and consultation should be provided by our firm during
construction to confirm that the conditions encountered are consistent with those indicated by the
explorations, to provide recommendations for design changes should the conditions revealed
during the work differ from those anticipated' and to evaluate whether earthwork and foundation
installation activities comply with contract plans and specifications.
The scope of our services does not include services related to environmental rennediation
and construction safety precautions. Our recommendations are not intended to direct the
contractor's methods, techniques, sequences or procedures, except asspecifically described in our
report for consideration indesign,
If there are any changes in the loads, grades, locations, configurations or type of facilities to
be constructed, the conclusions and recommendations presented in this report may not be fully
applicable. If such changes are made, we should be given the opportunity to review our
recommendations and provide written modifications or verifications, as appropriate.
���
Karnafe|.B34thSt.Se
February 1.2021
Page 6
We have appreciated working for you on this project. Please do not hesitate to call at your
earliest convenience if you have any questions or comments.
es
SCOTT
KEITH
Kyle E.Billingsley, pE KebhS. Schernbs,LEG
Project Engineer Principal
JZ:KEB:KSS/jz
Doc ID: xamafei6334thSt.SR
Attachments: Figure 1:Site Location Map
Figure l:Site & Exploration Plan
pigure3: Site Vicinity Map
Figure 4:mmS Soil Map
Figure S:Geologic Map
Appendix /tSubsurface Explorations
Appendix n:Laboratory Test Results
Approximate Site Location
Map created from King County iMap (https://gismaps.kingcounty.gov/iMap/)
"TOffm 707�a
GEORESOURCES
earth science & geotechnical engineering
4809 P—lfic Hwy, F. I Fife, VVA 98424 1 253.896A01 1 1 --
Site Location Map
Proposed Single Family Residence
xxx - South 334 Ih Street
Federal Way, Washington
PN:6143600450
Not to Scale
- - - - - - ---- A, - - - - - - - - -
T FENCE:'�
FT P 21
410 410
Z
K)
M
r
L— — — — — — — — — — —
Notes:
Excerpt from the Site Plan, Sheet AO prepared
by Architects Northwest dated April 13 th 2020.
FW TP-XX Approximate Test Pit Location
IN
5_5L — — — — — — — — — — — — — — — — — — —
41'
Na-765--T
Scale: 1" = 20'
UTILITY EA5EMENTS
I
0111111111"T"Mow—an
00 wwwftw!�
_.aM00'0 0-.0 M WMM
E S "'
earth science & geotechnical engineering
4809 Pad fit Hwy- E.. I Fife, WA 98424 1 253.896A011 1 www- georesources.rocks
IN
Z X,
vl
WETLAND 2
PER BLA
L04L0030
REC. NO,
20050630900012
Site & Exploration Plan
Proposed Single -Family Residential
xxx - South 334 th Street
Federal Way, Washington
PN:6143600450
DocID: Karnafel.S334thSt.F I February 2021 1 Figure 2
Approximate Site Location
Map created from King County iMap (https://gismaps.kingcounty.gov/iMap/)
"TOffm 707�a
GEORESOURCES
earth science & geotechnical engineering
4809 P—lfic Hwy, F. I Fife, VVA 98424 1 253.896A01 1 1 --
Site Vicinity Map
Proposed Single Family Residence
xxx - South 334 Ih Street
Federal Way, Washington
PN:6143600450
Not to Scale
Approximate Site Location
Map created from Web Soil Survey (http://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx)
Soil
Hydrologic
Type
Soil Name
Parent Material
Slopes
Erosion Hazard
Soils Group
AgB
Alderwood gravelly sandy
Glacial drift and/or glacial outwash
0 to 8
Slight
B
loam
over dense glaciomarine deposits
GEORESOUROES
earth science & geotechnical engineering
4809 Pa lfic Hwy, F. I Fife, VVA 98424 1 253.896A01 1 1
NRCS Soils Map
Proposed Single -Family Residence
xxx - South 334 th Street
Federal Way, Washington
PN:6143600450
Not to Scale
{Yt vS J,Stt tti, .
,, ., ,
S i} x}: � }Y ,'z,. S t� ..'C,... ? L. d. r \ �. 5:•. :'i{it, l
))��ii t\ 9 , t. �rr?~',-^-,,.. �:,� 'r •, e.,£.c.tii z �'Y .a} `\i �'1 t \� �S �..,
S��t�ti�
7�. 4i.t l.tti`,l ;r, �t .t F,.�tfir "h\3i . �".��� �:. «S..,t1 `,•: % >ft's 1�4., �. i �. ,
�» t„ tolr Kr §``s kr ': u. rYi t,:;v t.i lF£� `Y'„�a.�.3 ,. ,'.. ���fi�• f Yt .<::it 2t`P',.G }. � ,} t,:.xi� Y '.. t, � :a; `:
`�, uS�, }y \,�{ ,1o•+,`. �E}i�, ?' ":.�tSs Y��4 �i :tf r`�.. ,,,r� s,.`+.i`tti,. . �.,xF '4 tiR e ,`\. trikr. �, .' :��;
,tt .'�., t,3t 4. {'•,.tiiskf{} rzt f,j,`'',, ,anr �:'r,v t ..�,. r< `+;,��:
r �i
"\�i\, t,'�i11! f � }'tt ��1�`.v �:, fSs`�Si�,'t'+ §�'it e., ,,; 5•sC,4S, 1l lilt? ttF `} \?:f �,��""�tr2 ,tii, � +2
'', � A'4r}� {k`��9.
}� :31�t tG;2}it ,t;.
£ ��}a,�\, )f14.i;r ,�il•S\lc,,,r ��.a ;}4f1'',, AF /.. `S}:) '� � i,r}:` `t it A,��f vA::" fi,,} ? vlr. .��v2 ,;i7"I 1 '. ,., .`t.,'! ��'
��''\\\'„\rs"
�� �:; � #t} } ,r s : C\ 4, ? ' ? S S .°s',S',it�{ l ' t �S z � U d � S �s' i � , `"w a•" }?u
•?{, 5 ,.,`< 'r ��tz S\'4{li` fs"i$ �`»C i:zr b) 55....t%{} } SR$4��{?Sz ... �Ftft `„ -inf t;?y <., } `P�h ' � kf}Ty{\�L ,"4`�
5 tt �� �' 41 t �v �"§2 '} � � \ `�� V,, � {'ti..
:7i'. 4 $.ER �rniA E5, v 11 t : y �Siv::1 } . ., i ' ?• a?+.y ,. kf
( t; p`ti„ ,..., 5.. {a�� 41. ,. ki l'`.•s,� (,}SC n `r ).,t l +tr�4v { � t - �, #J ,..3� ri C ;•~:' �X t .. ,c , :� '.l .� �� (.tit..
4.�r, Y't,: , „l r {{��, Z '{S\s. #S. ys�•,ti\ ''� {? ?\; ...t % .t. �?tFtst �} t�}� ,fa, ., �3, �.t" .+d1Yt;}S\ {s�� 4t ti.
:.. Y; frt `St, fi{ VS4��»1•�T"'ryt i��t`y}:»4�r a�:r�. i ;elt `;t} t ., b:1. ,+1 tt1.2 ✓� rR"t§l t.;`}�yt\ "\i ,,
P§}f,`„}k�� \\`:J.t ti\,t,Z'iit#tC ��k}��'. ? ?§S.2 7�}} •3 I' `f'kr ti?; Y
"r}\2'ti �, �.
`n,.,,b
:}1t~3i�,.,;
S •t;1 r £ .{ {i tt3 1rr}r,}�y,+u, '1\, 2 ,, � :fit U i "v11�. `Y, " "r�
i t 4 a ti. , rt
�Y , ,�._. ,.'. �#.' } 1? 3kti fzt, L?�\�. rr1 Iti t ✓ °f { s � {"�r
, 2 si,> '. � S? \ `\''t.. { ,& t ��. � � �y . t t � t. '\�{'}. 'z ;u, � , rtr Sk 4'?: , ; r t i��� :' , "4•.t
i19 . F,akra}} ,'.34 2,fi,. ti ,.� . �ti i ,-�•r,i,. } S F } 3 � Z .. `igt$S � , , �i4 t1., ttt
t
:,, , e`t xt..,,. ,.o tr<Szs~"•k. e.�, t?. s, .7�.. :t .ti.2 } '\ +rrna .'.\ 1, .,. •. e ,.w
yy
�i2. �; � �,.ac
}•`tia3:..
l:.\., lr�t�{t :l Z,1t } 1 }.L:, al, ,# tw`i ti ,t � �,, ,,
��b{..,. �=;'az,�
it\ti,§+; ?.g+FrtiY�t4 \1 ...t`,. `, 4i, }�fr ...,? � +1 t i':, •, ,,t, .tt. \ t 1 : },st��
�1 �..
!•e ,.\ � {t i ,{»S ��,.1 ,»ti .z !tli e.? .}?C. ty. e 1 Zh?��`..0 s'yl`�'t,. `,' tlY;. s; `':t =.
,n,>S. : ,:Ulna Sal{,� \ .., ',.l} \. {. Z.. x'�r , t•,}:,: 3i ehZ', F , .{ tt £� .:: �'£. 1\t `� �1...' ,,k � :..4 :.+, ,,.,.. �, a ,$ e., .va, n..
c
�� ?\'. G .�1rr4 �'e � , •}n zti(N 3} h 1"S11 `Y ?'} �..? EY R %1,i �lr :: i,rht% U ����\'\�:, i3 t iM P,
`'r�SS i? rs� t.ti� ate .. i
} y"., i
�}',�{;.r,Sstf„f,, 'tt � lr f?,, +: 2 `2!',`a\:i }}Z,a ,,, ,
�. � Ge.{rY � \�
�
tFe zi ,Ukt
'r S. r.. t
{1 :r 11 tti`. srs ;i 51�7:' "t± ��:':
..,. }, \ }, t l �,1 ;,. �. : ,, t.§, 2 if}} ?.. ' � H +a: 6{.€>•>,t�?:}�2'.� �,, �.. � t fJ ;:::
R��,},2
er+tl' „,r:,,,-.»i Ji4�`�""k�� .��u�&4�a�r� :5 v'' t'Stiat"•th'o�$}MYtc'w",�Yo- t',4h 5',: ..,,, "�,r�rw ;< �. �"`,., x�*,v..a
;,:'� r r,":3. r,r tki}},,y }l'?�-Yt`�}) f1��:��rstr�\2 §d$, , ,'�� ;'.ti�rt�*;'��,5\'t�.`•a\{� iilhirf �{ `.: t :;, :� �?��\ss ,` ��'� � �"� ,':�;,..
.,,
t(!
Y
�Sr 1 }
tU?{ f S2t5'de
i'. fS tti3 Y,
v�
4 i
S tU ?t E
k elf gyp?
{ r
�fT 1i )•i {,'{ } , r 1 4v ''i� V
H"�`'��
. a a { { ,{�A� }tea: t, 3'»
u
f
U � ?s
Itt??t
rF t r4Gk t t4it
Approximate Site Location
An excerpt from the Lidar-revised geologic map of the Poverty bay 7.5' quadrangle, King and Pierce Counties, Washington
by R.W. Tabor, D.B. Booth, and K.G. Troost (2014)
Ya{t�iil i�SS i{ittlk`i,t?t`l
Ice Contact deposits
n
Glacial Till
Not to Scale
Geologic Map
Proposed Single -Family Residence
xxx - South 334t" Street
G E O R E S O U R C E S
Federal Way, Washington
earth science & geotechnical engineering
PN: 6143600450
4809 Pact Fic Hwy, F. I Fife, VJA 98424 1 253. 896,1011 1 www.. geo resources.r®cks
DocID: Karnafel.S334thSt.F
February 2021
Figure 5
Appendix
Subsurface Explorations
SOIL CLASSIFICATION SYSTEM
MAJOR DIVISIONS
GROUP
GROUP NAME
SYMBOL
GRAVEL
CLEAN
GW
WELL -GRADED GRAVEL, FINE TO COARSE GRAVEL
GRAVEL
GP
POORLY -GRADED GRAVEL
COARSE
GRAINED
More than 50%
GRAVEL
GM
SILTY GRAVEL
SOILS
Of Coarse Fraction
WITH FINES
Retained on
GC
CLAYEY GRAVEL
No. 4 Sieve
SAND
CLEAN SAND
SW
WELL -GRADED SAND, FINE TO COARSE SAND
More than 50%
SP
POORLY -GRADED SAND
Retained on
No. 200 Sieve
More than 50%
SAND
SM
SILTY SAND
Of Coarse Fraction
WITH FINES
Passes
Sc
CLAYEY SAND
No. 4 Sieve
SILT AND CLAY
INORGANIC
ML
SILT
CL
CLAY
FINE
GRAINED
SOILS
Liquid Limit
ORGANIC
OL
ORGANIC SILT, ORGANIC CLAY
Less than 50
SILT AND CLAY
INORGANIC
MH
SILT OF HIGH PLASTICITY, ELASTIC SILT
CH
CLAY OF HIGH PLASTICITY, FAT CLAY
More than 50%
Passes
No. 200 Sieve
Liquid Limit
ORGANIC
OH
ORGANIC CLAY, ORGANIC SILT
50 or more
HIGHLY ORGANIC SOILS
PT
PEAT
NOTES:
SOIL MOISTURE MODIFIERS:
1. Field classification is based on visual examination of soil Dry- Absence of moisture, dry to the touch
in general accordance with ASTM D2488-90.
Moist- Damp, but no visible water
2. Soil classification using laboratory tests is based on
ASTM D2487-90. Wet- Visible free water or saturated, usually soil is
obtained from below water table
3. Description of soil density or consistency are based on
interpretation of blow count data, visual appearance of
soils, and or test data.
Qan
GEORESOURCES
earth science & gecftechnnical engineering
4809 Pacific Hwy, F. I Fife, WA 98424 1 253.896,1011 I www. georesources.rocks
Unified Soils Classification System
Proposed Single -Family Residence
xxx - South 3341h Street
Federal Way, Washington
PN: 6143600450
DocID: Karnafel.S334thSt.F February 2021 Figure A-1
■
LOG OF TEST PIT
Karnafel.S334thSt
xxx - South 334th Street
Federal Way, Washington
1. Refer to log key for definition of symbols, abbreviations, and codes Excavation Company: Client Porovided
2. USCS disination is based on visual manual classification Excavation Rig: Small Track Excavator
and selected lab testing
3. Groundwater level, if indicated, is for the date shown and may vary Sampler Type: Grab
4. NE = Not Encountered Mottling From: 3.5' - 4' GBS
5. ATE = At Time of Excavation Groundwater Seepage From: NE
Caving From: NE
Notes: Eastern portion of the site; near pro
a v v Exploration
v w v °/ notes
o�
w
0 —I— 410
1 --I— 409
2 T 408 Increase in density
and moisture with
depth
3--407
4 4— 406
5 4— 405
6 4— 404
Logged By:
Ecavation Date:
Datum:
Elevation:
Termination Depth:
Latitude:
fla
1/19/2021
NAVD 88
410 ft
4 ft
NA
driveway
Longitude:
NA
sTest
Results
o
_°Q
Plastic Limit i
Liquid Limit
3
Soil description
o
E
% Fines (<0.075mm) O
m
0-
N
% Water Content •
o
a
�
�
Topsoil/duff rootzone
Brown to black silty SAND with gravel (medium dense,
moist)(Weathered ice -contact deposits)
Grey cemented silty SAND with gravel (dense to very dense,
moist)(Undisturbed ice -contact deposits)
(Termination Depth - 111912021)
S1
S2
nTopsoil Silty sand
Sheet 1 of 1 JOB: Karnafel.S334thSt FIG. A-2
. LOG OF TEST PIT TP-2
A.r
Karnafel.S334thSt
G E E S E xxx - South 334th Street
earth Science & g otechnical engineering Federal Way, Washington
1. Refer to log key for definition of symbols, abbreviations, and codes Excavation Company:
Client Porovided
Logged By:
JZ
2. USCS disination is based on visual manual
classification Excavation Rig: Small
Track Excavator
Ecavation Date:
1 /19/2021
and selected lab testing
3. Groundwater level, if indicated, is for
the date shown and may vary Sampler Type:
Grab
Datum:
NAVD 88
4. NE = Not Encountered
Mottling From:
2' - 4' GBS
Elevation:
410 ft
5. ATE = At Time of Excavation
Groundwater Seepage From:
2.5 ft
Termination Depth:
4 ft
Caving From:
1 ft to 3ft
Latitude:
NA
Notes: Western portion of the site; within proposed backyard
Longitude:
NA
sTest
Results
a v
o
v
Exploration
Soil description
o
o
v
o
s
E
Plastic
% Fines
Limit i
(<0.075mm) O
Liquid Limit
3
o°
v
notes
m
0.
N
% Water
Content •
o
w
a
a
E
i7
�
Penetration
- ♦ (blows per foot)
0
410
o
0
Topsoil/duff rootzone
S1
Brown to black silty SAND with gravel (loose to medium
dense, moist to wet)(reworked native?)
1
409
2
408
Rapid groundwater
ATE
seepage @ 2.5 ft BGS
3
407
Grey cemented silty SAND with gravel (dense to very dense,
moist)(Undisturbed ice -contact deposits)
4
406
(Termination Depth - 111912021)
5
405
6
404
Topsoil
Silty sand Silty sand and gravel
Sheet 1 of 1
JOB: Karnafel.S334thSt
FIG. A-3
Appendix B
Laboratory Test Results
ly
W
Z
H
Z
W
U
ly
LLJ
IL
100
90
80
70
60
50
40
30
20
10
0
Particle Size Distribution Report
GRAIN SIZE - mm.
% Gravel % Sand % Fines
%Coarse Fine Coarse Medium Fine Silt Clay
i 0.0 5.9 28.8 8.1 14.6 26.7 15.9
Test Results (ASTM D 6913 & ASTM D 1140)
Opening
Percent
Spec.* Pass?
Size
Finer
(Percent) (X=Fail)
1.25
100.0
1
97.4
.75
94.1
.5
82.6
.3125
76.7
#4
65.3
#10
57.2
#20
50.6
#40
42.6
#60
32.1
#100
23.5
#200
15.9
F (no specification provided)
Sample Number: S2 Depth: 3.511
E
GeoResources, LLC
Fife, WA
Material Description
Grey cemented silty SAND with gravel (dense to very dense,
moist)(Undisturbed ice -contact deposits)
Atter_berg—Limits A( STM D 43101
PL= NP LL= NV PI= NP
Classification
USCS (D 2487)= SM AASHTO (M 145)= A-1-b
Coefficients
Dgo= 16.3436 D85= 13.9190 D60= 3.2269
D50= 0.7984 D30= 0.2235 D15=
D10= Cu= Cc=
Remarks
Natural Moisture: 12.0%
Test Pit: TP-1
Date Received: 1/18/2021 Date Tested: 1/18/2021
Tested By: JZ
Checked By: KSS
Title: LEG
Client: Dmitriy Karnafel
Project: Karnafel.S334thSt
Date Sampled: 1/18/2021
Tested By: Checked By:
APPENDIX B:
DRAINAGE PLAN
APPENDIX C:
APPENDIX D:
KARNAFEL FAMILY RESIDENCE STORM DRAINAGE FACILITIES
This Operation and Maintenance Manual is for the dispersion facilities serving the
single family residence located on parcel number 6143600450. The purpose of the
stormwater facilities is to provide management of stormwater runoff generated by the
residence and the proposed driveway.
The storm drainage facilities include the splash -block for the roof downspouts and the
dispersion trench for the driveways. A catch basin will be installed between the surfaces
to provide a point for some trash and any other substances that could clog the systems
to be removed from the runoff. Sediment and trash should be prevented from entering
the dispersion facilities to keep the rock and native soils from clogging.
The following pages identify and describe the maintenance tasks associated with the
storm drainage facilities.
This Operation and Maintenance Manual shall be kept on the premises of the home on
parcel number 6143600450 and must be made available for inspection by the City of
Federal Way.
The operation and maintenance of the storm drainage facilities will be the responsibility
of the home owner.
Long-term maintenance shall be performed as described hereinafter. All conveyance
systems shall be inspected for sediment and blockages on an annual basis or after large
storm events. Catch basin sumps shall be removed of sediment and debris on an annual
basis or if a blockage occurs. The main contributors of sediment to the storm system are
total suspended solids (TSS) and detritus from trees. The debris collected shall be placed
in the trash, not the roadway catch basins. Long-term maintenance of the storm
drainage system shall be completed in accordance with the following checklists.
Instructions for Use of Maintenance Checklists
The following pages contain maintenance needs for most of the components that are
part of your drainage system, as well as for some components that you may not have.
Ignore requirements that do not apply to your system. You should plan to complete a
checklist for all system components on the following schedule:
1. Monthly from November through April.
2. Once in late summer (preferably in September).
3. After any major storm (use 1-inch in 24-hours as a guideline), for items marked "S"
only.
Using photocopies of the checklist pages, check off the problems that you looked for
each time you conducted an inspection. Add comments on problems found and remedy
actions taken. Keep these "checked" sheets in your records. Some items do not need to
be looked at every time an inspection is done. Use the suggested frequency at the left of
each item as a guideline for your inspection.
APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
CATCH
Maintenance
Defect or Problem
Condition When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed
Structure
Sediment
Sediment exceeds 60% of the depth from the
Sump of catch basin contains no
bottom of the catch basin to the invert of the
sediment.
lowest pipe into or out of the catch basin or is
within 6 inches of the invert of the lowest pipe
into or out of the catch basin.
Trash and debris
Trash or debris of more than '% cubic foot which
No Trash or debris blocking or
is located immediately in front of the catch basin
potentially blocking entrance to
opening or is blocking capacity of the catch basin
catch basin.
by more than 10%.
Trash or debris in the catch basin that exceeds
No trash or debris in the catch
'/s the depth from the bottom of basin to invert
basin.
the lowest pipe into or out of the basin.
Dead animals or vegetation that could generate
No dead animals or vegetation
odors that could cause complaints or dangerous
present within catch basin.
gases (e.g., methane).
Deposits of garbage exceeding 1 cubic foot in
No condition present which would
volume.
attract or support the breeding of
insects or rodents.
Damage to frame
Corner of frame extends more than % inch past
Frame is even with curb.
and/or top slab
curb face into the street (If applicable).
Top slab has holes larger than 2 square inches
Top slab is free of holes and cracks.
or cracks wider than '/4 inch.
Frame not sitting flush on top slab, i.e.,
Frame is sitting flush on top slab.
separation of more than % inch of the frame from
the top slab.
Cracks in walls or
Cracks wider than '/2 inch and longer than 3 feet,
Catch basin is sealed and is
bottom
any evidence of soil particles entering catch
structurally sound.
basin through cracks, or maintenance person
judges that catch basin is unsound.
Cracks wider than inch and longer than 1 foot
No cracks more than inch wide at
at the joint of any inlet/outlet pipe or any
the joint of inlet/outlet pipe.
evidence of soil particles entering catch basin
through cracks.
Settlement/
Catch basin has settled more than 1 inch or has
Basin replaced or repaired to design
misalignment
rotated more than 2 inches out of alignment.
standards.
Damaged pipe joints
Cracks wider than 1/2-inch at the joint of the
No cracks more than 1/4-inch wide at
inlet/outlet pipes or any evidence of soil entering
the joint of inlet/outlet pipes.
the catch basin at the joint of the inlet/outlet
pipes.
Contaminants and
Any evidence of contaminants or pollution such
Materials removed and disposed of
pollution
as oil, gasoline, concrete slurries or paint.
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Inlet/Outlet Pipe
Sediment
Sediment filling 20% or more of the pipe.
Inlet/outlet pipes clear of sediment.
accumulation
Trash and debris
Trash and debris accumulated in inlet/outlet
No trash or debris in pipes.
pipes (includes floatables and non-floatables).
Damaged
Cracks wider than %-inch at the joint of the
No cracks more than '/4-inch wide at
inlet/outlet pipes or any evidence of soil entering
the joint of the inlet/outlet pipe.
at the joints of the inlet/outlet pipes.
2016 Surface Water Design Manual — Appendix A 4/24/2016
A-9
APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 5 - CATCH BASINS AND MANHOLES 7771
Maintenance
Defect or Problem
Condition When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed
Metal Grates
Unsafe grate opening
Grate with opening wider than 7/8 inch.
Grate opening meets design
(Catch Basins)
standards.
Trash and debris
Trash and debris that is blocking more than 20%
Grate free of trash and debris.
of grate surface.
footnote to guidelines for disposal
Damaged or missing
Grate missing or broken member(s) of the grate.
Grate is in place and meets design
Any open structure requires urgent
standards.
maintenance.
Manhole Cover/Lid
Cover/lid not in place
Cover/lid is missing or only partially in place.
Cover/lid protects opening to
Any open structure requires urgent
structure.
maintenance.
Locking mechanism
Mechanism cannot be opened by one
Mechanism opens with proper tools.
Not Working
maintenance person with proper tools. Bolts
cannot be seated. Self-locking cover/lid does not
work.
Cover/lid difficult to
One maintenance person cannot remove
Cover/lid can be removed and
Remove
cover/lid after applying 80 lbs. of lift.
reinstalled by one maintenance
person.
4/24/2016 2016 Surface Water Design Manual — Appendix A
A-10
APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 6 - CONVEYANCE PIPES AND DITCHES
Maintenance
Defect or Problem
Conditions When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed
Pipes
Sediment & debris
Accumulated sediment or debris that exceeds
Water flows freely through pipes.
accumulation
20% of the diameter of the pipe.
Vegetation/roots
Vegetation/roots that reduce free movement of
Water flows freely through pipes.
water through pipes.
Contaminants and
Any evidence of contaminants or pollution such
Materials removed and disposed of
pollution
as oil, gasoline, concrete slurries or paint.
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Damage to protective
Protective coating is damaged; rust or corrosion
Pipe repaired or replaced.
coating or corrosion
is weakening the structural integrity of any part of
pipe.
Damaged
Any dent that decreases the cross section area
Pipe repaired or replaced.
of pipe by more than 20% or is determined to
have weakened structural integrity of the pipe.
Ditches
Trash and debris
Trash and debris exceeds 1 cubic foot per 1,000
Trash and debris cleared from
square feet of ditch and slopes.
ditches.
Sediment
Accumulated sediment that exceeds 20% of the
Ditch cleaned/flushed of all
accumulation
design depth.
sediment and debris so that it
matches design.
Noxious weeds
Any noxious or nuisance vegetation which may
Noxious and nuisance vegetation
constitute a hazard to County personnel or the
removed according to applicable
public.
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
Any evidence of contaminants or pollution such
Materials removed and disposed of
pollution
as oil, gasoline, concrete slurries or paint.
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Vegetation
Vegetation that reduces free movement of water
Water flows freely through ditches.
through ditches.
Erosion damage to
Any erosion observed on a ditch slope.
Slopes are not eroding.
slopes
Rock lining out of
One layer or less of rock exists above native soil
Replace rocks to design standards.
place or missing (If
area 5 square feet or more, any exposed native
Applicable)
soil.
2016 Surface Water Design Manual — Appendix A 4/24/2016
A-11
APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
. —
Maintenance
Defect or Problem
Conditions When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed
Site
Trash or litter
Any trash and debris which exceed 1 cubic foot
Trash and debris cleared from site.
per 1,000 square feet (this is about equal to the
amount of trash it would take to fill up one
standard size office garbage can). In general,
there should be no visual evidence of dumping.
