APPROVED STM RESUB1 BLD2023-1219+STORMWATER REPORT+1.25.2024_4.14.15_PM+4021251RESUB BLD2023-1219
Jan 29 2024
CITY OF EDMONDS
DEVELOPMENT SERVICES
DEPARTMENT 654 411 Ave S
Single Family Residence
654 411 Ave S
Edmonds, WA 98020
BLD 2023-1219
Stormwater Site Plan Report
Prepared for:
Jay and Merri Fulton
Date: September 13, 2023
Revised: January 24, 2024
1/24-/2022
Prepared by: Rob Long, PE
RAM Fnginininring, Inr,
19109 3611 Ave W, Suite 103, Lynnwood WA 98036
(425) 678-6960 RAMengineeringinc.com
COMPLIES WITH APPLICABLE
CITY STORMWATER CODE
03/21 /2024
Job No. 23-005
654 411 Ave S
Single Family Residence
Introduction: This summary report provides site design information for a single-family residence
at 654 4t" Ave S. This report includes stormwater analysis to support permit review and approval.
The property is located on the west side of 41" Ave S in the Northeast 1/4 of the Northeast 1/4 of
Section 26, Township 27N, Range 3E, W.M.
Site Address: Applicant:
654 4t" Ave S Jay Fulton and Merri Keefer
Edmonds, WA 98020 8630 112th Lane NE
Kirkland, WA 98033
Tax Parcel Number:
004009600101100
TABLE OF CONTENTS
SECTION PAGES
A. Project Overview.............................................................................................................................. 5
B. Existing Conditions Summary........................................................................................................... 1
C. Developed Site Hydrology................................................................................................................ 4
D. Soils Reports................................................................................................................................... 20
E. Construction SWPPPP Requirements................................................................................................ 2
F. Operation and Maintenance Guidelines............................................................................................ 5
R.4MEngineering, Inc.
RAM No. 23-005
654 4th Ave S SFR
Stormwater Site Plan Report
Page
A. PROJECT OVERVIEW:
This report provides engineering information for the proposed construction of a single family residence on
a 0.19 acre parcel; the project is located on the northwest corner of 41h Ave S and Erben Dr in the City of
Edmonds. The applicants, Jay and Merri Fulton propose to remove the existing residence and all existing
hard surface to construct a new single family residence with an attached garage and partially covered deck
on the subject site. This report provides the evaluation for the new single family residential development.
Summary of Minimum Requirements for Category 1 Project:
Minimum Requirement #1 — Preparation of Stormwater Site Plan. The proposed site development
consists of disturbing the entire 0.19 acres site with the removal of all existing improvements onsite. The
project will create/replace about 3,874 sf of hard surface area; thus, the project is classified as a Category 1
project per the City's classification system. Per ECDC 18.30, Category 1 projects must comply with
Minimum Requirements No. 1 through No. 5. The civil site development plans and this report have been
prepared to address the projects impacts.
Minimum Requirement #2 — Construction Stormwater Pollution Prevention (SWPPP). A construction
Stormwater Pollution Prevention Plan (SWPPP) has been incorporated into the site development plans. A
summary of the site's erosion control measures that evaluates the typical 13 elements of a SWPPP are
included in section E. The total site disturbance area (0.19 ac) of the project will not exceed one acre, thus
a formal Notice of Intent application for NPDES coverage will not be made to the Department of Ecology.
Minimum Requirement #3 —Source Control of Pollution. Specific source controls are not required for
single family residential sites. General requirements for these sites include preventing the discharge of
pollutants to the City's storm drainage system per Edmonds City Code Chapter 7.200 (Illicit Discharges).
This includes common household items such as pesticides, herbicides, fertilizers, detergents and fluids
from vehicle maintenance.
Single family residences shall incorporate DOE's S411 BMPs for landscape and lawn vegetation
management. Lawn and vegetation management can include control of objectionable weeds, insects,
mold, bacteria, and other pests with pesticides. Examples include weed control on golf course lawns,
access roads, and utility corridors and during landscaping; sap stain and insect control on lumber and logs;
rooftop moss removal; killing nuisance rodents; fungicide application to patio decks, and residential
lawn/plant care. It is possible to release toxic pesticides such as pentachlorophenol, carbamates, and
organometallics to the environment by leaching and dripping from treated parts, container leaks, product
misuse, and outside storage of pesticide contaminated materials and equipment. Poor management of the
vegetation and poor application of pesticides or fertilizers can cause appreciable stormwater
contamination.
RAMEngineering, Inc.
RAM No. 23-005
654 41" Ave S SFR
Stormwater Site Plan Report
Page A-1
Minimum Requirement #4 —Preservation of Natural Drainage Systems and Outfalls. The natural flow
path and outfall of the site has been significantly altered by the historic urban development. The site
generally slopes in a northwesterly direction; runoff flows across the adjacent alley and private property
towards 3rd Ave S. The curb and gutter system along the east side of 3rd Ave S collects and conveys runoff
in a northerly direction to a catch basin at the southeast corner of the intersection of 3rd Ave S and Howell
Way about 660 feet from the site. Stormwater collected in the City of Edmonds municipal separate storm
sewer systems (MS4) pipe system continues north and then discharges to Shellabarger creek about 200
feet north of 3rd Ave S and Howell Way (900 feet from the site).
Due to the fact there is no formal collection and conveyance system in the alley west of the site; the
project will discharge the site stormwater runoff to the pipe and catch basin MS4 within 4th Ave S along
the easterly boundary of the site. The stormwater system in 4th Ave S flows north to Howell Way and then
is directed west to 3rd Ave S merging with the existing site flow path about 860 ft via the 4th Ave S route.
Due to the fact the existing and developed flow paths mere within a % mile; the developed downstream
path is within the same threshold discharge area. Additional discussion and maps of the downstream path
are included in Section C below.
Minimum Requirement #5 — Onsite Stormwater Management. The proposed project is a category 1
project, thus is subject to the City's on -site stormwater management BMPs found in "List No. 1" in the
City's code. A site -specific geotechnical evaluation of the site's soil demonstrates that infiltration is a not a
viable option for stormwater management onsite. The project geotechnical evaluation recommends
infiltration not be used due to low infiltration rates encountered on site.
Additionally, adequate flow length paths are not available for any dispersion type BMP. Only post
construction soil amendment and BMP detention pipe are proposed for onsite stormwater BMP. A
summary table of the project Stormwater Management BMPs are provided below.
RAMEngineering, Inc.
RAM No. 23-005
654 41" Ave S SFR
Stormwater Site Plan Report
Page A-2
MR#5 Stormwater Management BMP List No. 1 Evaluation
Lawn and landscaped areas:
BMP
Viable
Limitations / Infeasibility Criteria
BMP T5.13: Post -Construction Soil Quality and Depth
Yes
BMP T5.13 shall be applied to the site post construction.
(Volume V, Chapter 11)
Roofs:
BMP T5.30: Full Dispersion
Infeasibility: A viable vegetated flow path 50 or 100 feet and
(Volume V, Chapter 3)
No
less than 20% is not achievable onsite.
BMP T5.10A: Downspout Full Infiltration Systems
Infeasibility: The project geotechnical evaluation recommends
(Volume V, Chapter 4)
No
infiltration not be used due to Hard Pan (type C) Soils
BMP T5.14 Rain Gardens
(Volume V, Chapter 11) or
Infeasibility: The project geotechnical evaluation recommends
BMP T7.30: Bioretention
No
infiltration not be used due to Hard Pan (type C) soils
(Volume V, Chapter 7)
BMP T5.1013: Downspout Dispersion Systems
Infeasibility: A viable vegetated flow path 50 or 100 feet and
(Volume V, Chapter 4)
No
less than 20% is not achievable onsite.
Detention Vaults or Pipes
A detention vault/pipe is viable and proposed to meet
(Edmonds Stormwater Addendum)
Yes
Minimum Requirement No. 5.
Infeasibility: The project geotechnical evaluation recommends
BMP T5.10C: Perforated Stub -out
infiltration not be used due to reasonable concerns about
(Volume V, Chapter 4)
No
erosion and slope failure of nearby slopes. Existing slopes
about 75 feet west of the subject site have been classified as
"erosion hazard" slopes.
Other Hard Surfaces:
BMP T5.30: Full Dispersion
Infeasibility: A viable vegetated flow path 50 or 100 feet and
(Volume V, Chapter 3)
No
less than 20% is not achievable onsite.
BMP T5.10A: Full Infiltration
(Volume V, Chapter 4)
Infeasibility: The project geotechnical evaluation recommends
BMP T5.15: Permeable Pavement
No
infiltration not be used due to Hard Pan (type C) soils
(Volume V, Chapter 5)
BMP T5.14 Rain Gardens
(Volume V, Chapter 11) or
Infeasibility: The project geotechnical evaluation recommends
BMP T7.30: Bioretention
No
infiltration not be used due to Hard Pan (type C) soils
(Volume V, Chapter 7)
BMP T5.12: Sheet Flow Dispersion
Infeasibility: A viable vegetated flow path 50 or 100 feet and
(Volume V, Chapter 3)
No
less than 20% is not achievable onsite.
Detention Vaults or Pipes
A detention vault/pipe is viable and proposed to meet
(Edmonds Stormwater Addendum)
Yes
Minimum Requirement No. 5.
RAMEngineering, Inc.
