23-105817-Draiange Report-12-06-23Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Level – I Drainage Report
Prepared for
Ohashi 2 – Lot Preliminary Short Plat
Shellie Emiko Ohashi
1225 SW 296th Street
Federal Way, WA 98023
(206) 349 – 1592
emi@mdgllc.net
RESIDENTIAL COMMERCIAL GOVERNMENT
Bellevue, WA 98005 (425) 615 – 6160
info@pacificlandwa.com
Prepared By:
Mazen Haidar, PE, CESCL
Principal Engineer
Date Prepared:
June 15th, 2023
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Disclaimer,
This Drainage Report was prepared for the Ohashi 2 Lot Preliminary Short Plat. Pacific Land Engineering, Inc. (PLE), prepared
this report for the exclusive use of its staff and its authorized agent(s) only. Any use of and/or reliance on this report and any
of its contents, and/or any revisions to the project’s information / description, design plans, documentation, and/or the
herein described development’s proposal design concepts without the advanced and explicit written authorization from
Pacific Land Engineering, Inc., (PLE) is strictly forbidden.
***
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Table of Contents
1. Project Overview
•Existing Site Conditions and Hydrology.
•Vicinity Map.
•Site Photos.
•Developed Site Conditions and Hydrology.
2. Downstream Analysis
•Downstream Analysis Description.
•Quarter Mile Downstream Map and Photos.
3. Stormwater Compliance
•Impervious Surface Area Calculations.
•New Pollution Generating Impervious Surface (NPGIS) Area Calculations.
•Compliance with Federal Way 2021 Surface Water Addendum provisions.
•Compliance with 2021 KCSWDM Drainage Core Requirements.
4. Special Reports
•Geotechnical Report, by GEORESOURCES.
•Arborist Report, by CASCARA Tree Consulting.
5. Pre-Application Summary
•Pre-Application Conference Summary File # 21-104278-00PC
6. Engineer’s Conclusion
•Engineer’s Conclusion.
***
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Project Overview
•Existing Site Conditions and Hydrology,
The subject parcel is 30,000 square-feet = 0.69 acre of developed land that is King County parcel number
5153200015 located at 1225 SW 296th Street, in Marine View Estate Addition, Federal Way, WA 98023. The
subject parcel is bordered by developed residential parcels across its west, east, and south property lines, by SW
296th Street across its northerly property lines, see Exhibit – 1 for Vicinity Map.
The subject parcel is an urban residential lot zoned RS 15.0 and is currently occupied by existing single-family-
residence (SFR) in its northerly half, detached studio / storage building, and paved driveway all to remain (TR).
The subject parcel is currently accessed directly off SW 296th Street 24’ wide paved city roadway with
approximately 8’ gravel shoulders. A 20’ wide recorded access and utilities easement 9902223232 over and
across property address 29633 SW Marine View Drive, parcel number 5153200010 provide access to the southern
half of the subject parcel directly off SW Marine View Drive.
The subject site existing ground cover has been in existence since the build of the existing house in 1957 and
predominantly consist of SFR lawns, hedges, few scattered trees, and other landscape improvements in its
northerly half, while SFR lawns, pasture, hedges, and few scattered trees dominate the southerly half of the
subject parcel. See Arborist Report prepared by CASCARA Tree Consulting dated June 14th, 2023 in the Special
Reports Section, and see Exhibit – 2, 2A for existing site conditions, and Exhibit – 3 for site photos for more
information.
The site general topography is oriented southeast north and northeast and it ranges from 7% in its southerly half
to approximately 16% in its northerly half, and according to the city of Federal Way GIS map information the
subject site does not, nor it is adjacent to any steep slope critical areas. Similarly, the site does not appear to
contain, or it is adjacent to any wetland or other critical areas.
According to Geotechnical Report prepared by GEORESOURCES dated March 30th, 2023 (see Special Reports
Section) the site soils are underlain by Kitsap Silt Loam (KpC).
The subject parcel is currently served by existing Lakehaven water and sewer mains in SW 296th Street.
Additionally, there is an existing Lakehaven sewer main running along the south property line within existing
sewer easement record number 8505220736, there is also an existing sewer stub in the vicinity of the southwest
corner of the subject parcel, see Exhibit – 2, and Plan Sheet C – 2 of the attached Civil Plans for more information.
The are two existing fire hydrants around the subject parcel, the first hydrant is located in SW 296th Street
approximately 200’ west of the subject parcel, whereas the second hydrant located in Marine View Drive SW
almost 200’ east of the subject parcel.
Based on our field and site investigation we did not observe concentrated surface flows existing the subject site,
most of the site surfaces flows appear to infiltrate on-site before leaving the subject site in sheet flow format in
the north and northwesterly direction to enter and existing public storm water conveyance system in SW 296th
Street, see ¼ mile downstream analysis for more information.
***
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Ohashi Preliminary 2 Lot Short Plat
NTS 06 /15 / 2023
Exhibit – 1, Vicinity Map
Project Name:
Scale:Date:
N.T.S.
Puget so
u
n
d
Subject Site
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Ohashi Preliminary 2 Lot Short Plat
NTS 06 /15 / 2023
Exhibit – 2, Existing Site Conditions
Project Name:
Scale:Date:
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Ohashi Preliminary 2 Lot Short Plat
NTS 06 /15 / 2023
Exhibit – 2A, Site Aerial Photo
Project Name:
Scale:Date:
N.T.S.
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Ohashi Preliminary 2 Lot Short Plat
NTS 06 /15 / 2023
Exhibit – 3, Site Photos
Project Name:
Scale:Date:
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
•Developed Site Conditions and Hydrology,
The project proposal is to sub-divide the subject parcel into two residential lots consistent with the City of Federal
Way RS 15 zone. The total area of the subject parcel is 30,000 sf = 0.69 acres, the total area of proposed Lot (1) is
15,000 sf with building envelope approximately 10,624.19 sf, whereas proposed Lot (2) area is 15,000 sf with
building envelope approximately 11,699.15 sf, each lot will have 5’ rear and side yard setbacks, and 20’ front yard
setback consistent with RS 15 zone. Proposed 10’ drainage easement along the easterly parcel line will be
provided over and across proposed Lot (1) for the benefit of proposed Lot (2), see Exhibit – 5 for the site
developed conditions map.
Please note, this proposed 2 lot sub-division has already gone through Pre-Application process file number 21-
104278-00-PC, see attached copy of pre-application conference summary dated December 2nd, 2021 at the end of
this report for more information.
Proposed Lot (1) will contain the existing house and detached studio / storage building and will be accessed
directly off SW 296th Street via existing concrete and paved driveway. Existing Lakehaven water and sewer
connections in SW 296th Street will continue to serve the existing house.
Proposed Lot (2) will be accessed off SW Marine View Drive via existing / recorded access and utilities easement
number 9902223232. A new 1” water line will be installed within this easement to connect this proposed lot to
the existing Lakehaven water main in SW Marine View Drive. Whereas existing sewer stub located in the vicinity
of the southwest corner of the subject parcel will connect this proposed lot to existing Lakehaven sewer main
running along the south property line within existing sewer easement record number 8505220736, see Exhibit –
5, and Plan Sheet C – 6 in the attached Civil Plans for more information. Also, see attached Water and Sewer
Availability Certificate for more information.
Proposed Lot (2) will be connected to existing dry utilities such as power, gas, telephone, and cable consistent
with each respective utility connection requirements.
The two existing fire hydrants around the subject parcel as explained above will provide adequate fire protection
measures in fire situations, and therefore, no additional fire hydrant installation will be provided by this proposed
2 lot Short Plat.
Pursuant to FWRC 19.135, DWG No. 3-2CC the existing paved driveway within existing access and utilities
easement located southwest of the subject parcel will be widened to a total of 16’ as stated in Pre-Application
conference summary. Whereas a deviation application will be submitted to the City Engineer to waive required
frontage road improvement in SW 296th Street consistent with FWRC 19.135, Type “T” for Local Streets, see
attached.
The project owner will pay fee in-lieu as assessed by the City of Federal Way to comply with Open Space
requirements.
School Access Analysis requirement consistent with FWRC 18.55.070 has been waived by Jen Thomas of Federal
Way School District, see attached email for more information.
Developed site conditions will be retain existing trees consistent with FWRC 19.120.130 and will add 7 more trees
as recommended by the project Arborist, see attached Arborist report and Plan Sheet C – 5 in the attached Civil
Plans set for more information.
Stormwater compliance will be consistent with 2021 King County Surface Water Design Manual (KCSWDM), and
the City of Federal Way Addendum, see the following pages for more information.
****
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Ohashi Preliminary 2 Lot Short Plat
NTS 06 /15 / 2023
Exhibit – 5, Developed Site Conditions
Project Name:
Scale:Date:
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Downstream Analysis
Level – 1 downstream was conducted on February 4th, 2023 at 11:00 am, at the time the weather condition was
dry, overcast, approximately 45 degree following prior rainy days.
Referencing attached Exhibit – 6 for downstream ¼ mile drainage course and Exhibits – 6A and 6B for
downstream ¼ mile drainage course photos the subject site surface runoff appears to sheet flow in to an existing
catch basin located in the vicinity of the northwest corner of the existing driveway connection with SW 2196th
Street at Point – 1, entering the existing public stormwater conveyance system surface flows travel westerly
approximately 100’ before arriving at an existing catch basin at Point – 2, continuing westerly in said public
conveyance system surface flow travels additional 65’ before entering another existing catch basin across the
frontage of parcel address 1245 SW 296th Street at Point – 3, turning north and crossing under SW 296th Street
surface flows travel approximately 40’ before arriving at an existing catch basin on the north side of SW 296th
Street near the entrance of Marine View Demarwood Tract at Point – 4. Thereafter, surface flows continue
northerly in said existing public stormwater conveyance system for additional 260’ within Marine View
Demarwood Tract before arriving at another catch basin at Point – 5, also continuing northerly in said public
storm water conveyance system surface flows travel approximately 70’ before discharging into an existing rock
bed stream channel at Point – 6. Thereafter, surface flows continue north and northwesterly in said rock bed
stream channel approximately 175’ before discharging on the sandy shores of Puget Sound at Point – 7, forming a
narrow, shallow, and concentrated water course on the sandy shores of Puget Sound at Point – 8 surface flows
travel additional 100’ in the northwesterly direction before joining the waters of Puget Sound which is Major
Water Receiving body located approximately 710’ downstream of the subject project site where we terminated
the downstream analysis. During our field and downstream drainage course investigation we did not observe
sings of flooding, erosion, or scouring problems, and the existing stormwater conveyance system as well as
existing bed rod stream channel appear to function properly with sufficient conveyance capacity.
***
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Ohashi Preliminary 2 Lot Short Plat
NTS 06 /15 / 2023
Exhibit – 6, ¼ Downstream Drainage Course
Project Name:
Scale:Date:
N.T.S.
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Ohashi Preliminary 2 Lot Short Plat
NTS 06 /15 / 2023
Exhibit – 6A, ¼ Downstream Drainage Course Photos
Project Name:
Scale:Date:
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Ohashi Preliminary 2 Lot Short Plat
NTS 06 /15 / 2023
Exhibit – 6B, ¼ Downstream Drainage Course Photos
Project Name:
Scale:Date:
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Stormwater Compliance
We begin with area calculations for the existing and developed site conditions based on actual topographic survey for the
subject parcel, see Plan Sheet C – 2 and C – 3 in the attached Civil Plans set.
Impervious and Pervious Area Calculations,
Existing Site Conditions,
Total parcel area is 30,000 s.f. = 0.69 Acre.
Total existing impervious surfaces = 5,605.0 s.f.
Percentage of existing impervious surfaces 5,605 / 30,000 = 18.7 % < 35%
Total existing pervious surfaces = 24,395.0 s.f.
Percentage of existing pervious surfaces = 81.3 %
Developed Site Conditions,
•On – Site
New house roof area = 3,912.0 s.f.
New driveway area = 420.0 s.f.
New deck area = 145.0 s.f.
New concrete walkway area = 65.0 s.f.
Total On-Site New Impervious surface area = 4,542.0 s.f.