Noxious weeds
Any noxious or nuisance vegetation which may
Noxious and nuisance vegetation
constitute a hazard to County personnel or the
removed according to applicable
public.
regulations. No danger of noxious
vegetation where County personnel
or the public might normally be.
Contaminants and
Any evidence of contaminants or pollution such
Materials removed and disposed of
pollution
as oil, gasoline, concrete slurries or paint.
according to applicable regulations.
Source control BMPs implemented if
appropriate. No contaminants
present other than a surface oil film.
Grass/groundcover
Grass or groundcover exceeds 18 inches in
Grass or groundcover mowed to a
height.
height no greater than 6 inches.
Trees and Shrubs
Hazard
Any tree or limb of a tree identified as having a
No hazard trees in facility.
potential to fall and cause property damage or
threaten human life. A hazard tree identified by
a qualified arborist must be removed as soon
as possible.
Damaged
Limbs or parts of trees or shrubs that are split or
Trees and shrubs with less than 5%
broken which affect more than 25% of the total
of total foliage with split or broken
foliage of the tree or shrub.
limbs.
Trees or shrubs that have been blown down or
No blown down vegetation or
knocked over.
knocked over vegetation. Trees or
shrubs free of injury.
Trees or shrubs which are not adequately
Tree or shrub in place and
supported or are leaning over, causing exposure
adequately supported; dead or
of the roots.
diseased trees removed.
4/24/2016 2016 Surface Water Design Manual — Appendix A
A-16
APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO. 32 - RAINWATER HARVESTING BMP
Maintenance
Defect or Problem
Conditions When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed
Preventative
Storage volume
No rain water in storage unit at the beginning of
Maximum storage available at the
the rain season.
beginning of the rain season (Oct.
Collection Area
Trash and debris
Trash of debris on collection area may plug filter
Collection area clear of trash and
system
debris.
Filter
Restricted or plugged
Filter is partially or fully plugged preventing water
Filter is allowing collection water
from getting in to the storage unit.
into storage unit.
Inspection
Frequency
Annually and after large storms
Rain harvesting equipment is
functioning normally.
Maintenance log
A Maintenance log must be kept and available for
Maintenance log is kept and is
review by KC staff.
available to KC staff.
NO. 3 - ROCK PAID BMP
Maintenance
Defect or Problem
Conditions When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed
Site
Trash and debris
Trash and debris accumulated on rock pad site.
Rock pad site free of any trash or
debris.
Rock Pad Area
Rock pad size
Rock pad is not 2 feet by 3 feet by 6 inches thick
Rock pad is 2 feet by 3 feet by 6
or as designed.
inches thick or as designed.
Vegetation
Vegetation is seen growing in or through rock
No vegetation within rock pad area.
pad.
Rock
Exposed soil
Soil can be seen through the rock pad.
Full thickness of the rock pad is in
place, no soil visible through rock
pad.
Inspection
Frequency
Annually and after large storms
Rock pad is functioning normally.
NO. 34 - SHEET FLOW BMP
Maintenance
Defect or Problem
Conditions When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed
Site
Trash and debris
Trash and debris accumulated on the sheet flow
Sheet flow site free of any trash or
site.
debris.
Sheet flow area
Erosion
Soil erosion occurring in sheet flow zone.
Soil erosion is not occurring and
rills and channels have been
repaired.
Concentrated flow
Sheet flow is not occurring in the sheet flow zone.
Sheet flow area is regraded to
provide sheet flow.
Inspection
Frequency
Annually and after large storms
Rain harvesting equipment is
functioning normally.
4/24/2016 2016 Surface Water Design Manual — Appendix A
A-40
APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES
NO.35 - SPLASH BLOCK BMP
Maintenance
Defect or Problem
Conditions When Maintenance is Needed
Results Expected When
Component
Maintenance is Performed
Site
Trash and debris
Trash and debris accumulated on the splash
Splash block site free of any trash or
block.
debris.
Splash Block
Dislodged
Splash block moved from outlet of downspout.
Splash block correctly positioned to
catch discharge from downspout.
Channeling
Water coming off the splash block causing
No erosion occurs from the splash
erosion.
block.
Downspout water
Water coming from the downspout is not
Water is discharging normally to the
misdirected
discharging to the dispersal area.
dispersal area.
Inspection
Frequency
Annually and after large storms.
Rain harvesting equipment is
functioning normally.
2016 Surface Water Design Manual — Appendix A 4/24/2016
A-41
APPENDIX E:
DRAINAGE CALCULATIONS
S 334TH ST EXISTING PGIS = 3,041 SF (0.070 AC)
(COLLECTOR STREET) I-
PROPOSED OFFSITE PGIS
94 SF (0.002 AC) or rr �� OFFSITE PERVIOUS AREA=
%�/'%%fir /
861 SF (0.020 AC)
ON SITE SIDEWALK AREA = 75 SF-----
(0.002 AC) ONSITE PERVIO
ROOF ARE A=3,9185E
LI I L1 I ..
LI I LI
LLLLL
LLI LI I LI
LLLLLL
- -I LLI u I LI LLLLLLL
�
LLLLLL
�`. 1 LI LI LI I L1
I LI LI LI I LI LLI LI I LI I LI L
_ LI ..L _LI LI I Ll LLI LI I LI I Ll t - ..
LI L1 .I LI I LI L
LLLLLLLLI-
N SITE BASIN MAP
W*—E
SCALE 1" =2D FT
S 0 10 20 40
UNIT OF MEASUREMENTINUSFEET
TOTAL DISTURBED AREA
(INCLUDING REPAVED ASPHALT)
=12,266 SF (0.282 AC)
2,767 SF
Project Name:
2021.2.1 -Karnafel
Site Name:
Site Address:
City:
Report Date:
2/3/2021
Gage:
Seatac
Data Start:
1948/10/01
Data End:
2009/09/30
Timestep:
15 Minute
Precip Scale:
1.000
Version Date:
2019/09/13
Version:
4.2.17
POC Thresholds
Low Flow Threshold for POC1: 50 Percent of the 2 Year
High Flow Threshold for POCII: 50 Year
20212 1 -Karnafel 2/3/2021 5:06:14 PM Page 2
Landuse Basin
Data
Predeveloped Land
Use
Predeveloped
Bypass:
No
GroundWater:
No
Pervious Land Use
acre
C, Forest, Mod
0.182
Pervious Total
0.182
Impervious Land Use
acre
Impervious Total
0
Basin Total
0.182
Element Flows To:
Surface Interflow Groundwater
20212 1 -Karnafel 2/3/2021 5:06:14 PM Page 3
Mitigated Land Use
Basin 2
Bypass: No
GroundWater: No
Pervious Land Use acre
C, Lawn, Mod 0.067
Pervious Total 0.067
Impervious Land Use acre
ROADS MOD 0.024
ROOF TOPS FLAT 0.089
SIDEWALKS MOD 0.002
Impervious Total 0.115
Basin Total 0.182
Element Flows To:
Surface Interflow Groundwater
20212 1 -Karnafel 2/3/2021 5:06:14 PM Page 4
Routing Elements
20212 1 -Karnafel 2/3/2021 5:06:14 PM Page 5
20212 1 -Karnafel 2/3/2021 5:06:14 PM Page 6
Analysis Results
POC I
)x
+ Predeveloped
Predeveloped Landuse Totals for POC #1
Total Pervious Area: 0.182
Total Impervious Area: 0
Mitigated Landuse Totals for POC #1
4
x Mitigated
Total Pervious Area:
0.067
Total Impervious Area:
0.115
Flow Frequency Method:
Log Pearson Type III 17B
Flow Frequency Return Periods for Predeveloped. POC #1
Return Period
Flow(cfs)
2 year
0.005419
5 year
0.00888
10 year
0.011105
25 year
0.013752
50 year
0.015585
100 year
0.017297
Flow Frequency Return Periods for Mitigated. POC #1
Return Period
Flow(cfs)
2 year
0.050418
5 year
0.065817
10 year
0.076548
25 year
0.090748
50 year
0.101807
100 year
0.113292
AnnualPeaks
Annual Peaks for Predeveloped and Mitigated. POC #1
Year
Predeveloped
Mitigated
1949
0.006
0.071
1950
0.007
0.065
1951
0.012
0.043
1952
0.004
0.032
1953
0.003
0.036
1954
0.005
0.041
1955
0.007
0.046
1956
0.006
0.044
1957
0.005
0.053
1958
0.005
0.041
20212 1 -Karnafel 2/3/2021 5:06:14 PM Page 7
1959
0.005
0.039
1960
0.008
0.045
1961
0.004
0.044
1962
0.003
0.036
1963
0.004
0.045
1964
0.005
0.040
1965
0.004
0.055
1966
0.003
0.034
1967
0.008
0.062
1968
0.005
0.073
1969
0.005
0.050
1970
0.004
0.047
1971
0.004
0.057
1972
0.009
0.063
1973
0.004
0.032
1974
0.004
0.054
1975
0.006
0.054
1976
0.004
0.042
1977
0.001
0.040
1978
0.004
0.050
1979
0.002
0.067
1980
0.011
0.076
1981
0.003
0.051
1982
0.007
0.076
1983
0.006
0.057
1984
0.004
0.037
1985
0.002
0.051
1986
0.009
0.044
1987
0.008
0.065
1988
0.003
0.038
1989
0.002
0.052
1990
0.020
0.106
1991
0.010
0.083
1992
0.004
0.037
1993
0.004
0.032
1994
0.001
0.033
1995
0.006
0.045
1996
0.014
0.056
1997
0.011
0.050
1998
0.003
0.046
1999
0.012
0.108
2000
0.004
0.050
2001
0.001
0.052
2002
0.005
0.067
2003
0.007
0.057
2004
0.008
0.100
2005
0.006
0.044
2006
0.006
0.040
2007
0.015
0.096
2008
0.018
0.080
2009
0.008
0.060
Ranked Annual Peaks
Ranked Annual Peaks for Predeveloped and Mitigated. POC #1
Rank
Predevelloped
Mitigated
1
0.0196
0.1076
2
0.0181
0.1065
3
0.0148
0.1000
20212 1 -Karnafel 2/3/2021 5:06:55 PM Page 8
4
0.0137
0.0963
5
0.0118
0.0826
6
0.0116
0.0797
7
0.0106
0.0760
8
0.0106
0.0757
9
0.0104
0.0726
10
0.0093
0.0709
11
0.0090
0.0670
12
0.0084
0.0670
13
0.0083
0.0648
14
0.0082
0.0648
15
0.0082
0.0625
16
0.0076
0.0621
17
0.0074
0.0597
18
0.0074
0.0572
19
0.0072
0.0570
20
0.0069
0.0568
21
0.0064
0.0564
22
0.0062
0.0554
23
0.0061
0.0542
24
0.0059
0.0541
25
0.0059
0.0535
26
0.0059
0.0519
27
0.0057
0.0515
28
0.0054
0.0512
29
0.0053
0.0508
30
0.0048
0.0504
31
0.0048
0.0504
32
0.0047
0.0503
33
0.0046
0.0502
34
0.0046
0.0474
35
0.0046
0.0464
36
0.0045
0.0464
37
0.0044
0.0455
38
0.0044
0.0453
39
0.0042
0.0446
40
0.0041
0.0440
41
0.0041
0.0437
42
0.0041
0.0436
43
0.0040
0.0435
44
0.0038
0.0430
45
0.0037
0.0417
46
0.0037
0.0412
47
0.0037
0.0406
48
0.0036
0.0401
49
0.0035
0.0399
50
0.0035
0.0396
51
0.0033
0.0392
52
0.0032
0.0379
53
0.0030
0.0369
54
0.0028
0.0369
55
0.0026
0.0364
56
0.0022
0.0360
57
0.0021
0.0341
58
0.0021
0.0327
59
0.0014
0.0324
60
0.0007
0.0324
61
0.0006
0.0320
2021.2.1-Karnafel
2/3/2021 5:06:55 PM
20212 1 -Karnafel 2/3/2021 5:06:55 PM Page 10
Flow(cfs)
Predev
mit
Percentage
Pass/Fail
0.0027
17079
110666
647
Fail
0.0028
15490
106431
687
Fail
0.0030
14072
102474
728
Fail
0.0031
12801
98731
771
Fail
0.0032
11569
95159
822
Fail
0.0034
10519
91715
871
Fail
0.0035
9567
88443
924
Fail
0.0036
8752
85299
974
Fail
0.0037
8040
82304
1023
Fail
0.0039
7343
79459
1082
Fail
0.0040
6733
76829
1141
Fail
0.0041
6188
74262
1200
Fail
0.0043
5726
71802
1253
Fail
0.0044
5309
69449
1308
Fail
0.0045
4924
67204
1364
Fail
0.0047
4569
65022
1423
Fail
0.0048
4235
62926
1485
Fail
0.0049
3951
60937
1542
Fail
0.0051
3643
58969
1618
Fail
0.0052
3388
57065
1684
Fail
0.0053
3133
55311
1765
Fail
0.0054
2915
53643
1840
Fail
0.0056
2706
51953
1919
Fail
0.0057
2490
50349
2022
Fail
0.0058
2314
48809
2109
Fail
0.0060
2136
47291
2213
Fail
0.0061
1973
45836
2323
Fail
0.0062
1822
44510
2442
Fail
0.0064
1702
43141
2534
Fail
0.0065
1577
41858
2654
Fail
0.0066
1442
40617
2816
Fail
0.0067
1325
39334
2968
Fail
0.0069
1232
38136
3095
Fail
0.0070
1147
37045
3229
Fail
0.0071
1083
35955
3319
Fail
0.0073
1020
34949
3426
Fail
0.0074
947
33944
3584
Fail
0.0075
886
33003
3724
Fail
0.0077
824
32105
3896
Fail
0.0078
760
31163
4100
Fail
0.0079
725
30244
4171
Fail
0.0080
674
29388
4360
Fail
0.0082
623
28575
4586
Fail
0.0083
589
27741
4709
Fail
0.0084
549
26928
4904
Fail
0.0086
506
26137
5165
Fail
0.0087
469
25389
5413
Fail
0.0088
427
24747
5795
Fail
0.0090
388
24084
6207
Fail
0.0091
356
23357
6560
Fail
0.0092
328
22715
6925
Fail
0.0093
297
22095
7439
Fail
0.0095
270
21496
7961
Fail
0.0096
241
20923
8681
Fail
20212 1 -Karnafel 2/3/2021 5:06:55 PM Page 11
0.0097
218
20375
9346
Fail
0.0099
197
19851
10076
Fail
0.0100
173
19344
11181
Fail
0.0101
152
18820
12381
Fail
0.0103
130
18326
14096
Fail
0.0104
119
17819
14973
Fail
0.0105
104
17321
16654
Fail
0.0106
95
16867
17754
Fail
0.0108
83
16448
19816
Fail
0.0109
74
16035
21668
Fail
0.0110
69
15614
22628
Fail
0.0112
61
15182
24888
Fail
0.0113
53
14805
27933
Fail
0.0114
46
14476
31469
Fail
0.0116
39
14106
36169
Fail
0.0117
29
13738
47372
Fail
0.0118
25
13406
53624
Fail
0.0119
22
13079
59450
Fail
0.0121
20
12767
63834
Fail
0.0122
17
12444
73200
Fail
0.0123
14
12145
86750
Fail
0.0125
12
11849
98741
Fail
0.0126
8
11567
144587
Fail
0.0127
7
11274
161057
Fail
0.0129
7
10998
157114
Fail
0.0130
7
10729
153271
Fail
0.0131
6
10453
174216
Fail
0.0132
6
10202 '
170033
Fail
0.0134
6
9986
166433
Fail
0.0135
6
9728
162133
Fail
0.0136
6
9522
158700
Fail
0.0138
5
9317
186340
Fail
0.0139
5
9129
182580
Fail
0.0140
5
8921
178420
Fail
0.0142
5
8688
173760
Fail
0.0143
5
8481
169620
Fail
0.0144
5
8271
165420
Fail
0.0145
5
8076
161520
Fail
0.0147
4
7892
197300
Fail
0.0148
4
7694
192350
Fail
0.0149
3
7507
250233
Fail
0.0151
3
7343
244766
Fail
0.0152
3
7155
238500
Fail
0.0153
3
6996
233200
Fail
0.0155
3
6838
227933
Fail
0.0156
3
6669
222300
Fail
The development has an increase in flow durations
from 1 /2 Predeveloped 2 year flow to the 2 year flow
or more than a 10% increase from the 2 year to the 50
year flow.
The development has an increase in flow durations for
more than 50% of the flows for the range of the
duration analysis.
2021.2.1-Karnafel 2/3/2021 5:06:55 PM Page 12
Water Quality BMP Flow and Volume for POC #1
On-line facility volume:
0 acre-feet
On-line facility target flow:
0 cfs.
Adjusted for 15 min:
0 cfs.
Off-line facility target flow:
0 cfs.
Adjusted for 15 min:
0 cfs.
20212 1 -Karnafel 2/3/2021 5:06:55 PM Page 13
M� M
LID Technique
Usedfor
Total Volume
Volume
Infiltration
Cumulative
Percent
Water Quality
Percent
Comment
Treatment'?
Needs
Through
Volume
Volume
Volume
Water Quality
Treatment
Facility
(ac-ft)
Infiltration
Infiltrated
Treated
(a c-ft)
(a c-ft)
Credit
Total Volume lnflltrated
10.00
U10
0.00,
04D
0.00
0%
No -Treat
Credit
Compliance withILID
Duration
StandardS%02-yrto, 50% of
Analysis
Z-Yf
Result=
Failed
20212 1 -Karnafel 2/3/2021 5:06:55 PM Page 14
Total of 0 changes have been made.
PERLND Changes
No PERLND changes have been made.
141PLI1Changes
• IMPLND changes have •- mada
20212 1 -Karnafel 2/3/2021 5:07:25 PM Page 15
Wei =0
Predeveloped Schematic
20212 1 -Karnafel 2/3/2021 5:07:25 PM Page 16
20212 1 -Karnafel 2/3/2021 5:07:26 PM Page 17
r .ice op.d UCI File
RUN
GLOBAL
WWHM4 model simulation
START 1948 10 01 END
RUN INTERP OUTPUT LEVEL 3 0
RESUME 0 RUN 1
END GLOBAL
2009 09 30
FILES
<File>
<Un#>
END FILES
OPN SEQUENCE
UNIT SYSTEM
1
<----------- File Name----
-------------------------->***
***
INGRP INDELT 00:15
PERLND 11
COPY 501
DISPLY 1
END INGRP
END OPN SEQUENCE
DISPLY
DISPLY-INFO1
# - #<---------- Title ----------- >***TRAN PIVL DIG1 FILL
1 Predeveloped MAX
END DISPLY-INF01
END DISPLY
COPY
TIMESERIES
# - # NPT NMN ***
1 1 1
501 1 1
END TIMESERIES
END COPY
GENER
OPCODE
# # OPCD ***
END OPCODE
FARM
# # K ***
END FARM
END GENER
PERLND
GEN-INFO
PYR DIG2 FIL2 YRND
1 2 30 9
<PLS ><------- Name ------- >NBLKS Unit -systems Printer ***
# - # User t-series Engl Metr ***
in out ***
11 C, Forest, Mod 1 1 1 1 27 0
END GEN-INFO
*** Section PWATER***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PROS TRAC ***
11 0 0 1 0 0 0 0 0 0 0 0 0
END ACTIVITY
PRINT -INFO
<PLS > ***************** Print -flags ***************************** PIVL PYR
# - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PROS TRAC *********
11 0 0 4 0 0 0 0 0 0 0 0 0 1 9
END PRINT -INFO
2021.2.1-Karnafel 2/3/2021 5:07:26 PM Page 18
PWAT-PARMl
<PLS > PWATER variable monthly parameter value flags ***
# - # CSNO RTOP UZFG VCS VUZ VNN VIEW VIRC VLE INFC HWT ***
11 0 0 0 0 0 0 0 0 0 0 0
END PWAT-PARM1
PWAT-PARM2
<PLS > PWATER input info: Part 2 ***
# - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC
11 0 4.5 0.08 400 0.1 0.5 0.996
END PWAT-PARM2
PWAT-PARM3
<PLS > PWATER
input info:
Part 3
***
# - # ***PETMAX
PETMIN
INFEXP
INFILD
DEEPFR
BASETP AGWETP
11 0
0
2
2
0
0 0
END PWAT-PARM3
PWAT-PARM4
<PLS > PWATER
input info:
Part 4
***
# - # CEPSC
UZSN
NSUR
INTFW
IRC
LZETP ***
11 0.2
0.5
0.35
6
0.5
0.7
END PWAT-PARM4
PWAT-STATEI
<PLS > *** Initial conditions at start of simulation
ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 ***
# - # *** CEPS SURS UZS IFWS LZS AGWS
11 0 0 0 0 2.5 1
END PWAT-STATEI
END PERLND
IMPLND
GEN-INFO
<PLS ><------- Name ------- > Unit -systems Printer ***
# - # User t-series Engl Metr ***
in out ***
END GEN-INFO
*** Section IWATER***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # ATMP SNOW IWAT SLD IWG IQAL ***
END ACTIVITY
PRINT -INFO
<ILS > ******** Print -flags ******** PIVL PYR
# - # ATMP SNOW TWAT SLD IWG IQAL *********
END PRINT -INFO
TWAT-PARM1
<PLS > IWATER variable monthly parameter value flags ***
# - # CSNO RTOP VRS VNN RTLI ***
END TWAT-PARM1
IWAT-PARM2
<PLS > IWATER input info: Part 2 ***
# - # *** LSUR SLSUR NSUR RETSC
END IWAT-PARM2
IWAT-PARM3
<PLS > IWATER input info: Part 3 ***
# - # ***PETMAX PETMIN
END IWAT-PARM3
TWAT-STATEI
<PLS > *** Initial conditions at start of simulation
# - # *** RETS SURS
END TWAT-STATEI
GWVS
0
2021.2.1-Karnafel 2/3/2021 5:07:26 PM Page 19
END IMPLND
SCHEMATIC
<-Source->
<Name> #
Predeveloped***
PERLND 11
PERLND 11
******Routing******
END SCHEMATIC
<--Area--> <-Target-> MBLK
<-factor-> <Name> # Tbl#
0.182 COPY 501 12
0.182 COPY 501 13
NETWORK
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # #<-factor->strg <Name> # # <Name> # # ***
COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # #<-factor->strg <Name> # # <Name> # # ***
END NETWORK
RCHRES
GEN-INFO
RCHRES Name Nexits Unit Systems Printer ***
# - #<------------------ >< --- > User T-series Engl Metr LKFG ***
in out ***
END GEN-INFO
*** Section RCHRES***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # HYFG ADFG CNFG,HTF'G SDFG GQFG OXFG NUFG PKFG PHFG ***
END ACTIVITY
PRINT -INFO
<PLS > **********'******* Print -flags ******************* PIVL PYR
# - # HYDR ADCA CONSHEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR *********
END PRINT -INFO
HYDR-PARM1
RCHRES Flags for each HYDR Section ***
# - # VC Al A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each
FG FG FG FG possible exit *** possible exit possible exit
* * * * * * * * * * * * * * ***
END HYDR-PARM1
HYDR-PARM2
# - # FTABNO LEN DELTH STCOR KS DB50 ***
<------ ><-------- ><--------><--------><--------><--------><--------> ***
END HYDR-PARM2
HYDR-INIT
RCHRES Initial conditions for each HYDR section ***
# - # *** VOL Initial value of COLIND Initial value of OUTDGT
*** ac-ft for each possible exit for each possible exit
<------><-------- > <---><---><---><---><---> *** <---><---><---><---><--->
END HYDR-INIT
END RCHRES
SPEC -ACTIONS
END SPEC -ACTIONS
FTABLES
END FTABLES
EXT SOURCES
<-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # ***
WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC
WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC
2021.2.1-Karnafel 2/3/2021 5:07:26 PM Page 20
WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP
WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP
END EXT SOURCES
EXT TARGETS
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd ***
<Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg***
COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL
END EXT TARGETS
MASS -LINK
<Volume> <-Grp>
<-Member-><--Mult-->
<Target>
<-Grp> <-Member->***
<Name>
<Name>
# #<-factor->
<Name>
<Name> # #***
MASS -LINK
12
PERLND PWATER
SURO
0.083333
COPY
INPUT MEAN
END MASS -LINK
12
MASS -LINK
13
PERLND PWATER
IFWO
0.083333
COPY
INPUT MEAN
END MASS -LINK
13
END MASS -LINK
END RUN
2021.2.1-Karnafel 2/3/2021 5:07:26 PM Page 21
Mitigated UCI File
RUN
GLOBAL
WWHM4 model simulation
START 1948 10 01 END
RUN INTERP OUTPUT LEVEL 3 0
RESUME 0 RUN 1
END GLOBAL
2009 09 30
FILES
<File>
<Un#>
END FILES
OPN SEQUENCE
UNIT SYSTEM
1
<----------- File Name----
-------------------------->***
***
INGRP INDELT 00:15
PERLND 17
IMPLND 2
IMPLND 4
IMPLND 9
COPY 501
DISPLY 1
END INGRP
END OPN SEQUENCE
DISPLY
DISPLY-INFO1
# - #<---------- Title ----------- >***TRAN PIVL DIG1 FILL
1 Basin 2 MAX
END DISPLY-INF01
END DISPLY
COPY
TIMESERIES
# - # NPT NMN ***
1 1 1
501 1 1
END TIMESERIES
END COPY
GENER
OPCODE
# # OPCD ***
END OPCODE
FARM
# # K ***
END FARM
END GENER
PERLND
GEN-INFO
PYR DIG2 FIL2 YRND
1 2 30 9
<PLS ><------- Name ------- >NBLKS Unit -systems Printer ***
# - # User t-series Engl Metr ***
in out ***
17 C, Lawn, Mod 1 1 1 1 27 0
END GEN-INFO
*** Section PWATER***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PROS TRAC ***
17 0 0 1 0 0 0 0 0 0 0 0 0
END ACTIVITY
PRINT -INFO
<PLS > ***************** Print -flags ***************************** PIVL PYR
# - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PROS TRAC *********
2021.2.1-Karnafel 2/3/2021 5:07.26 PM Page 22
17 0 0 4 0
0
0 0
0 0 0
0 0 1 9
END PRINT -INFO
PWAT-PAP.Ml
<PLS > PWATER variable monthly
parameter
value flags
# - # CSNO RTOP UZFG VCS
VUZ
VNN VIEW
VIRC VLE INFC HWT
17 0 0 0 0
0
0 0
0 0 0
0
END PWAT-PARM1
PWAT-PARM2
<PLS > PWATER input info:
Part 2
# - # ***FOREST LZSN
INFILT
LSUR SLSUR
KVARY AGWRC
17 0 4.5
0.03
400 0.1
0.5 0.996
END PWAT-PARM2
PWAT-PARM3
<PLS > PWATER input info:
Part 3
# - # ***PETMAX PETMIN
INFEXP INFILD
DEEPFR
BASETP AGWETP
17 0 0
2
2 0
0 0
END PWAT-PARM3
PWAT-PARM4
<PLS > PWATER input info:
Part 4
# - # CEPSC UZSN
NSUR INTFW
IRC
LZETP
17 0.1 0.25
0.25
6 0.5
0.25
END PWAT-PARM4
PWAT-STATE1
<PLS > Initial conditions
at
start of
simulation
ran from 1990 to
end
of 1992 (pat
1-11-95) RUN 21
# - # CEPS SURS
UzS
IFWS LZS
AGWS GWVS
17 0 0
0
0 2.5
1 0
END PWAT-STATE1
END PERLND
IMPLND
GEN-INFO
<PLS >< ------- Name ------- >
Unit
-systems
Printer
# - #
User
t-series
Engl Metr
in out
2 ROADS/MOD
1
1 1
27 0
4 ROOF TOPS/FLAT
1
1 1
27 0
9 SIDEWALKS/MOD
1
1 1
27 0
END GEN-INFO
*** Section IWATER***
ACTIVITY
<PLS > Active
Sections
# - # ATMP SNOW IWAT SLD
IWG
IQAL
2 0 0 1 0
0
0
4 0 0 1 0
0
0
9 0 0 1 0
0
0
END ACTIVITY
PRINT -INFO
<ILS > ******** Print -flags
********
PIVL
PYR
# - # ATMP SNOW TWAT SLD
IWG
IQAL
2 0 0 4 0
0
0 1
9
4 0 0 4 0
0
0 1
9
9 0 0 4 0
0
0 1
9
END PRINT -INFO
TWAT-PARM1
<PLS > IWATER variable monthly
parameter
value flags
# - # CSNO RTOP VRS VNN
RTLI
2 0 0 0 0
0
4 0 0 0 0
0
9 0 0 0 0
0
END TWAT-PARMl
2021.2.1-Karnafel 2/3/2021 5:07:26 PM Page 23
IWAT-PARM2
<PLS > IWATER
input info:
Part 2
***
# - # *** LSUR
SLSUR
NSUR
RETSC
2 400
0.05
0.1
0.08
4 400
0.01
0.1
0.1
9 400
0.05
0.1
0.08
END IWAT-PARM2
TWAT-PARM3
<PLS > IWATER
input info:
Part 3
***
# - # ***PETMAX
PETMIN
2 0
0
4 0
0
9 0
0
END TWAT-PARM3
IWAT-STATEI
<PLS > *** Initial
conditions
at start
of simulation
# - # *** RETS
SURS
2 0
0
4 0
0
9 0
0
END IWAT-STATEI
END IMPLND
SCHEMATIC
<-Source->
<--Area-=>
<-Target->
<Name> #
<-factor-->
<Name>
#
Basin 2***
PERLND 17
0.067
COPY
501
PERLND 17
0.067
COPY
501
IMPLND 2
0.024
COPY
501
IMPLND 4
0.089
COPY
501
IMPLND 9
0.002
COPY
501
******Routing******
END SCHEMATIC
MBLK
Tbl#
12
13
15
15
15
NETWORK
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # #<-factor->strg <Name> # # <Name> # # ***
COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # #<-factor->strg <Name> # # <Name> # # ***
END NETWORK
RCHRES
GEN-INFO
RCHRES Name Nexits Unit Systems Printer ***
# - #<------------------ >< --- > User T-series Engl Metr LKFG ***
in out ***
END GEN-INFO
*** Section RCHRES***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG ***
END ACTIVITY
PRINT -INFO
<PLS > ***************** Print -flags ******************* PIVL PYR
# - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR *********
END PRINT -INFO
HYDR-PARM1
RCHRES Flags for each HYDR Section
***
2021.2.1-Karnafel 2/3/2021 5:07:26 PM Page 24
# - # VC Al A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each
FG FG FG FG possible exit *** possible exit possible exit
* * * * * * * * * * * * * * ***
END HYDR-PARM1
HYDR-PARM2
# - # FTABNO LEN DELTH STCOR KS DB50 ***
<------ ><-------- ><--------><--------><--------><--------><--------> ***
END HYDR-PARM2
HYDR-INIT
RCHRES Initial conditions for each HYDR section ***
# - # *** VOL Initial value of COLIND Initial value of OUTDGT
*** ac-ft for each possible exit for each possible exit
<------><-------- > <---><---><---><---><---> *** <---><---><---><---><--->
END HYDR-INIT
END RCHRES
SPEC -ACTIONS
END SPEC -ACTIONS
FTABLES
END FTABLES
EXT SOURCES
<-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name>
#
<Name>
# tem
strg<-factor->strg
<Name>
#
#
<Name> # # ***
WDM
2
PREC
ENGL
1
PERLND
1
999
EXTNL
PREC
WDM
2
PREC
ENGL
1
IMPLND
1
999
EXTNL
PREC
WDM
1
EVAP
ENGL
0.76
PERLND
1
999
EXTNL
PETINP
WDM
1
EVAP
ENGL
0.76
IMPLND
1
999
EXTNL
PETINP
END EXT SOURCES
EXT TARGETS
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd ***
<Name> # <Name> #'#<-factor->strg <Name> # <Name> tem strg strg***
COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL
COPY 501 OUTPUT MEAN 1 148.4 WDM 801 FLOW ENGL REPL
END EXT TARGETS
MASS -LINK
<Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->***
<Name> <Name> # #<-factor-> <Name> <Name> # #***
MASS -LINK 12
PERLND PWATER SURO 0.083333 COPY INPUT MEAN
END MASS -LINK 12
MASS -LINK 13
PERLND PWATER IFWO 0.083333 COPY INPUT MEAN
END MASS -LINK 13
MASS -LINK 15
IMPLND IWATER SURO 0.083333 COPY INPUT MEAN
END MASS -LINK 15
END MASS -LINK
END RUN
2021.2.1-Karnafel 2/3/2021 5:07:26 PM Page 25
lmm��
20212 1 -Karnafel 2/3/2021 5:07:26 PM Page 26
20212 1 -Karnafel 2/3/2021 5:07:26 PM Page 27
Legal Notice
This program and accompanying documentation are provided 'as -is' without warranty of any kind. The
entire risk regarding the performance and results of this program is assumed by End User. Clear
Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either
expressed or implied, including but not limited to implied warranties of program and accompanying
documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever
(including without limitation to damages for loss of business profits, loss of business information,
business interruption, and the like) arising out of the use of, or inability to use this program even
if Clear Creek Solutions Inc. or their authorized representatives have been advised of the
possibility of such damages. Software Copyright @ by: Clear Creek Solutions, Inc. 2005-2021; All
Rights Reserved.