RAM No. 23-005
654 41" Ave S SFR
Stormwater Site Plan Report
Page A-3
Parcel (Vicinity) Map:
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Stormwater Site Plan Report
Page A-4
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B. EXISTING CONDITIONS SUMMARY
Existing Conditions. The total site consists of 8,168 sf (0.19 acres) and is currently occupied by an existing
single-family residence, and detached garage. The site's existing garage is accessed via an alley along the
west boundary of the subject site. The existing house is surrounded by grass lawn and landscape areas.
The site is surrounded by single family residences to the west, and north; and 4t" Ave S along the east
boundary and Erben Dr along the southern boundary. (see aerial photo below).
The site generally slopes in a northwesterly direction at a relatively flat to moderate slope with only 3 feet
of drop across the site. No defined drainage courses are found on -site, and stormwater runoff would
sheet flow west/northwesterly to the alley along the westerly boundary of the site. No stream or
wetlands are located onsite; Shellabarger Creek is located about 1,200 feet northwest of the site.
Additional discussion of the local drainage basin and downstream path is discussed in Section C of this
report.
Soils: In accordance with the project's site -specific geotechnical engineering evaluation by Earth Solutions NW,
LLC the on -site soils consist of Everett very gravely sandy Loam (USCS: SP-SM and SP) advance outwash
deposits. The subject site soils are generally consistent with Alderwood-Everett series soil. Full soils
description is included in the project's site specific geotechnical engineering study by Earth Solutions NW, LLC.
Aerial Photo (City of Edmonds GIS, 2022 photo)
RAMEngineering, Inc.
RAM No. 23-005
654 41" Ave S SFR
Stormwater Site Plan Report
Page B-1
C. DEVELOPED SITE HYDROLOGY.
Developed Conditions. The proposed project includes the construction of a single family residence with
an attached garage, partially covered deck, and associated driveway and utilities. All existing structures
and impervious (hard) surface onsite will be removed/replaced with the site development; landscaping
and grass lawn around the new residence will stabilize the site upon building construction.
The project proposes to create and/or replace 3,874 sf of hard surface with the complete site
development, all existing hard surface will be removed with the project site development. The following is
a summary of the proposed new/replaced hard surface areas:
Total Hard Surface to be Mitigated = 3,874 sf (0.07584 ac)
Roof Area = 3,304 sf
Walkway/Patio Area = 352 sf
Driveway Area = 218 sf
Total Pervious Surface (Lawn/Landscape) = 4,294 sf (0.0986 ac)
Lot Lawn/Landscape Area = 4,294 sf
In accordance with the Edmonds City Code (18.30) Category 1 projects shall meet MR#5 (see discussion in
Section A above) and provide on -site stormwater management. To meet these criteria, the proposed hard
surfaces of the site shall implement BMPs from "List No. 1" or meet the LID performance standard.
As discussed above in the MR#5 evaluation above in Section A, an individual lot stormwater BMP
detention pipe (Edmonds Storm water Addendum Section 6.3) will be utilized to manage the project's
new/replaced hard surfaces. BMP T5.13: Post -Construction Soil Quality and Depth will be applied to the
disturbed pervious areas of the site development.
The total proposed new replaced hard surface of 3,874 sf will be mitigated with a detention pipe system.
The onsite detention pipe systems have been sized in accordance with the Edmonds Stormwater
Addendum simplified sizing approach, below is a summary of the system:
Detention Pipe Sizing Calculations:
■ Hard Surface =
■ Required 18" Detention Pipe =
■ Provided 18" Detention Pipe =
3,874 sf
131.76 ft = (0.034 x 3,874 sf)1
132 ft
1. Per Edmonds Stormwater Addendum simplified sizing approach Section 6.3.1.
Additionally, all disturbed pervious (lawn and landscape) areas will preserve or restore the health and water -
holding capacity of the soils by compost -amending (Per DOE BMP T5.13: Post -Construction Soil Quality and
Depth). See attached City of Edmonds Standard Detail SD-642 criteria for BMP T5.13: Post -Construction Soil
Quality and Depth.
RAMEngineering, Inc. 654 41" Ave S SFR
RAM No. 23-005 Stormwater Site Plan Report
Page C-1
UNDISTURBED
NATIVE VEGETATION
UNDISTURBED NATIVE SOIL
2" ORGANIC MULCH
3" OF COMPOST
INCORPORATED INTO 5" OF
SITE SOIL (TOTAL AMENDED
DEPTH OF 9.5", FOR A
SETTLED DEPTH OF 8")
SUBSOIL SCARIFIED 4" BELOW
COMPOST AMENDED LAYER
(12" BELOW SOIL SURFACE)
2" ORGANIC
MULCH
6" IMPORTED
TOPSOIL MIX
(COMPACTED
DEPTH)
SUBSOIL IS
SCARIFIED 6"
BELOW
IMPORTED
TOPSOIL MIX
UNDISTURBED PLANTS
(SEE NOTE 1)
UNDISTURBED TURF (LAWN)
AREAS (SEE NOTE 1)
PLANTING BEDS TURF (LAWN) AREAS
m
8"
UNDISTURBED
TURF/LAWN/LANDSCAPE
UNDISTURBED NATIVE SOIL
STEEP SLOPE NOTE:
AMENDED SOILS SHOULD NOT BE
INSTALLED ON FINISHED SLOPES
EXCEEDING 33%. AREAS EXCEEDING
33% SHALL BE STABILIZED PER THE
ENGINEER/GEOTECH OF RECORD.
3RASS: SEED OR SOD
1.75" OF COMPOST INCORPORATED
NTO 6.25" OF SITE SOIL (TOTAL
4MENDED DEPTH OF 9.5", FOR A
SETTLED DEPTH OF 8")
SUBSOIL SCARIFIED 4" BELOW
COMPOST AMENDED LAYER
,12" BELOW SOIL SURFACE)
OPTION 2 — AMEND IN PLACE OR
STOCKPILE
AND AMEND
GENERAL NOTES:
PLANTING BEDS TURF (LAWN) AREAS
1. AREAS OF NO DISTURBANCE
-GRASS:
SHALL BE FENCED AND EXISTING
,� ���,�������
SEED
VEGETATIONANDSOIL BE
O"
R
SHALL
ON
f II =_ — 1=III=III=I IT- aI IIIE-1II
I �I T1=r�ll� 1T1=1T1�T1=1T1�T1�T1=ul
IMPACTS.
I I I I I I I —III —III— I I I I I I —I T I —I I III— T
- II
6" IMPORTED
2. TO MEASURE SETTLED DEPTH,
I I- —I I -III -III -III II -III -III -III -II
L=JJl fJ1-JJJJ1 11= �J-11=L=�=
II -III -II III-III-III-III=III II -III -III -III -II
TOPSOIL MIX
WATER SOIL SUFFICIENTLY TO
FULLY SATURATE WITHOUT
III=1Tf= 1TI= 1Tf— III -I �11=1TI=III=1(i=
(COMPACTED
CAUSING EROSION.
111- Tff 1Tf 1=111�Tf=1Tf=III=TfI=_
I11=III=111= -1 6' III-i
DEPTH)
3. COMPOST SHALL MEET SPEC.
=Ih Ilf / I \/ \�\ I //\\ III- III/�
SUBSOIL IS11
REQUIREMENTS IN THE
EDMONDS STORMWAT R 2017
RIFIED 6
ADDENDUM (CHECKLIST 7).
BELOW
IMPORTED
4. COMPACTION OF TOPSOIL (WHERE
TOPSOIL MIX
REQUIRED) TO BE TO 85% (MAX)
OF THE MAXIMUM DRY DENSITY
OPTION 3 — IMPORT TOPSOIL
PER MODIFIED PROCTOR TEST
(ASTM D 1557).
-� POST CONSTRUCTION SOIL RaPIRioN2o2iE
CITY OF EDMONDS QUALITY AND DEPTH
PUBLIC WORKS STANDARD
4T1
D
DEPARTMENT DETAIL
Fs t . jag° APPROVED BY: R. ENGLISH S D — 642
RAAf Engineering, Inc.
RAM No. 23-005
654 41h Ave S SFR
Stormwater Site Plan Report
Page C-2
Offsite Basin Analysis. The site is located in the Shellabarger Creek watershed basin. The Shellabarger
Creek basin is an urban basin that collects stormwater runoff primarily from residential areas in the City
Edmonds. Shellabarger Creek generally flows westerly and ultimately discharges to Puget Sound
approximately 1.0 mile from the site (see attached watershed map).
The subject site slopes in a northwesterly direction and runoff sheet -flows to the alley along the westerly
boundary of the site. There is no stormwater collection or conveyance system in the alley and surface
runoff continues to flow in a northwesterly direction towards 3rd Ave S. The curb and gutter system along
the east side of 3rd Ave S collects and conveys runoff in a northerly direction to a catch basin at the
southeast corner of the intersection of 3rd Ave S and Howell Way about 660 feet from the site.
Stormwater collected in the City of Edmonds municipal separate storm sewer systems (MS4) pipe system
continues north and then discharges to Shellabarger creek about 200 feet north of 3rd Ave S and Howell
Way (900 feet from the site). Shellabarger creek travels in a westerly direction until it eventually
discharges into the Puget Sound about 1.0 mile downstream of the site.