•Off – Site
To widen existing paved roadway to 16’ within existing recorded access and utility easement as required by DWG
No. 3 – 2CC a total of 400 s.f. of new paved surface will be added
Total New Impervious Surfaces to be created by the entire project is 4,942.0 s.f. < 5,000 s.f. OK.
Based on the above information and pursuant to Federal Way Surface Water Addendum dated December 12, 2021,
Figure 1.1.1.B (see next page) since the project is a proposed 2 lots subdivision with existing impervious coverage that is
less than 35%, the proposed project does not meet the definition of Redevelopment Project as defined in the 2021
KCSWDM.
Similarly, pursuant to Redevelopment foot-note-1 on page 6 in the City of Federal Way Surface Water Addendum dated
December 12, 2021 since the project is a proposed 2 lots residential subdivision with existing impervious coverage that
is less than 35%, the proposed project does not meet the definition of Redevelopment Project.
However, since the proposed project will create more than 2,000 square feet of new impervious surface, the project
meets thresholds 1 – 5 in Section 1.1.1.B in said Surface Water Addendum and requires drainage review.
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
New Pollution Generating Impervious Surface (NPGIS) Area Calculations,
Existing driveway area to existing house (on-site + off-site) installed prior to 2001 = 684.50 s.f.
Proposed new driveway to proposed new Lot (2) = 420.0 s.f.
Proposed new pavement widening to 16’ (including repaving after new 1” water line installation) = 400.0 s.f.
Total PGIS (existing + new) = 1,504.50 s.f. < 5,000 s.f. OK
Pursuant to Redevelopment foot-note-1 on page 6 in the City of Federal Way Surface Water Addendum dated
December 12, 2021 since the project is a proposed 2 lots residential subdivision with existing impervious coverage
that is less than 35%, the proposed project does not meet the definition of Redevelopment Project, and therefore,
the proposed 2 Lot residential short plat is not considered redevelopment project and is not subject to compliance
with 2021 Federal Way Surface Addendum, Section 1.2.8 -1a, b, and c.
Since the proposed 2 lot residential short plat will result in total of 1,504.50 sf of new plus replaced PGIS (on-site +
off-site / existing + new) which is less than 5,000 s.f., and since the proposed 2 lot residential short plat will result in
total pollution generating pervious grass / lawn surfaces of 10,458.0 s.f. which is less than ¾ acre of new PGPS,
then pursuant to the 2021 KCSWDM the proposed 2 lot residential short plat meet the Surface Area Exemption
criteria from Core Requirement number 8, see excerpt below, and therefore, the proposed 2 Lot residential short
plat is exempt from water quality compliance per Section 1.2.8 -2 of the 2021 Federal Way Surface Water
Addendum and none will be provided.
***
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Compliance with Federal Way 2021 Surface Water Addendum provisions,
Pursuant to Chapter 1 of said addendum the following summarizes compliance with drainage review requirements
for regulated activities consistent with FWRC 16.15.010.
Step – 1,
Per FWRC 16.15.020, 1, 2, and 3, the proposed 2 lot residential short plat subject to drainage review since it will
create more than 2,000 sf of new + replaced impervious surfaces, will result in more than 7,000 sf of land
disturbance activities.
Step – 2,
The proposed 2 lot residential short plat is exempt from compliance with water quality requirements as explained
in detail above.
Step – 3,
The proposed 2 lot residential short plat meet the definition of New Development and will provide surface BMP /
LID devices such on-site Dry-Well Infiltration BMP with emergency overflow system to mitigate for the new house
room and new driveway. See Plan Sheet C – 5.0 in the attached Civil Plans set for more information.
The proposed 2 lot residential short plat will employ standard temporary erosion and sedimentation control (TESC)
devices to mitigate for construction activities during the construction of the future new house with associated
driveway and utilities, such Fabric Silt Fence, marking limits of site disturbance, and temporary construction
entrance. See Plan Sheet C – 4.0 in the attached Civil Plans set for more information.
The proposed 2 lot residential short plat does not meet the definition of Redevelopment stated in Foot-Note-1 on
page 6 of the referenced 2021 Surface Water Addendum is exempt from compliance with water quality
requirements as explained in detail above.
Step – 4,
Per section 1.1.1.B and Figure 1.1.1.B The proposed 2 lot residential short plat requires drainage review since it will
create more than 2,000 sf of new impervious surfaces and will result in more than 7,000 s.f. of land disturbing
activities.
It is important to mention that based on the above ¼ mile downstream analysis the subject project site will
discharge storm water in Puget Sound Water a Major Receiving Water Body approximately 710’ downstream of the
project site and therefore, the proposed project is qualified for Direct Discharge Exemption pursuant to 2021
KCSWDM, Section 1.2.3 on page 1-41.
***
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Compliance with 2021 KCSWDM Drainage Core Requirements.
Referencing impervious area calculations included in this drainage report, the proposed 2 Lot residential short plat will
create more than 2,000 sf of new impervious surfaces but less than 5,000 sf, and result in more than 7,000 sf of land
disturbing activities but less than ¾ acre, and therefore the subject project site qualified for Simplified Drainage Review
(SDR) and subject to compliance with the following drainage Core requirements.
Core Requirement # 1, Discharge at Natural Discharge Location,
The subject proposed project site will maintain discharge of storm water at the natural discharge location as shown in the
attached Civil Plan set.
Core Requirement # 2, Off Site Analysis,
Please refer to the ¼ Mile Downstream Analysis included in this report for more information.
Core Requirement # 3, Flow Control,
The proposed project will create less than 5,000 s.f. of new /replaced impervious surfaces and there for is exempt
from compliance with flow control requirements per Section 1.2.3 on page 1-38, and based on the above ¼ mile
downstream analysis the subject project site will discharge storm water in Puget Sound Water a Major Receiving
Water Body approximately 710’ downstream of the project site and therefore, the proposed project is qualified for
Direct Discharge Exemption pursuant to 2021 KCSWDM, Section 1.2.3 on page 1-41.
The developed site conditions will utilize LID / BMP measures such on-site Dry-Well infiltration BMP with
emergency overflow system to mitigate for the new future house and associated driveway. The emergence
overflow system will discharge over rock pad dispersion BMP within proposed Lot – 1 within new 10’ drainage
easement to promote sheet flow discharge toward the existing public storm water system in SW 296 Street, see
Plan Sheet C – 5, in the attached Civil Plans set for additional information.
Core Requirement # 4, Conveyance System,
The proposed 2 Lot short plat will not add any storm water conveyance system, the developed site conditions will
utilize LID / BMP measures such on-site Dry-Well infiltration BMP with emergency overflow system to mitigate for
the new future house and associated driveway.
The developed site conditions will utilize LID / BMP measures such on-site Dry-Well infiltration BMP with
emergency overflow system to mitigate for the new future house and associated driveway. The emergence
overflow system will discharge over rock pad dispersion BMP within proposed Lot – 1 within new 10’ drainage
easement to promote sheet flow discharge toward the existing public storm water system in SW 296 Street, see
Plan Sheet C – 5, in the attached Civil Plans set for additional information.
Core Requirement # 5, Erosion and Sediment Control,
Standard TESC measures will be installed during construction progress consistent with the 2021 KCSWDM,
Appendix D, see Plan Sheet C – 4, in the attached Civil Plans set for additional information.
Core Requirement # 6, Maintenance and Operation,
The proposed Dry-Well BMP will be maintained by the future homeowner consistent with 2021 KCSWDM.
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Core Requirement # 7, Financial Guarantees & Liabilities,
The project owner will provide the necessary bond and financial guarantees as mandated by the City of Federal Way.
Core Requirement # 8, Water Quality,
Since the proposed 2 lot residential short plat will result in total of 1,504.50 sf of new plus replaced PGIS (on-site +
off-site / existing + new) which is less than 5,000 s.f., and since the proposed 2 lot residential short plat will result in
total pollution generating pervious grass / lawn surfaces of 10,458.0 s.f. which is less than ¾ acre of new PGPS,
then pursuant to the 2021 KCSWDM the proposed 2 lot residential short plat meet the Surface Area Exemption
criteria from Core Requirement number 8, see excerpt below, and therefore, the proposed 2 Lot residential short
plat is exempt from water quality compliance per Section 1.2.8 -2 of the 2021 Federal Way Surface Water
Addendum and none will be provided.
Core Requirement # 9, Flow Control BMP,
The developed site conditions will utilize LID / BMP measures such on-site Dry-Well infiltration BMP with
emergency overflow system to mitigate for the new future house and associated driveway. The emergence
overflow system will discharge over rock pad dispersion BMP within proposed Lot – 1 within new 10’ drainage
easement to promote sheet flow discharge toward the existing public storm water system in SW 296 Street, see
Plan Sheet C – 5, in the attached Civil Plans set for additional information.
Special Requirement # 1, Other Adopted Requirements
The proposed 2 Lot residential short plat is subject to compliance with 2021 Federal Way Storm Water Addendum,
see Compliance with Federal Way 2021 Surface Water Addendum provisions section in this report for more
information.
Special Requirement # 2, Flood Hazard, and Delineation,
The proposed 2 Lot residential short plat is not located within or adjacent to any flood plain and therefore is exempt
from this core requirement.
Special Requirement # 3, Flood Protection Facilities,
The proposed 2 Lot residential short plat is not located within or adjacent to any flood plain and therefore is exempt
from this core requirement.
Special Requirement # 4, Source Control,
The proposed 2 Lot residential short plat is not source control improvement and therefore is exempt from this core
requirement.
Special Requirement $ 5, Oil Control,
Oil pollution is not anticipated during the construction of the future new house and associated driveway, and
therefore the proposed 2 Lot residential short plat is exempt from this core requirement.
***
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Special Reports
See attached Geotechnical Report and Arborist Report prepared for this proposed 2 Lot Residential Short Plat.
***
March 30, 2023
Emiko Ohashi
1225 SW 296th Street
Federal Way, Washington 98023
seohashi@gmail.com
Soils Report
Proposed Short Plat
1225 SW 296th Street
Federal Way, Washington
PN: 5153200015
Doc ID: Ohashi.SW296thStreet.SR
INTRODUCTION
This Soils Report presents the results of our subsurface explorations, laboratory testing, and
geotechnical analyses for evaluating the feasibility of on-site stormwater infiltration of runoff
generated by the new impervious surfaces for a single-family residence. The project site is located at
1225 Southwest 296th Street in Federal Way, Washington. The approximate site location is shown on
the attached Site Location Map, Figure 1.
Our understanding of the project is based on our discussions with you, our review of the
available geologic and soils literature for the site and City of Federal Way; our subsurface explorations
completed on February 28, 2023; our understanding of the City of Federal Way Municipal Code and
the adopted 2021 King County Surface Water Design Manual (2021 KCSWDM); and our experience in the
City of Federal Way (the City). We understand that the parcel is developed as a single-family residence
and that you wish to subdivide the existing parcel into two parcels and to construct a new single-family
residence on the newly created (south) parcel, along with associated utilities. Access to the south
portion of the site is gained from an unnamed alley way off of Marine View Drive SW.
PURPOSE & SCOPE
The purpose of our services was to evaluate the surface and subsurface conditions across the
site as a basis for providing stormwater management recommendations for the proposed short plat.
Specifically, the scope of services for this project included the following:
1. Reviewing the available geologic, hydrogeologic, and geotechnical dat a for the site area;
2. Exploring surface and subsurface conditions by reconnoitering the site and excavating 3 test
pits at select locations across the site;
3. Performing laboratory testing on samples collected from the exploration, including up to two
grain size analyses;
4. Submitting one sample to a third party laboratory for cation exchange capacity (CEC) and
organic testing;
5. Describing surface and subsurface conditions, including soil type and depth to groundwater,
if encountered;
Ohashi.SW296thStreet.SR
March 30, 2023
page | 2
6. Providing our opinion about the feasibility of onsite infiltration of stormwater generated by
the new impervious surfaces in accordance with the 2016 KCSWDM with Federal Way
Amendments, including a preliminary design infiltration rate , as appropriate; and,
7. Preparing a written Soils Report, summarizing our site observations and conclusions, along
with the supporting data.