Clear Creek Solutions, Inc.
6200 Capitol Blvd. Ste F
Olympia, WA. 98501
Toll Free 1(866)943-0304
Local (360)943-0304
0 0 •
20212 1 -Karnafel 2/3/2021 5:07:26 PM Page 26
Project Name:
2021.2.1 -ROW
Site Name:
Site Address:
City:
Report Date:
2/3/2021
Gage:
Seatac
Data Start:
1948/10/01
Data End:
2009/09/30
Timestep:
15 Minute
Precip Scale:
1.000
Version Date:
2019/09/13
Version:
4.2.17
POC Thresholds
Low Flow Threshold for POC1: 50 Percent of the 2 Year
High Flow Threshold for POCII: 50 Year
202121-ROW 2/3/2021 8:09:08 AM Page 2
Landuse Basin Data
Predeveloped Land Use
Pre Exg (Exclude Exg Imp)
Bypass: No
GroundWater: No
Pervious Land Use
acre
C, Forest, Mod
0.03
Pervious Total
0.03
Impervious Land Use acre
Impervious Total 0
Basin Total 0.03
Element Flows To:
Surface Interflow Groundwater
202121-ROW 2/3/2021 8:09:08 AM Page 3
Mitigated Land Use
ROW (Exclude Exg Imp)
Bypass: No
GroundWater: No
Pervious Land Use acre
C, Lawn, Mod 0.02
Pervious Total 0.02
Impervious Land Use acre
ROADS MOD 0.002
SIDEWALKS MOD 0.008
Impervious Total 0.01
Basin Total 0.03
Element Flows To:
Surface Interflow Groundwater
202121-ROW 2/3/2021 8:09:08 AM Page 4
Routing Elements
202121-ROW 2/3/2021 8:09:08 AM Page 5
202121-ROW 2/3/2021 8:09:08 AM Page 6
Analysis Results
POC I
00
0,5 1 2 5 10 n 50 70 00 N 95 w 39 n,� ido
Predeveloped Landuse Totals for POC #1
Total Pervious Area: 0.03
Total Impervious Area: 0
Mitigated Landuse Totals for POC #1
Total Pervious Area:
0.02
Total Impervious Area:
0.01
Flow Frequency Method:
Log Pearson Type III 17B
Flow Frequency Return Periods for Predeveloped. POC #1
Return Period
Flow(cfs)
2 year
0.000893
5 year
0.001464
10 year
0.00183
25 year
0.002267
50 year
0.002569
100 year
0.002851
Flow Frequency Return Periods for Mitigated. POC #1
Return Period
Flow(cfs)
2 year
0.00612
5 year
0.008457
10 year
0.010158
25 year
0.012488
50 year
0.014358
100 year
0.016346
AnnualPeaks
Annual Peaks for Predeveloped and Mitigated. POC #1
Year
Predeveloped
Mitigated
1949
0.001
0.009
1950
0.001
0.009
1951
0.002
0.005
1952
0.001
0.004
1953
0.000
0.004
1954
0.001
0.005
1955
0.001
0.005
1956
0.001
0.005
1957
0.001
0.006
1958
0.001
0.005
202121-ROW 2/3/2021 8:09:08 AM Page 7
1959
0.001
0.004
1960
0.001
0.006
1961
0.001
0.005
1962
0.000
0.004
1963
0.001
0.006
1964
0.001
0.005
1965
0.001
0.007
1966
0.001
0.004
1967
0.001
0.009
1968
0.001
0.009
1969
0.001
0.006
1970
0.001
0.006
1971
0.001
0.007
1972
0.001
0.008
1973
0.001
0.003
1974
0.001
0.007
1975
0.001
0.007
1976
0.001
0.005
1977
0.000
0.005
1978
0.001
0.006
1979
0.000
0.007
1980
0.002
0.012
1981
0.001
0.006
1982
0.001
0.010
1983
0.001
0.006
1984
0.001
0.004
1985
0.000
0.005
1986
0.002
0.005
1987
0.001
0.006
1988
0.001
0.004
1989
0.000
0.006
1990
0.003
0.015
1991
0.002
0.012
1992
0.001
0.005
1993
0.001
0.004
1994
0.000
0.004
1995
0.001
0.005
1996
0.002
0.008
1997
0.002
0.006
1998
0.000
0.006
1999
0.002
0.014
2000
0.001
0.006
2001
0.000
0.006
2002
0.001
0.008
2003
0.001
0.008
2004
0.001
0.013
2005
0.001
0.005
2006
0.001
0.005
2007
0.002
0.014
2008
0.003
0.011
2009
0.001
0.007
Ranked Annual Peaks
Ranked
Annual Peaks for Predeveloped and Mitigated. POC #1
Rank
Predevelloped
Mitigated
1
0.0032
0.0153
2
0.0030
0.0142
3
0.0024
0.0140
202121-ROW 2/3/2021 8:09:40 AM Page 8
4
0.0023
0.0130
5
0.0020
0.0117
6
0.0019
0.0116
7
0.0017
0.0109
8
0.0017
0.0096
9
0.0017
0.0093
10
0.0015
0.0091
11
0.0015
0.0089
12
0.0014
0.0087
13
0.0014
0.0085
14
0.0014
0.0083
15
0.0013
0.0082
16
0.0013
0.0080
17
0.0012
0.0071
18
0.0012
0.0070
19
0.0012
0.0069
20
0.0011
0.0069
21
0.0011
0.0067
22
0.0010
0.0067
23
0.0010
0.0065
24
0.0010
0.0065
25
0.0010
0.0065
26
0.0010
0.0065
27
0.0009
0.0062
28
0.0009
0.0061
29
0.0009
0.0060
30
0.0008
0.0060
31
0.0008
0.0059
32
0.0008
0.0058
33
0.0008
0.0057
34
0.0008
0.0056
35
0.0008
0.0056
36
0.0007
0.0055
37
0.0007
0.0055
38
0.0007
0.0055
39
0.0007
0.0054
40
0.0007
0.0054
41
0.0007
0.0053
42
0.0007
0.0053
43
0.0007
0.0051
44
0.0006
0.0051
45
0.0006
0.0051
46
0.0006
0.0050
47
0.0006
0.0050
48
0.0006
0.0050
49
0.0006
0.0049
50
0.0006
0.0047
51
0.0005
0.0045
52
0.0005
0.0043
53
0.0005
0.0042
54
0.0005
0.0041
55
0.0004
0.0040
56
0.0004
0.0038
57
0.0004
0.0038
58
0.0003
0.0037
59
0.0002
0.0036
60
0.0001
0.0035
61
0.0001
0.0032
2021.2.1-ROW
2/3/2021 8:09:40 AM
202121-ROW 2/3/2021 8:09:40 AM Page 10
Flow(cfs)
Predev
mit
Percentage
Pass/Fail
0.0004
17139
88272
515
Fail
0.0005
15548
83202
535
Fail
0.0005
14095
78112
554
Fail
0.0005
12838
73813
574
Fail
0.0005
11582
69514
600
Fail
0.0006
10555
65771
623
Fail
0.0006
9574
62049
648
Fail
0.0006
8778
58819
670
Fail
0.0006
8036
55525
690
Fail
0.0006
7362
52723
716
Fail
0.0007
6759
49986
739
Fail
0.0007
6194
47333
764
Fail
0.0007
5747
45002
783
Fail
0.0007
5313
42692
803
Fail
0.0007
4934
40639
823
Fail
0.0008
4569
38650
845
Fail
0.0008
4250
36874
867
Fail
0.0008
3961
35142
887
Fail
0.0008
3645
33431
917
Fail
0.0009
3397
31912
939
Fail
0.0009
3133
30351
968
Fail
0.0009
2924
29025
992
Fail
0.0009
2706
27698
1023
Fail
0.0009
2492
26501
1063
Fail
0.0010
2314
25260
1091
Fail
0.0010
2137
24169
1130
Fail
0.0010
1978
23121
1168
Fail
0.0010
1827
22116
1210
Fail
0.0010
1706
21062
1234
Fail
0.0011
1578
20035
1269
Fail
0.0011
1445
19175
1326
Fail
0.0011
1325
18296
1380
Fail
0.0011
1235
17535
1419
Fail
0.0012
1147
16816
1466
Fail
0.0012
1086
16129
1485
Fail
0.0012
1022
15466
1513
Fail
0.0012
948
14803
1561
Fail
0.0012
888
14224
1601
Fail
0.0013
825
13625
1651
Fail
0.0013
764
13062
1709
Fail
0.0013
725
12581
1735
Fail
0.0013
675
12138
1798
Fail
0.0013
627
11665
1860
Fail
0.0014
589
11154
1893
Fail
0.0014
552
10739
1945
Fail
0.0014
506
10329
2041
Fail
0.0014
470
9982
2123
Fail
0.0015
427
9616
2251
Fail
0.0015
388
9272
2389
Fail
0.0015
356
8932
2508
Fail
0.0015
328
8609
2624
Fail
0.0015
298
8325
2793
Fail
0.0016
270
8014
2968
Fail
0.0016
242
7717
3188
Fail
202121-ROW 2/3/2021 8:09:40 AM Page 11
0.0016
218
7428
3407
Fail
0.0016
198
7184
3628
Fail
0.0016
173
6924
4002
Fail
0.0017
152
6669
4387
Fail
0.0017
130
6438
4952
Fail
0.0017
119
6203
5212
Fail
0.0017
104
6017
5785
Fail
0.0018
95
5826
6132
Fail
0.0018
84
5636
6709
Fail
0.0018
74
5441
7352
Fail
0.0018
69
5268
7634
Fail
0.0018
61
5082
8331
Fail
0.0019
53
4945
9330
Fail
0.0019
46
4768
10365
Fail
0.0019
39
4607
11812
Fail
0.0019
30
4470
14900
Fail
0.0019
25
4295
17180
Fail
0.0020
22
4141
18822
Fail
0.0020
20
3985
19925
Fail
0.0020
17
3859
22700
Fail
0.0020
14
3728
26628
Fail
0.0021
12
3621
30175
Fail
0.0021
9
3508
38977
Fail
0.0021
7
3401
48585
Fail
0.0021
7
3298
47114
Fail
0.0021
7
3185
45500
Fail
0.0022
6
3084
51400
Fail
0.0022
6
3001
50016
Fail
0.0022
6
2900
48333
Fail
0.0022
6
2817
46950
Fail
0.0022
6
2712
45200
Fail
0.0023
5
2627
52540
Fail
0.0023
5
2554
51080
Fail
0.0023
5
2488
49760
Fail
0.0023
5
2421
48420
Fail
0.0024
5
2355
47100
Fail
0.0024
5
2299
45980
Fail
0.0024
5
2239
44780
Fail
0.0024
4
2182
54550
Fail
0.0024
4
2119
52975
Fail
0.0025
3
2061
68700
Fail
0.0025
3
2000
66666
Fail
0.0025
3
1942
64733
Fail
0.0025
3
1887
62900
Fail
0.0025
3
1840
61333
Fail
0.0026
3
1787
59566
Fail
The development has an increase in flow durations
from 1 /2 Predeveloped 2 year flow to the 2 year flow
or more than a 10% increase from the 2 year to the 50
year flow.
The development has an increase in flow durations for
more than 50% of the flows for the range of the
duration analysis.
2021.2.1-POW 2/3/2021 8:09:40 AM Page 12
Water Quality BMP Flow and Volume for POC #1
On-line facility volume:
0 acre-feet
On-line facility target flow:
0 cfs.
Adjusted for 15 min:
0 cfs.
Off-line facility target flow:
0 cfs.
Adjusted for 15 min:
0 cfs.
202121-ROW 2/3/2021 8:09:40 AM Page 13
M� =
LID Technique
Usedfor
Total Volume
Volume
Infiltration
Cumulative
Percent
Water Quality
Percent
Comment
Treatment'?
Needs
Through
Volume
Volume
Volume
Water Quality
Treatment
Facility
(ac-ft)
Infiltration
Infiltrated
Treated
(a c-ft)
(a c-ft)
Credit
Total Volume lnflltrated
10.00
U10
0.00,
04D
0.00
0%
No -Treat
Credit
Compliance withILID
Duration
StandardS%02-yrto, 50% of
Analysis
Z-Yf
Result=
Failed
202121-ROW 2/3/2021 8:09:40 AM Page 14
Total of 0 changes have been made.
PERLND Changes
No PERLND changes have been made.
141PLI1Changes
• IMPLND changes have •- mada
202121-ROW 2/3/2021 8:09:49 AM Page 15
Wei =0
Predeveloped Schematic
202121-ROW 2/3/2021 8:09:49 AM Page 16
202121-ROW 2/3/2021 8:09:50 AM Page 17
r .ice op.d UCI File
RUN
GLOBAL
WWHM4 model simulation
START 1948 10 01 END
RUN INTERP OUTPUT LEVEL 3 0
RESUME 0 RUN 1
END GLOBAL
FILES
<File>
<Un#>
END FILES
OPN SEQUENCE
2009 09 30
UNIT
SYSTEM 1
<-----------File Name ------------------------------>***
***
INGRP INDELT 00:15
PERLND 11
COPY 501
DISPLY 1
END INGRP
END OPN SEQUENCE
DISPLY
DISPLY-INFO1
# - #<---------- Title -------- >***TRAN PIVL DIG1 FILL
1 Pre Exg (Exclude Exg Imp) MAX
END DISPLY-INFO1
END DISPLY
COPY
TIMESERIES
# - # NPT NMN ***
1 1 1
501 1 1
END TIMESERIES
END COPY
GENER
OPCODE
# # OPCD ***
END OPCODE
FARM
# # K ***
END FARM
END GENER
PERLND
GEN-INFO
PYR DIG2 FIL2 YRND
1 2 30 9
<PLS ><------- Name ------- >NBLKS Unit -systems Printer ***
# - # User t-series Engl Metr ***
in out ***
11 C, Forest, Mod 1 1 1 1 27 0
END GEN-INFO
*** Section PWATER***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PROS TRAC ***
11 0 0 1 0 0 0 0 0 0 0 0 0
END ACTIVITY
PRINT -INFO
<PLS > ***************** Print -flags ***************************** PIVL PYR
# - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PROS TRAC *********
11 0 0 4 0 0 0 0 0 0 0 0 0 1 9
END PRINT -INFO
2021.2.1-ROW 2/3/2021 8:09:51 AM Page 18
PWAT-PARMl
<PLS > PWATER variable monthly parameter value flags ***
# - # CSNO RTOP UZFG VCS VUZ VNN VIEW VIRC VLE INFC HWT ***
11 0 0 0 0 0 0 0 0 0 0 0
END PWAT-PARM1
PWAT-PARM2
<PLS > PWATER input info: Part 2 ***
# - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC
11 0 4.5 0.08 400 0.1 0.5 0.996
END PWAT-PARM2
PWAT-PARM3
<PLS > PWATER
input info:
Part 3
***
# - # ***PETMAX
PETMIN
INFEXP
INFILD
DEEPFR
BASETP AGWETP
11 0
0
2
2
0
0 0
END PWAT-PARM3
PWAT-PARM4
<PLS > PWATER
input info:
Part 4
***
# - # CEPSC
UZSN
NSUR
INTFW
IRC
LZETP ***
11 0.2
0.5
0.35
6
0.5
0.7
END PWAT-PARM4
PWAT-STATEI
<PLS > *** Initial conditions at start of simulation
ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 ***
# - # *** CEPS SURS UZS IFWS LZS AGWS
11 0 0 0 0 2.5 1
END PWAT-STATEI
END PERLND
IMPLND
GEN-INFO
<PLS ><------- Name ------- > Unit -systems Printer ***
# - # User t-series Engl Metr ***
in out ***
END GEN-INFO
*** Section IWATER***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # ATMP SNOW IWAT SLD IWG IQAL ***
END ACTIVITY
PRINT -INFO
<ILS > ******** Print -flags ******** PIVL PYR
# - # ATMP SNOW TWAT SLD IWG IQAL *********
END PRINT -INFO
TWAT-PARM1
<PLS > IWATER variable monthly parameter value flags ***
# - # CSNO RTOP VRS VNN RTLI ***
END TWAT-PARM1
IWAT-PARM2
<PLS > IWATER input info: Part 2 ***
# - # *** LSUR SLSUR NSUR RETSC
END IWAT-PARM2
IWAT-PARM3
<PLS > IWATER input info: Part 3 ***
# - # ***PETMAX PETMIN
END IWAT-PARM3
TWAT-STATEI
<PLS > *** Initial conditions at start of simulation
# - # *** RETS SURS
END TWAT-STATEI
GWVS
0
20212.1-R OW 2/3/2021 8:09:51 AM Page 19
END IMPLND
SCHEMATIC
<-Source->
<Name> #
Pre Exg (Exclude Exg Imp)***
PERLND 11
PERLND 11
******Routing******
END SCHEMATIC
<--Area--> <-Target-> MBLK
<-factor-> <Name> # Tbl#
0.03 COPY 501 12
0.03 COPY 501 13
NETWORK
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # #<-factor->strg <Name> # # <Name> # # ***
COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # #<-factor->strg <Name> # # <Name> # # ***
END NETWORK
RCHRES
GEN-INFO
RCHRES Name Nexits Unit Systems Printer ***
# - #<------------------ >< --- > User T-series Engl Metr LKFG ***
in out ***
END GEN-INFO
*** Section RCHRES***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # HYFG ADFG CNFG,HTF'G SDFG GQFG OXFG NUFG PKFG PHFG ***
END ACTIVITY
PRINT -INFO
<PLS > **********'******* Print -flags ******************* PIVL PYR
# - # HYDR ADCA CONSHEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR *********
END PRINT -INFO
HYDR-PARM1
RCHRES Flags for each HYDR Section ***
# - # VC Al A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each
FG FG FG FG possible exit *** possible exit possible exit
* * * * * * * * * * * * * * ***
END HYDR-PARM1
HYDR-PARM2
# - # FTABNO LEN DELTH STCOR KS DB50 ***
<------ ><-------- ><--------><--------><--------><--------><--------> ***
END HYDR-PARM2
HYDR-INIT
RCHRES Initial conditions for each HYDR section ***
# - # *** VOL Initial value of COLIND Initial value of OUTDGT
*** ac-ft for each possible exit for each possible exit
<------><-------- > <---><---><---><---><---> *** <---><---><---><---><--->
END HYDR-INIT
END RCHRES
SPEC -ACTIONS
END SPEC -ACTIONS
FTABLES
END FTABLES
EXT SOURCES
<-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # ***
WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC
WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC
2021.2.1-ROW 2/3/2021 8:09:51 AM Page 20
WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP
WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP
END EXT SOURCES
EXT TARGETS
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd ***
<Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg***
COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL
END EXT TARGETS
MASS -LINK
<Volume> <-Grp>
<-Member-><--Mult-->
<Target>
<-Grp> <-Member->***
<Name>
<Name>
# #<-factor->
<Name>
<Name> # #***
MASS -LINK
12
PERLND PWATER
SURO
0.083333
COPY
INPUT MEAN
END MASS -LINK
12
MASS -LINK
13
PERLND PWATER
IFWO
0.083333
COPY
INPUT MEAN
END MASS -LINK
13
END MASS -LINK
END RUN
2021.2.1-POW 2/3/2021 8:09:52 AM Page 21
Mitigated UCI File
RUN
GLOBAL
WWHM4 model simulation
START 1948 10 01 END
RUN INTERP OUTPUT LEVEL 3 0
RESUME 0 RUN 1
END GLOBAL
FILES
<File>
<Un#>
END FILES
OPN SEQUENCE
2009 09 30
UNIT
SYSTEM 1
<-----------File Name ------------------------------>***
***
INGRP INDELT 00:15
PERLND 17
IMPLND 2
IMPLND 9
COPY 501
DISPLY 1
END INGRP
END OPN SEQUENCE
DISPLY
DISPLY-INF01
# - #<---------- Title ---------- >***TRAN PIVL DIG1 FIL1
1 ROW (Exclude Exg Imp) MAX
END DISPLY-INF01
END DISPLY
COPY
TIMESERIES
# - # NPT NMN ***
1 1 1
501 1 1
END TIMESERIES
END COPY
GENER
OPCODE
# # OPCD ***
END OPCODE
FARM
# # K ***
END PARM
END GENER
PERLND
GEN-INFO
PYR DIG2 FIL2 YRND
1 2 30 9
<PLS ><------- Name ------- >NBLKS Unit -systems Printer ***
# - # User t-series Engl Metr ***
in out ***
17 C, Lawn, Mod 1 1 1 1 27 0
END GEN-INFO
*** Section PWATER***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR RHOS TRAC ***
17 0 0 1 0 0 0 0 0 0 0 0 0
END ACTIVITY
PRINT -INFO
<PLS > ***************** Print -flags ***************************** PIVL PYR
# - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR RHOS TRAC *********
17 0 0 4 0 0 0 0 0 0 0 0 0 1 9
2021.2.1-ROW 2/3/2021 8:09:52 AM Page 22
END PRINT -INFO
PWAT-PARM1
<PLS > PWATER variable
monthly
parameter
value
flags ***
# - # CSNO RTOP UZFG
VCS VUZ VNN VIFW
VIRC
VLE INFC
HWT ***
17 0 0
0 0
0 0 0
0
0 0
0
END PWAT-PARM1
PWAT-PARM2
<PLS > PWATER
input info:
Part 2
***
# - # ***FOREST
LZSN
INFILT
LSUR
SLSUR
KVARY
AGWRC
17 0
4.5
0.03
400
0.1
0.5
0.996
END PWAT-PARM2
PWAT-PARM3
<PLS > PWATER
input info:
Part 3
***
# - # ***PETMAX
PETMIN
INFEXP INFILD
DEEPFR
BASETP
AGWETP
17 0
0
2
2
0
0
0
END PWAT-PARM3
PWAT-PARM4
<PLS > PWATER
input info:
Part 4
***
# - # CEPSC
UZSN
NSUR
INTFW
IRC
LZETP
***
17 0.1
0.25
0.25
6
0.5
0.25
END PWAT-PARM4
PWAT-STATEI
<PLS > *** Initial conditions at start of simulation
ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 ***
# - # *** CEPS SURS UZSIFWS LZS AGWS GWVS
17 0 0 0 0 2.5 1 0
END PWAT-STATEI
END PERLND
IMPLND
GEN-INFO
<PLS ><------- Name ------- > Unit -systems Printer ***
# - # User t-series Engl Metr ***
in out ***
2 ROADS/MOD 1 1 1 27 0
9 SIDEWALKS/MOD 1 1 1 27 0
END GEN-INFO
*** Section IWATER***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # ATMP SNOW IWAT SLD IWG IQAL ***
2 0 0 1 0 0 0
9 0 0 1 0 0 0
END ACTIVITY
PRINT -INFO
<ILS > ******** Print -flags ******** PIVL PYR
# - # ATMP SNOW TWAT SLD IWG IQAL *********
2 0 0 4 0 0 0 1 9
9 0 0 4 0 0 0 1 9
END PRINT -INFO
IWAT-PARM1
<PLS > IWATER variable monthly parameter value flags ***
# - # CSNO RTOP VRS VNN RTLI ***
2 0 0 0 0 0
9 0 0 0 0 0
END IWAT-PARM1
TWAT-PARM2
<PLS > IWATER input info: Part 2 ***
# - # *** LSUR SLSUR NSUR RETSC
2 400 0.05 0.1 0.08
9 400 0.05 0.1 0.08
2021.2.1-ROW 2/3/2021 8:09:52 AID Page 23
END IWAT-PARM2
TWAT-PARM3
<PLS > IWATER input info: Part 3 ***
# - # ***PETMAX PETMIN
2 0 0
9 0 0
END IWAT-PARM3
IWAT-STATEl
<PLS > *** Initial conditions at start of simulation
# - # *** RETS SURS
2 0 0
9 0 0
END TWAT-STATEI
SCHEMATIC
<-Source->
<--Area-->
<-Target->
MBLK ***
<Name> #
<-factor->
<Name>
#
Tbl# ***
ROW (Exclude Exg Imp)***
PERLND 17
0.02
COPY
501
12
PERLND 17
0.02
COPY
501
13
IMPLND 2
0.002
COPY
501
15
IMPLND 9
0.008 '
COPY
501
15
******Routing******
END SCHEMATIC
NETWORK
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # #<-factor->strg <Name> # # <Name> # # ***
COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # #<-factor->strg <Name> # # <Name> # # ***
END NETWORK
RCHRES
GEN-INFO
RCHRES Name Nexits Unit Systems Printer ***
# - #<------------------ >< --- > User T-series Engl Metr LKFG ***
in out ***
END GEN-INFO
*** Section RCHRES***
ACTIVITY
<PLS > ************* Active Sections *****************************
# - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG ***
END ACTIVITY
PRINT -INFO
<PLS > ***************** Print -flags ******************* PIVL PYR
# - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR *********
END PRINT -INFO
HYDR-PARM1
RCHRES Flags for each HYDR Section ***
# - # VC Al A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each
FG FG FG FG possible exit *** possible exit possible exit
* * * * * * * * * * * * * * ***
END HYDR-PARM1
HYDR-PARM2
# - # FTABNO LEN DELTH STCOR KS DB50 ***
<------ ><-------- ><--------><--------><--------><--------><--------> ***
END HYDR-PARM2
2021.2.1-POD! 2/3/2021 8:09:52 AM Page 24
HYDR-INIT
RCHRES Initial conditions for each HYDR section ***
# - # *** VOL Initial value of COLIND Initial value of OUTDGT
*** ac-ft for each possible exit for each possible exit
<------><-------- > <---><---><---><---><---> *** <---><---><---><---><--->
END HYDR-INIT
END RCHRES
SPEC -ACTIONS
END SPEC -ACTIONS
FTABLES
END FTABLES
EXT SOURCES
<-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> ***
<Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # ***
WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC
WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC
WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP
WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP
END EXT SOURCES
EXT TARGETS
<-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd ***
<Name> #
<Name>
#
#<-factor->strg
<Name> #
<Name> tem strg
strg***
COPY 1 OUTPUT
MEAN
1
1 48.4.