Due to the fact there is no formal collection and conveyance system in the alley west of the site; the
project will discharge the site stormwater runoff to the pipe and catch basin MS4 within 4th Ave S along
the easterly boundary of the site. The stormwater system in 4th Ave S flows north to Howell Way and then
is directed west to 3rd Ave S merging with the existing site flow path about 860 ft via the 4th Ave S route.
Due to the fact the existing and developed flow paths mere within a % mile; the developed downstream
path is within the same threshold discharge area. See the Downstream Drainage Facility Map and
Watershed Basin Map delineating the downstream path to the discharge point in the Puget Sound
attached below.
Downstream Drainage Facility Map (City of Edmonds GIS)
1 �: CL:�= � O., ,�.� Wit'. ❑' "d-
(Predeveloped flows are shown in red and developed flows shown in blue)
RAMEngineering, Inc.
RAM No. 23-005
654 41" Ave S SFR
Stormwater Site Plan Report
Page C-3
Watershed Basin Map:
N
v FIGURE B-1
C I T Y O F E D M O N D S
/���
Lund's Gulch'"o,, /\1
° i.a° WATERSHEDS
I
3 I
I
Deer Creek ® Perrinville
i I --
i
Edmonds Marsh Puget Sound
Meadowdale A -'
Edmonds Way EL Puget Sound Piped
Meadowdale B dd
Fruitdale Shell Creek
�aa�end
Good Hope Pond J Shellabarger
Halls Creek _Southwest Edmonds A
169th St S%
'Nil
Hindley Creek Southwest Edmonds B
Lake Ballinger Stilthouse Creek
Out II CreekStiltltouse Creek /
i
-
Lund's Gulch Talbot Park A
-Taleot"6
Meadowdale A Talbot Park B
i
`
Meadowdale BTerrace Creek
Terrace Creek
I
Northstream Westgate Pond
Outfall Creek Willow Creek
'nville
0 1,010 2,000 4,000 6,000 8,000
) a' -'
Pug
a P ;'
/
Feet
OUnd
cc
1 in = 2,000 ft
Talbot Park A
talb&
m i
Park B
-
t_I
No warranty of arry sort, including accuracy, fitness, or merchantability I
accompany this product. I
March 30, 2010 r ��
A
SITE
RAN Engineering, Inc.
RAM No. 23-005
Fruitdale
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3
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654 4t" Ave S SFR
Stormwater Site Plan Report
Page C-4
D. SOILS REPORTS:
1. Geotechnical Evaluation Letter
Prepared by: Earth Solutions NW, LLC
Date: April 12, 2023
Pages: 19
MAN =ngineering, Inc.
RAM No. 23-005
654 4t" Ave S SFR
Stormwater Site Plan Report
Page D-1
April 12, 2023
ES-9113
Mr. Jay Fulton
8630 — 112t" Lane Northeast
Kirkland, Washington 98033
Subject: Geotechnical Evaluation
Proposed Single -Family Residence
654 — 4t" Avenue South
Edmonds, Washington
Earth
Solutions
NW«C
Earth Solutions NW LLC
Geotechnical Engineering, Construction
Observation/Testing and Environmental Services
Reference: Encompass Engineering & Surveying
Boundary & Topographic Survey, Job No. 22730, dated January 30, 2023
Minard, J.P.
Geologic Map MF-1541 (Edmonds East/West Quadrangles), dated 1983
Soil Survey of Snohomish County Area, Washington, issued July 1983
Palmer, S.P. et al.
Liquefaction Susceptibility Map of Snohomish County, dated September 2004
Snohomish County Planning and Development Services
Seismic Hazard Areas Map, dated February 1, 2016
City of Edmonds, Washington
1. Edmonds City Code (ECC) Chapter 23.80
2. Interactive GIS Mapping Portal
Dear Mr. Fulton:
As requested, Earth Solutions NW, LLC (ESNW) has prepared this geotechnical evaluation letter
report for the proposed project. We performed our work in general accordance with the scope of
services outlined in the proposal dated March 1, 2023, which was authorized on March 3, 2023.
A summary of the subsurface exploration, laboratory analyses, and recommendations with
respect to the proposed construction are provided in this letter report.
15365 N.E. 90th Street, Suite 100 0 Redmond, WA 98052 0 (425) 449-4704 0 FAX (425) 449-4711
Mr. Jay Fulton
April 12, 2023
Protect & Site Description
ES-9113
Page 2
The subject site is located immediately northwest of the intersection between 41h Avenue South
and Erben Drive, in Edmonds, Washington. The project area consists of one tax parcel
(Snohomish County Parcel No. 004096-001 -011 -00) and totals about 0.19 acres of land area.
The approximate site location is depicted on Plate 1 (Vicinity Map).
The property is currently developed with a single-family residence and associated improvements.
Per the referenced topographic survey, the existing topography is relatively level, with an
estimated maximum of about three feet of topographic relief across the property. The site is
bordered to the north and west by existing residential development and to the south and east by
Erben Drive and 41h Avenue South, respectively.
We understand the existing structure and site improvements will be removed, and a new single-
family residence with associated improvements will be constructed. At the time of letter report
preparation, neither site plans nor specific building load values were available for review;
however, we anticipate that the new single-family residence will consist of relatively lightly loaded
wood framing supported on conventional foundations. Based on our experience with similar
projects, we estimate wall loads of about 2 to 3 kips per linear foot and slab -on -grade loading of
150 pounds per square foot (psf) will be incorporated into the final design.
Subsurface Conditions
An ESNW representative observed, logged, and sampled two test pits on March 21, 2023. The
test pits were advanced at accessible locations within the property boundaries using a mini-
trackhoe and operator retained by ESNW. The test pits were completed to assess and classify
the site soils, to characterize the groundwater conditions within areas proposed for new
development, and to complete one small-scale Pilot Infiltration Test at a location designated by
the client. The maximum exploration depth was approximately seven -and -one-half feet below
the existing ground surface (bgs).
The approximate locations of the test pits are depicted on Plate 2 (Test Pit Location Plan). Please
refer to the attached test pit logs for a more detailed description of subsurface conditions.
Representative soil samples collected at the exploration locations were analyzed in general
accordance with Unified Soil Classification System (USCS) and United States Department of
Agriculture (USDA) methods and procedures.
Topsoil and Fill
Topsoil at the test pit locations was observed extending between 30 and 36 inches bgs. The
observed topsoil profiles were anomalously thick for typical topsoil thicknesses atop glacial drift
deposits in the Puget Sound region. Scrap metal and PVC plastic debris were encountered within
both test pit excavations and within the topsoil profiles, suggesting that the topsoil profile has
been thickened by the addition of organic fill (thus resulting in the relatively thick topsoil sections
observed). It is possible that deeper or shallower pockets of topsoil may be encountered locally
across the site. Topsoil can be characterized by its dark brown color, the presence of fine organic
material, and small root intrusions.
Earth Solutions NW. LLC
Mr. Jay Fulton ES-9113
April 12, 2023 Page 3
Neither structural fill nor non -organic fill were observed during the subsurface investigation. As
noted above, topsoil fill was observed at both test locations.
Native Soil
Underlying the topsoil and fill, native soils were encountered and characterized as transitional
bed deposits consisting primarily of medium dense to dense silty sand with gravel (USCS: SM).
Thin laminations and interbeds of silt and sand as well as iron oxide staining were noted within
the native deposits. Notably, cemented soils were not observed. The native transitional bed
deposits extended to the termination depth of both test pits.
Based on laboratory analyses of representative soil samples, the native transitional bed deposits
have a fines content between about 11 and 19 percent and were primarily observed in a moist to
wet condition at the time of exploration.
Geologic Setting
Geologic mapping of the area identifies transitional bed deposits (Qtb) as the primary geologic
unit underlying the subject site. Vashon glacial till (Qvt) is mapped immediately south and east
of the site, and Whidbey Formation sediments (Qw) are mapped immediately north and west of
the site.
Transitional bed deposits are characterized as both glacial and non -glacial deposits comprised
mostly of massive, thick or thin beds and laminae of clay, silt, and fine to very fine sand deposited
in lakes beyond the ice front and in fluvial systems prior to the advance of glacial ice.
Vashon glacial till is described as a non -sorted mixture of clay, silt, sand, and gravel in variable
amounts that was deposited directly beneath the glacier as it advanced over older sediment and
bedrock. Whidbey Formation sediments consist of bedded, compact, commonly oxidized,
medium to coarse grained sand, commonly exhibiting contorted bedding.
USDA soil mapping indicates the site is underlain by Everett very gravelly sandy loam on 0 to 8
percent slopes. Everett series soils formed on terraces and outwash plains in glacial outwash
soils. Per the referenced USDA soil survey, this soil unit maintains slow surface water runoff and
a slight hazard of water erosion.
In our opinion, the native soils observed during the subsurface exploration are representative of
transitional bed deposits and are generally consistent with the geologic and soil mapping
resources outlined in this section.
Groundwater
Natural groundwater seepage was not encountered during the March 2023 field exploration.
However, groundwater seepage is common within glacially derived deposits. In our opinion,
zones of perched groundwater should be expected within site excavations, especially if
construction occurs during the wet season. Groundwater seepage rates and elevations may
fluctuate depending on many factors, including precipitation duration and intensity, the time of
year, and soil conditions. In general, groundwater flow rates are higher during the winter, spring,
and early summer months.