The above scope of work was summarized in our Proposal for Geotechnical Engineering Services
dated February 8, 2023. We received written authorization to proceed on February 13, 2023.
SITE CONDITIONS
Surface Conditions
As stated, the site is located at 1225 SW 296th Street in Federal Way, Washington. The site is
located in an area of existing residential development. Based on the King County iMap website, the
project site is rectangular in shape, measures approximately 100 feet wide (east to west) by
approximately 300 feet long (north to south) and encompasses approximately 0.69 acres. The site is
bounded by existing residential development to the west, south, and east, and by SW 296th Street to the
north.
According to topographic information obtained from King County iMap, the ground surface
generally slopes up to the south from SW 296th Street. From SW 296th Street, the ground surface slopes
up to the south at approximately 25 to 35 percent before leveling out in the area of the existing
residence. South of the existing residence, the ground surface slopes up steeply to the south at
approximately 35 to 45 percent over a topographic relief of approximately 10 feet. In the southern
portion of the site, the ground surface slopes up to the south at approximately 15 to 20 percent. The
total topographic relief of the site is on the order of 35 feet. The existing site conditions and topography
are shown on the Site & Exploration Map, Figure 2.
Vegetation in the northern portion of the site, in the area of the existing residence, generally
consists of maintained grass lawn and typical residential landscaping. In the southern portion of the
site, vegetation generally consists of scattered fir trees and low lying shrubs with open, unmaintained
grass areas. No seeps, springs, or standing water was observed during our site reconnaissance. No signs
of erosion or slope instability was observed during our site reconnaissance.
Site Soils
The USDA Natural Resource Conservation Survey (NRCS) Web Soil Survey maps the site as being
underlain by Kitsap Silt Loam (KpC). An excerpt of the NRCS Web Soil Survey mapping for King County
that covers the project site and general vicinity is attached as Figure 3.
• Kitsap Silt Loam (KpC): The Kitsap soils are mapped as underlying the entire site. These soils are
derived from lacustrine deposits with a minor amount of volcanic ash, form on slopes of 8 to
15 percent, are considered to have a “moderate” erosion hazard when exposed, and are
included in hydrologic soils group C.
Site Geology
The Geologic Map of the Tacoma 1:100,000-scale Quadrangle, Washington by Schuster et al.
(2015) maps the site as being underlain by Pre-Vashon continental glacial drift and nonglacial deposits
Ohashi.SW296thStreet.SR
March 30, 2023
page | 3
(Qgpc). No landslide deposits are mapped at or within 300 feet of the project site by the above
referenced geologic map. An excerpt of the referenced geologic map for the site and surrounding
area is attached as Figure 4.
• Pre-Fraser continental glacial drift and nonglacial deposits (Qgpc): The older and stratigraphically
lower pre-Fraser deposits were deposited before the Fraser glaciation. These soils generally
consist of interbedded sand, gravel and silt of indeterminate age and or igin. The pre-Fraser
deposits were overridden by the prehistoric ice mass and should be considered over -
consolidated, and offer high strength and low compressibility characteristics, where
undisturbed. The infiltration potential of these soils is typically limited due to their silty and
overconsolidated nature.
Subsurface Explorations
On February 28, 2023, we visited the site and monitored the excavation of three test pits to
depths of approximately 7½ to 8½ feet below the existing ground surface. The test pits were
excavated using a mini track-mounted excavator operated by a licensed earthwork contractor working
for GeoResources. Our field representatives logged the subsurface conditions encountered in each
test pit and obtained representative soil samples. Table 1, below, summarizes the approximate
location, elevations, and termination depth of our explorations.
TABLE 1:
APPROXIMATE LOCATIONS, ELEVATIONS, AND DEPTHS OF EXPLORATIONS
Exploration
Number Functional Location1
Surface
Elevation
(feet)
Termination
Depth
(feet)
Termination
Elevation1
(feet)
TP-1
TP-2
TP-3
West-central portion of site
East-central portion of site
Southeast portion of site
182
184
188
8
7½
8½
174
176½
179½
Notes:
1 = Approximate elevations based on interpolating between King County 5-foot elevation contours by the King County GIS Center
The subsurface explorations excavated as part of this evaluation indicate the 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 specific number, locations, and depths of our explorations were selected based on the
configuration of the proposed short plat 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 our explorations were placed in sealed plastic bags and
then taken to our laboratory for further examination and testing as deemed necessary. Soil densities
presented on the logs are based on the difficulty of excavation and our experience. The test pits were
then backfilled with the excavated soils and bucket tamped, but not otherwise comp acted.
The approximate locations of our explorations are labeled on the attached Site & Exploration
Plan, Figure 2. The indicated locations were determined by taping or pacing from existing site features
Ohashi.SW296thStreet.SR
March 30, 2023
page | 4
and reference points; as such, the locations should only be considered as accurate as implied by the
measurement method. 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 pit explorations are included as Figures A -2 and A-3.
Subsurface Conditions
Soil conditions at the test pit locations consisted of uniform subsurface conditions that, in our
opinion, confirmed the mapped stratigraphy. Table 2, below, summarizes the approximate
thicknesses, depths, and elevations of selected soil layers. Logs of explorations are available in
Appendix A.
• Topsoil: At the locations explored, we encountered approximately ½ to 1 foot of
topsoil/rootzone.
• Weathered Pre-Vashon Glacial Drift: Underlying the topsoil in all explorations we encountered
approximately 1¼ to 2 feet of brown sandy silt with trace gravel in stiff, moist to wet condition.
We interpret these soils to be Weathered Pre -Vashon Glacial Drift.
• Pre-Vashon Glacial Drift: Underlying the weathered Pre-Vashon Glacial Drift, we encountered
grey sandy silt with some gravel in a hard, moist condition. We interpret these soils to be Pre-
Vashon Glacial Drift. These soils were encountered to the full depth explored in all test pits.
TABLE 2:
APPROXIMATE THICKNESS, DEPTHS, AND ELEVATION OF SOIL TYPES ENCOUNTERED IN BORINGS
Exploration
Number
Thickness of
Topsoil
(feet)
Thickness of
Weathered Pre-
Vashon Glacial Drift
(feet)
Depth to Pre-
Vashon Glacial
Drift
(feet)
Elevation of Pre-
Vashon Glacial
Drift
(feet)
TP-1
TP-2
TP-3
1
¾
½
2
1¼
1¾
3
2
2¼
179
182
185¾
Notes:
1 = Surface elevations estimated by interpolating between contours obtained from King County iMap
Laboratory Testing
Geotechnical laboratory tests were performed on select samples retrieved from the borings
to estimate the index engineering properties of the soils encountered. Laboratory testing included
visual soil classification per ASTM D2487 and ASTM D2488, moisture content determinations per ASTM
D2216, and grain size analyses per ASTM D6913 standard procedures. The results of the laboratory
tests are summarized in Table 3 below and included in Appendix B.
LID systems for water quality require Cation Exchange Capacity (CEC) of at least 5 mEq/100g and
a minimum organic content of 1 percent in order for the native soils to be used as a treatment layer
beneath water quality facilities, such as permeable pavement. We submitted one representative sample
to a third party laboratory for CEC and organic content testing. These resulted in 8.7 mEq/100g and 6.3%
organic content, exceeding the minimum threshold values.
Ohashi.SW296thStreet.SR
March 30, 2023
page | 5
TABLE 3:
LABORATORY TEST RESULTS FOR ON-SITE SOILS
Soil Type Sample
Gravel
Content
(percent)
Sand
Content
(percent)
Silt/Clay
Content
(percent)
D10 Ratio
(mm)
Moisture
(percent)
ML TP-1, S-1 8.8 30.1 61.1 <0.075 18.7
ML TP-3, S-1 2.9 32.4 64.7 <0.075 37
Groundwater Conditions
Slow groundwater seepage was observed in test pits TP-1 and TP-3 at approximately 3 feet
below existing ground surface. Additionally, iron-oxide staining that may be indicative of seasonal high
levels of a perched groundwater table was observed in all explorations from depths of approximately
1½ to 2¾ feet below existing ground surface. We interpret this to be indicative of perched groundwater.
Perched groundwater typically develops when the vertical infiltration of precipitation through a more
permeable soil is slowed at depth by a deeper, less permeable soil type. We anticipate fluctuations in
the local groundwater levels will occur in response to precipitation patterns, off-site construction
activities, and site utilization. As such, water level observations made at the time of our field
investigation may vary from those encountered during the construction phase.
CONCLUSIONS AND RECOMMENDATIONS
The City of Federal Way Municipal Code Chapter 16.20.010 adopted the most recent version
of the 2021 King County Surface Water Design Manual (KCSWDM) for stormwater design with Federal
Way amendments. For this scope of work, we referenced the 2021 KCSWDM for determining the
feasibility of the site soils to support stormwater infiltration systems and BMPs for use in management
of stormwater. Based on our explorations, observations, and laboratory testing, the infiltration of
stormwater may be feasible, provided separation requirements can be met.
Infiltration Feasibility
Based on our grain size analyses in accordance with ASTM D6913 and field observations
during the excavation of test pits, the primary soils observed at the site were a sandy silt with some
gravel consistent with Pre-Vashon Glacial Drift. Mottling was observed from 1½ to 2¾ feet below
existing ground surface in all explorations. Additionally, slow groundwater seepage was observed at
approximately 3 feet below existing ground surface in test pits TP-1 and TP-3.
Low Impact Development (LID) BMPs such as bioretention and/or permeable pave ment may
be considered for this project in help with managing stormwater, provided the proposed bottom of
facility elevations are within the weathered pre-Vashon Drift soils observed in our test pit explorations.
Ohashi.SW296thStreet.SR
March 30, 2023
page | 6
Preliminary Design Infiltration Rate for Infiltration Systems & LID BMPs
We completed a soil gradation analysis of a representative sample of the weathered sandy silt
soils at test pits TP-1 and TP-3 in accordance with ASTM D6913. For a preliminary design infiltration
rate, we used the Soil Grain Size Method derived from the Massmann equati on to determine the
preliminary measured rate of the weathered pre-Vashon soils encountered at the site. We applied
correction factors to the measured infiltration rate in general accordance with the correction factors
presented in the 2021 KCSWDM. The correction factors applied were for test method (0.4 for the Soil
Grain Size Method), facility geometry (0.25) and plugging (0.7). After applying the appropriate
correction factors to the preliminary measured rate, we recommend a preliminary design infiltration
rate of 0.15 inches per hour be used for infiltration systems and BMPs founded in the weathered Pre-
Vashon soils encountered at test pit TP-1 and TP-3. In-situ infiltration testing in accordance with the
2021 KCSWDM should be completed once a final location and bottom elevation is determined for any
infiltration system.
Construction Considerations
Appropriate design, construction and maintenance measures will be required to ensure the
infiltration rate can be effectively maintained over time. Stormwater Best Management Practices (BMPs)
in accordance with the 2021 KCSWDM should be included in the project plans and specifications to
minimize the potential for fines contamination of Low Impact Development BMPs or infiltration systems
utilized at the site. If an overflow is incorporated into the final design of an infiltration system, we
recommend the overflow be connected to an existing stormwater system or directed to another
discharge point away from any existing or proposed structures.
Suspended solids could clog the underlying soil and reduce the infiltration rate of the facilities.
Additional measures may also be taken during construction to minimize the potential of fines
contamination of the proposed infiltration system, such as utilizing an alternative storm water
management location during construction or leaving the bottom of the permanent systems 1 to 2 feet
high, and subsequently excavating to the finished grade once the site soils have been stabilized. All
contractors working on the site (builders and subcontractors) should divert sediment laden stormwater
away from proposed infiltration facilities during construction and landscaping activities. No concrete
trucks should be washed or cleaned, and washout areas should not be within the vicinity of the
proposed infiltration facilities.