WDM 701
FLOW ENGL
REPL
COPY 501 OUTPUT
MEAN
1
1 48.4
WDM 801
FLOW ENGL
REPL
END EXT TARGETS
MASS -LINK
<Volume> <-Grp>
<-Member-><--Mult-->
<Target>
<-Grp> <-Member->***
<Name>
<Name>
#
#<-factor->
<Name>
<Name>
# #***
MASS -LINK
12
PERLND PWATER
SURO
0.083333
COPY
INPUT MEAN
END MASS -LINK
12
MASS -LINK
13'
PERLND PWATER
IFWO
0.083333
COPY
INPUT MEAN
END MASS -LINK
13
MASS -LINK
15
IMPLND IWATER
SURO
0.083333
COPY
INPUT MEAN
END MASS -LINK
15
END MASS -LINK
END RUN
2021.2.1-POW 2/3/2021 8:09:52 AM Page 25
lmm��
202121-ROW 2/3/2021 8:09:52 AM Page 26
202121-ROW 2/3/2021 8:09:52 AM Page 27
Legal Notice
This program and accompanying documentation are provided 'as -is' without warranty of any kind. The
entire risk regarding the performance and results of this program is assumed by End User. Clear
Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either
expressed or implied, including but not limited to implied warranties of program and accompanying
documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever
(including without limitation to damages for loss of business profits, loss of business information,
business interruption, and the like) arising out of the use of, or inability to use this program even
if Clear Creek Solutions Inc. or their authorized representatives have been advised of the
possibility of such damages. Software Copyright @ by: Clear Creek Solutions, Inc. 2005-2021; All
Rights Reserved.
Clear Creek Solutions, Inc.
6200 Capitol Blvd. Ste F
Olympia, WA. 98501
Toll Free 1(866)943-0304
Local (360)943-0304
0 0 •
202121-ROW 2/3/2021 8:09:52 AM Page 28
APPENDIX F:
SPECIAL REPORTS
PIERSON DRIVEWAY
TECHNICAL INFORMATION REPORT
FILE No. 12-101 079-00-PC
Rreparect t))/-
Ed McCarthly. R.E., P.S.
9957 1.71st Avenwe SE
Renton. WA 98059
TeL (425) 271-5734
Fax (425) 271-3432
PreparecIf" r"
Rich,ard Pierson
35:1-6 & 336th Street
Federa� Way, WA 98198
J an u a ry 3,1-, 2 0,',1- 3
Pierson Driveway
TECHNICAL INFORMATION REPORT
FILE No. 12-101079-00-PC
Prepared by:
Ed McCarthy, P.E., P.S.
9957 171st Avenue SE
Renton, WA 98059
Tel. (425) 271-5734
Fax (425) 271-3432
Submitted to:
City of Federal Way
Community and Economic
Development Department
33325 8th Avenue South
Federal Way, WA 98003
January 31, 2013
C P
war
0
TABLE OF CONTENTS
LProject
Overview .............................................................................................................. l-1
2.
Conditions and Requirements Summary ------------------------..
2-1
l(lffsite
Analysis -------------------------------------.
3-1
4.
Flow Control and Water Quality [uoUitn Analysisand Design -------------4-1
5.
Conveyance System Analysis and Design ------------------------5-]
6.8oeciu1
Reports and Studies .............................................................................................. 0-1
7.
Other Permits ....................................................................................................................
7-L
0.ESC
Analysis and Design --------------------------------.N-1
9.I3ond
Quantities and Facility Summary -------------------------.9-1
\O.
Operationsand Maintenance Manual ...........................................................................
|0-|
\LRekereocey
---------------------------------------
ll-\
\2.
Appendices
Appendix A. Photos ofthe Project Site
AnnendixB. Flow Control Design
Appendix C. KCRTSDocunentutioo
AnpeudizD. Hydrologic Model Documentation
A»peudixl3. Special Reports and Studies
AnpoudixF. Stoonvvo1ecPollution Prevention and Spill Plan
LIST OF TABLES
Table 1. Existing and Developed Site Basin Conditions ................................................ 4-1
Table 2. Summary of Performance Standards................................................................ 4-5
Table 3. Summary of Special Reports and Studies......................................................... 6-1
Table 4. Summary of Other Permits Required................................................................ 7-1
Table 5. Summary of Maintenance Requirements for Stormwater Facilities ............... 10-1
LIST OF FIGURES
Figure1.
TIR Worksheet................................................................................................ 1-2
Figure2.
Vicinity Map....................................................................................................
1-7
Figure3.
Basin Map........................................................................................................
1-8
Figure4.
Soils Map.........................................................................................................
1-9
Figure 5A. Predeveloped Basins.....................................................................................
4-3
Figure 5B. Developed Basins.........................................................................................
4-4
Figure 6.
Stormwater Dispersion....................................................................................
4-7
Figure7.
TESC Plan.....................................................................................................
8-11
Figure 8.
Site Improvement Bond Quantity Worksheet.................................................
9-2
Figure 9.
Summary of Onsite Stormwater Facilities....................................................
9-11
1. PROJECT OVERVIEW
Project Description
This report provides details for the stormwater design of the Pierson Driveway project. A summary
of the project is provided in the TIR Worksheet (Figure 1). This technical information report (TIR)
addresses the design of stormwater facilities and the offsite drainage analysis for the project. The
project is required to comply with the 2009 King County Surface Water Design Manual with City of
Federal Way amendments. Flow control best management practices (BMPs) including dispersion
have been adopted for the drainage plan and follow Appendix C of the 2009 King County Surface
Water Design Manual.
The property includes Tax Parcel Nos. 06143600657, 6143600451 and 6143600450, that will be
accessed off 334th Street. The project is located east of 33rd Place South, South of 3341h Street
and north of South 336rh Street. The proposal for redevelopment includes constructing a private
driveway to access two lots (Tax Parcel Nos. 61.43600451 and 6143600450) from South 334th
Street. The driveway will be constructed within an existing easement on the property.
Stormwater BMPs will also be constructed to meet the City's design requirements for flow
control and water quality treatment. A 16-foot wide driveway pavement width within a 20-foot
wide easement will be used to access the two parcels.
Site Description
The site has a total area of 2.74 acres. Two wetlands have been delineated in Lot C on the site. A
northerly wetland collects onsite runoff and flows to the north and discharges to a storm system that
continues to flow to the north, discharging to North Lake within 700 feet from the site (Figure 3). An
onsite southerly wetland drains through offsite forested properties to the south. Adjacent properties
to the west contribute minor sheet flow runoff to the site but no stormwater structures were
identified on the property. Runoff from the east is largely collected in the stormwater system for
North Lake Ridge development and conveyed around the project site.
Based on the county's Sensitive Areas Map Folio (King County Department of Parks, Planning,
and Resources, 1990), the site does not have inventoried wetlands, streams, flood hazard areas,
seismic hazard areas, or coal mine hazard areas. Federal Way's critically sensitive areas maps
identify wetlands associated with North Lake along the drainage course from the site's north
basin. The downstream drainage courses from both the north and south onsite basins are
tributary to Hylebos Creek (Figure 3).
Stormwater Design
The drainage plan includes dispersing stormwater by sheet flow from the edge of the driveway into
the adjacent buffer. A flow path having at least 20 feet of native vegetation will be provided before
runoff reaches the onsite wetland in the north basin. A portion of the driveway will be pervious
pavement. The proposed driveway has an impervious area of less than 5,000 square feet. Water
quality treatment is therefore not required.
1-1
Pierson Driveway TIR
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Figure 1. TIR Worksheet
Project Owner Richard Pierson
Phone (253) 927-7465
Address 3516 South 3361h Street
Federal Way, WA 98198
Project Engineer Ed McCarthy
Company Ed McCarthy, PE, PS
Phone (425)271-5734
❑ Landuse Services
Subdivison / Short Subd. / UPD
❑- Building Services
M/F / Commerical
IK Clearing and Grading
❑ Right -of -Way Use
❑ Other
Project Name Pierson Driveway
Permit #
Location Township 21
Range 4
Section 15
Site Address South 334th Street; Parcels
6143600657,6143600450,6143600451
❑
DFW HPA
❑
COE 404
❑
DOE Dam Safety
❑
FEMA Floodplain
❑
COE Wetlands
0
Other Wetland
❑ Shoreline
Management
❑ Structural/
Rockery/Wall
❑ ESA Section 7
Part 5 PLAN AND REPORT INFORMATION
Technical Information Report
Site Improvement Plan (Engr. Plans)
Type of Drainage Review Full / Targeted /
Type (circle one): Full / Modified /
(circle): Large Site
Small Site
Date (include revision 1-31-13
Date (include revision 1-31-13
dates):
dates):
Date of Final:
Date of Final:
Type (circle one): Standard / Complex / Preapplication / Experimental / Blanket
Description: (include conditions in TIR Section 2)
Date of Approval:
1-2
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 7 MONITORING REQUIREMENTS
Monitoring Required: Yes / No
Start Date:
Completion Date:
Describer
Community Plan: N/A
Special District Overlays: N/A
Drainage Basin: Hylebos Creek Basin Plan
Stormwater Requirements: Covered by KCSWDM
❑ River/Stream
❑ Lake
❑- Wetlands
❑ Closed Depression
❑ Floodplain
❑ Other
Part 10 SOILS
Soil Type Slopes Erosion Potential
Alderwood Flat Medium
❑ High Groundwater Table (within 5 feet) ❑ Sole Source Aquifer
❑ Other ❑ Seeps/Springs
❑ Additional Sheets Attached
1-3
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
REFERENCE
❑ Core 2 — Offsite Analysis
❑ Sensitive/Critical Areas
LIMITATION / SITE CONSTRAINT
None
❑ SEPA None
No
0
Part 12 TIR SUMMARY SHEET
(provide one TIR Summary Sheet per Threshold Discharge Area)
Threshold Discharge Area:
North and south subbasins
name or description)
Core Requirements (all 8 apply)
Discharge at Natural Location
Number of Natural Discharge Locations: 1
Offsite Analysis
Level: 1 / 2 / 3 dated: 12/10/12
Flow Control
Level: 1 / 2 / 3 or Exempt after applying BMPs
Incl. facility summary sheet
Small Site BMPs Dispersion, pervious pavement
Conveyance System
Spill containment located at: N/A
Erosion and Sediment Control
ESC Site Supervisor: Ed McCarthy
Contact Phone: 425-271-5734
Cell Phone: 425-736-6016
Maintenance and Operation
Responsibility: Private / Public
If Private, Maintenance Log Required: Yes / No
Financial Guarantees and
Provided: Yes / No
Liability
Water Quality
Type: Not required / Basic / Sens. Lake / Enhanced Basic
(include facility summary sheet)
/ Bog
or Exemption No.
Landscape Management Plan: Yes / No
Special Requirements as applicable)
Area Specific Drainage
Type: CDA / SDO / MDP / BP / LMP / Shared Fac. / None
Requirements
Name:
Flood plain/Floodway Delineation
Type: Major / Minor / Exemption / None
100-year Base Flood Elevation (or range):
Datum:
Flood Protection Facilities
Describe: None
Source Control
Describe landuse: SFR
(comm./industrial landuse)
Describe any structural controls: N/A
1-4
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Oil Control High -use Site: Yes / No
Treatment BMP:
Maintenance Agreement: Yes / No
with whom?
Other Drainage Structures
Describe:
Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS
MINIMUM ESC REQUIREMENTS
MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION
AFTER CONSTRUCTION
Clearing Limits
Stabilize Exposed Surfaces
0 Cover Measures
FX1 Remove and Restore Temporary ESC Facilities
X
F❑_� Perimeter Protection
FX
_� Clean and Remove All Silt and Debris, Ensure
IK Traffic Area Stabilization
Operation of Permanent Facilities
L) Sediment Retention
IK Flag Limits of SAO and Open Space
L) Surface Water Collection
Preservation Areas
Ll Dewatering Control
LJ Dust Control
L) Flow Control
Part 14 STORMWATER
FACILITY DESCRIPTIONS (Note: Include Facility Su mary and Sketch)
Flow Control
Type/Description
Water Quality
Type/Description
L) Detention
U Infiltration
U Regional Facility
U Shared Facility
Flow Control
BMPs
Ll Other
Ll Biofiltration
LJ Wetpool
U Media Filtration
Ll Oil Control
Ll Spill Control
Other
Dispersion, pervious
pavementLJ
1-5
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
Part 15 EASEMENTS/TRACTS
Part 16 STRUCTURAL ANALYSIS
❑ Cast in Place Vault
❑ Drainage Easement
❑Retaining Wall
❑ Covenant
❑Rockery > 4' High
IK Native Growth Protection Covenant
Structural on Steep Slope
❑ Tract
❑Other
❑ Other
Fart 17 SIGNATURE OF PROFESSIONAL ENGINEER
1, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were
incorporated into this worksheet and the attached Technical Information Report. To the best of my
knowledge the information provided here is accurate.
CclWar• d P CQrt
�� 1-3i.-13
Signed/Date
1-6
> 308th St
Stye/ Lake l
3p9tti:St, .,
.S 370ih St ` S 31,0 : , t `
S 311th St
c,
N
315th St
o
N
$315th Ln00
N
S 316th Ln
E
S 316th
PI
317th St m -
LO ,
St
m
'0 _
7�
3 ',
c
N
y
S 324th St `'�.
c*?
40/7 a
��-
a� ;
h OIYmPic waY m
GO ,
`V
3N,
�
�m
328th P c IX)
_��
_
S 330
ZY
North Lak1
S 33�1 t h-
S 332nd St
333rd $t
�.
M
S 336th St
.
ir
S 340th St
'
07
5 341 st PI
S 341st St,,:,,
�0 �
5 344th St r N04
CO
347th P1
5,343th t c
U) ,
S 350th St
�Q
S 357st St
�nt
Project
Site
.. S, 33'..
NO ,
Q
u?; S 356th-St 11. v'C
m:....r' S356thSt >'
d. (.
G ' a:nS 358th
r
nr N ,
S 316th St
P,O , No.
Vicinity Map Mz=
Pierson Technical Information 11/12/12
9957171st Avenue SE
Plat Report 1 2,000 Renton, Washington 98059
Federal Way, Washington Feet Phone: (425) 271-5734 Figure 2
TABLE 3, ,8 EQUIVALENCE BETWEEN
S,(:.S SOIL TYPES AND KC" TS SOIL TYPES
SGS Soil Type
SGS
Hydrologic
Soil Group
KCRTS Snail
Group
Notes
Alderwood A B A C A D
C
Till
Arents; Alderwood Material (AmB, AmC)
C
Till
Arents; Everett Material (An)
B
Outwash
1
Beausite (BeC, BeD, BeF)
C
Till
2
Bellingham (Bh)
D
Till
3
Briscot (Br)
D
Till
3
Buckley (Bu)
D
Till
4
Earlmont (Ea)
D
Till
3
Edgewick (Ed')
C
Till
3
Everett (EvB, EvC, EvD, EwC)
A/B
Outwash
1
Indianola (InC, lnA, MD)
A
Outwash
1
Kitsap (KpB. KpC, KpD)
C
Till
Klaus (KsC)
C
Outwash
1
Neilton (NeC)
A
Outwash
1
Newberg (Ng)
B
Till
3
Nooksack (Nk)
C
Till
3
Norma (No)
D
Till
3
Orcas (Or)
D
Wetland
Oridia (Os)
D
Till
3
Ovall (OvC, OVD, OvF)
C
Till
2
Pilchuck (Pc)
C
Till
3
Puget (Pu)
D
Till
3
Puyallup (Py)
B
Till
3
Ragnar (RaC, RaD, RaC, RaE)
B
Outwash
1
Renton (Re)
D
Till
3
Salal (Sa)
C
Till
3
Sammamish (Sh)
D
Till
3
Seattle (Sk)
D
Wetland
Shalcar (Sm)
D
Till
3
Si (Sn)
C
Till
3
Snohomish (So, Sr)
D
Till
3
Sultan (Su)
C
Till
3
Tukwila (Tu)
D
Till
3
Woodinville (Wo)
D
Till
3
Notes:
1. Where outwash soils are saturated or underlain at shallow depth (<5 feet) by glacial till, they should
be treated as till soils.
2. These are bedrock sails, but calibration of HPF by King County DNR shows bedrock soils to have
similar hydrologic response to till soils.
3. These are alluvial soils, some of which are underlain by glacial till or have a seasonally high water
table. In the absence of detailed study, these soils should be treated as till soils.
4. Buckley soils are formed on the low -permeability Osceola mudflow. Hydrologic response is
assumed to be similar to that of till soils.
1-10
Pierson Driveway TIR
2. CONDITIONS AND REQUIREMENTS SUMMARY
A summary of design requirements for the project are presented in this section.
Design Requirements
The following is a summary of core and special requirements from the 2009 King County Surface
Water Design Manual:
Core Requirement 1: Discharge at the Natural Location
Runoff from the driveway project drains to the north basin on the site. The existing flow path
from the site will be maintained.
Core Requirement 2: Off -site Analysis
A Level 1 downstream drainage analysis is presented in Section 3 of this report.
Core Requirement 3: Flow Control
The site is entirely within the Hylebos Creek watershed. Conservation flow control standards are
required based the City of Federal Way Flow Control Maps. Dispersion, an approved flow
control BMP, will provide flow control for the proposed driveway.
Core Requirement 4: Conveyance System
The onsite stormwater conveyance system will be designed to convey at least the 25-year storm.
Core Requirement 5: Erosion and Sedimentation Control Plan
Proposed erosion and sedimentation control procedures are described in Section 8.
Core Requirement 6: Maintenance and Operations
The proposed system for managing stormwater will be privately maintained and operated.
Recommended maintenance activities are provided in Section 10.
Core Requirement 7: Financial Guarantees and Liability
Calculations for bonds and liability requirements are provided in Section 9 of this report.
Core Requirement 8: Water Quality
The proposed driveway has an impervious area of no more than 5,000 square feet. Water quality
treatment is therefore not required.
2-1
Pierson Driveway TIR
Special Requirement 1: Other Adopted Area -Specific Requirements
The site is within the Hylebos Creek watershed. The detention standards adopted for the project
are consistent with the watershed's basin plan.
Special Requirement 2: Flood Hazard Area Delineation
The site is not within a FEMA 100-year floodplain or flood hazard area.
Special Requirement 3: Flood Protection Facilities
The project does not contain nor is it adjacent to a flood protection facility.
Special Requirement 4: Source Control
No source controls are proposed.
Special Requirement 5: Oil Control
The proposed development does not meet the definition of a high -use site requiring oil control.
2-2
Pierson Driveway TIR
3. OFFSITE ANALYSIS
A Level 1 Downstream Drainage Analysis was prepared for the project in :December 2012 and is
presented in this section.
3-1
Pierson Driveway TIR
P.erson Driveway
LEVEL 1 DOWNSTREAm DRAINAGE ANALYSIS
FILE No. 12-101079-00-PC
Prepared by:
Ed McCarthy, ,P'S.
9S57171"Avenue GE
Renton, VVA98059
Tel. (425)271-5734
Fax (425)271-3432
Submitted to:
City of Federal Way
Community and Economic
Development Department
333258"'Avenue South
Federal Way, WA 98003
December 10.2012
TABLE OF CONTENTS
Task 1: Study Area Definition and Maps............................................................................1
Task 2: Resource Review.....................................................................................................1
Task3: Field Inspection.......................................................................................................2
Task 4: Drainage System Description and Problem Descriptions.......................................2
Task 5: Mitigation of Existing or Potential Problems.........................................................3
References..........................................................................................................................11
Appendix A. Downstream Drainage System
LIST OF TABLES
Table 1. Description of Downstream Conveyance System................................................9
LIST OF FIGURES
Figure1. Vicinity Map........................................................................................................5
Figure2. Soils Map.............................................................................................................6
Figure3. Basin Map............................................................................................................7
Figure 4. Downstream Drainage Course.............................................................................8
i
Pierson Driveway
TASK 1: STUDY AREA DEFINITION AND MAPS
Site Description
The Pierson Driveway project consists of constructing a private driveway to access 2 currently
vacant lots located in Federal Way (Figure 1). The site has two basins including a northerly basin
that drains to North Lake and a southerly basin that ultimately which drains to a tributary to
Hylebos Creek. The property address is 3516 South 3361h Street (Tax Parcel Nos. 06143600657,
6143600451 and 6143600450). The project is located east of 33rd Place South, South of 3341h
Street and north of South 336th Street. The site is currently forested. The site is generally flat at
an average elevation of 403 feet NGVD 29. Based on the King County Soil Survey (U.S.
Department of Agriculture, 1973) the site and surrounding area consists of Alderwood soils
(Figure 2). The site is surrounded by single-family residential development. The proposal for
development includes constructing a private driveway to access two lots from South 334th Street.
The driveway will be constructed within an existing easement on the property. Stormwater best
management practices (BMPs) will also be applied to meet the City's design requirements. The
site is vested under the 2009 King County Surface Water Design Manual.
TASK 2: RESOURCE REVIEW
Based on a review of available resources, including the King County's Sensitive Areas Map Folio
(King County Department of Parks, Planning, and Resources, 1990) and resources available the City
of Federal Way, the site and downstream system within 1 mile from the site are characterized as
follows:
■ Critical Drainage Area Map
Runoff from the site's north basin drains to North Lake, within the Hylebos Creek
watershed. Runoff from the site's south basin drains to an offsite forested wetland to the
south.
■ Floodplain/Floodway (FEMA) Maps
The site is not within a mapped 100-year floodplain. The site has two basins, each of
which drains to a tributary to Hylebos Creek.
■ Offsite Analysis Reports
The downstream analyses for East Campus Residential South (ESM, January 1994)
and East Campus Parcel 3 (ESM, October 1998) were used in helping to assess the
drainage course downstream from the south basin of the project site.
■ Basin Plans
The site is within the Hylebos Creek watershed. Stormwater standards for the site
include Conservation Flow Control and Enhanced Water Quality Treatment in
consideration of downstream receiving waters.
Pierson Driveway
■ Sensitive Area Information
Based on iMAP from the King County website and the Sensitive Areas Map Folio,
the site is not located within a coal mine, 100-year floodplain, seismic, landslide, or
wetland area.