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Geologically Hazardous Areas Review
ES-9113
Page 4
ESNW reviewed ECC Chapter 23.80 to evaluate the presence of geologically hazardous areas
at the subject site. We also reviewed the City of Edmonds (City) online GIS resource, which
depicts suspected geologically hazardous areas within city limits. Geologically hazardous areas
in the City include areas susceptible to erosion, land sliding, earthquake, or other geological
events.
Based on our review, the site does not contain areas susceptible to erosion or landslide hazards.
However, a fault strand associated with the Southern Whidbey Island Fault zone is located within
about 500 feet (to the southwest) of the subject site. As such, seismic hazard is discussed in the
following section.
Seismic Hazard Areas
Seismic hazard areas in the City are areas subject to severe risk of damage as a result of
earthquake -induced ground shaking, slope failure, settlement, soil liquefaction, lateral spreading,
or surface faulting.
Liquefaction is a phenomenon that can occur within a soil profile as a result of an intense ground
shaking or loading condition. Most commonly, liquefaction is caused by ground shaking during
an earthquake. Soil profiles that are loose, cohesionless, and present below the groundwater
table are most susceptible to liquefaction. During the ground shaking, the soil contracts, and
porewater pressure increases. The increased porewater pressure occurs quickly and without
sufficient time to dissipate, resulting in water flowing upward to the ground surface and a liquefied
soil condition. Soil in a liquefied condition possesses very little shear strength in comparison to
the drained condition, which can result in a loss of foundation support for structures.
In our opinion, and consistent with the depiction on the referenced liquefaction susceptibility map,
site susceptibility to liquefaction may be considered very low. The absence of a shallow
groundwater table and the relatively dense and fine-grained characteristics of the native soil were
the primary bases for this opinion.
Fault mapping resources indicate an inferred Class B fault trace, in association with the Southern
Whidbey Island Fault Zone, is located within about 500 feet (to the southwest) of the subject site,
trending in a northwest -southeast orientation. Class B faults are defined as faults for which
Quaternary -age (within the past 2,588,000 years) deformation is suspected but insufficient
evidence has been gathered to support the determination. The locations and activity of Class B
faults are inferred based on best available data but have not been confirmed.
During the fieldwork, ESNW did not observe any evidence of faulting, deformation, or other
disturbances within the native stratigraphy or surficial geomorphology. We also reviewed readily
available LIDAR mapping resources for evidence of fault scarps or associated linear features on
site and in the surrounding area. No evidence of surficial deformation was observed during
LIDAR review.
Earth Solutions NW. LLC
Mr. Jay Fulton ES-9113
April 12, 2023 Page 5
With respect to the subject site, earthquake magnitude would be dictated by the type of
earthquake event, e.g., shallow crustal, intra-plate, or subduction zone event. Although evidence
of shallow faults and related lineaments have been identified throughout the Puget Sound region
(Seattle Fault, South Whidbey Island Fault Zone, and others), evidence of surface fault
expressions on or in the vicinity of the subject site has not been identified. In any case, seismic
activity associated with a shallow crustal event would be expected to produce relatively low to
moderate earthquake magnitude of relatively short duration. In terms of larger magnitude events
associated with intra-plate and subduction zone events, distance between the source of these
events and the site is expected to be greater. However, a longer duration of ground shaking
would likely occur.
Based on the field observations and analysis outlined above, it is our opinion the risk of surface
rupture during a seismic event is very low to negligible, and the site does not meet the ECC
definition of a seismic hazard area.
Geotechnical Recommendations
In our opinion, construction of the proposed single-family residence is feasible from a
geotechnical standpoint. The geotechnical recommendations, conclusions, and considerations
provided in the following sections are intended to support the proposed construction.
In -situ and Imported Soil
The in -situ soils encountered at the subject site generally have a moderate to high sensitivity to
moisture and were generally in a moist to wet condition at the time of exploration. Soils
anticipated to be exposed on site will degrade if exposed to wet weather and construction traffic.
Compaction of the soils to the levels necessary for use as structural fill may be difficult or
impossible during wet weather conditions. Soils encountered during site excavations that are
excessively over the optimum moisture content will likely require aeration or treatment prior to
placement and compaction. Conversely, soils that are substantially below the optimum moisture
content will require moisture conditioning (by adding water) prior to use as structural fill. An
ESNW representative should be contacted to evaluate the suitability of in -situ soils for use as
structural fill at the time of construction.
Imported soil intended for use as structural fill should be evaluated by ESNW during construction.
The imported soil must be workable to the optimum moisture content, as determined by the
Modified Proctor Method (ASTM D1557), at the time of placement and compaction. During wet
weather conditions, imported soil intended for use as structural fill should consist of a well -graded,
granular soil with a fines content of 5 percent or less (where the fines content is defined as the
percent passing the Number 200 sieve, based on the minus three -quarter -inch fraction).
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Structural Fill
ES-9113
Page 6
Structural fill is defined as compacted soil placed in foundation, slab -on -grade, roadway,
permanent slope, retaining wall, and utility trench backfill areas. Soils placed in structural areas
should be placed in loose lifts of 12 inches or less and compacted to a relative compaction of 95
percent, based on the laboratory maximum dry density as determined by the Modified Proctor
Method (ASTM D1557). For soil placed in utility trenches underlying structural areas, compaction
requirements are dictated by the local city, county, or utility district, and are typically specified to
a relative compaction of at least 95 percent.
Subgrade Preparation
Following site stripping, ESNW should be contacted to observe the subgrade to confirm soil
conditions are as anticipated and to provide supplementary recommendations for subgrade
preparation, as necessary. In general, foundation subgrade on native cut surfaces should be
compacted in situ to a minimum depth of one foot below the design subgrade elevation.
Where encountered, existing fill soils should be removed and/or reworked to the specifications of
structural fill previously detailed in this letter report. Topsoil and organic -rich soils are not suitable
for structural support and should be removed from areas proposed for new structural loading.
Uniform compaction of structural fill and the foundation and slab subgrade areas will establish a
relatively consistent subgrade condition below the foundation and slab elements. Supplementary
recommendations for subgrade improvement may be provided at the time of construction and
would likely include further mechanical compaction or overexcavation and replacement with
suitable structural fill.
Void Space Restoration
The process of removing the existing structures may produce voids where existing foundations
are removed and where crawl space areas may have been present. Complete restoration of
voids from old foundation areas must be executed as part of the subgrade preparation activities.
The following guidelines for preparing subgrade areas should be incorporated into the final
design:
• Where voids and related demolition disturbances extend below planned subgrade
elevations, restoration of these areas should be completed. Structural fill should be used
to restore voids or unstable areas resulting from the removal of existing structural
elements.
• Recompact, or overexcavate and replace, areas of existing fill exposed at the design
subgrade elevations. Overexcavations should extend into competent native soils and
structural fill should be utilized to restore subgrade elevations, as necessary.
• ESNW should confirm subgrade conditions, as well as the required level of recompaction
and/or overexcavation and replacement, during site preparation activities. ESNW should
also evaluate the overall suitability of prepared subgrade areas following site preparation
activities.
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Foundations
ES-9113
Page 7
The proposed residential structure can be supported on conventional spread and continuous
footings bearing on undisturbed (competent) native soil, compacted native soil or structural fill, or
new structural fill placed atop a competent subgrade surface. Thick sections of topsoil fill were
encountered at the test pit locations extending at least 30 to 36 inches bgs in the western portion
of the site. Where encountered, the existing organic -rich fill soils should be removed from
structural areas of the site.
In general, competent native soil suitable for support of foundations will likely be encountered
beginning at depths of about three feet bgs. Where loose or unsuitable soil conditions are
encountered at foundation subgrade elevations, compaction of the soils to the specifications of
structural fill or overexcavation and replacement with suitable structural fill will likely be
necessary. An ESNW representative should be contacted to confirm the suitability of foundation
subgrades at the time of construction.
Provided the structures will be supported as described above, the following parameters may be
used for design of the new foundations:
• Allowable soil bearing capacity 2,500 psf
• Passive earth pressure
• Coefficient of friction
300 pcf
NE,I K
A one-third increase in the allowable soil bearing capacity can be assumed for short-term wind
and seismic loading conditions. The passive earth pressure and coefficient of friction values
include a safety factor of 1.5. With structural loading as expected, total settlement in the range
of one inch is anticipated, with differential settlement of about one-half inch. Most of the
anticipated settlement should occur during construction as dead loads are applied.
Slab -on -Grade Floors
Slab -on -grade floors for the proposed residence should be supported on competent, firm, and
unyielding subgrades comprised of competent native soil or compacted structural fill. Unstable
or yielding subgrade areas should be recompacted or overexcavated and replaced with suitable
structural fill prior to slab construction. As noted previously in this letter report, areas with existing
fill soil should be removed and/or reworked to the specifications of structural fill. Organic -rich
soils should be removed from slab subgrades prior to slab construction.
A capillary break consisting of at least four inches of free -draining crushed rock or gravel should
be placed below each slab. The free -draining material should have a fines content of 5 percent
or less (percent passing the Number 200 sieve, based on the minus three-quarter inch fraction).
In areas where slab moisture is undesirable, installation of a vapor barrier below the slab should
be considered. If a vapor barrier is to be utilized, it should be a material specifically designed for
use as a vapor barrier and should be installed in accordance with the specifications of the
manufacturer.
