APPROVED ENG RESUB 1-BLD2023-0070+Storm_Drainage_Report+6.2.2023_4.07.43_PM+3585546RAM Engineering
To: City of Edmonds
Engineering Division
From: Rob Long, PE
RAM Engineering
Subject: 23909 9111 PI W, Lot 2 Brackett's Reserve
Stormwater Memo
RAM Job No. 20-024
Memorandum
Date: December 8, 2022
Update: June 2, 2023
ENGINEERING DIVISION
v ' _ v 16/20/2022
This memo provides a summary of the stormwater drainage control system for Lot 2 of the Brackett's Reserve
Plat (PLN 2021-0037). A site -specific geotechnical evaluation recommends one stormwater BMP for the site;
BMP T5.13: Post -Construction Soil Quality and Depth based on the site's soil conditions. In accordance with
Edmonds Code, lawn and landscape areas will be managed by post -construction soil quality and depth (soil
amendments). The roof top, driveway, walk and patio areas will be managed by the Brackett's Reserve
detention vault located in Track 999 of the plat. The plat design has allocated 2,600 sf of hard surface (base
2,800 sf less 100 sf transferred to each Lot 3 and Lot 4) for Lot 2 hard surface areas.
Below is a stormwater control summary table for Lot 2:
Stormwater Control Summary:
Project Site Category: Category 2 (part of the Brackett's Reserve Plat)
Discharge Location: City's Municipal Separate Storm Sewer System (MS4)
Type of Area
Square Footage
Storm water Facility
Lawn and Landscape
2,464 sf
Soil Amendments (BMP T5.13)
Roof
1,975 sf
Plat Detention Vault
Hard Surfaces
406 sf
Plat Detention Vault
(Driveway/Apron, Walk and Patio)
25% Retrofit
0 SF
None
PKAM Engineering 19109 3611 Ave W, Suite 100 Lynnwood WA 98036 (425)678-6960 RAMengineeringinc.com
23909 91st PI W, Lot 1 Brackett's Reserve Page 2 of 2
Stormwater Memo
RAM lob No. 20-024
23909 91st PI W, Lot 2 Brackett's Reserve Hard Surface Summary:
Roof = 1,975 sf
Driveway = 406 sf
Sidewalk/Patio = 0 sf
Total = 2,381 sf
Allowed/Allocated = 2,600 sf (base 2,800 sf less 100 sf transferred to each Lot 3 and Lot 4)
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PKAM Engineering 19109 3611 Ave W, Suite 100 Lynnwood WA 98036 (425)678-6960 RAMengineeringinc.com