Federal Way's critically sensitive areas maps identify wetlands associated with North
Lake along the drainage course from the site's north basin. Wetlands have been
delineated by others on properties to east and south. The downstream drainage
courses from the site's north and south basins are tributary to Hylebos Creek.
■ SWM Drainage Complaints
A map and summary of registered drainage complaints are included in Appendix A. 1.
No relevant complaints within one mile from the site were filed subsequent to 2002.
■ King County Soils Map
Based on the King County Soil Survey (U.S. Department of Agriculture, 1973) the site
and surrounding area consist of Alderwood soils (Figure 2).
TASK 3: FIELD INSPECTION
A downstream drainage analysis for the site is presented in this section. The site has drainage areas
referred to in this report as the north and south basins (Figure 3). The drainage courses from the site
were assessed on 12/5/12. The downstream conveyance system is described below and illustrated in
Figure 4. Further descriptions of drainage features are summarized in Table 1.
Upstream Drainage
Sheet flow from adjacent properties to the west likely contributes runoff to the site but no
stormwater structures were identified on the property. The tributary area to the west is low -density
residential development and forestland. Runoff from offsite tributary areas, as well as from the site is
collected in the onsite wetlands (Locations 1 and 8 in Figure 4; Table 1) and conveyed to the
downstream drainage courses described below. A large subdivision, known as North Lake Ridge, is
located to the east of the project site (Figure 4). Stormwater from the developed areas of North Lake
Ridge is collected in a pipe system and conveyed to a stormwater pond in the south portion of the
plat. The stormwater pond discharges to a wetland complex south of the Pierson project site.
Onsite Drainage
The site has a total area of 2.74 acres with two onsite basins. The site is forested and flat. Two
wetlands have been delineated in Lot C on the site. Runoff from the site's northerly basin (Location
1; Photo 1 in Appendix A.2) discharges to a storm system that continues to flow to the north,
discharging to North Lake within 700 feet from the site (Figure 3). Runoff from the site's southerly
basin (Location 8; Photos 5 and 6) discharges from the site in a shallow open channel and flows
through an offsite forested wetland to the south.
2
Pierson Driveway
Downstream Drainage Course — North Basin
Runoff leaves the site's north basin through an 18-inch diameter culvert under South 334th Street
(Location 3; Photo 2). Drainage is conveyed to the north in a pipe system (Location 4). The pipe
system discharges to an open channel within a landscaped area (Location 5; Photo 3). The shallow
open channel is lined with concrete and has rock lined sidewalls. The channel is low -gradient and
meanders through the back yards of surrounding residences (Location 6; Photo 4) and ultimately
discharges to North Lake (Location 7) approximately 740 feet from the site.
Downstream Drainage Course — South Basin
Runoff leaves the site's southerly basin in a shallow open channel (Location 9; Photo 6). The
channel conveys drainage in a southerly direction along the edge of a church parking lot (Location
10; Photo 7). The channel broadens (Location 11) before entering a large forested wetland (Location
12). The wetland has dense brush undergrowth and standing water with no distinct flow path. Water
collects at the southwest corner of the wetland and enters a constructed channel (Location 13; Photo
8) within the right-of-way (ROW) along SR-18. Access to the ROW channel was prevented by a
chain link fence. Based on descriptions of the channel by others (ESM, January 2004), it is
apparently lined with asphalt. At a distance of about 1,500 feet from the site, drainage enters a closed
pipe system (ESM, October 1998). There may be a blockage in the pipe system that was causing a
backwater into the ROW channel at the time of the investigation.
TASK 4: DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS
Downstream Drainage Complaints
Drainage complaints along the downstream system were investigated using King County iMap. A
summary of the drainage complaints is provided in Table A.1 of Appendix A.1. Based on available
information, the drainage -related complaints that are relevant to the study reach would likely be
classified as Type 1 problems, or conveyance system nuisance problems. No substantial drainage
complaints were identified in the review of county's files.
Since complaint 2003-0005 was filed, the stormwater system was re -aligned to accommodate the
property owner's plans for lot development. Under the City's jurisdiction, a structure and length of
pipe was added to the conveyance system.
Stormwater Design
The project site is in an area requiring Conservation Flow Control standards. Flow control best
management practices (BMPs), including flow dispersion and pervious pavement, will be
incorporated into the drainage design to meet requirements for best management practices. There are
no significant drainage complaints or obvious drainage -related problems in the downstream system,
other than a potentially plugged pipe along the downstream drainage course to the south. The
Pierson Driveway
selected BMPs will maintain natural drainage paths and help sustain the hydrology of onsite
wetlands.
Water Quality Treatment
The site is in an area mapped for Enhanced Water Quality Treatment. The surface area of
pollution generating impervious surfaces associated with the driveway project will be kept to less
than 5,000 square feet. Therefore, no water treatment, other than that provided by dispersion is
required. Based on the site topography and organics present in the upper soil horizon, it is
expected that dispersion will be an effective measure in improving water quality before
stormwater reaches wetlands on the site.
4
Pierson Driveway
S 332nd
Proip(-t
3�O
S 31Qth St
>1
rt 1
.. s
_ _�_ _
3 � I
rHylebos-
f Green Watershed � � , _
-
'- -
' cif '
_J;Jx
sir
f,f cE
t 42
_.. -
J Est: e. r xJ
�.
%
3rdS, .... I i \1 , \ � =V�\ '
. .
r
'North
� orth
Basin
South
f
m i Basin
'—
OSite
I
Table 1. Description of Downstream Conveyance System
Site Visit on 12/5/12
Basin: North Lake Weather: Clear
Location
Drainage
Drainage
Slope
Distance from
Existing Potential
Observations of Field
ID
Component Type,
Component
Site Discharge
Problems Problems
Inspector, Resource
Name, ,and Size
Description
Reviewer, or
Resident
See Fig. 4
Type: sheet flaw, swale,
drainage basin,
1/4 mile--1,320 ft !
constrictions, under capacity, ponding,
tributary area, likelihood of
stream, channel, pipe.
vegetation, cover, depth,,
C/o)
(FT)
overtopping, scouring, bank sloughing,
problem, overflow
Size: diameter, width
type of sensitive area
sedimentation, incision, other erosion
pathways, potential impacts '
1
Onsite north basin —
Forestland/wetland
0-1
-
Shallow standing water
sheet flow
onsite in wetland
2
Onsite — north basin —
Stream/ditch
0-1
-
Low gradient ditch flows
channel flow
to north
3
18-inch diameter
Culvert crossing
1
0-40
Potential for
No signs of overtopping
concrete pipe
plugging with leaf
debris
4
18-inch diameter
Storm pipe and catch
1
40-340
No signs of erosion
concrete pipe
basin system
5
18-inch diameter
Pipe outfall to open
1
340
plastic pipe
channel.
6
Open channel through
Channel has concrete
1
340-740
Channel pedestrian
Channel pedestrian
landscaped area
lining and rock
crossing has
crossing includes 12-
Width: 1'
sidewalls
potential for
inch diameter culvert
Depth: 1'
creating flow
Side slope: 1:1
constrictions
7
North Lake
Open water
0
740
+-
I
Table 1 (continued)
Basin: Tributary to Hylebos Creek
Location
Drainage
Drainage
dope
distance from
Existing
Potential
Observations of Field
ID
Component Type,
Component
Site Discharge;
Problems
Problems
Inspector, Resource
Name, and Size
Description
Reviewer, or
Resident
See Fig. 4
Type: sheet flow, Swale,
drainage basin,
1/4 mile=1,320 ft
constrictions, under
capacity, ponding,
tributary area, likelihood of
stream, channel, pipe.
vegetation, cover, depth,;
(%)
(FT)
overtopping, scouring,
bank sloughing,
problem, overflow
Size: diameter, width
DTe of sensitive area
sedimentation, incision,
other erosion
pathways, potential impacts
8
Onsite — south basin —
Forestland/wetland
0-1
-
Shallow standing water
sheet flow
onsite in wetland
9
Ditch
Shrub
1
0-100
Drainage from wetland
Width: 1'
concentrates into shallow
Depth: 0.5'
ditch as it flows south
Side slope: 5:1
off site
10
Ditch
Shrub/grass
0.5
100-300
Low -gradient channel —
Width: 1'
no signs of erosion
Depth: 0.5'
Side slope: 5:1
11
Stream channel
Channel broadens as it
0.5
300-500
Width: 3'
enters forested area•,
Depth: 0.5'
forest cover
Side slope: 5:1
12
Wetland
Forested wetland —
0.5
500-1,300
Width: 6'
forest with underbrush
Depth: 24'
Side slope: 3:1
13
Constructed channel
Forest/shrub
0.5
1,300-2,300
Potential blockage
Width: 6'
drainage course enters
in downstream
Depth: 2-4'
ROW along north side
pipe system
Side slope: 3:1
of SR-18
causing backwater
into SR-18 ROW
channel
REFERENCES
ESM, January 2004. Technical Information Report for East Campus Residential South. Federal Way,
Wash.
ESM, October 1998. Downstream Analysis for East Campus Parcel 3. Federal Way, Wash.
King County Department of Natural Resources, 2005. King County Surface Water Design Manual.
Seattle.
King County Department of :Parks, Planning, and Resources, 1990. Sensitive Areas Map Folio.
Seattle.
U.S. Department of Agriculture, Soil Conservation Service, 1973. Soil Survey of King County Area,
Washington. Seattle.
11
Pierson Driveway
Appendix A. Downstream Drainage System
Appendix A.1 Drainage Complaints
Appendix A.2 Photos of the Site and Downstream System
Pierson Driveway
Table A.I. Summary of Downstream Drainage Complaints (within 3. mile from site)
Complaint
Number
Date
Location of
Problem
Description of Complaint
1988-0343
5/13/1988
3616 S 334" St
Outlet to North Lake obstructed/damaged.
Existing enclosed conveyance across private
1/2/2003
property; request to move drainage from lot.
Approval to relocate storm pipe system was
ultimately approved under City of Federal Way
2003-0005
3632 S 334th St
jurisdiction.
Note: Drainage complaints prior to 2002 have been archived by the county and their retrieval was
not requested.
Pierson Driveway
P'O" N.,
Drainage Complaint Map MCC= --
Pierson Downstream Drainage 11/12/12
9957 171st Avenue SE
Plat Analysis 490 Renton, Washington 98059 Figure A.1
Federal Way, Washington Feet I Phone: (425) 271-5734 1
KING COUNTY
DRAINAGE INVESTIGATION REPORT
FIELD INVESTIGATION
FILE NO: 2003-0005
NAME: Ed Irvin
ADDRESS: 3632 S 3341h St, Milton, WA 98354
PHONE: 252-627-0930
TH. BROS PG: 745D6
KROLL PAGE: 728W
MAINT. DIV: 3
INITIALS:MAG
On site 01-08-03. The existing catch basin in the access road was not flooding at the time. It had been dry for several
days prior to my site visit. Upon locating the outlet pipe I noted it was plugged with leaves and stick debris. I removed
the plug and the pipe flowed normally. I could not see anything more restricting the flow. I spoke with Mr. Irvin on
the telephone while at the site. He indicated he is trying to get the parcel to pass a perk test. I did see a number of
holes dug for perk testing. Mr. Irvin stated the parcel would not perk because of the water being conveyed from the
basin through his property. He wants to know why the county has a pipe running under his parcel. If he can get a
positive perk he would like to build. He expressed concerns he won't be able to build with the pipe running under the
property. Mr. Irving would like to know if there is an easement allowing roadside discharge onto his property or
conveyance through his parcel. I could not locate any information indicating easements other than the road that
services the parcels to the north of Mr. Irvin's parcel. North lake shore lands is an unrecorded plat. Mr. Irvin would
request King County remove the outlet pipe or relocate the pipe along S. 334th St so his parcel is not impacted.
1W
S 334th St
6
From: Lazaro, Desi
Sent: Thursday, January 23, 2003 11:28 AM
To: Holwegner, Margaret
Subject: FW: 3632 S 334th St, Milton
Margaret,
We did not find anything at this location.
-----Original Message -----
From: Meininger, Rick
Sent: Monday, January 13, 2003 12:52 PM
To: Lazaro, Desi
Subject: RE: 3632 S 334th St, Milton
Desi: Looking thru both Trackers and the Thos Bros, I find nothing at that location.
RM
-----Original Message -----
From: Lazaro, Desi
Sent: Monday, January 13, 2003 12:40 PM
To: Jacobovitch, Jake; Meininger, Rick
Cc: Holwegner, Margaret
Subject: FW: 3632 S 334th St, Milton
Rick, can you please check our records and help Margaret?
Jake, do you happen to know if County installed the drainage system at the above location? See
e-mail below.
Thanks.
Desi
-----Original Message -----
From: Holwegner, Margaret
Sent: Monday, January 13, 2003 10:07 AM
To: Lazaro, Desi
Subject: 3632 S 334th St, Milton
Hi Desi,
I have a question on some existing drainage on S 334th St. At 3632, there is a private drive on the
north side of the road that serves three parcels. There is a type one catch basin in the middle of the
drive on the county ROW. A 12" concrete tile outlets the basin approximately 120' cutting across
parcel 6143600205. There are no easements that I can find or any indication that this was a county
install or project. The property owner has owned this parcel since the early 70's. It was existing at that
time. He wants to develop the lot now and can't get a positive perk on the site. The pipe from the
basin cuts directly through at a diagonal on his parcel from SW to the NE corner. At the outlet it
daylights to a conveyance ditch that carries flow to North Lake. I have attached a copy of my
Drainage investigation report to aid with any questions. I was hoping you could tell me if this was a
county install or if the county has any part in this drainage. The North Shore Lands Plat is unrecorded
so I have been unable to find county involvement.
I appreciate any information you can share.
Many Thanks,
Margaret
Margaret Holwegner
Engineer 1/Drainage Investigator
Storm water Services Section
Appendix A.2 Photos of the Downstream System
Pierson Driveway
Appendix A.2: Photos of the Downstream System
♦ Photo Number 1
Date of Photo:
12-5-12
Location:
North basin. Near Location 1 in Figure 4.
Description:
The north onsite basin is flat forestland with
some wetlands.
♦ Photo Number 2
Date of Photo:
12-5-12
Location:
Culvert draining north basin on site.
Location 3 in Figure 4.
Description:
An 18-inch diameter culvert conveys
drainage from the site's north basin to
under S. 334t' Place.
Appendix A.2: Photos of the Downstream System
♦ Photo Number 3
Date of Photo:
12-5-12
Location:
Location 5 in Figure 4.
Description:
The stormwater pipe system that starts onsite
discharges to an open channel with a concrete
lining.
♦ Photo Number 4
Date of Photo:
12-5-12
Location:
Location 6 in Figure 4.
Description:
A constructed open channel conveys
drainage through a landscaped area to
North Lake.
Appendix A.2: Photos of the Downstream System
♦ Photo Number 5
Date of Photo:
12-5-12
Location:
Location 8 in Figure 4.
Description:
The south onsite basin is flat forestland with.
some wetlands.
♦ Photo Number 6
Date of Photo:
12-5-12
Location:
Location 9 in Figure 4.
Description:
A shallow ditch conveys drainage away from
the site's south basin.
Appendix A.2: Photos of the Downstream System
♦ Photo Number 7
Date of Photo:
12-5-12
Location:
Location 10 in Figure 4.
Description:
A low gradient open channel conveys
drainage further south and then enters a large
forested wetland.
♦ Photo Number 8
Date of Photo:
12-5-12
Location:
Location 13 in Figure 4.
Description:
A constructed channel within SR-18 conveys
drainage to the southwest. A potentially
plugged pipe in the downstream system is
backing up water in the ROW channel.
4. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN
Part A: Existing Site Hydrology
The site has a total area of 2.74 acres (Figure 5A). The site is generally flat at an average
elevation of 403 feet NGVD 29. Based on the King County Soil Survey (U.S. Department of
Agriculture, 1973) the site and surrounding area consists of Alderwood soils (Figure 4). The site
is surrounded by single-family residential development.
The site is located entirely in the Hylebos Creek watershed. The site has two basins including a
northerly basin that drains to North Lake and a southerly basin that ultimately drains to Hylebos
Creek. Runoff from the north basin sheet flows to a ditch located in Lot C. The ditch discharges to a
storm system located at the north end of Lot C. Runoff from the south basin sheet flows to a forested
wetland located in the south portion of Lot C. Small tributary areas from both the west and east sheet
flow onto the site. Cover types on the site include forest. A summary of cover type areas is provided
in Table 1. The project area for the proposed driveway is within the site's north basin.
Table 1. Existing and Developed Site Basin Conditions
Existing Conditions
Basin
Till
Forest
(AC)
Till
Grass
(AC)
Imperv.
(AC)
Total
(AC)
Project area
0.15
0.00
0.00
0.15
Total
0.15
0.00
0.00
0.15
Developed Conditions
Basin
Till
Forest
(AC)
Till
Grass
(AC)
Imperv.
(AC)
Total
(AC)
Project Area
0.00
0.03
0.12
0.15
Total
0.00
0.03
0.12
0.15
Note: Developed areas are prior to assigning credits for flow control BMPs. Flow control BMPs will include pervious
pavement and dispersion. After considering flow control BMPs, the effective impervious area will be 0.06 acre.
Part B: Developed Site Hydrology
A driveway with a total area of 6,580 square feet will be constructed. Of this area, at least 1,316
square feet will be landscape and 2,320 square feet will be pervious pavement. No more than 5,000
square feet will be conventional asphalt. Therefore, a pollution generating impervious area of 5,000
square feet or less will be constructed. The driveway enters the site from South 334th Street and is
within the north basin on the site. The north basin represents a threshold discharge area.
4-1
Pierson Driveway TIR
Existing drainage flow paths on the site will be maintained. Conservation flow control standards are
required based on the city's flow control applications map (City of Federal Way). Flow control best
management practices (BMPs), including pervious pavement and dispersion, will be incorporated
into the drainage design to meet project requirements. The driveway will be graded to sheet flow
from along its east edge to native vegetation. Water flowing from the surface of the driveway will be
dispersed along the driveway and will flow through at least 20 feet of native vegetation.
4-2
Pierson Driveway TIR
0 40 80
Feet
0
m
—._ ,,
DESIGNED
Figure 5A. Predeveloped Basins
�99Sartven's'F '
1
DRANRJ
Renton, Washington 98059
APPROVED
Pierson Driveway
425.271.5734 Fax 425.271.3432
O
T
HYDROLOGY HYDRAULICS ENGINEERING
PROJECT MANAGER
0 40 80
Feet
$
DESIGNED
Figure 5B. Developed Basins
McCarthy, PE, PS
.Oy
m
1
DRAWN
9957771stAvenueBE
Remora, Washington 98059
c
APPROVED
Pierson Driveway
425.271.5734 Fax 425.271.3432
O
0
HYDROLOGY . HYDRAULICS • ENGINEERING
PROJECT MANAGER
Part C: Performance Standards
A summary of flow control, conveyance, and water quality treatment performance standards for the
project is presented in Table 2, below.
Table 2. Summary of Performance Standards
Category
Performance Standard
Source
Flow Control
■ Conservation Flow Control
■ Surface Water Design
Manual Section 5.3;
Detention Facilities
■ Flow Control BMPs — flow
. Surface Water Design
dispersion and pervious
Manual Section 5.2
pavement will be provided
Conveyance System
■ Provide conveyance for
■ :Surface Water Design
Capacity
developed 25-year storm
Manual Section 1.2.4.1
Water Quality
■ Driveway area is below
■ Surface Water Design
Treatment Menu
threshold of 5,000 square feet -
Manual Section 1.2
no treatment required
Source Control
■ NIA
■ Stormwater Pollution
.Prevention Manual
Oil Control
■ The site does not meet the
■ Surface Water Design
definition of a high -use site
Manual Section 1.3.5
4-5
Pierson Driveway TIR
Part D: Flow Control System
Flow Control BMPs
Flow control BMP requirements will be met by providing dispersion for the entire driveway
impervious area, or for a total of 0.1.5 acre. Tn addition, a portion of the driveway will be
constructed of pervious pavement. After considering the attenuation provided by dispersion, the
increase in the 15-minute 100-year peak flow rate on the site was predicted to be less than 0.10
cubic foot per second. Therefore, the flow control BMPs, as proposed, are the only flow control
required for the project.
Design Methodoloav
KCRTS was used to predict flow rates from the project area under both forested and proposed
developed conditions. Procedures and design criteria specified in the 2009 King County Surface
Water Design Manual were followed for the hydrologic modeling. Descriptions of the
stormwater system and details of the design analysis are provided below. A plan view of the
stormwater dispersion system for the project is provided in Figure 6.
For the hydrology assessment, the reduced KCRTS time series data set was used for the Sea-Tac
rainfall region with a correction factor of 1.0. Documentation of the KCRTS input and output
including descriptions of executable files and times series are listed in Appendix D. Paved
driveway areas were modeled in KCRTS as 50 percent impervious and 50 percent till grass in
modeling flow control BMPs.
Under forested conditions, the 1.00-year peak flow rate from the project area was predicted to be
0.017 cubic foot per second. Under proposed developed conditions, with flow control BMPs in
place, the 100-year peak flow rate from the project area was predicted to be 0.116 cubic foot per
second (Appendix C.2). The predicted increase with developed conditions is less than 0.10 cubic
foot per second.
4-6
Pierson Driveway TIR
Figure 6. Stormwater Dispersion
WEST ?
OR ESMT 4i
-1
'5
_� —2%
WALL — 16"H
SEE NOTE 4
WT
PROFILE
POINT
4 " POROUS HMA
SEE NOTE 3
4" PERMEABLE GRAVEL
SEE NOTE 6
EAST
ESMT
2%
DISPERSION
GRAVEL
OUTLET
EX, GRADE
GEOTEXTILE
SEE NOTE 7
FIRM, UNYIELDING
SUBGRADE AFTER
STRIPPING. SEE NOTE 7
& DET 113
Driveway cross section illustrates method in which runoff will be dispersed from the edge of the driveway
surface.
4-7
Pierson Driveway TIR
Part E: Water Quality System
The site is in an area mapped for Enhanced Water Quality Treatment. The proposed driveway
has an area of less than 5,000 square feet of pollution generating impervious surface. Water
quality treatment of runoff is therefore not required.
Nevertheless, since the driveway serves only two lots, the volume of traffic over the driveway
surface will be low and pollutant loadings are anticipated to be insignificant. The proposed
application of dispersion to provide flow control will also improve water quality as the stormwater
percolates through the organic material in the upper profile of native soil.
4-8
Pierson Driveway TIR
5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN
Stormwater R/D System Conveyance
The stormwater system has been designed to convey at least the 100-year peak flow rate for the
onsite conveyance system. The conveyance system consists of sheet flow dispersion from the edge
of the proposed driveway surface. From the dispersion area, runoff flows to an area of native
vegetation in the north basin on the site.
6-1
Pierson Driveway TIR
G. SPECIAL REPORTS AND STUDIES
A summary of special reports and studies conducted for the project is presented below.
Table 3. Summary of Special Reports and Studies
Geotechnical/soils
Floodplains
Anadromous fisheries impacts
Water quality
6-1
Pierson Driveway TIR
N/A
N/A
IMM
N/A
7. OTHER PERMITS
A summary of permits required for the project is listed in the table below.
Table 4. Summary of Other Permits Required
Onsite Sewage Disposal No — City of Federal Way
proposed
lots will
connect to
public
sewer
Developer/Local Agency No Washington State Department of
Agreement Transportation
NPDES Stormwater No Washington State Department of Ecology
Section 10, 401, 404 No United States Army Corps of Engineers
7-1
Pierson Driveway TIR
S. ESC ANALYSIS AND DESIGN
Part A: ESC Plan Analysis and Design
The project's erosion control plan was designed in accordance with the 2009 KCSWDM. The
following is a description of the elements of the Erosion and Sediment Control (ESC) Plan. BMPs
listed below are referenced from the Stormwater Management Manual for Western Washington
(Washington. State Department of Ecology, February 2005). The ESC Plan is illustrated in Figure 7.
1. Mark Clearing Limits
Description: The site will be delineated by a high visibility orange fence or silt fence with
orange fabric. The fence will provide clear and physical limits for construction.
Recommended BMPs:
BMP C 103: High Visibility Plastic or Metal Fence
BMP C233: Silt Fence or Compost Berm
2. Establish Construction Access
Description: Construction access to the site will be directly off South 3341h Street. The
staging areas, parking areas and other onsite vehicle transportation routes will be stabilized.
Recommended BMPs:
BMP C107: Construction Road/Parking Area Stabilization
3. Control Flow Rates
Description: Construction stormwater will be dispersed by sheet flow from the project area.
In the event that turbidity requirements for discharged water are consistently not met,
construction water will be dispersed to a separate vegetated area using a temporary electric
pump and flow dispersion system.
Recommended BMPs: Stormwater Dispersion
Construction stormwater will be dispersed by sheet flow to an onsite adjacent forested area.
8-1
Pierson Driveway TIR
4. Install Sediment Controls
Description: A construction water dispersion system has been design and included on the
TESC plan. Surrounding forested ground will filter and infiltrate the dispersed construction
water.
Silt fence has been specified at locations on the work boundaries where runoff has the
potential to leave the project site or enter the onsite wetland. As an alternative to silt fence,
compost berms may be substituted. This method of perimeter control is less resource
intensive and can be left onsite to improve soil conditions at completion of construction.
Recommended BMPs:
BMP C233: Silt Fence or Compost Berm
5. Stabilize Soils
Description: Disturbed soils will be stabilized with appropriate measures. The exact BMP
will depend upon the final configuration of that portion of the site and the phase of
construction. Areas that will ultimately become landscape will be seeded and mulched once
they reach their final grade and configuration. The area of clearing will be limited where
possible to minimize the amount of exposed soil surfaces, and the potential of erosion and
sedimentation impacts on surface water. Temporary and permanent cover measures will be
provided to protect disturbed areas. Mulching will be used to provide immediate temporary
protection from erosion and to enhance plant growth. Plastic covering will be used to cover
soil stock piles and trench excavations, and to protect steep slopes behind wall construction,
stockpiles or to encourage grass growth in newly seeded areas. All of these features will be
maintained throughout the construction effort.
From October 1 through March 31, no soils shall remain exposed and unworked for more
than 2 days. From April 1 to September 30, no soils shall remain exposed and unworked for
more than 7 days. This stabilization requirement applies to all soils on site, whether or not at
final grade.
Recommended BMPs:
BMP C120: Temporary and Permanent Seeding
BMP C121: Mulching
BMP C122: Nets and Blankets
BMP C123: Plastic Covering
BMP C130: Surface Roughening
8-2
Pierson Driveway TIR
6. Protect Slopes
Description: Nets and blankets, seeding, and surface roughening may be used to stabilize
embankments.
Recommended BMPs:
BMP C120: Temporary and Permanent Seeding
BMP C121: Mulching
BMP C122: Nets and Blankets
BMP C130: Surface Roughening
7. Protect Drain Inlets
Description: Existing drainage structures may collect surface runoff within the project area if
constructed prior to other improvements. Sediment should not be allowed to enter any of
these structures. Filter fabric or socks will be placed on or in the inlets.
Recommended BMPs:
BMP C220 Storm Drain Inlet Protection
8. Stabilize Channels and Outlets
Description: Water will be managed such that stormwater from undisturbed areas is kept
separate from construction runoff.