LIMITATIONS
We have prepared this report for use by Emiko Ohashi and other members of the design team
for use in the design of a portion of this project. The data used in preparing this report and this report
should be provided to prospective contractors for their bidding or estimating purposes only. Our report,
conclusions and interpretations are based on our subsurface explorations, data from others and limited
site reconnaissance, and should not be construed as a warranty of the 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
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
Ohashi.SW296thStreet.SR
March 30, 2023
page | 7
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 remediation and
construction safety precautions. Our recommendations are not intended to direct the contractor's
methods, techniques, sequences or procedures, except as specifically described in our report for
consideration in design.
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.
◆ ◆ ◆
Ohashi.SW296thStreet.SR
March 30, 2023
page | 8
We have appreciated the opportunity to be of service to you on this project. If you have any
questions or comments, please do not hesitate to call at your earliest convenience.
Respectfully submitted,
GeoResources, LLC
Davis W. Carlsen, GIT
Senior Staff Geologist
Eric W. Heller, PE, LG Seth T. Mattos, LEG
Senior Geotechnical Engineer Associate
DC:EWH:STM/dc
DocID: Ohashi.SW296thStreet.SR
Attachments: Figure 1: Site Location Map
Figure 2: Site Vicinity Map
Figure 3: NRCS Soils Map
Figure 4: Geologic Map
Appendix A – Subsurface Explorations
Appendix B – Laboratory Results
Approximate Site Location
(Map created from King County iMap (https://gismaps.kingcounty.gov/iMap/)
Not to Scale
Site Location Map
Proposed Short Plat
1225 – SW 296th Street
Federal Way, Washington
PN: 5153200015
DocID: Ohashi.SW296thStreet.F March 2023 Figure 1
Approximate Site Location
(Map created from King County iMap (https://gismaps.kingcounty.gov/iMap/)
Approximate location and number of test pit exploration (GeoResources 2023)
Not to Scale
Site & Exploration Map
Proposed Short Plat
1225 – SW 296th Street
Federal Way, Washington
PN: 5153200015
DocID: Ohashi.SW296thStreet.F March 2023 Figure 2
TP-3
TP-2
TP-1
Approximate Site Location
Map created from Web Soil Survey (http://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx)
Soil Type Soil Name Parent Material Slopes Erosion Hazard Hydrologic
Soils Group
AgB Alderwood gravelly
sandy loam
Glacial drift and/or glacial
outwash over dense
glaciomarine deposits
0 to 8
Slight B AgD 15 to 30
KpC Kitsap silt loam
Lacustrine deposits with a
minor amount of volcanic
ash
8 to 15 Moderate C
Not to Scale
NRCS Soils Map
Proposed Short Plat
1225 – SW 296th Street
Federal Way, Washington
PN: 5153200015
DocID: Ohashi.SW296thStreet.F March 2023 Figure 3
Approximate Site Location
An excerpt from the Geologic Map of the Tacoma 1:100,000-scale quadrangle, Washington by Schuster, J.E., Cabibbo, A.A.,
Schilter, J.F, and Hubert, I.J. (2015)
Symbol Geologic Unit
Qga Advance outwash
Qgpc Pre-Vashon continental glacial
drift and nonglacial deposits
Not to Scale
Geologic Map
Proposed Short Plat
1225 – SW 296th Street
Federal Way, Washington
PN: 5153200015
DocID: Ohashi.SW296thStreet.F March 2023 Figure 4
Appendix A
Subsurface Explorations
SOIL CLASSIFICATION SYSTEM
MAJOR DIVISIONS
GROUP
SYMBOL
GROUP NAME
COARSE
GRAINED
SOILS
More than 50%
Retained on
No. 200 Sieve
GRAVEL
More than 50%
Of Coarse Fraction
Retained on
No. 4 Sieve
CLEAN
GRAVEL
GW
WELL-GRADED GRAVEL, FINE TO COARSE GRAVEL
GP
POORLY-GRADED GRAVEL
GRAVEL
WITH FINES
GM
SILTY GRAVEL
GC
CLAYEY GRAVEL
SAND
More than 50%
Of Coarse Fraction
Passes
No. 4 Sieve
CLEAN SAND
SW
WELL-GRADED SAND, FINE TO COARSE SAND
SP
POORLY-GRADED SAND
SAND
WITH FINES
SM
SILTY SAND
SC
CLAYEY SAND
FINE
GRAINED
SOILS
More than 50%
Passes
No. 200 Sieve
SILT AND CLAY
Liquid Limit
Less than 50
INORGANIC
ML
SILT
CL
CLAY
ORGANIC
OL
ORGANIC SILT, ORGANIC CLAY
SILT AND CLAY
Liquid Limit
50 or more
INORGANIC
MH
SILT OF HIGH PLASTICITY, ELASTIC SILT
CH
CLAY OF HIGH PLASTICITY, FAT CLAY
ORGANIC
OH
ORGANIC CLAY, ORGANIC SILT
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.
Unified Soils Classification System
Proposed Short Plat
1225 – SW 296th Street
Federal Way, Washington
PN: 5153200015
Doc ID: Ohashi.SW296thStreet.F March 2023 Figure A-1
Test Pit TP-1
Location: West-central portion of site
Approximate Elevation: 182 feet
Depth (ft) Soil Type Soil Description
0 - 1 - Topsoil/rootzone
1 - 3 ML Brown sandy SILT with trace gravel (stiff, moist to wet) (Weathered Pre-Vashon Glacial
Drift)
3 - 8 ML Grey sandy SILT with some gravel (hard, moist) (Pre-Vashon Glacial Drift)
Terminated at 8 feet below ground surface (BGS).
Slow groundwater seepage observed at approximately 3 feet BGS.
No caving observed at time of excavation.
Mottling observed at approximately 2¾ feet BGS.
Test Pit TP-2
Location: East-central portion of site
Approximate Elevation: 184 feet
Depth (ft) Soil Type Soil Description
0 - ¾ - Topsoil/rootzone
¾ - 2 ML Brown sandy SILT with trace gravel (stiff, moist) (Weathered Pre-Vashon Glacial Drift)
2 - 7½ ML Grey sandy SILT with some gravel (hard, moist) (Pre-Vashon Glacial Drift)
Terminated at 7½ feet BGS.
No groundwater seepage observed at time of exploration.
No caving observed at time of excavation.
Mottling observed at approximately 1½ feet BGS.
Logged by: DC Excavated on: February 28, 2023
Test Pit Logs
Proposed Short Plat
1225 – SW 296th Street
Federal Way, Washington
PN: 5153200015
Doc ID: Ohashi.SW296thStreet.F March 2023 Figure A-2
Test Pit TP-3
Location: Southeast portion of site
Approximate Elevation: 188 feet
Depth (ft) Soil Type Soil Description
0 - ½ - Topsoil/rootzone
½ - 2¼ ML Brown sandy SILT with trace gravel (stiff, moist to wet) (Weathered Pre -Vashon Glacial
Drift)
2¼ - 8½ ML Grey sandy SILT with some gravel, occasional thin sand lenses (hard, moist to wet) (Pre-
Vashon Glacial Drift)
Terminated at 8 feet below ground surface (BGS).
Slow groundwater seepage observed at approximately 3 feet BGS.
No caving observed at time of excavation.
Mottling observed at approximately 2¾ feet BGS.
Logged by: DC Excavated on: February 28, 2023
Test Pit Logs
Proposed Short Plat
1225 – SW 296th Street
Federal Way, Washington
PN: 5153200015
Doc ID: Ohashi.SW296thStreet.F March 2023 Figure A-3
Appendix B
Laboratory Results
These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By:
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 6.8 2.0 1.8 6.0 22.3 61.16 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM D 6913 & ASTM D 1140)
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: TP-1, S-1
Sample Number: 103801 Depth: 3.5'
Client:
Project:
Project No:Figure
Sandy SILT with some gravel (ML)
1.25
1
.75
.5
0.375
#4
#10
#20
#40
#60
#100
#200
100.0
93.2
93.2
92.5
92.1
91.2
89.4
87.4
83.4
75.9
69.0
61.1
NP NV NP
ML A-4(0)
2.6445 0.5608
Natural Moisture: 18.7%
2/28/23 3/6/23
MAW
STM
PM
2/28/23
Emiko Ohashi
Proposed Short Plat
Ohashi.SW296thStreet
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
GeoResources, LLC
Fife, WA B-1
These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By:
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 0.0 2.9 2.8 12.5 17.1 64.76 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM D 6913 & ASTM D 1140)
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: TP-3, S-1
Sample Number: 103802 Depth: 1.25'
Client:
Project:
Project No:Figure
Sandy SILT with trace gravel (ML)
.5
0.375
#4
#10
#20
#40
#60
#100
#200
100.0
99.2
97.1
94.3
89.5
81.8
76.6
71.8
64.7
NP NV NP
ML A-4(0)
0.9233 0.5661
Natural Moisture: 37%
2/28/23 3/6/23
MAW
STM
PM
2/28/23
Emiko Ohashi
Proposed Short Plat
Ohashi.SW296thStreet
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
GeoResources, LLC
Fife, WA B-2
CASCARA TREE CONSULTING
ARBORIST REPORT
1 | Page
TO:
Shellie Emiko Ohashi
REFERENCE:
Tree Inventory & Arborist Report
SITE ADDRESS:
1225 SW 296th St, Federal Way, WA (Parcel #: 5153200015)
DATE:
6/14/2023
PREPARED BY: Katie Hogan, ISA Certified Arborist PN-8078A
ISA Tree Risk Assessment Qualified
Summary
This report documents the June 3, 2023 tree inventory and assessment at the above-addressed site. This
assessment was requested in preparation for the submittal of building permits to the City of Federal Way and to
meet the requirements of Federal Way Revised Code (FWRC) 19.120.130.
There are 11 trees that measured 6-inches Diameter at Breast Height (DBH) or larger or which will reach 20-feet
tall or greater at maturity on the subject property. There are 15 additional trees located adjacent to the site with
overhanging canopy.
The City requires that 25 tree credit units are retained per acre of site. For this 0.69-acre property, 18 tree units
must be retained or replanted.
The proposed short subdivision and new single-family home supports the retention of 9 of the 11 trees. One
additional tree is recommended for removal due to declining condition resulting in total retention of 13 tree unit
credits. Five additional tree unit credits are required for replanting to meet the tree retention standards in FWRC
19.120.130(2).
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
2 | Page
Observations & Discussion
Site Conditions
The subject site is a 0.69-acre property located in the City of Federal Way. The site currently has a single-family
residence and is planned for a short subdivision with a new home proposed in the southern lot.
The vegetation is mostly maintained ornamental trees and shrubs, with a few larger conifer trees in the
southern portion of the lot.
Trees
Eleven trees exist on the subject property, most of which are in fair condition. There are five native trees located
in the proposed southern lot; two of which are proposed for removal. One additional tree (#50503) is
recommended for removal due to being previously topped with a weak attachment at the old topping point.
This tree is not a good long-term tree and may pose future risk to the new residence.
Tree #s 50504 and 50506 are proposed for removal to accommodate the new residence and driveway.
Tree #s 50514 and 50532 are in the southeast corner of the lot and are proposed for retention. Both trees will
be approximately 7-feet away from the new home and driveway, however, they are located upslope on a
rockery and impacts should be minimal. See the recommendations section below for specifications for working
around these trees. Tree #50532 is enveloping the existing wire fencing and may be more suitable for removal is
desired.
There are 13 trees located off-site along the existing utility easement. The plans propose to utilize this easement
as the main access for the new residence which includes slightly widening the access easement and adding 400
additional square feet of pavement. No neighboring trees will be impacted by this proposed work.
Tree Retention
The proposed project is required to replant 5 additional tree unit credits to meet the requirements of FWRC
19.120.130(2). The City requires that replacement tree species be a mix of evergreen and deciduous trees and
be a minimum size of 6-feet in height for evergreen trees and two-inches caliper for deciduous trees.
Table 1. Tree Units
Summary Tree Unit Credit Table
Total Tree Units Required 18
Total Existing Tree Units 18.5
Total Tree Units Retained 13
Additional Tree Units Required 5
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
3 | Page
Tree Planting Recommendations
Five tree unit credits are required to replant on the subject property. See table below with recommendations
for tree species, quantity, and spacing of replacement trees.