Earth Solutions NW. LLC
Mr. Jay Fulton ES-9113
April 12, 2023 Page 8
Retaining Walls
Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The
following parameters may be used for retaining wall design:
• Active earth pressure (unrestrained condition)
• At -rest earth pressure (restrained condition)
• Traffic surcharge* (passenger vehicles)
• Passive earth pressure
• Coefficient of friction
• Seismic surcharge
* Where applicable.
t Where H equals the retained height (in feet).
35 pcf
55 pcf
70 psf (rectangular distribution)
300 pcf
0.40
8H psft
The above passive earth pressure and coefficient of friction values include a safety factor of 1.5.
Additional surcharge loading from adjacent foundations, sloped backfill, or other loads should be
included in the retaining wall design. Retaining walls should be backfilled with free -draining
material that extends along the height of the wall and a distance of at least 18 inches behind the
wall. The upper 12 inches of the wall backfill may consist of a less permeable soil, if desired.
Drainage should be provided behind retaining walls such that hydrostatic pressures do not
develop. If drainage is not provided, hydrostatic pressures should be included in the wall design.
A perforated drainpipe should be placed along the base of the wall and connected to an approved
discharge location. A typical retaining wall drainage detail is provided on Plate 3.
Drainage
Groundwater seepage is likely to be encountered within site excavations depending on the time
of year grading operations take place. Temporary measures to control surface water runoff and
groundwater during construction would likely involve interceptor trenches, interceptor swales, and
sumps. ESNW should be consulted during preliminary grading to identify areas of seepage and
provide recommendations to reduce the potential for seepage -related instability.
Finish grades must be designed to direct surface drain water away from structures. Water must
not be allowed to pond adjacent to structures. The grade adjacent to the buildings should be
sloped away at a gradient of at least 2 percent for a horizontal distance of at least four feet. In
our opinion, a foundation drain should be installed along building perimeter footings. A typical
foundation drain detail is provided on Plate 4.
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Infiltration Feasibility
ES-9113
Page 9
ESNW completed one small-scale Pilot Infiltration Test (PIT) at test location TP-2 at a depth of
approximately four -and -one-half feet bgs. The small-scale PIT was completed in general
accordance with the applicable requirements of the 2019 Stormwater Management Manual for
Western Washington (2019 SWMMWW), which has been adopted by the City for flow control
design.
Based on the results of the PIT, the measured (short-term) infiltration rate recorded at the
conclusion of the infiltration testing was 0.8 inches per hour (in/hr). Per the 2019 SWMMWW, a
series of correction factors must be applied to the measured rate to calculate an appropriate
design rate. The following correction factors were selected:
• Site variability, CFv 0.7
• Test method, CFT 0.5
• Maintenance, CFm 0.9
Upon incorporation of the correction factors, a design (long-term) infiltration rate of 0.25 in/hr is
recommended for this site. Because this rate is relatively low, full infiltration is not considered
feasible from a geotechnical standpoint; however, small-scale (or limited -scale) flow control BMP
implementation may be feasible depending on BMP type, location, and depth. In any case,
overflow provisions are recommended for any flow control BMP design element on this site, and
in the event overflow provisions are not or cannot be incorporated into the design, it is our opinion
infiltration should not be considered feasible from a geotechnical standpoint.
Regarding groundwater protection, and in accordance with the subsurface characterization
criteria for infiltration BMPs (outlined in Chapter 5 of Volume V of the 2019 SWMMWW), shallow
samples of topsoil were collected and are being held in our laboratory for future organic content
and cation exchange capacity analyses, upon request. The samples will be discarded after 60
days unless requested otherwise by the client.
ESNW can provide additional consulting services and design considerations regarding infiltration
and/or BMP feasibility, upon request. ESNW should be contacted to confirm suitable native soils
are exposed at the design facility subgrade elevation(s) and location(s) during construction.
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Seismic Design
ES-9113
Page 10
The 2018 International Building Code (2018 IBC) recognizes the most recent edition of the
Minimum Design Loads for Buildings and Other Structures manual (ASCE 7-16) for seismic
design, specifically with respect to earthquake loads. Based on the soil conditions encountered
at the test pit locations, the parameters and values provided below are recommended for seismic
design per the 2018 IBC.
Parameter
Value
Site Class
D*
Mapped short period spectral response acceleration, Ss (g)
1.283
Mapped 1-second period spectral response acceleration, S1 (g)
0.451
Short period site coefficient, Fa
1.0
Long period site coefficient, Fv
1.849t
Adjusted short period spectral response acceleration, SMs (g)
1.283
Adjusted 1-second period spectral response acceleration, Sm1 (g)
0.834t
Design short period spectral response acceleration, SIDS (g)
0.856
Design 1-second period spectral response acceleration, SD1 (g)
0.556t
Assumes medium dense to dense native soil conditions, encountered to a maximum depth of seven -and -one-half
feet bgs during the March 2023 field exploration, remain dense to at least 100 feet bgs.
t Values assume Fv maybe determined using linear interpolation per Table 11.4-2 in ASCE 7-16.
As indicated in the table footnote, several of the seismic design values provided above are
dependent on the assumption that site -specific ground motion analysis (per Section 11.4.8 of
ASCE 7-16) will not be required for the subject project. ESNW recommends the validity of this
assumption be confirmed at the earliest available opportunity during the planning and early
design stages of the project. Further discussion between the project structural engineer, the
project owner, and ESNW may be prudent to determine the possible impacts to the structural
design due to increased earthquake load requirements under the 2018 IBC. ESNW can provide
additional consulting services to aid with design efforts, including supplementary geotechnical
and geophysical investigation, upon request.
Liquefaction susceptibility is discussed in the Seismic Hazard Areas section in this report.
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Limitations & Additional Services
ES-9113
Page 11
This letter report has been prepared for the exclusive use of Mr. Jay Fulton and his
representatives. The recommendations and conclusions provided in this letter report are
professional opinions consistent with the level of care and skill that is typical of other members in
the profession currently practicing under similar conditions in this area. A warranty is neither
expressed nor implied. If the design assumptions outlined herein either change or are incorrect,
ESNW should be contacted to review the recommendations provided in this letter report. ESNW
should be contacted to review the final design to confirm that our geotechnical recommendations
have been incorporated into the plans.
ESNW should be retained to provide earthwork observations and testing services during
construction. Variations in the soil and groundwater conditions observed at the exploration
locations may exist and may not become evident until construction. ESNW should reevaluate
the conclusions provided in this letter report if variations are encountered.
We appreciate the opportunity to be of service to you and trust this letter meets your current
needs. Should you have any questions, or require additional information, please call.
Sincerely,
EARTH SOLUTIONS NW, LLC
b'1W6-- �Ly
Brian C. Snow, G.I.T.
Senior Staff Geologist
04/12/2023
Keven D. Hoffmann, P.E.
Associate Principal Engineer
Attachments: Plate 1 — Vicinity Map
Plate 2 — Test Pit Location Plan
Plate 3 — Retaining Wall Drainage Detail
Plate 4 — Footing Drain Detail
Test Pit Logs
Grain Size Distribution
Earth Solutions NW. LLC
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Reference: NORTHsollutions
Earth 1
Snohomish County, Washington
Observation/Testing00!
Open StreetMap.org
40
Vicinity Map
Fulton Property
Edmonds, Washington
Drawn MRS
Date 04/07/2023
Proj. No. 9113
NOTE: This plate may contain areas of color. ESNW cannot be
responsible for any subsequent misinterpretation of the information
Checked BCS
Date April 2023
Plate 1
resulting from black & white reproductions of this plate.
i
69 _ � ` 701
69 -
W TP=2 — ; 'I72
70
_—I
72
ERBEN DRIVE
LEGEND
TP-1 Approximate Location of
— . — ESNW Test Pit, Proj. No.
ES-9113, Mar. 2023
Subject Site
= Existing Building
NOTE: The graphics shown on this plate are not intended for design
purposes or precise scale measurements, but only to illustrate the
approximate test locations relative to the approximate locations of
existing and / or proposed site features. The information illustrated
is largely based on data provided by the client at the time of our
study. ESNW cannot be responsible for subsequent design changes
or interpretation of the data by others.
NORTH
0 15 30 60
1 "=30' � �
Scale in Feet
Test Pit Location Plan
Fulton Property
Edmonds, Washington
NOTE: This plate may contain areas of color. ESNW cannot be Drawn MRS Date 04/07/2023 Pro No. 9113
responsible for any subsequent misinterpretation of the information 1
resulting from black & white reproductions of this plate. Checked BCS Date April 2023 Plate 2
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0 0 0 0 oo
0 0 0 000 o0 o 000
o 0 0 0 g o
Ooop o 0 0o 00 p o oo
0
0 o So o0 0 0 0 0
o 0 0
00 o o 00 0 000 8 Oo
0 & o p 0o0o o Oo
.0 0 0�?,
NOTES:
• Free -draining Backfill should consist
of soil having less than 5 percent fines.
Percent passing No. 4 sieve should be
25 to 75 percent.
• Sheet Drain may be feasible in lieu
of Free -draining Backfill, per ESNW
recommendations.
• Drain Pipe should consist of perforated,
rigid PVC Pipe surrounded with 1-inch
Drain Rock.