9. Control Pollutants
Description: Pollutants other than sediment will be controlled as part of the implemented
Stormwater Pollution Prevention Spill (SWPPS) Plan provided in Appendix F.
Maintenance and repair of heavy equipment and vehicles that may result in discharge or
spillage of pollutants to the ground or surface water runoff will be conducted using spill
prevention measures. Contaminated surfaces will be cleaned immediately following any
discharge or spill incident. Spills will be reported within 24 hours. Emergency repairs may be
performed on -site using temporary plastic placed beneath and, if raining, over the vehicle.
Concrete truck chutes, pumps, and internals shall be washed out only into formed areas
awaiting installation of concrete or asphalt. Unused concrete remaining in the truck and
pump shall be returned to the originating batch plant for recycling. Hand tools including, but
not limited to, screeds, shovels, rakes, floats, and trowels shall be washed off only into
formed areas awaiting installation of concrete or asphalt. When no formed areas are
available, washwater and leftover product shall be contained in a lined container or in a sump
8-3
Pierson Driveway TIR
designed to receive the materials. Contained concrete shall be disposed of in a manner that
does not violate groundwater or surface water quality standards.
Recommended BMPs:
BMP C151: Concrete Handling
10. Control Dewatering
Description: Dewatering is not currently expected to be needed.
Recommended BMPs: Dewatering BMPs will be selected by the contractor.
11. Maintain BMPs
Description: Sediment control BMPs shall be inspected weekly or after a runoff -producing
storm during the dry season and daily during the wet season. BMPs shall be maintained
according to the standards presented below. Extra erosion control materials will be kept on
hand so that supplies are immediately available. A list of suggested materials is provided
below:
Material
Measure
Quantity
Clear plastic, 6 mil
100-foot roll
2
Drainpipe, 6 or 8 inch diameter
25-foot section
4
Sandbags, filled
Each
25
Straw bales for mulching
Approx. 50# each
10
Quarry s ails
Ton
2
Washed gravel
Cubic and
2
Geotextile fabric
100-foot roll
1
Catch basin inserts
Each
4
Steel "T" posts
Each
12
Recommended BMPs:
BMP C150: Materials On -Hand
8-4
Pierson Driveway TIR
12. Manage the Project
Description: Project management elements related to the ESC Plan are described below.
Surface water discharging from the site may need to be sampled and analyzed upon the
County's request. A Certified Professional in Erosion and Sediment Control will be on -site
or on -call at all times. Certification may be through the WSDOT/AGC of Washington
Education Foundation Construction Site Erosion and Sediment Control Certification
Program or any equivalent local or national certification and/or training program.
8-5
Pierson Driveway TIR
Recommended Maintenance for Erosion Control BMPs
BMP
Location of BMP
Maintenance Standards
BMP C103: High Visibility
Perimeters of
■ If the fence has been damaged or
Plastic or Metal Fence
construction
visibility reduced, it shall be repaired or
areas
replaced immediately and visibility
restored.
BMPC 105: Stabilized
Install at
■ Quarry spalls (or hog fuel) shall be
Construction Entrance
construction
added if the pad is no longer in
entrance
accordance with the specifications.
■ If the entrance is not preventing
sediment from being tracked onto
pavement, then alternative measures to
keep the streets free of sediment shall
be used. This may include street
sweeping, an increase in the
dimensions of the entrance, or the
installation of a wheel wash.
■ Any sediment that is tracked onto
pavement shall be removed by
shoveling and/or street sweeping. The
sediment collected by sweeping shall
be removed or stabilized on site. The
pavement shall not be cleaned by
washing down the street, except when
sweeping is ineffective and there is a
threat to public safety. If it is necessary
to wash the streets, the construction of
a small sump shall be considered. The
sediment would then be washed into
the sump where it can be controlled.
■ Any quarry spalls that are loosened
from the pad, which end up on the
roadway shall be removed immediately.
8-6
Pierson Driveway TIR
BMP
Location of BMP
Maintenance Standards
BMP 107: Construction
Staging areas
■ Inspect stabilized areas regularly,
Road/Parking Stabilization
especially after large storm events.
■ Crushed rock, gravel base, hog fuel,
etc. shall be added as required to
maintain a stable driving surface and to
stabilize any areas that have eroded.
■ Following construction, these areas
shall be restored to pre -construction
condition or better to prevent future
erosion.
BMP C120: Temporary and
Exposed soils
■ Any seeded areas that fail to establish
Permanent Seeding
that will be
at least 80 percent cover (100 percent
landscape
cover for areas that receive sheet or
concentrated flows) shall be reseeded.
If reseeding is ineffective, an alternate
method, such as sodding, mulching, or
nets/blankets, shall be used. If winter
weather prevents adequate grass
growth, this time limit may be relaxed
at the discretion of the local authority
when sensitive areas would otherwise
be protected.
■ After adequate cover is achieved, any
areas that experience erosion shall be
reseeded and protected by mulch. If the
erosion problem is drainage related, the
problem shall be fixed and the eroded
area reseeded and protected by mulch.
■ Seeded areas shall be supplied with
adequate moisture, but not watered to
the extent that it causes runoff.
BMP C121: Mulching
Exposed soils
■ The thickness of the cover must be
that will be
maintained.
landscaped
■ Any areas that experience erosion shall
including
be re -mulched and/or protected with a
biofiltration
net or blanket. If the erosion problem is
swales and
drainage related, then the problem shall
infiltration
be fixed and the eroded area re -
depressions
mulched.
8-7
Pierson Driveway TIR
BMP
Location of BMP
Maintenance Standards
BMP C122: Nets and Blankets
Exposed soils
■ Good contact with the ground must be
that will be
maintained, and erosion must not occur
landscaped
beneath the net or blanket.
including
■ Any areas of the net or blanket that are
biofiltration
damaged or not in close contact with
swales and
the ground shall be repaired and
infiltration
stapled.
depressions
If erosion occurs due to poorly
controlled drainage, the problem shall
be fixed and the eroded area protected.
BMP C123: Plastic Covering
Soil stock piles,
■ Torn sheets must be replaced and open
trench
seams repaired.
excavations
■ If the plastic begins to deteriorate due
to ultraviolet radiation, it must be
completely removed and replaced.
■ When the plastic is no longer needed, it
shall be completely removed.
BMP C130: Surface
Exposed soils
■ Areas that are graded in this manner
Roughening
that will be
should be seeded as quickly as possible.
landscaped
■ Regular inspections should be made of
including
the area. If rills appear, they should be
biofiltration
re -graded and re -seeded immediately.
swales and
infiltration
depressions
BMP C150: Materials On
General site
■ All materials with the exception of the
Hand
quarry spalls, steel "T" posts, and
gravel should be kept covered and out
of both sun and rain.
■ Re -stock materials used as needed.
8-8
Pierson Driveway TIR
BMP
Location of BMP
Maintenance Standards
BMP C220: Storm Inlet Drain
General site
■ Catch basin filters should be inspected
Protection
frequently, especially after storm
events. If the insert becomes clogged, it
should be cleaned or replaced.
■ For systems using stone filters: If the
stone filter becomes clogged with
sediment, the stones must be pulled
away from the inlet and cleaned or
replaced. Since cleaning of gravel at a
construction site may be difficult, an
alternative approach would be to use
the clogged stone as fill and put fresh
stone around the inlet.
■ Do not wash sediment into storm drains
while cleaning. Spread all excavated
material evenly over the surrounding
land area or stockpile and stabilize as
appro riate.
BMP C232: Gravel Filter
Inlets to catch
■ Regular inspection is required.
Berm
basins where the
Sediment shall be removed and filter
filter berm will
material replaced as needed.
not impede traffic
flow
BMP C233: Silt Fence
Perimeters of
■ Any damage shall be repaired
construction
immediately. If concentrated flows are
areas that flow
evident uphill of the fence, they must
offsite
be intercepted and conveyed to a
sediment pond.
■ It is important to check the uphill side
of the fence for signs of the fence
clogging and acting as a barrier to flow
and then causing channelization of
flows parallel to the fence. If this
occurs, replace the fence or remove the
trapped sediment.
■ Sediment deposits shall either be
removed when the deposit reaches
approximately one-third the height of
the silt fence, or a second silt fence
shall be installed.
8-9
Pierson Driveway TIR
Part B: SWPPS Plan Design
The site is in the Hylebos Creek watershed. A Stormwater Pollution Prevention (SWPPS) Plan is
provided in Appendix F.
8-10
Pierson Driveway TIR
ADOPT -LIONS
AD
AI.GEEEIRA47 DII'ERLNCI,
4-1
C BOUNDARY NE
BLDG
BUILDING
q
CE'NTE RUNE
DET
DETAIL
EX
LXISTIND
GF3
(LADE BRIMS
EG
EXISTING GRADE
ELE1
ELEVATION
EX
FG
Ell TIN'
FINISHED GRADE
GEN
l NERIAL.
H
HIGH
HT
HEIGHT
MMA
II JI MIX ASPHALT
IE
! AVERT ELEVATION
L.
GNG, LFNALH
LF
LINEAR FFFT
MIN
NO
MIN MUM
AvElA
IN 1,
PERMEABLE I (OT MIX ASPHALT
LOS
LOIN) OF REVILLSE COR'VE
PROP
PFOPOSfD
PVC
POINT OF VERTICAL CUP./ATURE
PVI
POINT ON VERTICAL. INTI RSECIION
PVT
ROW
POINT OF VE12 ,'CAL TANGENCY
RIGHT -OF RA"
A,
STORM DRAIN
SHT
SHEET
SPEC
SPFGIFANDON
sTA
STATION
STD
STANDARD
SS
'IDE ()IS SANITARY SERER
TYP
VC
PICAL
VERTICAL CURVE
2/3
RITAIi. NUMBER/SHEET NUMBER
SP,, G301S
STANDARD PLAN NUMBCR/SHEET NUMBER
M
AT
N
nHMBF.R
-,�0,. FX 61 a36G0a50
IS
r OR
ALI,
, D95I C
6 t �
FAR
ORVEES"T 6 A M y B
FLE
i z —D E ON
V! �E,
21
GIAVEL
-� —
GL NOTC4" ` -
AREGEO E E
�SN DL
SEE FIT 1/1 S C DE 'R
SPROLOW 1. DF.1' 1/1
1 6' DRIVEWAY — POROUS HMA
1 -4 'NA APPROX STF +26
TYPICAL STA 7 GG TO S7A 2+45
ET]PONT
OR ESMT B ESMT
�,o a
ISP
/ D E oN
2� z9 L
T _
L
i
FAE NLTD TEE 0 f > � '-
P GS E RASE -SUNG D F'
1 CRUS Ef. E <'E EE NOTES T ?E
SEE NOUCS4
Sir NOW 6
�116' DRIVEWAY I MA
4. .s.. APPITOX_ STA 3+40
TYP CAL STA 2�A5 TO STA 4f30-2
SEE SET 2/1 // a
TOE OF LOT
JT
�."�J t,RA EL
FEE NET
/^
l EARING� GPI Ll
SCE SET ITIL 1 --- SSE D£T E12
tiG - COSSINICITISN En IFANCE
SEE DEl2/1
FMCFl NO
INI
(1 \FELAN
'--,i6'
AI,LTL,_ RSTLs
OP
CIMITF F ' ARIF,' R't
u i0E OF 'I MA'TOP F CU'T
N A FRO
AND FOR HiuA DR1PI Ar E EPT 1TOPI-IOLTEST IN
FrTFPONFSinALAN ORIVEwnY EZCFPi pN REST SAGE
7I. P/R1MLNT M/RL-IL IDITS1111 IS AFTER F-PACTION-
2. FOR POROUS HMA INFO SEE SET 1/3 & NOTES ON SET 3
L- 1MASINLL DE CAS H. PD 6.1, 22 (CIAS A)
'EQU NEE° ENTS or VYSAOT o D STEP E C-11E R_ 1 ) CRUSHED SUPPAING.
Ho
GR E F I TAND A TEST OF
Ef
ISPI GFO F E OR PRODUCTAPPROVED El FOOPMER
MASGI DIN OPECC 0
FRPIF, LF o ERTSI AP DAL LOTS T to ,ialCT101
P11RIT RANIRANIF URAMIN(D OF PROPOSFP SEGIS171L AOICRETF
OALL FOR APEFORILB' OWNED 0 0 CO FIN
E. E' 0 D 0 BO BE:
8MIN HLIGLTD SOLID, 3000 PI GSNCkS1rE
INTERLOCKINC TO STINDL r SEE PLAN - . T0,4- D NEST o o.,u
SEE SET s/z
.DF ° E r F DAD.
A55 2 1 IS C F DT E ) OR I RATER STRUCTURE SERVICE
CE 11iSTORM
JEOfNLRWS 3. THE DAN SHALL HAVE A DUILT-IN, HIA -FLOW
REIJEF 'STEM OPPERFL0,1 T LESS).
4. THE R TRIF.unl. AISTFM MU1T A1.1.011 RFID-L OF
THE DO'D WTIHOUT SPILEMG THE CD,IFCTF0
RATE ss wA1
DETEAILE - a pas
C ROSE S[CTION ISOIeIET "C VIEW
5 VIA-1 P«C'TE=CHCN
G ROW-
I
FGr- IDm
• CLEARING & GRADING LIMITS
UMIT — & -AR FENCE
• COMPOST 6E1M
L) INLET PROTECTION
�PPPQIP.E AUPAwQBP NU �...
I
s DII PDT, L AL S ARDIN)
Call 811
2 WGftD y @e—You DU
CONTRACTOR SHAIL VFRAY LOCATION AND
DEPTHS Of NI SE4vG INS N111ITES IN
THE OLD PROD 10 COUSIRUCSON
4
Figure 7. TESC Plan.
9. BOND QUANTITIES AND FACILITY SUMMARY
The onsite stormwater facilities will be privately owned and maintained. A bond quantity worksheet
and summary of onsite stormwater facilities are provided in this section.
9-1
Pierson Driveway TIR
Figure 8. Site Improvement Bond Quantity Worksheet
King County
Department of Development & Environmental Services
900 Oakesdale Avenue Southwest
Renton, Washington 98055-1219
206-296-6600 TTY 206-296-7217
Project Name: Pierson Driveway
Location: 3516 South 336th Street, Federal Way WA 98198
Clearing greater than or equal to 5,000 board feet of timber?
yes X no
If yes,
Forest Practice Permit Number:
(RCW 76.09)
Page 1 of 9
Pierson Bond Quant_02-Prices.xlsx
For alternate formats, call 206-296-6600.
Date: 1 /25/2013
Project No.:
Activity No.:
12-101079-00-PC
Note: All prices include labor, equipment, materials, overhead and
profit. Prices are from IRS Means data adjusted for the Seattle area
or from local sources if not included in the IRS Means database.
Check out the DDES Web site at www.metrokc.pov/ddes
Unit prices updated: 02/12/02
Version: 04/22/02
Report Date: 12/9/2012
Figure 8. Site Improvement Bond Quantity Worksheet
................
I2ef rence #....
Unit . ,
Price
Jnit
.Quantit
of
Appii : t%cns
Cost
ER ICON EDfl4 ENT CONTRO `
Backfill & compaction -embankment
Dumber
ESC-1
$ 5.62
CY
Check dams, 4" minus rock
ESC-2
SWDM 5.4.6.3
$ 67.51
Each
Crushed surfacing 1 1/4" minus
ESC-3
WSDOT 9-03.9(3)
$ 85.45
CY
Ditching
ESC-4
$ 8.08
CY
Excavation -bulk
ESC-5
$ 1.50
CY
Fence, silt
ESC-6
SWDM 5.4.3.1
$ 1.38
LF
340
1
469
Fence, Temporary (NGPE)
ESC-7
$ 1.38
LF
300
Hydroseeding
ESC-8
SWDM 5.4.2.4
$ 0.59
SY
150
1
89
Jute Mesh
ESC-9
SWDM 5.4.2.2
$ 1.45
SY
Mulch, by hand, straw, 3" deep
ESC-10
SWDM 5.4.2.1
$ 2.01
SY
150
1
302
Mulch, by machine, straw, 2" deep
ESC-11
SWDM 5.4.2.1
$ 0.53
SY
Piping, temporary, CPP, 6"
ESC-12
$ 10.70
LF
Piping, temporary, CPP, 8"
ESC-13
$ 16.10
LF
Piping, temporary, CPP, 12"
ESC-14
$ 20.70
LF
Plastic covering, 6mm thick, sandbagged
ESC-15
SWDM 5.4.2.3
$ 2.30
SY
Rip Rap, machine placed; slopes
ESC-16
WSDOT 9-13.1(2)
$ 39.08
CY
Rock Construction Entrance, 50'x15'x1'
ESC-17
SWDM 5.4.4.1
$ 1,464.34
Each
Rock Construction Entrance, 100'x15'x1'
ESC-18
SWDM 5.4.4.1
$ 2,928.68
Each
1
1
2929
Sediment pond riser assembly
ESC-19
SWDM 5.4.5.2
$ 1,949.38
Each
Sediment trap, 5' high berm
ESC-20
SWDM 5.4.5.1
$ 17.91
LF
Sed. trap, 5' high, riprapped spillway berm section
ESC-21
SWDM 5.4.5.1
$ 68.54
LF
Seeding, by hand
Sodding, 1" deep, level ground
ESC-22
SWDM 5.4.2.4
$ 0.51
SY
ESC-23
SWDM 5.4.2.5
$ 6.03
SY
Sodding, 1" deep, sloped ground
ESC-24
SWDM 5.4.2.5
$ 7.45
SY
TESC Supervisor
ESC-25
$ 74.75
HR
Water truck, dust control
ESC-26
SWDM 5.4.7
$ 97.75
HR
WRITE-IN-Il I § see:am2
Each
Page 2 of 9
Pierson Bond Quant_02-Prices.xlsx
ESC SUBTOTAL:
30% CONTINGENCY & MOBILIZATION:
ESC TOTAL:
COLUMN:
Check out the DDES Web site at www.metrokc.pov/ddes
$ 3,787.88
$ 1,136.36
$ 4,924.24
A
Unit prices updated: 02/12/02
Version: 04/22/02
Report Date: 12/9/2012
. . . . . . . .
Unit Pficd ' Unit
isfi�ng Future Public Private quenti y.Z mplated
Rlght-of-Way Rp, Improvements Jmprovements {Bar d Rsducilan)*
8 Praina a FadlTe Quint.
Quanta Goat ` (uar t.17 i t Qu , nt. ' fist trmpiet ctst
I RAL iT`EM ..
hlt .
GI - 1
Backfill & Compaction- embankment
$ 5.62
CY
50
281.00
Backfill & Compaction- trench
GI - 2
$ &53
CY
Clear/Remove Brush, by hand
GI - 3
$ 0.36
SY
Clearing/Grubbing/Tree Removal
GI - 4
$ 8,876A6
Acre
0.11
976.38
Excavation - bulk
GI - 5
$ 1.50
CY
100
150.00
Excavation - Trench
GI - 6
$ 4.06
CY
Fencing, cedar, 6' high
GI - 7
$ 18.55
LF
Fencing, chain link, vinyl coated, 6' hig
GI - 8
$ 13.44
LF
Fencing, chain link, gate, vinyl coated,
GI - 9
$ 1,271.81
Each
Fencing, split rail, 3' high
GI - 10
$ 12.12
LF
Fill & compact - common barrow
GI - 11
$ 22.57
CY
Fill & compact - gravel base
GI - 12
$ 25.48
CY
Fill & compact - screened topsoil
GI - 13
$ 37.85
CY
Gabion, 12" deep, stone filled mesh
GI - 14
$ 54.31
SY
Gabion, 18" deep, stone filled mesh
GI - 15
$ 74.85
SY
Gabion, 36" deep, stone filled mesh
GI - 16
$ 132.48
SY
Grading, fine, by hand
GI - 17
$ 2A2
SY
Grading, fine, with grader
GI - 18
$ 0.95
SY
5001
475.00
Monuments, 3' long
GI - 19
$ 135.13
Each
Sensitive Areas Sign
GI - 20
$ 2M
Each
2
5.76
Sodding, 1" deep, sloped ground
GI - 21
$ 7.46
SY
Surveying, line & grade
GI - 22
$ 788.26
Day
Surveying, lot location/lines
GI - 23
$ 1,55&64
Acre
Traffic control crew ( 2 flaggers)
GI - 24
$ 85.18
HR
Trail, 4" chipped wood
GI - 25
$ 7.59
SY
Trail, 4" crushed cinder
GI - 26
$ 8.33
SY
Trail, 4" top course
GI - 27
$ 8A 9
SY
Wall, retaining, concrete
GI - 28
$ 44.16
SF
Wall, rockery
GI - 29
$ 9A9
SF
Page 3 of 9
SUBTOTAL
1,888A4
Unit prices updated: 02/12/02
*KCC 27A authorizes only one bond reduction. Version: 4/22/02
Pierson Bond Quant_02-Prices.xlsx Check out the DDES Web site at www.metrokc.povlddes Report Date: 12/9/2012
Existing Future: Public... ...iPrivate ...
fight- rfi tnr y2oa ! im ov menu Tprcxir rnent
& C�raina a 1=acuities
Unit:Prce Unit Gluant :" Gast Q'uant Cast Quint. Cosh
.... Bond Reduction* ...
Qu'ant,
Carnpiefe Cast '
AC Grinding, 4' wide machine < 1000s
RI - 1
$ 23.00
SY
AC Grinding, 4' wide machine 1000-20
RI - 2
$ 5.75
SY
AC Grinding, 4' wide machine > 2000s
RI - 3
$ 1.38
SY
AC Removal/Disposal/Repair
RI - 4
$ 41.14
SY
Barricade, type I
RI - 5
$ 30.03
LF
Barricade, type III ( Permanent)
RI - 6
$ 45.05
LF
Curb & Gutter, rolled
RI - 7
$ 13.27
LF
Curb & Gutter, vertical
RI - 8
$ 9.69
LF
Curb and Gutter, demolition and dispos
RI - 9
$ 13.58
LF
Curb, extruded asphalt
RI - 10
$ 2A4
LF
Curb, extruded concrete
RI - 11
$ 2.56
LF
Sawcut, asphalt, 3" depth
RI - 12
$ 1.85
LF
Sawcut, concrete, per 1" depth
RI - 13
$ 1.69
LF
Sealant, asphalt
RI - 14
$ 0.99
LF
Shoulder, AC, ( see AC road unit price
RI - 15
$ -
SY
Shoulder, gravel, 4" thick
RI - 16
$ 7.53
SY
Sidewalk, 4" thick
RI - 17
$ 30.52
SY
Sidewalk, 4" thick, demolition and disp
RI - 18
$ 27.73
SY
Sidewalk, 5" thick
RI - 19
$ 34.94
SY
Sidewalk, 5" thick, demolition and disp
RI - 20
$ 34.65
SY
Sign, handicap
RI - 21
$ 85.28
Each
Striping, per stall
RI - 22
$ 5.82
Each
Striping, thermoplastic, ( for crosswalk
RI - 23
$ 2.38
SF
Striping, 4" reflectorized line
IRI - 24
$ 0.25
LF
Page 4 of 9 SUBTOTAL
Unit prices updated: 02/12/02
*KCC 27A authorizes only one bond reduction. Version: 4/22/02
Pierson Bond Quant_02-Prices.xlsx Check out the DDES Web site at www.metrokc.povlddes Report Date: 12/9/2012
Existing
Future: Public... ...iPrivato...
.... Bond Reduction* ...
fight- rfi tnr y
Road Imppoyements rnprcxv menu
Draina a 1=acuities
Quarrt,
Unitfce
Unit
Quan#, "Gast
Q'uant. Cast Quin#. Cost
Campiefe Cast '
� CiA[? uliRFAGING (4" t2 c
2,5 base
,1.b"'trap
course}
i*af'J
CRS ( 6. "Rock, 5"'
base 1.5"top
course)
For KCRS '93, (additional 2.5" base) ac
IRS - 1
$ 3.60
SY
AC Overlay, 1.5" AC
IRS - 2
$ 7.39
SY
AC Overlay, 2" AC
IRS - 3
$ 8.75
SY
AC Road, 2", 4" rock, First 2500 SY
IRS - 4
$ 17.24
SY
AC Road, 2", 4" rock, Qty. over 2500S)
IRS - 5
$ 13.36
SY
AC Road, 3", 4" rock, First 2500 SY
IRS - 6
$ 19.69
SY
AC Road, 3", 4" rock, Qty. over 2500 S
IRS - 7
$ 15.81
SY
AC Road, 5", First 2500 SY
IRS - 8
$ 14.57
SY
AC Road, 5", Qty. Over 2500 SY
IRS - 9
$ 13.94
SY
AC Road, 6", First 2500 SY
RS - 1
$ 16.76
SY
AC Road, 6", Qty. Over 2500 SY
RS - V
$ 16.12
SY
Asphalt Treated Base, 4" thick
RS - 1
$ 9.21
SY
Gravel Road, 4" rock, First 2500 SY
RSS - 1
$ 11.41
SY
Gravel Road, 4" rock, Qty. over 2500 S
RS - 1
$ 7.53
SY
PCC Road, 5", no base, over 2500 SY
RS - 1
$ 21.51
SY
PCC Road, 6", no base, over 2500 SY
RS - 1
$ 21.87
SY
Thickened Edge
DIS - 1
$ 6.89
LF
Page 5 of 9
SUBTOTAL
Unit prices updated: 02/12/02
*KCC 27A authorizes only one bond reduction. Version: 4/22/02
Pierson Bond Quant_02-Prices.xlsx Check out the DDES Web site at www.metrokc.povlddes Report Date: 12/9/2012
Existing... F'ntni MIN*... fiV r fond T e iuotton*
Might -of -way Road Jmproysments tmprt� r r en '
i7raina Fecilitias . Cuant.
