20160729163443.pdfcivil & structural
EIIIGINEERII IG engineering &planning
July 29, 2016
Jennifer Lambert, Engineering Technician
City of Edmonds
Second Floor City Hall
121 51h Avenue N
Edmonds, WA 98020
RE: Application #BLD20160695 Review Comments #1
Project Name: Schuler Residence
Project Address: 932 Alder Street
Dear Ms. Lambert,
Itemized below is our response to the review comments in the July 22, 2016 letter for the above
referenced project. Our response appears in bold.
Cover Sheet & Site Plan
1. The water and sewer are shown as the same line. Please revise the plans accordingly.
Please refer to the correction response letter dated July 29, 2016 by Alexandra Immel.
2. Show how the surface water runoff from the new impervious area will be collected and discharged
to the onsite stormwater management system.
Please refer to the correction response letter dated July 29, 2016 by Alexandra Immel.
Stormwater Review Comments from Herrera
1. The Infiltration Sizing Summary (4/5/16) is missing the following information:
a. Project category (Category 1 Small Site Project).
Section I revised as noted.
b. Drainage basin/Watershed name.
Section I revised as noted.
2. The Infiltration Sizing Summary (4/5/16) and Site Plan A1.0 (5/26/16) contain different areas for the
proposed walkway and total impervious area. Please update for consistency.
250 4th Avenue South, Suite 200
Edmonds, WA 98020
ph.425.778.8500 1 f.425.778.5536
www.cgengineering.com
Schuler Residence 16050.20 July 29, 2016
Comment Response #1 Page 2 of 2
..................... _ .....
Infiltration Sizing Summary (4/5/16) Site Plan A1.0 (5/25/16)
..-.......�..... .. _ .......
Walkway 129.61 sf 142.9 sf
Total Impervious 4014.23 sf 4,027.52 sf
The Infiltration Sizing Summary has been updated.
Please verify that the depth of aggregate for the existing infiltration trench is 3 feet. If the existing
infiltration trench has a 3' aggregate depth, the existing trench was slightly oversized and the
proposed infiltration trench system length could be decreased slightly. Based on the total
impervious area (4,014.23 sf), the total infiltration trench system length would need to be 72.25 LF
(using a 1.8% sizing factor and a 3' aggregate depth). The additional infiltration trench length
needed would be 12.25 LF, instead of the proposed 21.16 LF.
The existing trench was designed, permitted, and constructed by others in 2006-2007. As-builts of
the system, infiltration testing, and/or engineering reports were not found for this work. The
project proposes only infiltration for the new and replaced impervious surfaces, which include the
unpermitted impervious areas that have been added since the original approval.
4. The Section II calculations include a typo (2828.55 sf should be 2838.55 sf); however, the calculated
result (1,176 sf) is based on the correct value of 2838.55 sf.
Corrected.
If you have any questions or comments regarding the responses to this review please do not hesitate to
call.
Sincerely,
CG Engineering
Greg Guillen, PE, SE
Principal
250 4th Avenue South, Suite 200
Edmonds, WA 98020
�I�MINf�� ph.425.778.8500 1 f.425.778.5536
www.cgengineering.com