LEGEND:
Q 00o O
p o000 Free -draining Structural Backfill
-inch Drain Rock
%. of of of ti
Structural
Fill
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
SCHEMATIC ONLY - NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Retaining Wall Drainage Detail
Fulton Property
Edmonds, Washington
Drawn MRS Date 04/07/2023 Proj. No. 9113
Checked BCS Date April 2023 1 Plate 3
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
NOTES:
• Do NOT tie roof downspouts
to Footing Drain.
• Surface Seal to consist of
12" of less permeable, suitable
soil. Slope away from building.
LEGEND:
FTT Surface Seal: native soil or
other low -permeability material.
1-inch Drain Rock
.tilti?ti?ti:'
SCHEMATIC ONLY - NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Drawn MRS Date 04/07/2023 Proj. No. 9113
Checked BCS Date April 2023 Plate 4
W
I
,1� ��
Well -graded gravel with
Moisture Content
Symbols
m
CU >
GW
or without sand, little to
0
c
no fines
Dry - Absence of moisture, dusty, dry to
Cement grout
U U
j L
11
the touch
ATD = At time
surface seal
0
O
o
o
of drilling
g
Bentonite
o p
o01 00(lo
Poorly graded gravel with
Damp Perceptible moisture, likely below
chips
o Z
v
UU
o 0 0 0
GP
or without sand, little to
optimum MC
Static water
i
LO C
o
Q�oQ
no fines
level (date)
eall
Co °
Moist - Damp but no visible water, likely
o
a)
H a)
at/near optimum MC
-
Filter pack with
65
0
a) tav,
0
0
uD
op
o
GM
Silty gravel with or without
Wet - Water visible but not free draining,
blank casing
section
o
0
2 �
O
Q
0
sand
likely above optimum MC
Screened casing
o
or Hydrotip with
U) °
0 .0
o
Saturated/Water Bearing - Visible free
filter pack
o
U)
0
�
Clayey gravel with or
water, typically below groundwater table
End cap
O
-0-0
�
° L
L LL
C7
^
GC
without sand
Terms Describing Relative Density and Consistency
_ 0
co Z
Coarse -Grained Soils: Test Symbols & Units
Well -graded sand with
u�
O
SW
or without gravel, little to
=
Density SPT blows/foot Fines Fines Content
( )
oo
N
o
c
IL
o°o°o°o°o°o
°°°°°°°°°°°
no fines
Very Loose < 4
O LO
U
._
U (n
o
MC =Moisture Content (%)
Loose 4 to 9
'::
ca
�
0
to
,
•:: •..:•.;: , .
Poorly graded sand with
DD = Dr Density cf
Medium Dense 10 to 29 Y Y (P )
a)o
v
Sp
or without gravel, little to
o Z
no fines
Dense 30 to 49 Str = Shear Strength (tsf)
0
a)Very
Dense _> 50
O U)
PID = Photoionization Detector (ppm)
co
a�
'.:'
.
SM
Silty sand with or without
o
Lo c
c
:;:
.::'•:.
;..
gravel
Fine -Grained Soils: OC = Organic Content (%)
e
.
•;.
Consistency SPT blows/foot CEC = Cation Exchange Capacity (meq/100 g)
:
Very Soft < 2
�
�
SC
Clayey sand with or
LL = Liquid Limit (%)
Soft 2 to 3
^
without gravel
Medium Stiff 4 to 7 PL = Plastic Limit (%)
(%)
Stiff 8 to 14 PI = Plasticity IndexLO
CD
Silt with or without sand
IVIL
or gravel; sandy or
Very Stiff 15 to 29
gravelly silt
Hard _> 30
0
0 0
U 0
F///
Clay of low to medium
Y
Component Definitions
>
a)—.1
plasticity; plasticity; lean clay with
cn
M t.
or without sand or gravel;
Descriptive Term Size Range and Sieve Number
00
cn E
sandy or gravelly lean clay
Boulders Larger than 12"
— —
_
�
rn .
— J
U .5
Cobbles 3" to 12"
�o
_
OL
Organic clay or silt of
Zo
—
low plasticity
Gravel 3" to No. 4 (4.75 mm)
-0 to
J
�_
—
Coarse Gravel 3" to 3/4"
Fine Gravel 3/4" to No. 4 (4.75 mm)
Elastic silt with or without
d
Sand No. 4 (4.75 mm) to No. 200 (0.075 mm)
0
0
o
MH
sand or gravel; sandy or
Coarse Sand No. 4 (4.75 mm) to No. 10 (2.00 mm)
c O
(n g
gravelly elastic silt
Medium Sand No. 10 (2.00 mm) to No. 40 (0.425 mm)
IL 2
>, -
Fine Sand No. 40 (0.425 mm) to No. 200 (0.075 mm)
0 °o U O
Clay of high plasticity;
Silt and Clay Smaller than No. 200 (0.075 mm)
o
-0 LO
CH
fat clay with or without
Modifier Definitions
o
E
sand or gravel; sandy or
J
gravelly fat clay
—_
Percentage by
fn
Weight (Approx.) Modifier
CY
OH
Organic clay or silt of
medium to high plasticity
< 5 Trace (sand, silt, clay, gravel)
5 to 14 Slightly (sandy, silty, clayey, gravelly)
o>
ca o
PT
Peat, muck, and other
15 to 29 Sandy, silty, clayey, gravelly
=
�U)
— =
highly organic soils
Q
_> 30 Very (sandy, silty, clayey, gravelly)
Classifications of soils in this geotechnical report and as shown on the exploration logs are based on visual
—
field and/or laboratory observations, which include density/consistency, moisture condition, grain size, and
ii
FILL
Made Ground
plasticity estimates, and should not be construed to imply field or laboratory testing unless presented herein.
Visual -manual and/or laboratory classification methods of ASTM D2487 and D2488 were used as an
identification guide for the Unified Soil Classification System.
Earth
Solutions
NW L�c
Earth Solutions NWLLC
Geotechnical Engineering, Construction
Observation/Testing and Environmental Services
EXPLORATION LOG KEY
r Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
PROJECT NUMBER ES-9113
DATE STARTED 3/21/23 COMPLETED 3/21/23
EXCAVATION CONTRACTOR NW Excavating
LOGGED BY BCS CHECKED BY KDH
NOTES
SURFACE CONDITIONS Lawn grass
TEST PIT NUMBER TP-1
PAGE 1 OF 1
PROJECT NAME Fulton Prooert
GROUND ELEVATION 70 ft
LATITUDE 47.8044 LONGITUDE-122.3793
GROUND WATER LEVEL:
V AT TIME OF EXCAVATION
AFTER EXCAVATION
W
CL
_
wJ
~W
CO
TESTS
_
Q O
MATERIAL DESCRIPTION
p
CL
fy
Q Z
0
co
0.0
Dark brown TOPSOIL (Fill)
-abundant small to medium root intrusions
TPSL
1
-probed 18"
MC - 19.0
-scrap metal debris
intermixed brown silty SAND, potential relic weathered zone
2.5
Gray silty SAND with gravel, dense, moist to wet
-light to moderate iron oxide staining
MC = 22.8
-thin interbeds of silt/sand
SM
-decreasing fines content
-probed 3"
MC = 17.0 6.0
Test pit terminated at 6.0 feet below existing grade. No groundwater encountered during
excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not
surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on
this test log as a standalone document. Refer to the text of the geotechnical report for a
complete understanding of subsurface conditions.
J
J
W
d
F
2
0]
J
Q
Uj
W
Z
W
Earth Solutions NW, LLC TEST PIT NUMBER TP-2
YPRII 15365 N.E. 90th Street, Suite 100 PAGE 1 OF 1
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
PROJECT NUMBER ES-9113 PROJECT NAME Fulton Property
DATE STARTED 3/21/23 COMPLETED 3/21/23 GROUND ELEVATION 70 ft
EXCAVATION CONTRACTOR NW Excavating LATITUDE 47.80429 LONGITUDE-122.37944
LOGGED BY BCS CHECKED BY KDH GROUND WATER LEVEL:
NOTES SZ AT TIME OF EXCAVATION
SURFACE CONDITIONS Lawn grass AFTER EXCAVATION
w
_
~W
_
wJ
CO
TESTS
Q O
MATERIAL DESCRIPTION
p
CL
W
Q Z
0
0.0
Dark brown TOPSOIL (Fill)
MC = 22.2
-abundant medium to large root intrusions to 2.5'
TPSL
-scattered PVC fragments
2.5 MC = 20.7 2.5
67.5
Brown silty SAND with gravel, medium dense to dense, moist
MC = 11.2
Fines = 11.4
[USDA Classification: very gravelly loamy SAND]
-probed 8"
-infiltration test
MC = 13.0
Fines = 18.4
[USDA Classification: gravelly loamy SAND]
5.0 SM
-increased post-test moisture content
MC = 21.3
[USDA Classification: gravelly sandy LOAM]
7.5 MC=14.3 7.5
62.5
Fines = 19.1
Test pit terminated at 7.5 feet below existing grade. No groundwater encountered during
excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not
surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on
this test log as a standalone document. Refer to the text of the geotechnical report for a
complete understanding of subsurface conditions.
