DNS-BLD2023-0103+Storm_Drainage_Report+1.23.2023_2.25.49_PM+3328740Snohomish County - Planning and Development Services
2nd Floor, Robert J. Drewel Building
3000 Rockefeller - Everett, WA - (425) 388-3311- www.snoco.org
Small Project Stormwater Pollution Prevention Plan (SWPPP)
Narrative and Plan Submittal
Complete this form to meet Minimum Requirement#2 for Small Projects as defined in
Section 30.63A.810 SCC and detailed in Volume I, Appendix I-F of the Snohomish
County Drainage Manual. Assistance Bulletins #90, 91 and #92 may also be helpful
when filling out this form.
BASIC PROJECT INFORMATION:
Project File Number:
Quarter: NW1/4 Section: 32
(PDS to Assign)
Property Tax Account Number(s): 00488800300501
Related project file numbers:
Site Address: 23422 74th AVENUE WEST, EDMONDS, WA 98026
Township: 27N Range: 4E
Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal Rev 3-18-16 1
NARRATIVE: (See attached sample narrative and site plan for guidance.)
Project Description:
ADDITION OF 125 SQ. FT. TO THE BASEMENT AND 549 SQ. FT. TO THE MAIN FLOOR OF AN EXISTING SINGLE
FAMILY RESIDENCE, WITH AN EXISTING 795 SQ. FT. OF DRIVEWAY OFF 74TH AVENUE WEST THAT IS A PUBLIC
ROAD.
LOT AREA IS 7,567 SQ. FT., 0.17 ACRES.
EXISTING DOWNSPOUTS ARE TIGHTLINED INTO UNDERGROUND PIPING AND DAYLIGHT OUT ON TO 74TH
AVENUE WEST.
Please check "yes" or "no" for each criteria below. Answer "yes" if the statement
accurately describes your project. (NOTE: If any answer below is "No" the project does
not qualify as a "small" project and a full SWPPP will be required.)
❑✓ Yes
❑ No
This project disturbs less than 1 acre and is not part of a common
plan of development.
❑✓ Yes
❑ No
This project will create, add, or replace (in any combination) less
than 2,000 sq. ft. of hard surface.
❑✓ Yes
❑ No
This project will move less than 100 cu. yds. of material graded on
site and less than 500 cu. yds. of material under the foundation of
a building to be built pursuant to an approved building permit.
❑✓ Yes
❑ No
This project will cause less than 7000 sq. ft. of land disturbing
activity.
❑✓ Yes
❑ No
This project site is located outside of a floodplain or shoreline
designation.
❑✓ Yes
❑ No
This project will not adversely impact a wetland, stream or water
of the state, or change a natural drainage course.
❑✓ Yes ❑ No This project does not require engineering to comply.
Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal Rev 3-18-16
Element 1 - Preserve Vegetation/Mark Clearing Limits
This element does not apply to my project because:
❑ The site was cleared as part of clearing activity that is subject to an enforcement action and is
revegetated. Restoration may be necessary to comply with Critical Area Regulations or NPDES
requirements. BMP C102 may apply if Critical Areas exist on -site and buffer zones shall be protected.
u
Additional comments:
If it does apply, describe the steps you will take and select the "best management practices"
(BMPs) you will use to minimize the area of clearing and vegetation removal:
0 To preserve native vegetation and to clearly show the limits of disturbance, the perimeter of the area
to be cleared shall be marked prior to clearing operation with visible flagging, orange plastic barrier fencing
and/or orange silt fencing as shown on the Stormwater Pollution Prevention Site Plan. The total disturbed
area shall be less than 7000 square feet. Vehicles will only be allowed in the areas to be graded, so no
compaction of the undeveloped areas will occur.
Additional comments:
THE LIMITS OF DISTURBANCE AREA SHALL BE FLAGGED WITH AN ORANGE PLASTIC BARRIER FENCING
AS SHOWN ON THE SWPPP. THE TOTAL AREA TO BE CLEARED IS LESS THAN
7000 SQ. FT.
Check the BMPs you will use:
❑ C101 Preserving Natural Vegetation
❑ C102 Buffer Zones
Element 2 - Construction Access
This element cgs not apply to my project because:
p C103 High Visibility Plastic or Metal Fence
❑ C104 Stake and Wire Fence
p The driveway to the construction area already exists and will be used for construction access. All
equipment and vehicles will be restricted to staying on that existing impervious surface.
Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal Rev 3-18-16 3
C
Additional comments:
If it does apply, describe the steps you will take and select the "best management practices" (BMPs) you
will use to minimize sediment transport onto roads:
❑ A stabilized construction entrance will be installed prior to any vehicles entering the site, at the location
shown on the SWPPP plan.
u
Additional comments:
Check the BMPs you will use:
❑ C105 Stabilized Construction Entrance
❑ C107 Construction Road/Parking Area Stabilization
Element 3 — Control Flow Rates
This element does no apply to my project because:
Additional comments:
If it does apply, describe the steps you will take and "best management practices" (BMPs) you will use
to control runoff flow rates from the site, referring to Element 4 BMPs below:
p Flow rates will be controlled by using SWPPP Element 4 sediment controls and BMP T.5.13 Amended
Soils if necessary.
Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal Rev 3-18-16 4
Element 4 - Sediment Control
This element does not apply to my project because:
❑ The site has already been stabilized and revegetated.
❑■
Additional comments:
If it does apply, describe the steps you will take and "best management practices" (BMPs) you will use
to minimize sediment leaving the site in runoff:
0 Sediment will be controlled on -site by placement of the required sediment control BMP'S for the site at the
locations shown on the Stormwater Pollution Prevention Plan (SWPPP).
Check the BMPs you will use:
0
C230 Straw Bale Barrier
R1
C233 Silt Fence
❑
C231 Brush Barrier
❑
C234 Vegetated Strip
❑
C232 Gravel Filter Berm
❑
C235 Straw Wattles
Element 5 — Stabilize Soils
This element does no apply to my project because:
u
Additional comments:
If it does apply, describe the steps you will take and "best management practices" (BMPs) you
will use to minimize soil exposure to wind and rain:
❑ Exposed soils shall be worked during the week until they have been stabilized. Soil stockpiles will be
located within the disturbed area shown on the SWPPP. Soil excavated for the foundation will be
backfilled against the foundation and graded to drain away from the building. No soils shall remain
exposed and unworked for more than 2 days from October 1 to April 30. Once the disturbed landscape
areas are graded, the grass areas will be seeded or sodded. All stockpiles will be covered with plastic or
burlap if left unworked.
Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal Rev 3-18-16 5
Additional comments:
Check the BMPs you will use:
❑ C120 Temp & PermSeeding ❑ C124 Sodding
❑ C121 Mulching ❑ C125 Topsoil (for solid stabilization)
❑ C122 Nets & Blankets ❑ C131 Gradient Terraces
p C123 Plastic Covering ❑ C140 Dust Control
Element 6 - Protect Slopes
This element does no apply to my project because:
❑ No cut slopes over 4 feet high or slopes steeper than 2 feet horizontal to 1 foot vertical, and no fill slopes
over 4 feet high will exceed 3 feet horizontal to 1 foot vertical. Therefore, there is no requirement for
additional engineered slope protection.
J
Additional comments:
If it does apply, describe the steps you will take and "best management practices" (BMPs) you will
use to control erosion from steep slopes:
7
Additional comments:
Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal Rev 3-18-16 6
Check the BMPs you will use:
0 C120 Temporary and Permanent Seeding
❑ C208 Triangular Silt Dike (Geotexti le-E n cased Check Dam)
Element 7 — Protect Permanent Drain Inlets
This element does not apply to my project because:
❑ The site is in a rural area with an open ditch in the county right-of-way or private road right-of-way.
0 There are no catch basins on or near the site.
If it does apply, describe the steps you will take and "best management practices" (BMPs) you will use
to keep runoff sediment out of storm drains:
❑ Catch basins on the site or immediately off site in the right-of-way are shown on the Storm Water Pollution
❑■
Nrevention ,site Fjian. Storm grain inlet protection snaii oe instaiiea.