Table 2. Recommended species
Species Size Spacing Mature
Canopy Size
Quantity Tree Unit
Credits
Chamaecyparis nootkatensis
‘Pendula’
(Weeping nootka cypress)
6 feet tall 12’ on
center
Small 2 0.5
Acer palmatum
(Japanese Maple)
2 inches
caliper
10’ on
center
Small 2 0.5
Cercis canadensis
(Eastern redbud)
2 inches
caliper
15’ on
center
Medium 1 1.0
Styrax japonicus
(Japanese Snowbell)
2 inches
caliper
15’ on
center
Medium 2 1.0
Total Tree Units 5.0
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
4 | Page
Recommendations/Specifications
Tree #s 50514, 50532 – Impacts from foundation and driveway construction.
• Use flat front buckets to avoid ripping/tearing of roots which can be worsened with toothed buckets.
• Roots 2-inches diameter or greater shall be cleanly cut using a sharp saw or other implement to avoid
fracturing or breaking roots.
• Tree protection fencing shall not be moved unless adequate soil protection is placed over top of
exposed soil. Acceptable soil protection methods include laying ¾ inch plywood over 6 inches of
woodchip mulch or utilizing alternative materials such as geotextile mats.
General Tree Protection Standards
• Landscaping. When installing final landscaping, minimize disturbances within the dripline of all existing
trees. Choose small container sizes where possible in areas beneath trees to reduce the size of the hole
that is required to install the plant(s). Avoid tilling or stripping the soil within the driplines of trees.
• Roots. If any roots 2-inches or greater in diameter are encountered, cleanly cut the root using a sharp
saw or other implement. Avoid ripping or tearing roots.
• Filter Fabric/Silt Fencing. If filter fencing is required within the dripline of protected trees, utilize
alternative methods for installation that does not require trenching such as weighing the fence down by
gravel or sand bags.
FWRC 19.120.160 Tree Protection Requirements
• No clearing shall be allowed on a proposed development site until the tree retention and landscape
plans have been approved by the city of Federal Way.
• A no disturbance area shall be established for each tree to be protected. The no disturbance zone shall
be equal to the critical root zone which is defined as 12 inches radius for every one inch of tree diameter
measured at four and one-half feet above ground. Any other no disturbance area proposed by the
applicant shall be determined by a qualified arborist and subject to review and approval by the director.
• The no disturbance zone shall be identified during the construction stage with:
(a) A temporary five-foot chain-link fence; and
(b) Tree protection signage attached to the fence which reads “TREE PROTECTION FENCE – No soil
disturbance, parking, storage, dumping, or burning of materials is allowed within the Tree Protection
Fence.”
• No soil disturbance, parking, storage, dumping, burning of materials, impervious surfaces, fill,
excavation, or storage of construction materials shall be permitted within the no disturbance area.
• If the grade level around the tree is to be raised by more than one foot, a rock well shall be constructed.
The inside diameter of the rock well shall be equal to the diameter of the tree trunk plus 10 feet. Proper
drainage, and irrigation if necessary, shall be provided in all rock wells.
• The grade level shall not be lowered within the larger of the drip line of the tree(s) or the critical root
zone of the tree(s).
• No trenching is allowed in any critical tree root zone areas.
• No installation of any impervious surfaces is allowed in critical root zones. Where road or sidewalk
surfaces are needed within critical root zones, unmortared porous pavers or flagstone (rather than
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
5 | Page
concrete or asphalt) may be used. Boardwalks or bridging may span root zones without harming the tree
roots.
• Tree protection areas (i.e., critical root zone) must be prepared to better withstand the stresses of the
construction phase by, if necessary, fertilizing, pruning, and mulching around them well in advance of
beginning any construction activities.
• Alternative protection methods may be used if accepted by the director to provide equal or greater tree
protection.
• Encroachment into the no disturbance area may be allowed where the director determines
encroachment would not be detrimental to the health of the tree.
Attachments
1) Photographs
2) Glossary
3) References
4) Inspection Methods
5) Appendix A – Assumptions & Limiting Conditions
6) Appendix B – Certification of Performance
7) Site Map/Plans
8) Tree Table
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
6 | Page
PHOTOGRAPHS
Photo 1. Looking north toward proposed new lot.
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
7 | Page
Photo 2. Tree #s 50503 (left) and 50504 (right). Tree 50503 is recommended for removal.
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
8 | Page
Photo 3. Looking west toward location of proposed driveway with tree #s 50514 and 50532 to left.
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
9 | Page
Photo 4. Looking west down existing utility easement.
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
10 | Page
GLOSSARY
ANSI A300: American National Standards Institute (ANSI) standards for tree care
Chlorotic: discoloration caused by lack of chlorophyll in the foliage
Codominant Stems: two or more stems (or leaders) of relatively similar size that emerge from the same location
on the main trunk (Gilman, 2002)
Conifer: a tree that bears cones and has evergreen needles or scales
Crown: the above ground portion of the tree comprised of branches and their foliage
Crown raise pruning: a pruning technique where the lower branches are removed, thus raising the overall
height of the crown from the ground
DBH or DSH: diameter at breast or standard height; the diameter of the trunk measured 54 inches (4.5 feet)
above grade
Deciduous: tree or other plant that loses its leaves annually and remains leafless generally during the cold
season
Epicormic: arising from latent or adventitious buds
Evergreen: tree or plant that keeps its needles or leaves year-round; this means for more than one growing
season
Increment: the amount of new wood fiber added to a tree in a given period, normally one year.
ISA: International Society of Arboriculture
Landscape function: the environmental, aesthetic, or architectural functions that a plant can have
Lateral: secondary or subordinate branch
Limits of disturbance: The boundary of minimum protection around a tree, the area that cannot be encroached
upon without possible permanent damage to the tree. It is a distance determined by a qualified professional and
is based on the age of the tree, its health, the tree species tolerance to disruption and the type of disturbance.
It also considers soil and environmental condition and previous impacts. It is unique to each tree in its location.
Limited visual assessment: a visual assessment from a specified perspective such as foot, vehicle, or aerial
(airborne) patrol of an individual tree or a population of trees near specified targets to identify specified
conditions or obvious defects (ISA 2013)
Live crown ratio: the percentage of living tissue in the canopy versus the tree’s height. It is a good indicator of
overall tree health and the trees growing conditions. Trees with less than a 30% crown ratio often lack the
necessary quantity of photosynthetic material to sustain the roots; consequently, the tree may exhibit low vigor
and poor health
Monitoring: keeping a close watch; performing regular checks or inspections
Owner/manager: the person or entity responsible for tree management or the controlling authority that
regulates tree management
Pathogen: causal agent of disease
Phototropic growth: growth toward light source or stimulant
ROW: right-of-way; generally referring to a tree that is located offsite on a city easement
Reaction wood: specialized secondary xylem which develops in response to a lean or similar mechanical stress,
it serves to help restore the stem to a vertical position
Self-corrected lean: a tree whose trunk is at an angle to the grade but whose trunk and canopy changes to
become upright/vertical
Significant tree: a tree measuring a specific diameter determined by the municipality the tree grows in. Some
municipalities deem that only healthy trees can be significant, other municipalities consider both healthy and
unhealthy trees of a determined diameter to be significant
Snag: a tree left partially standing for the primary purpose of providing habitat for wildlife
Soil structure: the size of particles and their arrangement; considers the soil, water, and air space
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
11 | Page
Sounding: process of striking a tree with a mallet or other appropriate tool and listening for tones that indicate
dead bark, a thin layer of wood outside a cavity, or cracks in wood
Structural defects: flaws, decay, or other faults in the trunk, branches, or root collar of a tree, which may lead to
failure; may be genetic, or environmental
Tree credit: a number assigned to a tree by a municipality that may be equal to the diameter of the tree or a
numerical count of the tree, or related to diameter by a factor conveyed in a table of the municipal code
Trunk area: the cross-sectional area of the trunk based upon measurement at 54 inches (4.5 ft.) above grade
Visual Tree Assessment (VTA): method of evaluating structural defects and stability in trees by noting the
pattern of growth. Developed by Claus Mattheck (Harris, et al 1999) detailed visual inspection of a tree and
surrounding site that may include the use of simple tools. It requires that a tree risk assessor walk completely
around the tree trunk looking at the site, aboveground roots, trunk, and branches (ISA 2013)
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
12 | Page
REFERENCES
Dirr, Michael A. Manual of Woody Landscape Plants, Their Identification, Ornamental Characteristics, Culture,
Propagation, and Uses. Champaign: Stipes Publishing Company, 1990.
Dunster & Associates Environmental Consultants Ltd. Assessing Trees in Urban Areas and the Urban-Rural
Interface. US Release 1.0. Silverton: Pacific Northwest Chapter ISA, 2006.
Dunster, J. A. 2003. Preliminary Species Profiles for Tree Failure Assessment. Bowen Island: Dunster & Associates
Environmental Consultants Ltd.
Dunster, Julian A., E. Thomas Smiley, Nelda Matheny and Sharon Lilly. Tree Risk Assessment Manual.
Champaign, Illinois: International Society of Arboriculture, 2013.
Harris, Richard W, James Clark, and Nelda Matheny. Arboriculture, Integrated Management of Landscape Trees,
Shrubs, and Vines. 4th ed. Upper Saddle River: Prentice Hall, 2004.
Lilly, Sharon. Arborists’ Certification Study Guide. Champaign, IL: The International Society of Arboriculture,
2001.
Matheny, Nelda and Clark, James R. A Photographic Guide to the Evaluation of Hazard Trees in Urban Areas.
Second Edition. Champaign, IL: The International Society of Arboriculture, 1994.
Matheny, Nelda and Clark, James R. Trees and Development: A Technical Guide to Preservation of Trees During
Land Development. Champaign, IL: The International Society of Arboriculture, 1998.
Mattheck, Claus and Breloer, Helge. The Body Language of Trees: A Handbook for Failure Analysis. London:
HMSO, 1994
Schwarze, Francis W.M.R. Diagnosis and Prognosis of the Development of Wood Decay in Urban Trees. Australia:
ENSPEC Pty Ltd. 2008
Sinclair, Wayne A., Lyon, Howard H., and Johnson, Warren T. Diseases of Trees and Shrubs. Ithaca, New York:
Cornell University Press, 1987.
Smiley, E. Thomas, Nelda Matheny, and Sharon Lilly. Tree Risk Assessment Best Management Practices, ANSI
A300 Part 9: Tree, Shrub, and Other Woody Plant Management—Standard Practices (Tree Risk Assessment: Tree
Structure Assessment). The International Society of Arboriculture Press. Champaign. IL. 2011.
Thies, Walter G. and Sturrock, Rona N. Laminated root rot in Western North American. United States
Department of Agriculture. Pacific Northwest. Resource Bulletin PNW-GTR-349. April 1995.
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
13 | Page
INSPECTION METHODS
I performed a Level 2 Visual Tree Assessment (VTA) for each tree. I visually inspected the tree from the ground,
walking around the tree to inspect for any basal defects. I then further from the tree, looking up into the crown
and branches for any notable defects and symptoms of canopy decline.
I measured the diameter of each tree using a Spencer Logging Tape. If a tree had multiple times, I measured
each stem individually and used the method outlined in the Guide for Plant Appraisal, 10th Edition Second
Printing, to obtain a single-stem equivalent diameter. The single-stem equivalent is calculated in post-processing
and due to this, some trees inventoried on the site may be smaller than the significant/regulated tree size for
the subject jurisdiction. These trees are included in the deliverables for informational purposes but are not
considered or discussed in the report. When ivy or other obstructions are present, I adjusted the diameter by
taking the ivy or obstruction into account. I measured the dripline of the first 5 trees using a measuring tape and
then estimated the average dripline of the remaining trees.
Using the VTA method, I rated the health and structural condition of each tree. This inspection method is an
international industry standard for assessing trees from the ground level and identifies external signs of decay,
physical damage, growth related defects, and abnormal or declining foliage. Tree health and structure are each
assigned their own condition rating. The following ratings are used:
Poor: Lacking a full crown, with more than 50% decline and dieback that especially affects larger branches.