Earth Solutions NW, LLC GRAIN SIZE DISTRIBUTION
15365 N.E. 90th Street, Suite 100
WWI Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
PROJECT NUMBER ES-9113 PROJECT NAME Fulton Property
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS I HYDROMETER
6 4 3 2 1Z 1 1 /23/8 3 4 6 810 1416 20 30 40 50 60 100140 200
100
95
90
85
80
75
70
65
H
x
cD
60
w
� 55
m
w 50
z
LL
45
z
w
40
w
a
35
30
25
20
15
10
5
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE IN MILLIMETERS
COBBLES
GRAVEL
SAND
SILT OR CLAY
fine
coarse medium fine
E. CONSTRUCTION SWPPP REQUIREMENTS:
The project will require grading to construct the proposed building and utilities (including the stormwater
control facilities). Standard erosion control measures are proposed to be used during construction. The
primary erosion and sediment control BMP during construction will be proper soil stabilization methods.
Exposed soils shall be stabilized by application of effective BMPs that protect the soil from the erosive forces
of raindrops, flowing water, and wind. Applicable practices include, but not limited to, temporary and
permanent seeding, sodding, mulching, plastic covering, erosion control fabrics, matting, the early
application of gravel base on areas to be paved, and dust control. The contractor shall select a soil
stabilization method best suited for the particular situation. Stockpiles must be stabilized and protected
with sediment trapping measures. In addition, site containment of exposed soils shall be sustained by using
silt fence barriers along the down -slope boundaries of the site's disturbance areas. See the site
development plan for details.
Construction Stormwater Pollution Prevention Plan (SWPPP): The following is a summary of the site's
erosion control measures that evaluates the typical DOE 13 elements of a SWPPP:
Element 1: Mark Clearing Limits: Clearing limits have been delineated on the engineering site development
plans.
BMP Recommended: Utilized: BMP C233: Silt Fence
Element 2: Establish Construction Access: A construction access has been delineated on the engineering
site development plans.
BMP Recommended: BMP C105: Stabilized Construction Access
Element 3: Control Flow Rates: Due to the relatively small size of the site's disturbance areas (less than 0.5
ad; it is recommended to maintain sheet flow dispersion (through downslope perimeter silt
fencing) and not install collect swales and a sediment trap that would concentrate runoff flows.
During construction silt fencing will provide attenuation of site runoff and upon project
completion and stabilization (established lawns and landscape of exposed soils).
BMP Recommended: No site specific BMP prescribed.
Element 4: Install Sediment Controls: Filter fabric fence has been delineated and detailed on the
engineering site development plans. At a minimum, silt fence will be installed along the down
gradient perimeter of the disturbed area that will receive sediment -laden runoff.
BMP Recommended: BMP C233: Silt Fence
Element 5: Stabilize Soils: Soils will be stabilized per the TESC notes listed on the engineering site
development plans.
BMP Recommended: BMP C120: Temporary and Permanent Seeding and BMP C123: Plastic
Covering
RAMEngineering, Inc.
RAM No. 23-005
654 41" Ave S SFR
Stormwater Site Plan Report
Page E-1
Element 6: Protect Slopes: Exposed slopes shall be stabilized per the TESC notes listed on the engineering
site development plans.
BMP Recommended: BMP C120: Temporary and Permanent Seeding and BMP C123: Plastic
Covering
Element 7: Protect Drain Inlets: Drain inlet protection will be installed on all catch basins that will receive
sediment -laden runoff. See the engineering site development plans for locations and detail.
BMP Recommended: BMP C220: Inlet Protection
Element 8: Stabilize Channels and Outlets: This element is not applicable since there are no temporary
channels or outlets proposed.
BMP Recommended: BMP C209: Outlet Protection
Element 9: Control Pollutants: Pollutants shall be managed as described in the TESC notes listed on the
engineering site development plans.
BMP Recommended: BMP C151: Concrete Handling
Element 10: Control De -Watering: Highly turbid or contaminated de -watering water shall be handled
separately from stormwater. The water from all de -watering systems for trenches and
foundations shall be treated or disposed of prior to discharging from the site.
BMP Recommended: No site specific BMP prescribed.
Element 11: Maintain BMPs: BMPs shall be maintained and removed at the end of the project as follows:
i. All temporary and permanent erosion and sediment control BMPs shall be inspected,
maintained and repaired in accordance with the Drainage Manual or as approved or
required by the City to assure continued performance of their intended function in
accordance with BMP specifications.
ii. The applicant may remove temporary BMPs when they are no longer needed.
iii. All temporary erosion and sediment control BMPs shall be removed within 30 days after
construction is completed and the City has determined that the site is stabilized.
BMP Recommended: BMP C150: Materials on Hand
Element 12: Manage the Project: The owner of the site is responsible for managing the installation and
maintenance of the site BMPs.
BMP Recommended: BMP C150: Materials on Hand and BMP C162: Scheduling.
Element 13. Protect Low Impact Development BMPs: No LID stormwater BMPs are proposed.
BMP Recommended: No site specific BMP prescribed.
Conclusion: The total site disturbance area (0.19 ac.) of the project is less than one acre, thus a formal
Department of Ecology Notice of Intent application for NPDES Construction Stormwater Permit coverage is
not required. The final site development construction plans include specific grading and drainage
improvement notes and details. With proper installation, maintenance, and inspections of the proposed
construction the project should have minimal impact on the surrounding environment.
RAMEngineering, Inc.
RAM No. 23-005
654 41" Ave S SFR
Stormwater Site Plan Report
Page E-2
F. OPERATION AND MAINTENANCE GUIDELINES:
These guidelines are intended to provide operation and maintenance instructions for the project's storm
drainage control facilities. The owner is responsible for maintenance of storm drainage facilities within
the property (private property owner system); the owner is not responsible for maintenance within the
public right-of-way (City system).
Private property owner is responsible for properly maintaining the stormwater infrastructure on their
property to ensure it operates as designed. The City has developed an inspection program to ensure
private property owners are properly maintaining their stormwater systems.
This manual is not comprehensive; although it explains the intended operation of the various
components of the drainage system, and suggests a routine of inspection and maintenance, it cannot
anticipate every problem. Once a historical record of maintenance is established, it may be prudent to
alter the routine. It is recommended that maintenance records be kept, and that the records be
reviewed periodically.
The onsite detention tank system, control structure, junction catch basins, and onsite conveyance pipes
are to be privately maintained by the project residence. Maintenance shall include the removal of
sediment from the detention tank system, using a vactor truck or equally effective method. Regular
inspections of the control structure within the catch basin shall be conducted to detect if non -routine
maintenance is required due to sediment or debris blocking or clogging the fixed orifice or standpipe
inlet. Regular sediment removal from the catch basins with a vactor truck or equally effective method
shall be conducted as determined by regular inspections. Regular inspection and maintenance of the
storm filter should occur according to the attached maintenance tables from the Washington State
Department of Ecology Stormwater Manual (2019- Volume V).
Semi-annual inspections shall be conducted to ensure proper operations of the drainage system. The
inspections should occur prior to the winter rain season (Oct/Nov), leaving sufficient time to correct any
detected maintenance problems, and at the end of the season (April/May) to determine the effect of
the season's runoff. Once a historical basis is developed the frequency of inspection may be modified as
necessary. Sediment can build up inside control structures and catch basins, blocking or restricting flow
to the inlet. To prevent this problem, these structures should be routinely cleaned. Regular inspections
of control structures should be conducted to detect the need for non -routine cleanout.
MAINTENANCE REQUIREMENTS
ECDC Section 18.30.090 requires privately -owned
stormwater management facilities, such as LID
BMPs be properly maintained. The owner of the
property is the responsible party for such
maintenance. The system must be kept in good
working order. The entire system should be
inspected once per year. An improperly maintained
BMP may cause private property or street flooding.
RAMEngineering, Inc.
RAM No. 23-005
Contact the City Engineering Division for
maintenance information.
The City may make periodic inspections of BMPs to
ensure they are operating properly. ECDC Section
18.30.100 contains the enforcement provisions the
City can use to ensure the system is properly
maintained.
654 41h Ave S SFR
Stormwater Site Plan Report
Page F-1
Appendix V-A: BMP Maintenance Tables
Ecology intends the facility -specific maintenance standards contained in this section to be
conditions for determining if maintenance actions are required as identified through inspection.
Recognizing that Permittees have limited maintenance funds and time, Ecology does not
require that a Permittee perform all these maintenance activities on all their stormwater BMPs.
We leave the determination of importance of each maintenance activity and its priority within the
stormwater program to the Permittee. We do expect, however, that sufficient maintenance will
occur to ensure that the BMPs continue to operate as designed to protect ground and surface
waters.
Ecology doesn't intend that these measures identify the facility's required condition at all times
between inspections. In other words, exceedance of these conditions at any time between
inspections and/or maintenance does not automatically constitute a violation of these standards.
However, based upon inspection observations, the Permittee shall adjust inspection and
maintenance schedules to minimize the length of time that a facility is in a condition that
requires a maintenance action.
Table V-A.3: Maintenance Standards - Closed Detention Systems (Tanks/Vaults)
Maintenance
Results Expected
Component
Defect
Conditions When Maintenance is Needed
When Maintenance is
Performed
Plugged Air Vents
One-half of the cross section of a vent is blocked at
Vents open and
any point or the vent is damaged.
functioning.
Accumulated sediment depth exceeds 10% of the
diameter of the storage area for 1/2 length of
storage vault or any point depth exceeds 15% of
All sediment and debris
Debris and Sediment
diameter.
removed from storage
(Example: 72-inch storage tank would require
area.
cleaning when sediment reaches depth of 7 inches
for more than 1/2 length of tank.)
