20170421_StormWaterComments.pdfStormwater Review
Date of Review: April 21, 2017
File/Address: PLN20160053 / 8509 240 S'
Reviewer: Robert C. Edwards, PE, Storrs ngineur, City of Edmonds
Background
This is classified as a Category 2 Small Site because it proposes impervious area exceeding 5,000 SF.
Category 2 Small Site Projects are subject to Small Site Minimum Requirements 1, 2, 3, 4, 5, 6, 7, 8, 9,
10, and 11.
Infeasibility Analysis
1. Page 6 of the TIR is missing. This would include the infeasibility analysis for hard surfaces
specifically permeable pavements.
Minimum Requirement #1— Preparation of Stormwater Site Plan
Comments:
1. Drainage easements will be required. Provide easement description.
2. The proposed easement runs through the property to the east. This property is proposing
redevelopment. This redevelopment shoes grading in the vicinity of the proposed level spreader.
3. The survey for the property to the east shows two sanitary sewer easements through the proposed
storm drain easement. Show these easements with their associated utilities and conflict analysis.
4. The Edmonds GIS system shows an existing sanitary sewer under the proposed Building 1 and
detention system. It appears that this sanitary sewer line is owned by the Olympic View Water
and Sewer District. The District may not allow buildings over the sewer line. The District may
require rerouting the sanitary sewer around the building. Show the sanitary sewer line and
conflict analysis.
5. The level spreader needs a vegetated flowpath of at least 25-feet between the outlet of the trench
and the property line. Show the dispersal path for the level spreader on the plans including
grading and any features. See 2014 DOE Section 3.1.2.
Minimum Requirement #2 — Construction Stormwater Pollution Plan
Comments: None
Minimum Requirement #3 — Source Control of Pollution
Comments: None
Minimum Requirement #4 — Preservation of Natural Drainage Systems
Comments: None
Minimum Requirement #5 — Onsite Stormwater Management
Comments: None
Minimum Requirement # 6 — Runoff Treatment
Comments: None
Minimum Requirement #7 — Flow Control
Comments: None
Minimum Requirement #8 — Wetland Protection
Comments: None
Minimum Requirement #9 — Operation and Maintenance
Comments: None
Minimum Requirement # 10 — Offsite Analysis and Mitigation
Comments:
1. Downstream Drainage Analysis, Page 3: The report is still referencing the 2010 code. This
project will use the 2017 Stormwater Code and Addendum, not the 2010 Supplement.
Minimum Requirement #11— Financial Liability
Comments: None