Low life expectancy for the species.
Fair: Crown decline and dieback up to 30% of the canopy. Below-average life expectancy for the species.
Good: Imperfect canopy density in 10% or less of the tree. Typical life expectancy for the species.
Excellent: Perfect specimen with excellent form and vigor, along with a well-balanced crown. Exceptional
life expectancy for the species.
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
14 | Page
APPENDIX A - ASSUMPTIONS & LIMITING CONDITIONS
1) Any legal description provided to the consultant/appraiser is assumed to be correct. Any titles and
ownerships to any property are assumed to be good and marketable. No responsibility is assumed for
matters legal in character. Any and all property is appraised or evaluated as though free and clear, under
responsible ownership and competent management.
2) It is assumed that any property is not in violation of any applicable codes, ordinances, statutes or other
governmental regulations.
3) The assessment in this report is based on information and data from sources believed to be reliable,
correct, and accurately reported. No responsibility is assumed for false or misleading information provided
by others.
4) The consultant/appraiser shall not be required to give testimony or to attend court by reason of the report
unless subsequent contractual arrangements are made including payment of an additional fee for such
services as described in the fee schedule and contract of engagement.
5) Loss or alteration of any part of this report invalidates the entire report.
6) Possession of this report or a copy thereof does not imply right of publication or use for any purpose by any
other than the person to whom it is addressed, without the prior expressed written or verbal consent of
the consultant/appraiser.
7) Neither all nor any part of the contents of the report, nor copy thereof, shall be conveyed by anyone,
including the client to the public through advertising, public relations, news, sales or other media, without
the prior expressed written or verbal consent of the consultant/appraiser – particularly as to value
conclusions, identity of the consultant/appraiser, or any reference to any professional society or instate or
to any initialed designation conferred upon the consultant/appraiser as stated in her qualification.
8) The report and any values expressed herein represent the opinion of the consultant/appraiser, and the
consultant’s/appraiser’s fee is in no way contingent upon the reporting of a specified value, a stipulated
result, the occurrence of subsequent event, nor upon any finding to be reported.
9) Sketches, diagrams, graphs, and photographs in this report, being intended as visual aid, are not necessarily
to scale and should not be construed as engineering or architectural reports or survey.
10) Unless expressed otherwise: 1) information contained in this report covers only those items that were
examined and reflects the condition of those items at the time of inspection; and 2) the inspection is
limited to visual examination of accessible items without dissection, excavation, probing or coring. There is
not warranty or guarantee, expressed or implied, that problems or deficiencies of the plants or property in
question may not arise in the future.
Arborist Report: Ohashi Short Plat – Federal Way
___________________________________________________________________________________________
15 | Page
APPENDIX B - CERTIFICATION OF PERFORMANCE
I, Katie Hogan, certify that:
• I have personally inspected the trees on the property referenced in this report and the statements of
fact contained in this report are true and correct.
• I have no present or prospective interest in the property that is the subject of this report, and I have no
personal interest with respect to the parties involved.
• The reported analysis, opinions, and conclusions are my personal, unbiased professional analysis,
opinions, and conclusions.
• My analysis, opinions, and conclusions were developed, and this report has been prepared according to
commonly accepted arboricultural best practices.
• No individuals or organizations have provided significant assistance with the preparation of this report,
except those named in the report.
• My compensation for completing this assignment is not contingent upon the development or reporting
of a predetermined outcome or direction that favors the cause of the client, the results of the
assessment, or the occurrence of any subsequent events.
Signed:
Cascara Tree Consulting, LLC
Client: OhashiSite Address: 1225 SW 296th St, Federal Way6/14/2023 Page 1 of 2Tree Inventory TablePrepared by: Cascara Tree ConsultingPN-8078A, TRAQTree No. Location Scientific Name Common Name Adjusted DBH (inches)Health Structural Arb Tag # Dripline Radius (feet)Tree Unit CreditsProposed ActionNotes/Defects50322 LOT 1Juniperus scopulorumRocky Mountain juniper7.2 Fair Fair 152 10.0 1.5 Retain Slightly suppressed, multi-trunk form, roots slightly uplifting59321 LOT 1Cornus floridaEastern Dogwood 7.9 Fair Fair 152 10.0 1.5 Retain Slightly suppressed with minor canopy decline50324 LOT 1Juniperus scopulorumRocky Mountain juniper13.3 Fair Poor 154 15.0 2.0 Retain One trunk failed, heavy sapsucker damage, canopy decline50356 LOT 1Sorbus aucupariaMountain-Ash 6.0 Fair Fair 155 5.0 1.0 Retain Previously topped, visible decay50355 LOT 1Sorbus aucupariaMountain-Ash 9.0 Poor Poor 156 8.0 1.5 Retain Previously topped, hollow50539 LOT 2Laurus nobilisBay laurel 5.7 Good Good 157 5.0 1.0 Retain Tag hanging on east side of canopy50503 LOT 2Pseudotsuga menziesiiDouglas-fir 11.0 Fair Fair 158 12.0 1.5RemovePreviously topped, very narrow union at 6 feet with weak attachment, branch die back, not good long-term tree & potential future hazard 50504 LOT 2Pseudotsuga menziesiiDouglas-fir 16.4 Fair Poor 159 15.0 2.0RemovePreviously topped at 15 feet, U-shaped union, likely some central decay, not good long-term tree & potential future hazard50506 LOT 2Thuja plicataWestern Redcedar 15.0 Good Good 160 12.0 2.0RemoveImpacted from proposed driveway50514 LOT 2Thuja plicataWestern Redcedar 20.0 Good Good 161 20.0 2.5 Retain Healthy cedar tree50532 LOT 2Alnus rubraRed alder 12.7 Good Fair 161 18.0 2.0 Retain Young alder tree, enveloping fence, narrow union at baseTotal Tree Units Required18.0Total Existing Tree Units18.5Total Tree Units Retained13.0Additional Tree Units Required5Summary Replanting TableOn-Site TreesCascara Tree Consulting
Client: OhashiSite Address: 1225 SW 296th St, Federal Way6/14/2023 Page 2 of 2Tree Inventory TablePrepared by: Cascara Tree ConsultingPN-8078A, TRAQTree No. Location Scientific Name Common Name Adjusted DBH (inches)Health Structural Arb Tag # Dripline Radius (feet)Tree Unit CreditsProposed ActionNotes/Defects50319 ROWJuniperus scopulorumRocky Mountain juniper10.2 Good Good 150 7.0 - Retain Maintained as shrub, view pruned50320 ROWAcer palmatumJapanese Maple 6.0 Good Good 151 4.0 - Retain Maintained as shrub, purple lace leaf maple50550 ESMTCalocedrus decurrensIncense Cedar 22.0 Good Good A 14.0 - Retain Growing atop rockery along access easement 50549 ADJ PROPThuja plicataWestern Redcedar 16.0 Good Good B 15.0 - Retain Growing atop rockery along access easement 50568 ADJ PROPAcer circinatumVine Maple 8.7 Good Good C 10.0 - Retain Growing atop rockery along access easement 50567 ADJ PROPArbutus unedoStrawberry tree 9.0 Good Good D 8.0 - Retain Growing atop rockery along access easement 50565 ADJ PROPPrunus domesticaCommon plum 5.0 Good Good E 6.0 - Retain Growing atop rockery along access easement, plum tree 50564 ADJ PROPAcer palmatumJapanese Maple 8.2 Good Good F 10.0 - Retain Growing atop rockery along access easement 50590 ROWCalocedrus decurrensIncense Cedar 8.0 Good Good G 4.0 - Retain At entryway to driveway about 3 feet from edge of driveway 50591 ROWFraxinus pennsylvanicaGreen Ash 8.0 Good Good H 15.0 - Retain At entryway to driveway about 8 feet from edge of driveway 50589 ROWPseudotsuga menziesiiDouglas-fir 10.0 Good Fair I 12.0 - Retain At entryway to driveway about 4 feet from edge of driveway 50585 ADJ PROPAcer palmatumJapanese Maple 6.0 Good Good J 10.0 - Retain Located on north side of driveway about 3 feet from edge of driveway50586 ADJ PROPAcer macrophyllumBigleaf Maple 3.0 Good Good K 4.0 - Retain Located on north side of driveway about 3 feet from edge of driveway50587 ADJ PROPMalus sp.Apple 4.0 Poor Poor L 6.0 - Retain Located on north side of driveway about 3 feet from edge of driveway50588 ADJ PROPCrataegus monogynaCommon hawthorn 4.0 Good Good M 6.0 - Retain Located on north side of driveway about 3 feet from edge of drivewayOff-Site TreesCascara Tree Consulting
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Pre-Application Summary
See Pre-Application Conference Summary in the following pages.
33325 8th Avenue South
Federal Way, WA 98003-6325
253-835-7000
www.cityoffederalway.com
Jim Ferrell, Mayor
December 2, 2021
Calvin Tam
10040 Sand Point Way NE
Seattle, WA 98125
calvint006@gmail.com
Re: File #21-104278-00-PC, PREAPPLICATION CONFERENCE SUMMARY
Ohashi Short Plat, 1225 SW 296th Street, Parcel 515320-0015, Federal Way
Dear Mr. Tam:
Thank you for participating in the preapplication conference with the City of Federal Way’s Development
Review Committee (DRC) held November 18, 2021. We hope that the information discussed at that meeting
was helpful in understanding the general requirements for your project as submitted.
This letter summarizes comments given to you at the meeting by the members of the DRC. The members
who reviewed your project and provided comments include staff from the City’s Planning and Building
Divisions, Public Works Department, and representatives from Lakehaven Water and Sewer District and
South King Fire and Rescue. Some sections of the Federal Way Revised Code (FWRC) and relevant information
handouts are enclosed with this letter. Please be advised, this letter does not represent all applicable codes. In
preparing your formal application, please refer to the complete FWRC and other relevant codes for all
additional requirements that may apply to your project.
The key contact for your project is, Becky Chapin, 253-835-2641, becky.chapin@cityoffederalway.com. For
specific technical questions about your project, please contact the appropriate DRC representative as listed
below. Otherwise, any general questions about the preapplication and permitting process can be referred to
your key contact.
PROJECT DESCRIPTION
Proposal to subdivide one existing single-family residential lot, parcel 515320-0015, into two separate single-
family residential lots and build a new single-family residence on the new lot.
MAJOR ISSUES
Outlined below is a summary of the major issues of your project based on the plans and information
submitted for preapplication review. These issues can change due to modifications and revisions in the plans.
The major issues section is only provided as a means to highlight critical requirements or issues. Please be
sure to read the comments made by all departments in the following section of this letter.
Mr. Tam
December 2, 2021
Page 2
21-104278-00-PC Doc ID:81812
Planning Division
1. All residential subdivisions are required to provide open space in the amount of 15 percent of the
gross land area of the subdivision site per FWRC 18.55.060(2). All or some of the open space
requirements may be satisfied by a fee-in-lieu payment.
Public Works Development Services Division
1. A surface and Stormwater Utility System Development Charge is required. System development
charges (SDCs) are one-time fees that will be paid at time of development and are intended to
recover a share of cost of system capacity needed to save growth.
Public Works Traffic Division
1.Transportation Concurrency Management (FWRC 19.90) – Transportation concurrency permit
with application fee of $1,801.00 is required for the proposed project.
2.Traffic Impact Fees (FWRC 19.91) - Traffic impact fees are required and assessed at building
permit for each lot.
3.Improvements (FWRC 19.135.040) – Construct half street improvement on SW 296th St to meet
planned Type “T” street.
4. The existing easement shall be improved to meet private street standard Dwg. No. 3-2CC.
DEPARTMENT COMMENTS
Outlined below are the comments made by the representatives of each department present at the
preapplication conference. Each section should be read thoroughly. If you have questions, please contact the
representative listed for that section.
COMMUNITY DEVELOPMENT – PLANNING DIVISION
Becky Chapin, 253-835-2641, becky.chapin@cityoffederalway.com
1.Comprehensive Plan and Zoning Designation – The city’s comprehensive plan designation for the
subject property is Single-Family Residential – Medium Density. The property is currently zoned
Residential Single-Family (RS15.0). The minimum lot area for residential lots in RS 15.0 zones is 15,000
square feet.
