APPROVED STM BLD2021-1075+Storm_Drainage_Report+8.3.2021_3.00.19_PM+2337095RAM Engineering
To: City of Edmonds
Engineering Division
From: Rob Long, PE
RAM Engineering
RECEIVED
Aug 09 2021
CITY OF EDMONDS
DEVELOPMENT SERVICES
DEPARTMENT
Subject: Adamant Homes, Inc. - 240th St SW Short Plat- Lot 1
Stormwater Memo
RAM Job No. 19-015
BLD2021-1075
Memorandum
Date: August 3, 2021
COMPLIES WITH APPLICABLE
CITY STORMWATER CODE
This memo provides a summary of the stormwater hard surface allocation for Lot 1 of the Adamant Homes
240th St SW Short Plat (PLN 2019-0052). A site -specific geotechnical evaluation only recommends two
possible stormwater BMPs for the site; perforated stub -out connection and BMP T5.13: Post -Construction Soil
CIO Quality and Depth. Project impervious/hard surface (roof, driveway, walk/patio areas) will be managed by a
shared stormwater detention tank system with the short plat development.
The shared detention tank system has been designed as part of the short plat development and thus includes
hard surface areas allocated for each individual lot (see Select 220t" St SW Short Plat Stormwater Site Plan
Report). Lot 1 has an allocation of 2,900 sf of impervious/hard surface, which include roof, driveway, and
patio/walkway areas.
Below is a stormwater control summary table for Lot 1:
Stormwater Control Summary:
Project Site Category: Category 2 (part of the Select- 8805 220th St SW Short Plat)
Discharge Location: City's Municipal Separate Storm Sewer System (MS4)
Type of Area
Square Footage
Storm water Facility
Lawn and Landscape
6,559 sf
Soil Amendments (BMP T5.13)
Roofs
2,237 sf
Detention Vault
Hard Surfaces
355 sf
Detention Vault
25% Retrofit
0 SF
None
Adamant Homes, Inc. - 240th St SW Short Plat- Lot 1
Stormwater Memo
RAM Job No. 19-015
Page 2 of 2
240th St SW Short Plat Lot 1 Hard Surface Summary:
Roof = 2,237 sf
Driveway = 335 sf
Patio/Walk = 20 sf
Total= 2,592 sf
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