Unit?rieeUrrit` Quant, Cast Quart, t` 4uant. < G'pstrrrle€e ;Cast
?� {Ci P ;Cornigated 'I
Access Road, R/D
ti l'ip
D - 1
;N1 " ,quiva,i rit)
$ 16.74 SY
Fcr'Culvert pvices;:nvera ecr crueruuas ssumecl.A
. p ...
u e erF ratedPU issame� rice s olid 3 e.'
to p p p.p
Bollards - fixed
D - 2
$ 240.74
Each
Bollards - removable
D - 3
$ 452.34
Each
* (CBs include frame and lid)
CB Type I
D - 4
$ 1,257.64
Each
CB Type IL
D - 5
$ 1,433.59
Each
CB Type II, 48" diameter
D - 6
$ 2,033.57
Each
for additional depth over 4'
D - 7
$ 436.52
FT
CB Type II, 54" diameter
D - 8
$ 2,192.54
Each
for additional depth over 4'
D - 9
$ 486.53
FT
CB Type II, 60" diameter
D-101
$ 2,351.52
Each
for additional depth over 4'
D - 11
$ 536.54
FT
CB Type II, 72" diameter
D - 12
$ 3,212.64
Each
for additional depth over 4'
D - 13
$ 692.21
FT
Through -curb Inlet Framework (Add)
D - 14
$ 366.09
Each
Cleanout, PVC, 4"
D - 15
$ 130.55
Each
Cleanout, PVC, 6"
D - 16
$ 174.90
Each
Cleanout, PVC, 8"
D - 17
$ 224.19
Each
Culvert, PVC, 4"
D - 18
$ 8.64
LF
Culvert, PVC, 6"
D - 19
$ 12.60
LF
Culvert, PVC, 8"
D - 20
$ 13.33
LF
Culvert, PVC, 12"
D - 21
$ 21.77
LF
Culvert, CMP, 8"
D - 22
$ 17.25
LF
Culvert, CMP, 12"
D - 23
$ 26.45
LF
Culvert, CMP, 15"
D - 24
$ 32.73
LF
Culvert, CMP, 18"
D - 25
$ 37.74
LF
Culvert, CMP, 24"
D - 26
$ 53.33
LF
Culvert, CMP, 30"
D - 27
$ 71.45
LF
Culvert, CMP, 36"
D - 28
$ 112.11
LF
Culvert, CMP, 48"
D - 29
$ 140.83
LF
Culvert, CMP, 60"
D - 30
$ 235.45
LF
Culvert, CMP, 72"
D - 31
$ 302.58
LF
Page 6 of 9
SUBTOTAL
Unit prices updated: 02/12/02
*KCC 27A authorizes only one bond reduction. Version: 4/22/02
Pierson Bond Quant_02-Prices.xlsx Check out the DDES Web site at www.metrokc.povlddes Report Date: 12/9/2012
[iRa1 a�E t7NTlNi {�
Culvert, Concrete, 8"
D- 32
Unit"ric
$ 21.02
r
LF
{fight
w
-of -way
cost
Road
si Draoao
ti Ptilisfivr
Jmproyernents
Facfitas
t
tmprt�
r r en '
Bond
Quaniet,te;
p
Teiuotton*....
Cost
Culvert, Concrete, 12"
D- 33
$ 30.05
LF
Culvert, Concrete, 15"
D- 34
$ 37.34
LF
Culvert, Concrete, 18"
D- 35
$ 44.51
LF
Culvert, Concrete, 24"
D- 36
$ 61.07
LF
Culvert, Concrete, 30"
D- 37
$ 104.18
LF
Culvert, Concrete, 36"
D- 38
$ 137.63
LF
Culvert, Concrete, 42"
D- 39
$ 158.42
LF
Culvert, Concrete, 48"
D - 40
$ 175.94
LF
Culvert, CPP, 6"
D - 41
$ 10.70
LF
Culvert, CPP, 8"
D - 42
$ 16.10
LF
Culvert, CPP, 12"
D - 43
$ 20.70
LF
20
414
Culvert, CPP, 15"
D - 44
$ 23.00
LF
Culvert, CPP, 18"
D - 45
$ 27.60
LF
Culvert, CPP, 24"
D - 46
$ 36.80
LF
Culvert, CPP, 30"
D - 47
$ 48.30
LF
Culvert, CPP, 36'
D - 48
$ 55.20
LF
Ditching
D - 49
$ 8.08
CY
Flow Dispersal Trench 1,436 base+)
D - 50
$ 25.99
LF
French Drain (3' depth)
D - 51
$ 22.60
LF
Geotextile, laid in trench, polypropylen
D - 52
$ 2.40
SY
Infiltration pond testing
D - 53
$ 74.75
HR
Mid -tank Access Riser, 48" dia, 6' dee
D - 54
$ 1,605A0
Each
Pond Overflow Spillway
D - 55
$ 14.01
SY
Restrictor/Oil Separator, 12"
D - 56
$ 1,045.19
Each
Restrictor/Oil Separator, 15"
D - 57
$ 1,095.56
Each
Restrictor/Oil Separator, 18"
D - 58
$ 1,146.16
Each
Riprap, placed
D - 59
$ 39.08
CY
6
234.48
Tank End Reducer (36" diameter)
D - 60
$ 1,000.50
Each
Trash Rack, 12"
D - 61
$ 211.97
Each
Trash Rack, 15"
D - 62
$ 237.27
Each
Trash Rack, 18"
D - 63
$ 268.89
Each
Trash Rack, 21"
D - 64
$ 306.84
Each
Page 7 of 9
SUBTOTAL
648.48
Unit prices updated: 02/12/02
*KCC 27A authorizes only one bond reduction. Version: 4/22/02
Pierson Bond Quant_02-Prices.xlsx Check out the DDES Web site at www.metrokc.povlddes Report Date: 12/9/2012
Exi tin ...
E t i P lilirs
Ptiy t r
Bond Reriuctlon*....
Riryht-of-way
Road Jmproyernents
tmprt� r r enfi
'Drain. Facilities .
`
Cuant.
Unit ?riee
Unit`
Quant, Prtc '''
Quant CcRst
" Gluant. ° o t
ornplefe Cost
R RKlN91911 URFAA IIat ' ..
No.
2" AC, 2" top course rock & 4" borrow
PL - 1
$ 15.84
SY
610
9662.4
2" AC, 1.5" top course & 2.5" base cot PL - 2
$ 17.24
SY
4" select borrow
PL - 3
$ 4.55
SY
1.5' top course rock & 2.5" base cours
PL-4
$ 11.41
SY
WR T -L,N4 S -
No.
Crsuhed rock for dispersion
WI-1
$ 40.00
CY
15
600.00
WI-2
SY
WI-3
CY
WI-4
LF
WI-51
FT
WI-6
WI-7
WI-8
WI-9
WI-10
SUBTOTAL 10,262A0
SUBTOTAL (SUM ALL PAGES):
30% CONTINGENCY & MOBILIZATION:
GRANDTOTAL:
COLUMN:
Page 8 of 9
C
12,799.02
3,839.71
16,63&72
D
rz
Unit prices updated: 02/12/02
*KCC 27A authorizes only one bond reduction. Version: 4/22/02
Pierson Bond Quant_02-Prices.xlsx Check out the DDES Web site at www.metrokc.pov/ddes Report Date: 12/9/2012
Original bond computations prepared by:
Name: Ed McCarthy Date: 1/25/2013
PE Registration Number: 28576 Tel. #: 425-271-5734
Firm Name: Ed McCarthy, PE, PS
Address: 9957 171 st Avenue SE, Renton, WA 98059 Project No:
ROAD IMPROVEMENTS & DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS
PERFORMANCE BOND* PUBLIC ROAD & DRAINAGE
AMOUNT BOND* AMOUNT MAINTENANCE/DEFECT BOND*
Stabilization/Erosion Sediment Control (ESC)
Existing Right -of -Way Improvements
Future Public Road Improvements & Drainage
Private Improvements
Calculated Quantity Completed
Total Right -of Way and/or Site Restoration Bond*/**
(First $7,500 of bond* shall be cash.)
Performance Bond* Amount (A+B+C+D)= TOTAL
Reduced Performance Bond* Total ***
Maintenance/Defect Bond* Total
NAME OF PERSON PREPARING BOND* REDUCTION:
(A)
$ 4,924.2
(B)
$
(C)
$
(D)
$ 16,638.7
(A+B) $ 4,924.2
(T) $ 21,563.0
Minimum bond* amount is $1000,
REQUIRED AT RECORDING OR
TEMPORARY OCCUPANCY ***
(E) $
F x 0.30 $ 6,468.9 OR
(T-E) $ 21,563.0
Use larger of Tx30% or (T-E)
Date:
(B+C) x
0.25 = $
* NOTE: The word "bond" as used in this document means any financial guarantee acceptable to King County.
** NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required.
The restoration requirement shall include the total cost for all TESC as a minimum, not a maximum. In addition, corrective work, both on- and off -site needs to be included.
Quantities shall reflect worse case scenarios not just minimum requirements. For example, if a salmonid stream may be damaged, some estimated costs for restoration
needs to be reflected in this amount. The 30% contingency and mobilization costs are computed in this quantity.
*** NOTE: Per KCC 27A, total bond amounts remaining after reduction shall not be less than 30% of the original amount (T) or as revised by major design changes.
SURETY BOND RIDER NOTE: If a bond rider is used, minimum additional performance bond shall be ' $ 16,(C+D)-E
REQUIRED BOND* AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY DDES
Page 9 of 9
Check out the DDES Web site at www.metrokc.pov/ddes
Pierson Bond Quant_02-Prices.xlsx
Unit prices updated: 02/12/02
Version: 4/22/02
Report Date: 12/9/2012
Figure 9. STORMWATER FACILITY SUMMARY SHEET
Permit Number
(provide one Stormwater Facility Summary Sheet per Natural Discharge Location)
Overview:
Project Name: Pierson Driveway
Date: 1-23-13
Downstream Drainage Basins
Major Basin Name: Hylebos Creek
Immediate Basin Name: North Lake, Hylebos tributary
Flow Control:
Flow Control Facility Name/Number: Driveway dispersion, pervious pavement
Facility Location: Along east edge of driveway
If none,
Flow control provided in regional/shared facility (give
location) N/A
No flow control required Exemption no.
General Facility Information:
Type/Number of detention facilities: Type/Number of infiltration facilities:
ponds ponds
vaults tanks
tanks trenches
Control Structure Location: N/A
Type of Control Structure: N/A
Number of Orifices/Restrictions:
Size of Orifice/Restriction:
No. 1
No. 2
No. 3
No. 4
Flow Control Performance Standard: Conservation
Live Storage Volume Required: 0 CF Depth: 0 feet Volume Factor of Safety: 0%
Number of Acres Served: 0.0
Number of Lots: Driveway serves 2 lots
Dam Safety Regulations (Washington State Department of Ecology)
Reservoir Volume above natural grade: 0 CF
Depth of Reservoir above natural grade: 0 feet
Facility Summary Sheet Sketch
All detention, infiltration and water quality facilities must include a detailed sketch.
(11 "x17" reduced size plan sheets may be used)
10. OPERATIONS AND MAINTENANCE MANUAL
The stormwater and water quality facilities for the project will be privately maintained. The table below
specifies the maintenance requirements for each component of the stormwater facility being constructed.
Applicable maintenance requirements for conventional stormwater design components were taken from the
2009 Surface Water Design Manual and are referenced to the pages that follow.
Table 6. Summary of Maintenance Requirements for Stormwater Facilities
10-1
Pierson Driveway TIR
NO. 1 B - POROUS PAVEMENT
Porous Pavement Standing water; Prevent landscape materials such as soil and No standing water on pavement;
visible debris on mulch from being placed on porous pavement water infiltrates freely into base
surface surface.
Keep adjacent landscape areas well maintained.
Prevent soil from washing onto pavement.
Organic matter on
Sweep or blow leaves and other organic debris
pavement surface
from pavement surface in coordination with
landscape maintenance.
Loosen and remove accumulations of moss.
Minimize use of sand and salts for deicing. If
necessary, used crushed nut shells or similar type
material.
Vacuum clean surface with professional sweeping
machine 1 to 2 times per year or as needed.
Erosion at edge of
Repair gravel base; add more gravel as required.
pavement surface
10-2
Pavement surface free from
organic debris
Water seeping from edge of
pavement should be well -
dispersed
NO.7 - ENERGY DISSIPATERS
External:
Rock Pad Missing or Moved Only one layer of rock exists above native soil in Replace rocks to design
Rock area five square feet or larger, or any exposure of standards.
native soil.
Dispersion Trench Pipe Plugged with
Accumulated sediment that exceeds 20% of the
Pipe cleaned/ flushed so that it
Sediment
design depth.
matches design.
Not Discharging
Visual evidence of water discharging at
Trench must be redesigned or
Water Properly
concentrated points along trench (normal condition
rebuilt to standards.
is a "sheet flow" of water along trench). Intent is to
prevent erosion damage.
Perforations
Over 1/2 of perforations in pipe are plugged with
Clean or replace perforated pipe.
Plugged.
debris and sediment.
Water Flows Out
Maintenance person observes water flowing out
Facility must be rebuilt or
Top of "Distributor"
during any storm less than the design storm or its
redesigned to standards.
Catch Basin.
causing or appears likely to cause damage.
Receiving Area
Water in receiving area is causing or has potential
No danger of landslides.
Over -Saturated
of causing landslide problems.
10-3
NO. 10 - CONVEYANCE SYSTEMS (PIPES & DITCHES)
Pipes
Sediment & Debris
Accumulated sediment that exceeds 20% of the
Pipe cleaned of all sediment and
diameter of the pipe.
debris.
Vegetation
Vegetation that reduces free movement of water
All vegetation removed so water
through pipes.
flows freely through pipes.
Damaged
Protective coating is damaged; rust is causing
Pipe repaired or replaced.
more than 50% deterioration to any part of pipe.
Any dent that decreases the cross section area of
Pipe repaired or replaced.
pipe by more than 20%.
Open Ditches
Trash & Debris
Trash and debris exceeds 1 cubic foot per 1,000
Trash and debris cleared from
square feet of ditch and slopes.
ditches.
Sediment
Accumulated sediment that exceeds 20 % of the
Ditch cleaned/ flushed of all
design depth.
sediment and debris so that it
matches design.
Vegetation
Vegetation that reduces free movement of water
Water flows freely through
through ditches.
ditches.
Erosion Damage to
See 'Ponds" Standard No. 1
See "Ponds" Standard No. 1
Slopes
Rock Lining Out of Place
Maintenance person can see native soil beneath
Replace rocks to design
or Missing (If
the rock lining.
standards.
Applicable).
Catch Basins
See "Catch Basins: Standard No. 5
See "Catch Basins" Standard
No. 5
Debris Barriers
See 'Debris Barriers" Standard No.6
See "Debris Barriers" Standard
(e.g., Trash Rack)
No. 6
10-4
FIR MffZIT-Tr.
King County Department of Natural Resources, 2009. King County Surface Water Design Manual.
Seattle.
King County Department of Natural Resources, January 2005. Stormwater Pollution Prevention
Manual — Best Management Practices, for Business and Residential Properties. Seattle.
King County Department of Parks, Planning, and Resources, 1990. Sensitive Areas Map Folio.
Seattle.
U.S. Department of Agriculture, Soil Conservation Service, 1973. Soil Survey of King County Area,
Washington. Seattle.
Washington State Department of Ecology, February 2005. Stormwater Management Manual for
Western Washington. Olympia.
11-1
Pierson Driveway TIR
12. APPENDICES
Appendix A.
Photos of the Project Site
Appendix B.
Flow Control Design
Appendix C.
KCRTS Documentation
Appendix D.
Hydrologic Model Documentation
Appendix E.
Special Reports and Studies
Appendix F.
Stormwater Pollution Prevention and Spill Plan
Pierson Driveway TIR
Appendix A. Photos of the Project Site
Pierson Driveway TIR
Appendix A: Photos of the Project Site
♦ Photo Number 1
Date of Photo:
12-5-12
Location:
Onsite wetland.
Description:
Two jurisdictional wetlands have been
delineated on the project property.
♦ Photo Number 2
Date of Photo:
12-5-12
Location:
Onsite north basin.
Description:
The site is mostly covered with mature second
growth forest.
Appendix A: Photos of the Project Site
♦ Photo Number 3
Date of Photo:
12-5-12
Location:
South 334t Street looking west.
Description:
The driveway will enter from South 334th
Street along the west boundary of the lot.
♦ Photo Number 4
Date of Photo:
12-5-12
Location:
South 334t Street looking east.
Description:
No changes to the road frontage are proposed.
Appendix B. Flow Control Design
Pierson Driveway TIR
Appendix C. KCRTS Documentation
Appendix C.1 KCRTS Time Series Calculations
Appendix C.2 KCRTS Peak Flow Rates
Appendix C.jL KCRTSl0mme Series Calculations
Basin Calculations
15-Minute Time Series (baoioo15.exz):
KCRTS Command
-------------
CREATE a new Time Series
------------------------
Production of Runoff Time Series
Project Location Sea-Tac
Computing Series fnrI5.tsf
Regional Scale Factor l'OO
Data Type Reduced
Creating I5-minute Time Series File
Loading Time Series FiIe:C:\KC_SWDM\BZ_DATA\3TTFI58.rnf �
Till Forest 0.I5 acres
--------------
TotaI Area 0.15 acres
Peak Discharge: 0.016 CFS at 9:30 on Jan 9 in Year O
Storing Time Series File:forI5.tof �
Time Series Computed
KCRT3 Command
-------------
Butez the Analysis TOOLS Module
-------------------------------
Analysis Tools Command
----------------------
Compute PEAKS and Flow Frequencies
----------------------------------
Loading Stage/Discharge cnrv*:forI5.Lof
Flow Frequency Analysis
--------------------------------------------------------
7ime Series File:fozI5'tsf
Project Locatinn:Sea-Tac
Frequencies a Peaks saved to FiIe:forI5.Dks
Analysis Tools Command
----------------------
Compute Flow DURATION and Exoeedeoc*
------------------------------------
Loading Time Series File:fozl5.taf
Computing Interval Locations
Computing Flow Durations
Durations a Exoeedence Probabilities to FiIe:forI5.doz
Analysis Tools Command
----------------------
RETURN to Previous Menu
_______________________
KCRT3 Command
-------------
CREATE a new Time Series
Pierson Driveway TIR
------------------------
Pzoduotioo of Runoff Time Series
Project Location Sea-Tac
Computing Series devIS.taf
Regional Scale Factor l'OO
Data Type Reduced
Creating I5-minute Time Series File
Loading Time Series FiIe:C:\BZ_3WDM\BZ_DATA\ST8ZI58.rof �
Impervious 0.I5 acres
--------------
TotaI Area 0.15 acres
Peak Discharge: 0.I77 CFS at 6:30 on Jan 9 in Year 8
Storing Time Series File:devI5.taf �
Time Series Computed
KCRT3 Command
_____________
Uoter the Analysis TOOLS Module
-------------------------------
Analysis Tools Command
----------------------
Compute PEAKS and Flow Frequencies
----------------------------------
Loadiog Stage/Discharge onrvo:devI5.tof �
Flow Frequency Analysis
--------------------------------------------------------
Time Series Filo:devI5'tsf
Project Locatioo:Sea-Tac
Frequencies a Peaks saved to File:devI5.Bko
Analysis Tools Command
----------------------
Compnt* Flow DURATION and Exoeodeoo*
------------------------------------
Loading Time Series File:denl5.tof �
Computing Interval Locations
Computing Flow Durations
Durations & Dxoeedeuce Probabilities to FiIe:devI5.dnz �
Analysis Tools Command
----------------------
RETURN to Previous Menu
-----------------------
KCRT3 Command
-------------
CREATE a new Time Series
------------------------
Production of Runoff Time Series
Project Location Sea -Tao
Computing Series mitl5.tuf
Regional Scale Factor l'OO
Data Type Reduced
Creating I5-minute Time Series File
Loading Time Series FiIe:C:\DC_SW0M\KC_DATA\STTG15D.ruf
Till Grass 0.09 acres
Pierson Driveway TIR
Loading Time Series File:C:\KC SWDM\KC DATA\STEI15R.rnf
Impervious 0.06 acres
--------------
Total Area 0.15 acres
Peak Discharge: 0.116 CFS at 6:30 on Jan 9 in Year 8
Storing Time Series File:mitl5.tsf
Time Series Computed
KCRTS Command
-------------
Enter the Analysis TOOLS Module
-------------------------------
Analysis Tools Command
----------------------
Compute PEAKS and Flow Frequencies
----------------------------------
Loading Stage/Discharge curve:mitl5.tsf
Flow Frequency Analysis
--------------------------------------------------------
Time Series File:mitl5.tsf
Project Location:Sea-Tac
Frequencies & Peaks saved to File:mitl5.pks
Analysis Tools Command
----------------------
Compute Flow DURATION and Exceedence
------------------------------------
Loading Time Series File:mitl5.tsf
Computing Interval Locations
Computing Flow Durations
Durations & Exceedence Probabilities to File:mitl5.dur
Analysis Tools Command
----------------------
RETURN to Previous Menu
-----------------------
KCRTS Command
-------------
eXit KCRTS Program
------------------
Pierson Driveway TIR
AppendUmC.2 KCRlS Peak Flow Rates
15-Minute Peak Rates
Flow Frequency Analysis
Time Series FiIe:foz15.tof
Project Looation:Sea-Tao
---AonnaI
Peak
Flow Rates ---
Flow Date
Rank
Time of
Peak
(CFS)
0.0I0
2
2/09/0I
I7:00
0.003
7
I/06/02
2:45
0.007
4
2/28/03
4:30
0.001
D
3/08/04
22:45
0.005
6
I/05/05
8:00
0.008
3
I/I8/06
I9:30
0.006
5
II/24/06
3:30
0.017
l
1/09/08
9:30
Computed Peaks
-----FIow
Frequency
Analysis -------
Peaks
- - Rank
Return
Pcob
(CFS)
Period
0.017
I
100.00
0.890
0.010
2
25'00
0.960
0.008
3
I0^00
0.900
0.007
4
5^00
0.800
0.006
5
3'00
0.667
0.005
6
2.00
0.500
0.003
7
I,30
0.23I
0.001
D
I^lO
0.09I
0.0I4
50'00
0.980
yI«w Frequency 8oaIyaio
Time Series File:dev16.tof (project area under unmitigated developed
conditions)
---AnnnaI
Peak
Flow Rates ---
Flow Bate
Rank
Time of
Peak
(CFS)
0.072
6
8/27/0I
I8:00
0.050
8
9/I7/02
I7:45
0.135
2
I2/08/02
I7:I5
0.057
7
8/23/04
I4:30
0.076
5
10/28/04
16:00
0.080
4
I0/27/05
I0:45
0.097
3
10/25/06
22:45
0.177
I
I/09/08
6:30
Computed Peaks
-----FIow
Frequency
Analysis -------
Peaks
- - Bank
Detnzu
Prob
(CFS)
Period
0.177
1
100.00
0.990
0.I35
2
25'00
0.960
0.097
3
I0.00
0.900
0.080
4
5^00
0.800
0.076
5
3'00
0.667
0.072
G
2'00
0.500
0.057
7
1.30
0.231
0.050
8
1.10
0.09I
0.163
50'00
0.980
Flow Frequency Analysis
Time Series FiIe:mit15.tef (project area under mitigated developed
conditions - dispersion installed)
---AonuaI
Peak
Flow Rates ---
Flow Rate
Rank
Time of
Peak
(CFS)
0.029
6
lO/OD/OO
4:15
0.023
7
1/05/02
15:00
0.074
2
I2/08/02
I7:I5
0.023
8
8/22/04
14:30
0.053
3
II/I7/04
5:00
0.038
5
I0/27/05
I0:45
0.042
4
I0/25/06
22:45
0.II6
I
I/09/08
6:30
Computed Peaks
-----FIow
Frequency
Analysis -------
Peaks
- - Rank
Return
Prob
(CFS)
Period
0.116
1
100.00
0.990
0.074
2
25^00
0.960
0.053
3
I0'00
0.900
0.042
4
5,00
0.800
0.038
5
3.00
0.667
0.029
6
2'00
0.500
0.023
7
I'30
0.23I
0.023
D
1.10
0.09I
0.IO2
50.00
0.980
Appendix D. Hydrologic Model Documentation
The following is a description of KCRTS input and output files used
in assessing the hydrology of the project area.
EXECUTABLE FILES
basinsl5.exc: This executable file creates 15-minute time series for all
contributing areas to the downstream system.
TIME SERIES FILES
Design
forl5.tsf: Project area under forested conditions.
devl5.tsf: Project area under proposed developed conditions. Credits for
flow control BMPs are not included in the time series calculations.
mitl5.tsf: Project area under proposed developed conditions. Credits for
flow control BMPs are included in the time series calculations. Paved
driveway areas were modeled as 50% impervious and 50% till grass in
modeling the flow control BMPs.
GENERAL NOTES
1. Seatac regional rainfall runoff files with a scale factor of 1.0 were
used in the hydrologic simulations.
2. R/D facilities were designed with the 8-year time series data set. 1-
hour peak flow rates were used for detention calculations.
3. 15-minute peak flow rates were used for conveyance calculations and
determining the threshold increase in flow rate due to development on
the site.
4. Dispersion flow control BMPs for impervious areas were represented by
modeling dispersed areas as 50 percent lawn and 50 percent
impervious. Pervious pavement BMPs were represented by modeling paved
areas as 50 percent lawn and 50 percent impervious.
Appendix E. Special Reports and Studies
Separately Bound Reports:
Environ , January 25, 2013. Pierson Driveway Wetlands. Seattle.
Appendix F. Stormwater Pollution Prevention and Spill Plan
Pierson Driveway TIR
Stormwater Pollution Prevention and Spill (SWPPS)
Plan
Pierson Driveway
King County, WASHINGTON
November 12, 2012
Prepared by Ed McCarthy, PE, PS
9957 171 st Ave SE
Renton, WA 98059
TABLE OF CONTENTS
INTRODUCTION..................................................................................................1
1.A. SITE INFORMATION....................................................................................1
GroundwaterFlow..............................................................................................1
Sensitive Areas/Receptors.................................................................................1
Potential Spill Sources or Releases...................................................................1
Contractor Personnel.........................................................................................2
1.13. PROJECT SITE DESCRIPTION...................................................................2
Pre-existing Site Conditions...............................................................................2
UnknownConditions..........................................................................................2
1.C. SPILL PREVENTION AND CONTAINMENT................................................3
Spill Prevention Best Management Practices....................................................3
Equipment Staging and Maintenance................................................................3
FuelingArea......................................................................................................3
Hazardous Material Staging Area......................................................................3
Hazardous Waste Storage Area........................................................................4
SpillContainment Methods................................................................................4
1.D. SPILL RESPONSE.......................................................................................4
Mitigating, Removing, and Disposing of Spilled Material...................................5
1.E. STANDBY, ON -SITE MATERIAL AND EQUIPMENT..................................6
1.F. REPORTING.................................................................................................6
1.G. PROGRAM MANAGEMENT........................................................................6
Security.............................................................................................................. 6
SiteInspections..................................................................................................8
General Responsibilities for Personnel..............................................................8
LIST OF TABLES
Table 1. Spill Response Equipment Brought On-Site...........................................7
Table 2. Agency Notification Reference List ......................................................... 8
Attachment A. Spill and Incident Report Forms
INTRODUCTION
This Stormwater Pollution Prevention and Spill (SWPPS) Plan has been
prepared for construction of a 5,000 square foot driveway. This is a site -specific
plan that outlines the project scope of work (including equipment, materials, and
activities) and presents a comprehensive plan to prevent, respond to, and report
spills or releases to the environment.
1.A. SITE INFORMATION
This SWPPS plan was developed for the drainage improvements required for
construction of a residential driveway serving the Pierson Plat in Federal Way,
Washington.
Groundwater Flow
The site is generally underlain by glacial till soils. A seasonally perched water
table is likely to occur on portions of the site during the wet winter months.
Sensitive Areas/Receptors
■ Construction activities on the project site have the potential to
introduce pollutants to adjacent areas and surface water resources.
Potential Spill Sources or Releases
Potential spill sources at the site include materials and equipment brought on -site
and potential unknown site conditions.
Equipment and Materials Brought On -site
■ Equipment staging and maintenance areas (fuel, lubricating oil, and
hydraulic oil from drill rig, backhoes, bulldozers, water trucks, pickup
trucks, support truck equipment, lighting units, pumps, and generators)
■ Fuel staging areas
■ Hazardous material staging
■ Hazardous waste storage
Unknown Site Conditions that may Be Encountered
No contaminated soil and groundwater are anticipated to be
encountered on the project site. Considering the relatively shallow
excavations required for construction, dewatering will likely not be
required.
