Herrera Review - 1.docx
August 25, 2016
City of Edmonds Public Works Department
Engineering Division
121 5th Avenue North
Edmonds, WA 98020
Attn: JoAnne Zulauf
Subject: Stormwater Plan Review of Lu Residence at 8038 Cyrus Place (BLD2016-0866)
Dear Ms. Zulauf:
After reviewing the storm drainage report and plans for the improvements proposed for the
Lu Residence (8038 Cyrus Place), we have the following comments:
1.The Stormwater Site Plan Report (5/11/16) states that the geotechnical report
identifies the site soils as outwash and the soil logs identified 2’ to 9’ of fill, so till
(class C soils) were used for modeling; however, based on the soil logs provided,
outwash (class A/B soils) should be used for modeling. In the 2015 geotechnical report
from AESI (11/4/15), the onsite boring (EB-1) contained outwash soils and EP-5 had
“similar conditions.” Based on the 2008 geotechnical report from AESI (4/24/08),
boring EP-5 (on the Lu Residence lot) contained outwash soils and the borings located
on other lots contained fill.
2.The soil log for EB-1 in the 2015 geotechnical report from AESI (11/4/15) was not
provided.
3.The Cover Sheet and General Notes (5-11-16) contains a note related to compost
amending soils (Construction Sequence Note #10); however, the plan and Stormwater
Site Plan Report (5/11/16) should be amended reference the specific requirements
outlined in BMP T5.13 – Post-Construction Soil Quality and Depth.
4.The Stormwater Site Plan Report (5/11/16) does not address all of the applicable
Small Site Minimum Requirements. Maintenance information for the onsite detention
pipe should be added to address Small Site Minimum Requirement #9 – Operation and
Maintenance.
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Stormwater Plan Review of Lu Residence
August 25, 2016
Page 2
5.WWHM3 (output report dated 6-30-15) was used for modeling instead of the most
recent version of WWHM (WWHM2012). The detention pipe modeling results are not
expected to be significantly different, but we would recommend updating the
modeling software used for this project and other projects in the future to the most
recently version of WWHM.
Sincerely,
Herrera Environmental Consultants, Inc.
Rebecca Dugopolski, PE
Senior Engineer