Response to Engineering Comments 3.pdfo.
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CITY OF EDMONDS
PLAN REVIEW COMMENTS
ENGINEERING DIVISION
(425) 771-0220
City Website: Eawxwv.e(Lnc c�
DATE: October 12, 2016
TO: Robin Kearsley
r@kearsleyhomes.com
FROM: Jeanie McConnell, Engineering Program Manager
jeanie.mcconnell@edmondswa.gov
RE: Application #: bld20160179
Project: Therrell - Single Family Residence Addition
Project Address: 8609 Talbot Rd
During review of the above noted application, it was found that the following information,
corrections, or clarifications are needed. Reviews by other divisions, such as Planning, Building, or
Fire may result in additional comments. Please redline plans or submit three (3) sets of revised
plans/documents with a written response to each of the items below to a permit coordinator.
Resubmittals can be made at the Development Services Department on the 2nd floor of City Hall.
Permit Center hours are M, T, Th & F from 8am-4:30pm and on Wednesdays from 8:30am-noon.
City of Edmonds handouts, standard details and development code can be referenced on the City
website.
Comments 1 — March 30, 2016
Comments 2 — August 19, 2016
Comments 3 — October 12, 2016
1) ok
2) ok
3) ok
4) October 12, 2016 comment — Thank you for providing a geotech report addressing the
infiltration system. Please address the comments provided below:
8/19/2016 comment — The plans have been revised to include additional impervious surface
area. The proposed impervious area for the project appears exceed 2000sf and therefore,
stormwater management shall be provided.
a. ok
b. October 12, 2016 — Please clearly identify the total for the "new" impervious
surface area. Clearly note that the existing (remaining) driveway was constructed
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in 1967. Please remove the "net impervious area" as this is not applicable to
w stormwater thresholds.
_i 8/19/2016 - Update the impervious surface area calculations shown on the plans to show
ItP�"'gall new impervious areas and existing pervious deck conversions to impervious. Credits
for the removal of existing impervious areas are not granted if the existing structure is
removed.
c, ok
d'.October 12, 2016 comment Calculations have been provided and infiltration
trenches have been shown on the plans. The infiltration system previously shown
on the plans is also ;Mill shown and needs to be removed. In addition, the following
needs to be added into the plans/design:
i. The 4" Dia. Perf. Pipe in the infiltration trench must be at least 12" from the
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trench bottom.
The infiltration trench rock is specified as 1-1/2" washed rock. Per our
fl.andont, it should bel -1/2" to 1-3/4" washed rock. (preferably 1-1/2" to 2-
1/2")
Both trenches need pre-treatment structures (catch basins), per City
handout.
8/19/2016 - Include infiltration trench sizing calculations consistent withm jjaLid it
E7213.
October 12, 2016 — comment not addressed. Clearly show how flows will be
directed on the driveway surface and label any structures that will be installed to
capture flows and direct to infiltration systems.
8/19/2016 - Clearly show how runoff from driveway will be collected and discharged to
the infiltration system. If the runoff from the new driveway area cannot be separated
from the existing driveway, then the infiltration system will need to be sized to
accommodate all runoff directed to the trench.