HomeMy WebLinkAboutEx 05_Drainage Memo.pdfD UNCANSON
Company, Inc. SURVEYING LAND PLANNING 145 SW 155th Street Suite 102 Seattle, Washington 98166
Phone 206.244.4141 Fax 206.244.4455 Web www.duncansonco.com
CIVIL ENGINEERING
DCI 22391.002
MEMO REPORT
To: City of Renton
From: Harold Duncanson
Date: 10/24/22
Subject: Comcast Kent
Drainage Review Evaluation
The Comcast – Kent project involves adding an equipment shelter building, generator and
battery cabinets to an existing telecommunication site. The site is located at 18809 116th
Avenue SE in the City of Renton. The existing telecom compound “Site” is a 45-foot
square fenced and gravel surfaced compound including an existing a shelter, generator and
various cabinets and vaults.
Based on plans by Lynx Consulting (8/3/22), the project will result in approximately 430
SF of replaced impervious surface including the new shelter building, battery cabinets and
generator, all of which will sit on new concrete slabs. The project will cause approximately
1,500 SF of land disturbance. The Site is not a high-use site.
Based on visual observation of the Site and immediate surroundings on October 14, 2022,
Site runoff appears to sheet flow north and then east on the paved access easement surface.
Runoff then appears to disperse over a 70-foot wide lawn area and ultimately to the gutter
flow line of 116th Ave SE. Property to the east, south and west is under construction for a
short plat that will have its own stormwater system according to plans available online.
This project will result in less than 2,000 SF of new, replaced, or new plus replaced
impervious surface and less than 7,000 SF of land disturbance. The project does not meet
any of the Criteria in Section 1.1.1 of the 2022 City of Renton Surface Water Design
Manual. Therefore, Drainage Review is not required for this project. See attached excerpt
and flow chart.
Please call if you have any questions.
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