2.Short Plat Process – Short plats are the division or re-division of land into nine or fewer lots, tracts,
parcels, sites, or divisions for sale, lease, or transfer as defined in FWRC 18.05.010.
According to FWRC 18.30.010, short plat applications are administratively processed through the
Department of Community Development. The administrative review process requires that the Director
of Community Development issue a decision on the short subdivision request and confirm conformance
with FWRC 18.30.110(2). Public notice of the complete short plat proposal is required per FWRC
18.30.080, and a 15-day public comment period is provided. However, no public hearing will be required
unless an appeal is filed.
A Master Land Use application and Short Plat Submittal Requirements handout are enclosed; relevant
code sections can be accessed from www.codepublishing.com/WA/FederalWay. Before the construction
of short plat improvements, if any, engineering approval must be granted by the Public Works
Department. Please see Sam Basmeh’s comments for specific information regarding engineering
requirements.
Mr. Tam
December 2, 2021
Page 3
21-104278-00-PC Doc ID:81812
3.State Environmental Policy Act (SEPA) – Short subdivision applications and associated permits for
less than 20 residential dwelling units are exempt from state environmental review according to FWRC
14.15.030, “Categorical Exemptions, Flexible Thresholds.” No environmental checklist is required.
4.Public Notice – Within 14 days of issuing the Letter of Complete Application, a Notice of Application
will be published in the Federal Way Mirror, posted on the subject property, posted on the city’s website,
and mailed to property owners within 300 feet of the subject property, per FWRC 18.30.080(2). The city
will prepare notice boards for the subject property to be posted by the applicant.
5.Critical Areas – The city’s Critical Areas Map does not identify any wetlands, fish and wildlife habitat
resource areas, or geologically hazardous areas on the subject property. The city’s map is for planning
level purposes and not all critical areas within the city have been identified. The department will require a
critical areas report if evidence is found of an apparent critical area located on the subject property, or
within proximity of the subject property, during the development application review process.
6.Single-Family Residential Regulations – Future and existing residences must conform to the
following bulk and dimensional requirements of FWRC 19.200.010, “Detached Dwelling Units,” front
yard 20 feet; side yard 5 feet; and rear yard 5 feet. For Parcel A, refer to FWRC 19.05.160, “Property
Line,” definition for the flag lot setbacks illustration to see how the building setbacks should be applied.
No improvements may be located in a required yard except those specified in FWRC 19.125.160.
Per 19.200.010(6)(c), lot coverage for residential uses is limited to 60 percent and includes all impervious
surfaces, such as driveways, walkways, patios, and roof overhangs. Maximum height of structures is 30
feet above average building elevation per FWRC 19.200.010.
Per FWRC 19.130.240(1)(a), a driveway and/or parking pad in a required front yard may not exceed 20
feet in width (except as specified in FWRC 19.130.240(1)(b)) and may not be closer than five feet to any
side property line.
7.Open Space – All residential subdivisions are required to provide open space in the amount of 15
percent of the gross land area of the subdivision site per FWRC 18.55.060(2). All or some of the open
space requirements may be satisfied by a fee-in-lieu payment at the discretion of the Parks Director, after
consideration of the city’s overall park plan, quality, location, and service area of the open space that
would otherwise be provided with the project. If the fee-in-lieu option is chosen, a written request to
Parks Director John Hutton is required. A copy of this request is a required component of the short plat
application. Open space fees-in-lieu shall be paid before recording the plat. Refer to FWRC 19.100.070,
“Timing of Fee Payments.”
Mr. Tam
December 2, 2021
Page 4
21-104278-00-PC Doc ID:81812
8.Tree Retention/Replacement – The short subdivision will be subject to tree density requirements of
FWRC 19.120.130(1); note that 25 tree units per acre are required for single-family zoned sites. A tree
unit is a value assigned to existing trees retained on the property or replacement trees. The larger the tree,
the greater value it is assigned. Required tree density can be composed of retained trees and replacement
plantings per FWRC 19.120.130.
In the case of the 0.69-acre site, 18 tree units are required (25 x 0.69 = 17.25). Per FWRC 19.120.130(3),
the total number of tree units required to be provided is calculated by multiplying gross site acreage.
A tree retention plan prepared by a certified arborist, or a certified landscape architect, detailing how the
subject property will meet tree unit density requirements shall be submitted with the short subdivision
application. Items required to be included in the plan are itemized in FWRC 19.120.040(2)(a) through (e).
The table below identifies tree unit values for retained and replacement trees. The tree and vegetation
plan must clearly show where the tree units are to be located. The formal application must indicate what
trees are to be removed.
Table 19.120.130-2 – Tree Unit Credits
Existing Tree Category Tree Unit Credit
Existing Tree 1" to 6" d.b.h.1.0 tree units per tree retained
Existing Tree > 6" to 12" d.b.h.1.5 tree units per tree retained
Existing Tree > 12" to 18" d.b.h.2.0 tree units per tree retained
Existing Tree > 18" to 24" d.b.h.2.5 tree units per tree retained
Existing Tree > 24" d.b.h.3.0 tree units per tree retained
Replacement Tree Category
Replacement Tree, Small Canopy Species
(Mature canopy area < 450 SF)
.50 tree units per tree planted
Replacement Tree, Medium Canopy Species
(Mature canopy area 450 to 1,250 SF)
1.0 tree units per tree planted
Replacement Tree, Large Canopy Species
(Mature canopy area > 1,250 SF)
1.5 tree units per tree planted
9.Clearing & Grading – A clearing and grading plan addressing items listed in FWRC 19.120.040(1)(a)
through (i) is required with a short subdivision application. Before beginning clearing and grading
activities, all trees/vegetation that are to be preserved within and adjacent to the construction area shall
be marked and protected per guidelines prescribed within FWRC 19.120.160.
10.Design Criteria and Improvements – Short plats are subject to the subdivision design and
improvements criteria outlined in FWRC Chapters 18.55 and 18.60, respectively. It is the responsibility of
the applicant to identify how the proposed short subdivision meets applicable design and improvements
criteria and is therefore entitled to the land division.
11.School Access Analysis – According to FWRC 18.55.070, pedestrian and bicycle access should be
provided for established or planned safe school routes, bikeways, trails, transit stops, and general
circulation. Please provide an analysis of access routes for schools serving this proposed short plat.
Mr. Tam
December 2, 2021
Page 5
21-104278-00-PC Doc ID:81812
Contact Jen Thomas, Federal Way Public Schools, at 253-945-2071 or jthomas@fwps.org, for
information about the school access analysis requirements and assignment information.
12.School Impact Fees – School impact fees are due at the time of the building permit application for new
dwelling units. This fee amount is subject to change as determined annually by the Federal Way School
District. Please check with the Permit Center at 253-835-2607, or permitcenter@cityoffederalway.com,
for up-to-date fees.
13.Application Fees –The formal application must be prepared in accordance with the city’s Short
Subdivision Submittal Requirements (enclosed) and must be accompanied by the appropriate fees. All
application submittals must be submitted electronically. Please visit the city’s website to request a
document upload link for submittal: www.cityoffederalway.com/node/4588. Please contact the Permit
Center at permitcenter@cityoffederalway.com or 253-835-2607 for updated fee schedules for
applications and permits, or for help with the submittal process.
14.Approval Duration – Short plat approval expires five years from the date of approval, per FWRC
18.30.260. Engineering plans must be approved, improvements constructed, and the plat must be
recorded within five years. According to FWRC 18.05.090, no less than 60 days before the lapse of
approval, the applicant may request a two-year time extension for the plat approval.
15.Recording – The applicant will record the short plat with the King County Recorder’s Office after the
Public Works Department approves the submitted as-built plans. Before recording the short plat, all
surveying and monumentation must be complete. Also, all other required improvements must be
substantially completed as determined by the departments of Community Development and Public
Works. The open space fee-in-lieu must be paid in full before recording.
PUBLIC WORKS – DEVELOPMENT SERVICES DIVISION
Sam Basmeh, 253-835-2746, Samir.basmeh@cityoffederalway.com
Land Use Issues – Stormwater
1. Surface water runoff control and water quality treatment will be required per the 2021 King County Surface
Water Design Manual (KCSWDM). This project meets the requirements for a full Drainage Review. At
the time of land use site plan preliminary short plat submittal, a preliminary Technical Information
Report (TIR), addressing the relevance of the project to the nine core and five special requirements of
the KCSWDM will be required. A Level 1 downstream analysis shall also be provided in the preliminary
TIR. The City has 1″ = 100′, five-foot contour planimetric maps in GIS format that may be used for
basin analysis.
2. The project lies within a Conservation flow control area, thus the applicant must design the flow control
facility to meet this performance criteria. In addition to flow control facilities, Best Management
Practices (BMP’s) are required as outlined in the KCSWDM. The project also lies within an Enhanced
Basic Water Quality Area. Water Quality Treatment shall be designed to meet the treatment criteria of
the Enhanced Basic Water Quality Menu.
3. In addition to the KCSWDM, our initial review suggests that FWRC Section 19.30.120,
“Nonconforming Water Quality Improvements” applies to this site. Specifically, the following:
Redevelopment which involves a change in use, and the changed use has a potential to release a new
pollutant(s) to surface water systems within the City. For the purposes of this subsection, “new
pollutant(s)” means a pollutant that was not discharged at that location immediately prior to the
change in use, as well as a pollutant that was discharged in less quantities immediately prior to the
Mr. Tam
December 2, 2021
Page 6
21-104278-00-PC Doc ID:81812
change in use; therefore, water quality treatment will be required for the entire easement area, including new and
existing pollution generating impervious surfaces. Treatment options must be selected from the Enhanced Basic Water
Quality Menu provided in the KCSWDM.
4. If infiltration is proposed, soil logs prepared by a licensed geotechnical engineer or septic designer must
be provided to verify infiltration suitability.
5. Show the proposed location and dimensions of the detention and water quality facilities on the
preliminary plans.
6. Federal Way Revised Code Chapter 19.96 requires that a system development charge (SDC) be paid
prior to connection of private storm water infrastructure to the public drainage system. This charge for
2021 is $981.00 per Equivalent Service Unit (ESU). One ESU is 3,200 square feet of impervious surface
area. For short plats, this is based on the total amount of new impervious surface area of the plat
infrastructure improvements; so, roads, sidewalk etc.
7. If work is to be done below the ordinary high water mark, a Hydraulic Project Approval (HPA) permit
may be required. Information regarding this permit can be obtained from the Washington Department
of Fish and Wildlife.
Right-of-Way Improvements
1. See the Traffic Division comments from Sarady Long, Sr. Transportation Planning Engineer for traffic
related items.
2. If dedication of additional right-of-way is required to install street frontage improvements, the
dedication shall be conveyed to the City through a statutory warranty deed. The dedicated area must
have clear title prior to recording.
3. All stormwater treatment and detention requirements outlined above may apply to any improvements
within the public right-of-way.
4. FWRC Section 11.05.110 requires that overhead utility lines be relocated underground if over 500 feet,
or three spans are affected by a project. This condition will be applied to SW 296th Street.
5. FWRC Section 19.135.280 requires that driveways serving residential uses may not be located closer
than 25 feet to any street intersection. Lots and intersections within new subdivisions or short plats
must be designed to meet this standard.
Building Permit Issues
1. Engineered plans are required for clearing, grading, road construction, and utility work. Plans must be
reviewed and approved by the City. Engineering review currently fees are ($ 2140.00) for the first 12
hours of review, and currently $175.00 per hour for additional review time. A final TIR shall be
prepared for the project and submitted with the engineering plans. Both the TIR and the plans will
require the signature/seal of a professional engineer registered/licensed in the State of Washington.
2. In addition to engineering approval, projects that will be filling or grading in the area of the future
building pads are required to obtain a separate grading permit from the Building Department.