Construction debris will be produced during demolition of the replaced
building and site infrastructure.
Contractor Personnel
The designated person responsible for managing, implementing, and maintaining
this SWPPS plan is Ed McCarthy. Phone numbers for project contact is as
follows:
Ed McCarthy, Project Engineer, cell 425-736-6016, office 425-271-
5734
Equipment Staging and Maintenance Area. Heavy equipment (backhoes,
bulldozers, water trucks, support truck, and pickup trucks) and smaller portable
equipment (generators, pumps, and light units) will be stored in a secured
equipment parking area. All repairs and routine maintenance will be performed in
this area.
Fueling Area. No fuel tanks will be stored on site for the project.
Hazardous Material Staging Area. No gasoline, oils, and hydraulic fluid will be
stored on site.
1.13. PROJECT SITE DESCRIPTION
Pre-existing Site Conditions
There are no known locations on site where soil and groundwater are
contaminated to levels which exceed the state or local discharge limits.
Considering the present and past land use of the site, it is unlikely that
contamination will be found.
Unknown Conditions
Potential spill sources at the project site could include:
• Dumped waste containers or motor oil.
If a tank or pipeline is uncovered during site activities, care will be taken to
prevent damage, which could result in a release.
2
1.C. SPILL PREVENTION AND CONTAINMENT
Spill Prevention Best Management Practices
This section describes spill prevention methods (e.g., Best Management
Practices [BMPs]) that will be used for the project. Suggested practices are
listed below.
Equipment Staging and Maintenance
■ Store and maintain equipment in a designated area.
■ Reduce the amount of hazardous materials and waste by substituting
non -hazardous or less hazardous materials.
■ Use secondary containment (drain pan) to catch spills when removing
or changing fluids.
■ Use proper equipment (pumps, funnels) to transfer fluids.
■ Keep spill kits readily accessible.
■ Check incoming vehicles for leaking oil and fluids.
■ Transfer used fluids and oil filters to waste or recycling drums.
■ Inspect equipment routinely for leaks and spills.
■ Repair equipment immediately, if necessary.
■ Implement a preventative maintenance schedule for equipment and
vehicles.
Fueling Area
■ Perform fueling in designated fueling area.
■ Do not "top -off' tanks
■ Use secondary containment (drain pan) to catch spills.
■ Use proper equipment (pumps, funnels) to transfer fluids.
■ Keep spill kits readily accessible.
■ Inspect fueling areas routinely for leaks and spills.
Hazardous Material Staging Area
Hazardous materials such as fuel will be stored in an offsite location. The onsite
storage area locations will be within an authorized staging area and will be
prepared as required prior to bringing the materials onsite. The staging of this
material will be based on a location that minimizes the possibility of material
entering natural or constructed drainage systems. The following BMPs will be
implemented:
Reduce the amount of hazardous materials and waste by substituting
non -hazardous or less hazardous materials.
Minimize the quantity of hazardous materials brought on -site.
Store hazardous materials in a designated area away from storm
drains.
3
■ Store hazardous materials in covered containers.
Hazardous Waste Storage Area
■ Use all products before disposing of the container.
■ Retain the original product label or MSDS.
■ Recycle any useful material (used oil, water -based paint)
■ Segregate wastes by waste type.
■ Minimize the quantity of hazardous waste generated and stored onsite.
■ Arrange for waste disposal before containers are full.
■ Dispose of hazardous waste at an approved waste disposal facility.
■ Train employees in proper hazardous material and waste
management.
Spill Containment Methods
This section identifies the types of secondary containment or diversionary
structures that will be used to handle spills.
Equipment Staging and Maintenance Area. An equipment leak from
a fuel tank, equipment seal, or hydraulic line will be contained within a
spill pad placed beneath potential leak sources. Temporary berms will
be installed to contain accidental spills at locations within the staging
and maintenance area that are within 100 feet of catch basins or flow
paths that lead to sensitive receptors.
Fueling Area. A spill during fueling operations will be contained within
a spill pallet for small container handling. The transfer of fuel into
portable equipment will be performed using a funnel and/or hand
pump, and a spill pad used to absorb any incidental spills/drips. A leak
of a drum will be repaired with a patch kit. A spill response kit will be
located near the fueling area for easy access.
■ Hazardous Materials. A spill pad will be used to absorb any incidental
spills of hazardous materials such as solvents, paints, and other liquid
chemical. Used spill pads will be disposed of in a designated waste
bin.
1.1). SPILL RESPONSE
Response in the first ten to fifteen minutes is critical to minimize the impacts to
human health and the environment and to minimize property damage and
cleanup costs.
The contractor will respond immediately to spills of regulated materials. The
standard approach toward spill response will be as follows:
■ Stop operations.
4
■ Stop the source of the spill by closing the valve or gate or by some
other means.
■ If the spill is moving towards a storm sewer catch basin, put a cover
over the grate to stop the flow. Grate covers and sand bags may be
needed to control the spill. Use the appropriate material to berm the
area to prevent further contamination.
■ Notify the construction site manager.
■ Determine the method of clean up required. All methods shall comply
with State and Local requirements for spill response. Clean up must be
complete and done immediately. The MSDS sheet for the chemical
spilled should be used for the proper method of clean up. Notification
and all required paperwork shall be provided to the appropriate
agency.
■ Contact a cleanup response firm if necessary.
Mitigating, Removing, and Disposing of Spilled Material
Only trained personnel will perform spill cleanup activities. A spill response
contractor will be responsible for cleanup activities as a result of spills or
leaks when the contractor does not have the training, equipment, or
materials to cleanup spills.
The following cleanup firm will be the primary contact for an emergency
response:
■ Ed McCarthy, Project Engineer, cell 425-736-6016, home 425-271-
5734
The following procedures shall be followed subsequent to a spill:
Spills Onto the Ground (Soil):
— Clean up the spill immediately.
— Apply absorbent material, berm, divert or contain the spill.
— Collect spilled material and place into labeled drums.
— Collect absorbent and other material used to clean up the spill,
label the container, and properly dispose of waste at an approved
disposal facility.
— Notify the project's spill response contractor, if necessary.
— Notify the Department of Ecology Spills (360) 407-6300.
— Decontaminate the affected area, equipment and surfaces that
have contacted the spilled material.
— Restore habitat, if necessary.
■ Spills Into Waterways:
— Notify the National Response Center and the State of Washington
5
Emergency Management Division.
— Notify the project's spill response contractor, if necessary.
— Stop the source of the spill immediately.
— Shut down all equipment and ignition sources in the area.
— Deploy boom and absorbent to contain the spill.
— Clean up absorbent and waste materials and dispose of at an
approved waste disposal facility.
— Decontaminate the affected area, equipment and surfaces that
have contacted the spilled material.
1.E. STANDBY, ON -SITE MATERIAL AND EQUIPMENT
Spill response equipment will be stored in spill response kits. The project site
must have at least one spill response kit, but more than one kit may be
necessary or warranted. The locations of all spill response kits at the project site
are clearly marked and accessible. The locations will be identified to all
personnel prior to beginning work.
Table 1 summarizes the spill response material and equipment designated for
equipment and maintenance, fueling, hazardous material staging, and hazardous
waste storage areas.
1.F. REPORTING
The construction manager will be responsible for reporting spill incidents. Table 2
identifies local, state, and federal authorities and private resources that may be
used in implementing this SWPPS plan. In addition, any spill occurrence will
require the completion of a Spill & Incident Report Form which is included in
Attachment A of this report. Attachment A provides a record of spills occurring on
the site. The contractor will keep all such records on file.
Site security measures, site inspection procedures, and personnel training
related to spill prevention, containment, response, management, and cleanup are
outlined below.
Security
Proper site security is important to minimize accidents, trespassing, and potential
spills and releases. Equipment staging and maintenance, fueling, hazardous
material staging, and waste storage areas for the project will be located in a
fenced area. The fence and all heavy equipment are locked at the end of each
workday. Only authorized personnel are permitted onto the project site.
0
Table 1. Spill Response Equipment Brought On -Site
The following items shall be in a spill kit kept on the site. Spill kits shall be easily
carried by two workers and transported in the bed of a pickup truck. Boxes shall be
painted safety yellow and labeled: "SPILL CONTAINMENT KIT — EMERGENCY
USE ONLY".
Item
Purpose
Quantity
SWPPS Plan
Reference
1
Emergency response telephone
numbers
Reference
1
Emergency response handbook
Reference
1
Grainger 95- allon over pack
1
95- allon plastic drum
1
SOCs - 3"x4'
4
SOCs - 3"x12'
2
Absorbent Pillows - 18"x18"
4
Disposable bags
10
Oil Absorbent Pads — 16" x 20"
50
Broom
1
Shovel
1
Table 2. Agency Notification Reference List
Agency & Responsibilities
Phone Contacts
Fire Department
911
• Fire fighting
• Emergency medical response
• Community evacuation
Police Department
911
• Police authority
City of Federal way Public Works Department
(253) 835-2720
Operations and Maintenance
• Information on storm drains and other utilities
Washington State Department of Ecology Spills
(360) 407-6300
Cleanup Program
• Reporting spills to soil
National Response Center
(800) 424-8802
• Reporting spills to water
Washington State Emergency Management Division
(800) 258-5990
• Reporting spills to water
Spill Response Contractor — Certified Cleaning
(253) 536-5500
Services, Inc.
• Emergency spill response
Site Inspections
The contractor will conduct daily inspections of the equipment staging and
maintenance, fueling, hazardous material staging, and waste storage areas to
ensure that spill control measures are in place. Inspections of the project site for
general housekeeping and BMPs will be performed weekly.
General Responsibilities for Personnel
All personnel have responsibility for spill prevention. Any worker who notices a
leak will respond as appropriate based on their training, or if a spill has occurred,
they will assume a defensive posture by avoiding the area and immediately
notifying the site construction manager.
0
The local fire department is responsible for emergency containment procedures
when called to the site. The fire department takes measures necessary to
prevent fire and explosion and to protect people and property in the event of a
fire or explosion.
A spill response contractor is responsible for cleanup activities when the
contractor does not have the training, equipment, or materials to cleanup spills
safely and effectively.
9
ATTACHMENT A: SPILL AND INCIDENT REPORT FORMS
Instructions: Complete for any type of petroleum product or hazardous materials/waste spill or
incident. Provide a copy of this report to management.
1. Person Reporting Spill or Incident:
2. Type of Spill:
3. Location of Spill:
4. If no spill, describe incident:
5. Actions taken:
Name
Address
Organization
Title
Telephone
Fax
Signature
Common Name of
Spilled Substance
Quantity Spilled (Estimate)
Concentration (Estimate)
Date of Spill
Time Spill
Time Spill
Started
AM PM
Ended
AM PM
SPILL TO LAND
SPILL TO WATER BODY
Name of Site:
Name of Water Body:
Street Address:
Location of Discharge with Reference to Fixed
Point:
City/Town:
Description of Area from which spilled material may
reach:
County:
6. Person responsible for managing termination/ closure of incident or spill:
Name: Phone: Fax:
January 25, 2013
Electronic Mail
Mr. Dick Pierson
3516 South 336th Street
Federal Way, WA 98001
Re: Pierson Driveway Wetlands
Dear Mr. Pierson:
At your request, ENVIRON conducted a site investigation to determine if there have been any
changes in wetland boundaries delineated on your properties in Federal Way. This investigation
focuses on the three, undeveloped King County tax parcels (06143600657 [Lot C], 6143600451 [Lot
B] and 6143600450 [Lot A]). As you know, I completed a wetland delineation in 2005 as required for
your application to complete a boundary line adjustment that resulted in the three parcels identified
above. The delineated wetland boundaries were confirmed by King County as stated in the
Ecological Solutions' April 2006 addendum to the March 2005 delineation report. The purpose of this
report is to update the wetland classifications as required by the City of Federal Way (City) for
permitting the proposed driveway access road from South 334th Street to Lots A and B. Per Matt
Herrera's pre -application conference summary letter dated April 10, 2012 and addressed to Mr. Eric
LaBrie, ESM Consulting Engineers, it is assumed that the stream/ditch on the northern portion of Lot
C is rated as major for the purposes of this proposed access road permit application. A brief
summary of my findings and rationale for the wetland classifications is provided below.
APPROACH
The approach used to identify whether wetland boundaries have changed and to classify existing
wetlands is provided as follows.
Onsite Wetlands
The onsite portions of existing wetlands were re-established and identified with red surveyor flagging
by others based upon the initial surveyed wetland boundaries. Portions of my old wetland boundary
flags were clearly visible in many locations where red flagging was hung re-establishing the
delineated, confirmed, and surveyed wetland boundaries. The entire western boundaries marked by
the red flagging were walked on November 27, 2012. There has been no change in wetland
parameters within the wetlands.
The absence of any continuous hydric soils and wetland hydrology between the two wetlands was
confirmed by digging a soil pit in the middle of the narrow ditch between the south end of Wetland 2
and north end of Wetland 1. Collective observations that I have made over the years and those of
the City's wetland consultant Otak and others were used to classify the wetlands using the Federal
Way Revised Code (FWRC) 19.175.020. Otak's Doug Gresham completed a peer review of the
wetland delineation and confirmed the delineated wetland boundaries as indicated in his January 29,
2007 Technical Memorandum titled Pierson Property Sensitive Areas Review addressed to Greg
Fewins, Deputy Director, Community Development Services Planning Division, City of Federal Way.
This Technical Memorandum is hereafter referred to as Otak.
901 Fifth Avenue, Suite 2820, Seattle, WA 98614 www.environcorp.com
Tel: +1 206,336,1650 Fax: +1 206,336,1651
Dick Pierson - 2 - January 25, 2013
Offsite Wetlands
Offsite wetlands were delineated by Talasaea Consultants (Talasaea) for the East Campus South
Residential Development, which abuts this site to the east. Four lobes of a wetland identified as
Wetland B identified by Talasaea are adjacent to the east boundary of Lot C. A fifth lobe is located in
within and extends south of South 336t" Street and the waterline easement. Though no wetland
category is provided in the August 5, 2003 letter regarding Wetland and Buffer Restoration Plans
addressed to Ms. Deb Barker, Associate Planner at the City, the letter does indicate that FWRC
requires a 100-foot buffer. That document also indicates that Wetland B consists of a series of 5
wetland areas connected by narrow ditches. Talasaea assumed that there was hydric soil and
hydrologic continuity and connectivity between all of these lobes in their June 2002 investigation.
There is not continuous hydric soil or hydrologic connectivity as described by both myself and Otak.
I examined the offsite lobes delineated by Talasaea during my onsite investigation on November 27,
2012. Total precipitation at Sea-Tac International Airport (NCDC Station 457473) was well above
average for the months of October and November, drier than average in July and August, and wetter
than average May through July. Table 1 shows the monthly total precipitation and standard deviation
around the mean compared to the total monthly precipitation. Immediately preceding my site
investigation weather has been much wetter than average.
Table 1. Average and total monthly precipitation for Sea-Tac Airport (NCDC Station 457473)
MAY
JUNE
JULY
AUGUST
SEPTEMBER
OCTOBER
NOVEMBER
AVGa
1.76
1.47
0.75
1.07
1.74
3.51
6.11
STD
0.87
0.84
0.53
1.04
4.35
4.91
2.79
2012b
2.05
2.96
1.04
0.00
0.03
6.71
8.28
a Long-term average for the National Climatic Data Center Station at Sea-Tac International Airport for the
period of record from 1948 through 2012 http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pI?wa7473.
b Monthly total precipitation. Two days missing data for November
FWRC 19.175.020 Wetland categories and standard buffers
The following Wetland categories and standard buffers in the FWRC are quoted directly from the
current Zoning and Development Code accessed online December 12, 2012
at http://www.codepublishing.comMA/FederalWay/:
(1) Regulated wetlands are classified into the following categories:
(a) Category I wetlands meet one of the following criteria:
(i) Contain the presence of species or documented habitat recognized by
state or federal agencies as endangered, threatened or potentially extirpated plant,
fish or animal species; or
(ii) Contain the presence of plant associations of infrequent occurrence,
irreplaceable ecological functions, or exceptional local significance including but not
limited to estuarine systems, peat bogs and fens, mature forested wetlands,
groundwater
901 Fifth Avenue, Suite 2820, Seattle, WA 98614 www.environcorp.com
Tel: +1 206,336,1650 Fax: +1 206,336,1651
Dick Pierson - 3 - January 25, 2013
exchange areas, significant habitat or unique educational sites; or
(iii) Have three or more wetland classes, one of which is open water.
(b) Category II wetlands are greater than 2,500 square feet in area, do not exhibit
the characteristics of Category I wetlands, and meet one of the following criteria:
(i) Are contiguous with water bodies or tributaries to water bodies which
under normal circumstances contain or support a fish population, including streams
where flow is intermittent; or
(ii) Are greater than one acre in size in its entirety; or
(iii) Are less than or equal to one acre in size in its entirety and have two or
more wetland classes, with neither class dominated by nonnative invasive species.
(c) Category I II wetlands are greater than 2,500 square feet in area and do not
exhibit those characteristics of Category I or II wetlands.
(2) Standard buffer widths for regulated wetlands are established as follows:
(a) Category I wetlands shall have a standard buffer width of 200 feet.
(b) Category II wetlands shall have a standard buffer width of 100 feet.
(c) Category III wetlands shall have a standard buffer width of 50 feet for wetlands
that are greater than 10,000 square feet in area, and shall have a standard buffer width of
25 feet for wetlands that are between 2,500 to 10,000 square feet in area.
This code was used to classify the wetlands and identify the required standard buffers.
RESULTS
The collective observations and results of onsite and offsite wetland delineation are used to update
the previous wetland report and classify the wetlands. Reduction of the major stream buffer is
required to permit the proposed access road under the City's Process IV procedure. A
wetland/stream buffer mitigation plan (buffer enhancement plan) will be provided separately.
There remain two wetlands on the site as shown in Figure 1. There are no surface water
connections or continuous hydric soils between Wetland 1 and Wetland 2 as explained in more detail
in the next subsection.
Discontinuous Wetland Characteristics
A test pit (Figure 1) excavated in the bottom of the narrow ditch constructed to drain the wetlands
contained no positive indicators of hydric soils or wetland hydrology, despite the wetter than average
conditions preceding this most recent investigation. The test pit was dug to a total depth of 17 inches
below the ground surface. From 0 to 9 inches below the ground surface, there was a very dark
grayish brown (10YR 3/2) gravelly sandy loam, which was moist but not saturated and contained no
redoximorphic features. Below this layer from 9 to 15 inches was a dark brown (10YR 3/3) gravelly
sandy loam, which was moist and approached saturation near the interface with the layer below but
was not saturated. This second layer contained a few, fine to medium, redox concentrations.
Beneath this layer from 15 to more than 17 inches below the ground surface was a light yellowish
brown (2.5Y 6/3) to pale yellow (2.5Y 7/3) weakly cemented gravelly sandy loam layer. This layer
appeared to be weathered glacial till. This layer also was unsaturated. About 50 percent of this layer
consisted of yellowish brown (10YR 5/6) and brownish yellow (10YR 6/8) redox concentrations.
There were no positive indicators of hydric soils in the test pit. Rather, observed soils are consistent
with and confirm the map unit designation of Alderwood gravelly sandy loam 0 to 6 percent slopes
(Attachment A). Alderwood gravelly sandy loam soils are non-hydric.
901 Fifth Avenue, Suite 2820, Seattle, WA 98614 www.environcorp.com
Tel: +1 206,336,1650 Fax: +1 206,336,1651
Dick Pierson - 4 - January 25, 2013
Inclusions of hydric soils, such as those observed in the delineated wetlands, are much different.
These are present within the Wetlands 1 and 2, which are located in depressions to the north and
south of the topographic saddle. Typical hydric soils in the wetlands consist of a very dark gray
(10YR 3/1) silt loam with abundant redoximorphic features in the surface layer. The surface layer is
underlain by a very dark brown (10YR 2/2) sandy loam with common and prominent redoximorphic
features as indicated in the original wetland delineation report.
It is important to note the absence of any positive indicators of wetland hydrology in the topographic
saddle between Wetlands 1 and 2 and that there have been significant changes in the catchment or
contributing drainage areas to these wetlands. The topographic contours in Figure 1 clearly show
there is a topographic saddle between Wetland 1 and Wetland 2. This is the area where the narrow
ditch was excavated. The ground surface here is a foot or more higher than the shallow depressions
where the closed depressional (Wetland 2) and depressional outflow wetlands (Wetland 1) are
located. There was up to six inches of standing water in the offsite portion of Wetland 2 to the
northeast of the north end of the ditch. The surface of the water was at least 12 inches below the
bottom of the excavated ditch. Both Talasaea and Otak noted this ditch in their reports. Otak agreed
that there was no hydrologic connection between the two wetlands. Even deeper standing water was
observed in depressional areas within Wetland 1. Surface water elevation at the south end of the
ditch was about 1.5 feet below the bottom of the south end of the narrow ditch between the wetlands
at the time of my site visit. Furthermore, you have indicated never seeing any surface water in the
excavated ditch between these wetlands in the 30 plus years you have lived on the property. Thus, it
is clear that neither hydric soils nor wetland hydrology are present in the ditch or topographic saddle
between Wetlands 1 and 2. Therefore, it is considered upland.
Contributing drainage area to both Wetland 1 and Wetland 2 has been reduced by the Quadrant East
Campus Residential development to the east. This reduction in the total area contributing to the
hydrology of these wetlands has likely altered the hydrologic regime of these wetlands making them
drier. According to your personal communication with Kevin Peterson, the Engineering Plans
Reviewer for the City of Federal Way Public Works Department, roof runoff from residences in the
East Campus development that would historically have contributed to shallow groundwater recharge
and interflow to Wetlands 1 and 2 as shown by the topographic gradient in Figure 1 is now collected
and routed to stormwater management facilities at the south end of that development thereby
bypassing the wetlands. This has reduced the area draining to these wetlands likely contributing to
reduced groundwater recharge and drier conditions. In conclusion, there is no wetland hydrology or
hydric soils in the narrow ditch or topographic saddle between Wetland 1 and Wetland 2. As noted in
Ed McCarthy's Level 1 Downstream Drainage Analysis Wetland 2 is within the north basin and
Wetland 1 is within the south basin. Surface flow from the north basin is towards the north through
the stream/ditch and the concrete culvert beneath South 334t" Street as depicted in Figure 1.
Surface flow from Wetland 1, which is within the area identified by Mr. McCarthy as the south basin,
is to the south.
Wetland Classification
The previously delineated, confirmed, and surveyed wetland boundaries on the site have not
changed. Clear indicators of hydrophytic vegetation, wetland hydrology, and hydric soils persist
within the previously identified wetland areas despite the considerable reduction in contributing
drainage area from the Quadrant East Campus Residential development to the east. Wetland 1
contains two wetland vegetation classes: scrub -shrub and forested. As was noted in the original
901 Fifth Avenue, Suite 2820, Seattle, WA 98614 www.environcorp.com
Tel: +1 206,336,1650 Fax: +1 206,336,1651
Dick Pierson - 5 - January 25, 2013
report and has been confirmed by Otak, there are no listed species present, nor any documented
habitat recognized by state or federal agencies for such species nor are there plant associations of
infrequent occurrence, irreplaceable ecological functions, or wetlands of local significance as
identified in FWRC 19.175.020.1.a.ii. Category II wetlands have a standard buffer of 100 feet,
according to FWRC 19.175.020.2.b.
Wetland 2 contains only one wetland vegetation class. In places, Himalayan blackberry, an invasive
species, is a codominant species. Total area of this wetland is approximately 8,734 square feet as
shown in Figure 1. It does not exhibit characteristics of either a Category I or Category II wetland
and is thus classified as a Category III wetland. In 2007, the City's consultant (Otak) agreed with this
Category III classification. Category III wetlands between 2,000 and 10,000 sq. ft. have a standard
buffer of 25 feet, according to FWRC 19.175.020.2.c.
Yours sincerely
Scott Luchessa
Senior Science Advisor I Certified Ecologist
Enclosures:
Figure 1. Delineated Wetland Boundaries and Standard Buffers
Attachment A. Soils in the Vicinity of the Pierson Driveway
901 Fifth Avenue, Suite 2820, Seattle, WA 98614 www.environcorp.com
Tel: +1 206,336,1650 Fax: +1 206,336,1651
Attachment A
Soils in the Vicinity of the Pierson Driveway
Soil Map —King County Area, Washington
(Soils in the Vicinity of the Pierson Driveway)
470 18' 11"
47' 18' 0"
Map Scale: 1:2,440 if printed on A size (8.5" x 11") sheet.
Meters
0 30 60 120 180
Feet
0 100 200 400 600
USDA Natural Resources Web Soil Survey
IiiiiiiiN Conservation Service National Cooperative Soil Survey
12/12/2012
Page 1 of 3
47' 18' 11"
47' 18' 0"
Soil Map —King County Area, Washington
(Soils in the Vicinity of the Pierson Driveway)
MAP LEGEND
MAP INFORMATION
Area of Interest (A01)
Very Stony Spot
Map Scale: 1:2,440 if printed on A size (8.5" X 11 ") sheet.
Area of Interest (AOI)
Wet Spot
The soil surveys that comprise your AOI were mapped at 1:24,000.
Soils
Soil Map Units
Other
Warning: Soil Map may not be valid at this scale.
Special
Point Features
Special Line Features
Enlargement of maps beyond the scale of mapping can cause
QJ
Blowout
Gully
misunderstanding of the detail of mapping and accuracy of soil line
® Short Steep Slope
placement. The maps do not show the small areas of contrasting
Borrow Pit
soils that could have been shown at a more detailed scale.
Other
j�
Clay Spot
Political Features
Please rely on the bar scale on each map sheet for accurate map
y
Closed Depression
Cities
measurements.
Gravel Pit
Water Features
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nres.usda.gov
A
Gravelly Spot
Streams and Canals
Coordinate System: UTM Zone 1ON NAD83
Landfill
Transportation
This product is generated from the USDA-NRCS certified data as of
Lava Flow
+++ Rails
the version date(s) listed below.
4L
Marsh or swamp
Interstate Highways
Soil Survey Area: King County Area, Washington
Mine or Quarry
US Routes
Survey Area Data: Version 7, Jul 2, 2012
O
Miscellaneous Water
Major Roads
Date(s) aerial images were photographed: 7/24/2006
p
Perennial Water
Local Roads
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
Rock Outcrop
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
+
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
,
Slide or Slip
p`
Sodic Spot
Spoil Area
Stony Spot
USDA Natural Resources Web Soil Survey 12/12/2012
all Conservation Service National Cooperative Soil Survey Page 2 of 3
Soil Map —King County Area, Washington
Soils in the Vicinity of the Pierson Driveway
Map Unit Legend
King County Area, Washington
(WA633)
Map Unit Symbol
Map Unit Name
Acres in AOI
Percent of A01
AgB
Alderwood gravelly sandy loam, 0 to 6
percent slopes
30.6
100.0%
Totals for Area of Interest
30.6
100.0%
EJSDA Natural Resources Web Soil Survey 12/12/2012
Conservation Service National Cooperative Soil Survey Page 3 of 3