Additional comments:
Check the BMPs you will use:
❑ C220 Storm Drain Inlet Protection
Element 8 — Stabilize Channels and Outlets
This element des not apply to my project because:
0 Construction will occur during the dry weather. No storm drainage channels or ditches shall be
constructed either temporary or permanent. A small swale shall be graded to convey yard drainage
around the structure using a shallow slope; it shall be seeded after grading and stabilized.
FEl
Additional comments:
Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal Rev 3-18-16 7
If it does apply, describe the steps you will take and "best management practices" (BMPs) you will use
to prevent erosion from entering existing storm water outfalls and conveyance systems, such as pipes
and ditches:
❑ A straw wattle shall be placed at the end of the swale to prevent erosion at the outlet of the swale.
C
Additional comments:
Check the BMPs you will use:
❑ C202 Channel Lining
❑ C209 Outlet Protection
Element 9 — Control Pollutants
This element does not apply to my project because:
0
Additional comments:
NO POLLUTANTS SHALL BE STORED AT THE SITE.
❑ C235 Straw Wattles
If it does apply, describe the steps you will take and "best management practices" (BMPs) you will use
to keep pollutants out of the storm water. Address all potential pollution sources on your project, such
as material storage, fuel handling, equipment cleaning, management of waste materials, etc.:
❑ Any and all pollutants, chemicals, liquid products and other materials that have the potential to pose a
threat to human health or the environment will be covered, contained, and protected from vandalism. All
such products shall be kept under cover in a secure location on -site. Concrete handling shall follow BMP
C151.
Check the BMPs you will use:
(] C151 Concrete Handling
❑ C152 Sawcutting and Surfacing Pollution Prevention
❑ C153 Material Storage, Delivery, and Containment
Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal Rev 3-18-16 8
Element 10 - Control De watering
This element does not apply to my project because:
121 No dewatering of the site is anticipated.
If it does apply, describe the steps you will take and "best management practices" (BMPs) you will use
to separate contaminated de -watering water from stormwater.
0
Additional comments:
Check the BMPs you will use:
❑ C220 Storm Drain Inlet Protection
Element 11 — Maintain Best Management Practices
Describe the steps you will take to ensure that BMPs are in place and properly functioning as needed
throughout construction:
0 Best Management Practices or BMP's shall be inspected and maintained during construction and removed
within 30 days after the County Inspector or Engineer determines that the site is stabilized, provided that
they may be removed when they are no longer needed.
Element 12 — Manage the Project
Describe the BMP sequencing you will use to ensure that the full SWPPP is properly coordinated and that
all BMPs are deployed at the proper time to achieve full compliance with county regulations throughout
the project:
r/1 The SWPPP will be implemented at all times. The applicable erosion control BMP's will be implemented in
the following sequence:
El Mark clearing limits
❑ Install stabilized construction entrance
❑ Install protection for existing drainage systems and permanent drain inlets
❑ Establish staging areas for storage and handling polluted material and BMP's
0 Install sediment control BMP's
0 Grade and install stabilization measures for disturbed areas
0 Maintain BMP's until site stabilization, at which time they may be removed.
Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal Rev 3-18-16 9
Element 13 - Protect on -site stormwater management BMPs for runoff from roofs
and other hard surfaces
On -site stormwater management BMPs used for runoff from roofs and other hard surfaces include: full
dispersion, roof downspout full infiltration or dispersion systems, perforated stubout connections, rain
gardens, bioretention systems, permeable pavement, sheetflow dispersion, and concentrated flow
dispersion. The areas on the site to be used for these BMPs shall be protected from siltation and
compaction during construction by sequencing the construction in a fashion to install these BMPs at the
latter part of the construction grading operations, by excluding equipment from the BMPs and the
associated areas, and by using the erosion and sedimentation control BMPs listed below. Additional
requirements for protecting these BMPs during the construction process, testing functionality, and
restoring functionality are needed at the final stage of the construction process and are included in the
specific BMP sections in the Snohomish County Drainage, Volume V.
Check the BMPs you will use:
❑
C102 Buffer Zone
❑
C103 High Visibility Fence
❑
C231 Brush Barrier
m
C233 Silt Fence
❑
C234 Vegetated Strip
Applicant Signature
Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal Rev 3-18-16 10