3. The Federal Way Public Works Development Standards Manual (including standard detail drawings, standard
notes, and engineering checklists) is available on the City’s website at
Mr. Tam
December 2, 2021
Page 7
21-104278-00-PC Doc ID:81812
http://www.cityoffederalway.com/index.aspx?nid=171 to assist the applicant’s engineer in preparing
the plans and TIR.
4. Bonding is required for all street improvements and temporary erosion and sediment control measures
associated with the project. The bond amount shall be 120 percent of the estimated costs of the
improvements. An administrative fee deposit will need to accompany the bond to cover any possible
legal fees in the event the bond must be called. Upon completion of the installation of the
improvements, and final approval of the Public Works Inspector, the bond will be reduced to 30
percent of the original amount and held for a two-year maintenance period.
5. The developer will be responsible for the maintenance of all storm drainage facilities (including the
detention and water quality facilities) and street systems during the two-year maintenance period. During
that time, the Public Works Inspector will make periodic visits to the site to ensure the developer’s
compliance with the maintenance requirements. Upon satisfactory completion of the two-year
maintenance period, the remainder of the bond will be released. Maintenance for public roads and
subdivision drainage facilities then become the responsibility of the City. Maintenance for private roads
and drainage facilities, including short plats, remain the responsibility of the individual property owners.
6. When topographic survey information is shown on the plans, the vertical datum block shall include the
phrase “DATUM: N.G.V.D.-29” or “DATUM: K.C.A.S.,” on all sheets where vertical elevations are
called out.
7. Drawings submitted for plan review shall be printed on 24″ x 36″ or 22″ x 34″ paper. Site plans shall be
drawn at a scale of 1″ = 20′, or larger. Architectural scales are not permitted on engineering plans.
8. Provide cut and fill quantities on the clearing and grading plan.
9. Temporary Erosion and Sediment control (TESC) measures, per Appendix D of the 2016 KCSWDM,
must be shown on the engineering plans.
10. The site plan shall show the location of any existing and proposed utilities in the areas affected by
construction.
PUBLIC WORKS TRAFFIC DIVISION
Sarady Long, 253-835-2743, sarady.longl@cityoffederalway.com
Transportation Concurrency Analysis (FWRC 19.90)
1. Based on the submitted materials for a two-lot short plat, the Institute of Transportation Engineers (ITE)
Trip Generation - 10th Edition, land use code 210 (Detached Single Family Residential), the proposed
project is estimated to generate approximately one (1) new weekday PM peak hour trips.
2. A concurrency permit is required for this development project. The PW Traffic Division will perform
concurrency analysis to determine if adequate roadway capacity exists during the weekday PM peak
period to accommodate the proposed development. Please note that supplemental transportation analysis
and concurrency mitigation may be required if the proposed project creates an impact not anticipated in
the six-year Transportation Improvement Plan (TIP).
3. The estimated fee for the concurrency permit application is $1,801 (1 - 10 Trips). This fee is an estimate
and based on the materials submitted for the pre-application meeting. The concurrency application fee
must be paid in full at the time the concurrency permit application is submitted with land use application.
Mr. Tam
December 2, 2021
Page 8
21-104278-00-PC Doc ID:81812
The fee may change based on the new weekday PM peak hour trips as identified in the concurrency trip
generation. The applicant has the option of having an independent traffic engineer prepare the
concurrency analysis consistent with City procedures; however, the fee remains the same.
Transportation Impact Fees (TIF) (FWRC 19.91)
1. Based on the submitted materials for 2 single family lots (1 new lot), the estimate traffic impact fee is
$7,407 per lot. The actual fee will be assessed and collected from the applicant when the building permit
is issued, using the fee schedule then in effect (FWRC 19.100.070 3(c)). At any time prior to building
permit issuance, the applicant may request to defer to final building inspection the payment of a
transportation impact fee for a single-family residential dwelling unit (FWRC 19.100.075). If this option is
selected, a covenants prepared by the city to enforce payment of the deferred fees will be recorded at the
applicant’s expense. Refer to defer payment of impact fee code for process.
Street Frontage Improvements (FWRC 19.135)
1. The applicant/owner would be expected to construct street improvements consistent with the planned
roadway cross-sections as shown in Map III-4 in Chapter III of the Federal Way Comprehensive Plan
(FWCP) and Capital Improvement Program (CIP) shown as Table III-10 (FWRC 19.135.040). Based on
the materials submitted, staff conducted a limited analysis to determine the required street improvements.
The applicant would be expected to construct improvements on the following streets to the City’s
planned roadway cross-sections:
SW 296th St shall be Type a “T” Local street, consisting of a 28-foot street with an 8-foot
ditch, 5-foot sidewalks and street lights in a 60-foot right-of-way (ROW). Assuming a
symmetrical cross section, no right-of-way dedication is required and half-street improvements
as measured from street centerline is required. At a minimum, the improvement shall consist
of a 20-foot paved road with an 8-foot ditch, 5-foot sidewalk and street lights.
Internal private street (easement) shall be improved to meet private street standard Dwg. No.
3-2CC, consisting of 20’ easement with a minimum 16’ pavement.
3. The applicant may make a written request to the Public Works Director to modify, defer, or waive the
required street improvements (FWRC 19.135.070). Information about a right-of-way modification
requests are available through the Public Works Development Services Division. These modification
requests have a nominal review fee currently at $500.00.
4. Tapers and transitions beyond the project frontage may be required as deemed necessary for safety
purposes, taper rate shall be WS^2/60 or as directed by the Public Works Director.
LAKEHAVEN WATER AND SEWER DISTRICT
Kathleen Mathena, 253-946-1655, kmathena@lakehaven.org
General
All Lakehaven Development Engineering related application forms, and associated standards
information, can be accessed at Lakehaven’s Development Engineering web pages
(http://www.lakehaven.org/204/Development-Engineering).
All comments herein are valid for one (1) year and are based on the proposal(s) submitted and
Lakehaven’s current regulations and policies. Any change to either the development proposal(s) or
Lakehaven’s regulations and policies may affect the above comments accordingly.
Mr. Tam
December 2, 2021
Page 9
21-104278-00-PC Doc ID:81812
Water
A Water Certificate of Availability issued separately by Lakehaven may be required to be submitted
with any land use and/or building permit applications (check with land use agency for requirement).
Certificate is valid for one (1) year from date of issuance. If Certificate is needed, allow 1-2 work days
to issue for typical processing. 2021 cost for a Water Certificate of Availability is $40.00.
The site has one (1) existing water service connection:5153200015: SvcNo. 21568, 5/8”x3/4” meter.
The proposed new parcel & home will require a new separate water service.
A water service connection application submitted separately to Lakehaven is required for each new
service connection to the water distribution system, or any modification to an existing water service
connection (e.g., larger meter/service, abandonment of existing service(s), etc.), in accordance with
standards defined in Lakehaven’s current ‘Fees and Charges Resolution’.
Service pressures greater than 80 psi indicated, Pressure Reducing Valves indicated, contact local
building official for requirements &/or additional information.
Proof of existing, recorded private, water easement will be required across adjacent Properties, for
the benefit of the portion of the owner’s building supply line (meter-to-property) across said adjacent
property. This private easement shall cover off-site property along the route of the affected portion
of the building supply line from the edge of public right-of-way or Lakehaven easement to the
owner’s property.
Based on the proposal submitted, preliminary estimated Lakehaven water service connection
fees/charges/deposits (2021 schedule) will be as follows. Actual connection charges will be
determined upon submittal of service connection application(s) to Lakehaven. All Lakehaven fees,
charges and deposits are typically reviewed & adjusted (if necessary) annually, and are subject to
change without notice.
Water Service/Meter Installation, preliminary 1” sizes: $5,370.00 dig service connection deposit.
Actual size TBD by Lakehaven based on the higher of UPC plumbing fixture counts or fire-
protection system flow demands.
Capital Facilities Charge(s)-Water: $4,764.71 per Equivalent Residential Units (ERU). Please contact
Lakehaven for further detail.
The fire system designer must provide the following information: Potable/Non-potable system;
Min/Max GPM; & Recommended size for service line, meter, and supply line.
A Right of Way permit will be required; Lakehaven will apply.
Sewer
A Sewer Certificate of Availability issued separately by Lakehaven may be required to be submitted
with any land use and/or building permit applications (check with land use agency for requirement).
Certificate is valid for one (1) year from date of issuance. If Certificate is needed, allow 1-2 work days
to issue for typical processing. 2021 cost for a Sewer Certificate of Availability is $40.00.
Mr. Tam
December 2, 2021
Page 10
21-104278-00-PC Doc ID:81812
A separate Lakehaven Sewer Service Connection Permit is required for each new connection to the
sanitary sewer system, in accordance with standards defined in Lakehaven’s current ‘Fees and
Charges Resolution’. Minimum pipe slope for gravity sewer service connections is 2%.
The site has one (1) existing side sewer connection SSCP#1433.
Records show there is a side sewer stub within the sewer easement on the south side of parcel that a
new service could connect to.
Based on the proposal submitted, preliminary estimated Lakehaven sewer service connection
fees/charges/deposits (2021 schedule) will be as follows. Actual connection charges will be
determined upon submittal of service connection application(s) to Lakehaven.
All Lakehaven fees, charges and deposits are typically reviewed & adjusted (if necessary) annually,
and are subject to change without notice.
Sewer Service Connection Permit: $377.13 fee (per lot).
Capital Facilities Charge (if applicable)-Sewer: $4,614.93 per ERU.
SOUTH KING FIRE AND RESCUE
Sean Nichols, 253-946-7242, Sean.Nichols@southkingfire.org
Water Supply:
Fire Flow:
o A Certificate of Water Availability shall be requested from the water district and provided at the
time of building permit application.
Fire Hydrants:
o Existing hydrant is acceptable.
o Fire hydrants shall be in service prior to and during the time of construction.
Emergency Access:
Fire apparatus access roads shall comply with all requirements of Fire Access Policy 10.006
http://southkingfire.org/DocumentCenter/Home/View/24
Fire apparatus access roads shall be installed and made serviceable prior to and during the time of
construction.
Fire Sprinkler System:
Fire sprinklers are required due to the lack of an approved turnaround for the new proposed house.
CLOSING
This letter reflects the information provided at the preapplication meeting and is intended to assist you in
preparing plans and materials for formal application. We hope you found the comments useful to your
project. We have made every effort to identify major issues to eliminate surprises during the City’s review of
the formal application. The completion of the preapplication process in the content of this letter does not
Mr. Tam
December 2, 2021
Page 11
21-104278-00-PC Doc ID:81812
vest any future project application. Comments in this letter are only valid for one year as per FWRC
19.40.070 (4).
As you know, this is a preliminary review only and does not take the place of the full review that will follow
submission of a formal application. Comments provided in this letter are based on preapplication materials
submitted.
Modifications and revisions to the project as presented for this preapplication may influence and modify
information regarding development requirements outlined above. In addition to this preapplication letter,
please examine the complete FWRC and other relevant codes carefully. Requirements that are found in the
codes that are not addressed in this letter are still required for your project.
If you have questions about an individual comment, please contact the appropriate department representative
noted above. Any general questions can be directed towards me, the key project contact, Becky Chapin, at
253-835-2641, becky.chapin@cityoffederalway.com. We look forward to working with you.
Sincerely,
Becky Chapin
Senior Planner
enc: Master Land Use Application
Short Subdivision Submittal Requirements
Tree Unit Calculation
2021 Concurrency Application
Lakehaven Water & Sewer District Map
c: Sam Basmeh, Development Services Reviewer
Sarady Long, Senior Transportation Planner
Sean Nichols, South King Fire & Rescue
Kathleen Mathena, Lakehaven Water & Sewer District
Brian Asbury, Lakehaven Water & Sewer District
Emi Ohashi, emi@mdgllc.net
Drainage Report 06/15/2023 D:\PLE Project\Ohashi SP\Drainage
Engineer Conclusion
In our opinion, the proposed 2 Lot Residential Short Plat is feasible and will not pose significant impacts
to the adjacent properties and to the surrounding environment, provided that required infiltration BMP
devices are installed to mitigate for the sites developed conditions, and provided erosion control
measures are installed and maintained properly during construction operations as required by City of
Federal Way.