Storage Area
Any openings or voids allowing material to be
Joints Between
transported into facility.
All joint between
Tank/Pipe Section
(Will require engineering analysis to determine
tank/pipe sections are
sealed.
structural stability).
Tank Pipe Bent Out of
Any part of tank/pipe is bent out of shape more than
Tank/pipe repaired or
Shape
10% of its design shape. (Review required by
replaced to design.
engineer to determine structural stability).
Cracks wider than 1/2-inch and any evidence of soil
Vault replaced or
particles entering the structure through the cracks,
repaired to design
Vault Structure Includes
or maintenance/inspection personnel determines
specifications and is
Cracks in Wall, Bottom,
that the vault is not structurally sound.
structurally sound.
Damage to Frame
and/or Top Slab
Cracks wider than 1/2-inch at the joint of any
No cracks more than
inlet/outlet pipe or any evidence of soil particles
1/4-inch wide at the joint
entering the vault through the walls.
of the inlet/outlet pipe.
RAMEngineering, Inc.
RAM No. 23-005
654 41h Ave S SFR
Stormwater Site Plan Report
Page F-2
Table V-A.3: Maintenance Standards - Closed Detention Systems (Tanks/Vaults)
Maintenance
Results Expected
Component
Defect
Conditions When Maintenance is Needed
When Maintenance is
Performed
Cover Not in Place
Cover is missing or only partially in place. Any open
Manhole is closed.
manhole requires maintenance.
Mechanism cannot be opened by one maintenance
Locking Mechanism Not
person with proper tools. Bolts into frame have less
Mechanism opens with
Manhole
Working
than 1/2 inch of thread (may not apply to self-locking
proper tools.
lids).
Cover Difficult to
One maintenance person cannot remove lid after
Cover can be removed
Remove
applying normal lifting pressure. Intent is to keep
and reinstalled by one
cover from sealing off access to maintenance.
maintenance person.
Ladder is unsafe due to missing rungs,
Ladder meets design
Ladder Rungs Unsafe
misalignment, not securely attached to structure
standards. Allows
maintenance person
wall, rust, or cracks.
safe access.
See Table V-A.5:
See Table V-A.5: Maintenance Standards -Catch
See Table V-A.5:
Catch Basins
Maintenance Standards
Basins
Maintenance Standards
Catch Basins
Catch Basins
Table V-A.4: Maintenance Standards - Control Structure/Flow Restrictor
Maintenance
Defect
Condition When Maintenance
Results Expected When
Component
is Needed
Maintenance is Performed
Trash and Debris (Includes
Material exceeds 25% of sump
Control structure orifice is not
Sediment)
depth or 1 foot below orifice
blocked. All trash and debris
plate.
removed.
Structure is not securely
attached to manhole wall.
Structure securely attached to wall
and outlet pipe.
General
Structure is not in upright
position (allow up to 10% from
Structure in correct position.
plumb).
Structural Damage
Connections to outlet pipe are
Connections to outlet pipe are
watertight; structure repaired or
not watertight and show signs of
replaced and works as designed.
rust.
Structure has no holes other than
Any holes - other than designed
designed holes.
holes - in the structure.
Cleanout gate is not watertight
Gate is watertight and works as
or is missing.
designed.
Gate cannot be moved up and
Gate moves up and down easily
down by one maintenance
and is watertight.
Cleanout Gate
Damaged or Missing
person.
Chain/rod leading to gate is
Chain is in place and works as
missing or damaged.
designed.
Gate is rusted over 50% of its
Gate is repaired or replaced to
surface area.
meet design standards.
Control device is not working
Plate is in place and works as
Orifice Plate
Damaged or Missing
properly due to missing, out of
designed.
place, or bent orifice plate.
Obstructions
Any trash, debris, sediment, or
Plate is free of all obstructions and
vegetation blocking the plate.
works as designed.
RAMEngineering, Inc.
RAM No. 23-005
654 41h Ave S SFR
Stormwater Site Plan Report
Page F-3
Table V-A.4: Maintenance Standards - Control Structure/Flow Restrictor
Maintenance
Defect
Condition When Maintenance
Results Expected When
Component
is Needed
Maintenance is Performed
Any trash or debris blocking (or
Pipe is free of all obstructions and
Overflow Pipe
Obstructions
having the potential of blocking)
the overflow pipe.
works as designed.
See Table V-A.3: Maintenance
See Table V-A.3: Maintenance
See Table V-A.3: Maintenance
Manhole
Standards - Closed Detention
Standards - Closed Detention
Standards - Closed Detention
Systems (Tanks/Vaults)
Systems (Tanks/Vaults)
Systems (Tanks/Vaults)
Catch Basin
See Table V-A.5: Maintenance
See Table V-A.5: Maintenance
See Table V-A.5: Maintenance
Standards - Catch Basins
Standards - Catch Basins
Standards - Catch Basins
Table V-A.S: Maintenance Standards - Catch Basins
Maintenance
Results Expected When
Component
Defect
Conditions When Maintenance is Needed
Maintenance is
performed
Trash or debris which is located immediately in front of
the catch basin opening or is blocking inletting capacity
of the basin by more than 10%.
No Trash or debris
located immediately in
Trash or debris (in the basin) that exceeds 60 percent of
front of catch basin or on
the sump depth as measured from the bottom of basin
grate opening.
to invert of the lowest pipe into or out of the basin, but in
no case less than a minimum of six inches clearance
No trash or debris in the
Trash & Debris
from the debris surface to the invert of the lowest pipe.
catch basin.
Trash or debris in any inlet or outlet pipe blocking more
Inlet and outlet pipes free
than 1/3 of its height.
of trash or debris.
Dead animals or vegetation that could generate odors
No dead animals or
that could cause complaints or dangerous gases (e.g.,
vegetation present within
methane).
the catch basin.
General
Sediment (in the basin) that exceeds 60 percent of the
sump depth as measured from the bottom of basin to
invert of the lowest pipe into or out of the basin, but in no
No sediment in the catch
Sediment
case less than a minimum of 6 inches clearance from
basin
the sediment surface to the invert of the lowest pipe.
Top slab has holes larger than 2 square inches or
Top slab is free of holes
cracks wider than 1/4 inch. (Intent is to make sure no
and cracks.
Structure Damage
material is running into basin).
to Frame and/or
Top Slab
Frame not sitting flush on top slab, i.e., separation of
Frame is sitting flush on
more than 3/4 inch of the frame from the top slab. Frame
the riser rings or top slab
and firmly attached.
not securely attached
Maintenance person judges that structure is unsound.
Basin replaced or
Fractures or
Grout fillet has separated or cracked wider than 1/2 inch
repaired to design
standards.
Cracks in Basin
and longer than 1 foot at the joint of any inlet/outlet pipe
Walls/ Bottom
or any evidence of soil particles entering catch basin
Pipe is regrouted and
through cracks.
secure at basin wall.
RAMEngineering, Inc.
RAM No. 23-005
654 41h Ave S SFR
Stormwater Site Plan Report
Page F-4
Table V-A.S: Maintenance Standards - Catch Basins
Maintenance
Results Expected When
Component
Defect
Conditions When Maintenance is Needed
Maintenance is
performed
Settlement/
If failure of basin has created a safety, function, or
Basin replaced or
repaired to design
Misalignment
design problem.
standards.
Vegetation growing across and blocking more than 10%
No vegetation blocking
of the basin opening.
opening to basin.
Vegetation
Vegetation growing in inlet/outlet pipe joints that is more
No vegetation or root
than six inches tall and less than six inches apart.
growth present.
Contamination and
See Table V-A.1: Maintenance Standards -Detention
No pollution present.
Ponds
Pollution
Cover Not in Place
Cover is missing or only partially in place. Any open
Cover/grate is in place,
meets design standards,
catch basin requires maintenance.
and is secured
Locking
Mechanism cannot be opened by one maintenance
Mechanism opens with
Catch Basin
Mechanism Not
person with proper tools. Bolts into frame have less than
proper tools.
Cover
Working
1/2 inch of thread.
One maintenance person cannot remove lid after
Cover Difficult to
applying normal lifting pressure.
Cover can be removed by
Remove
(Intent is keep cover from sealing off access to
one maintenance person.
maintenance.)
Ladder Rungs
Ladder is unsafe due to missing rungs, not securely
Ladder meets design
standards and allows
Ladder
Unsafe
attached to basin wall, misalignment, rust, cracks, or
maintenance person safe
sharp edges.
access.
Grate opening
Grate with opening wider than 7/8 inch.
Grate opening meets
Unsafe
design standards.
Trash and Debris
Trash and debris that is blocking more than 20% of
Grate free of trash and
Metal Grates (If
grate surface inletting capacity.
debris.
Applicable)
Grate is in place, meets
Damaged or
Grate missing or broken member(s) of the grate.
the design standards, and
Missing.
is installed and aligned
with the flow path.
Washington State Department of Ecology
2019 Stormwater Management Manual for Western Washington (2019 SWMMWW)
Publication No.19-10-021
RAMEngineering, Inc.
RAM No. 23-005
654 41h Ave S SFR
Stormwater Site Plan Report
Page F-5
ENGINEERING, INC.
Civil Engineering /Land Planning