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November 17, 2014
Jeanie McConnell, Engineering Program Manager
City of Edmonds, Engineering Division
121 Sth Ave North, Second Floor
Edmonds, WA 98020
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C&A Proj # 117-002-14
RE: Harter Residence ADU 9630 238th St SW - Plan Check #BLD20140871
Response to 1st Plan Review Comments
Dear Ms. McConnell:
This letter presents our response to the Engineering Division Plan Review Comments for the
subject project dated September 24th, 2014. The responses below correspond to each of the
comments in the September 24th letter.
ENGINEERING DIVISION COMMENTS
1. Please show all utility information on one plan, preferably the site grading and drainage
plan. Information related to the gas meter and the side sewer appears to be complete on
the site plan only. Other utility related information has been noted in the comments
below. Please address these comments on the site grading, drainage, and utility plan.
Response: Identification of existing utilities, as well as associated relocations, is called
out on Sheet C2.0. This includes existing power, cable, gas, and water services,
2. Please provide the impervious surface calculations as shown on the plan in the table
format provided below.
Response: A table with this information is included on Sheet C2.0.
3. Show location of the existing water service line from the meter to the house.
Response: The approximate location of the water service line is now shown on the
plans.
4. (In summary) Provide an analysis of Stormwater Requirements for the project, and how
they are met.
Response: The project is located in the Edinonds Way Watershed, which is a Direct
Discharge Basin. In accordance with the Storinivater Manual, small siteprojectsin Direct
Discharge .Basins can be exemptfi-oin SSMR 47 if 'a quantitative offsite analysis confirms
that there are no unacceptable downstream issues are found Downstream analysis of the
project (See Section 3) has confirmed that there are no unacceptable downstream issues. In
accordance with the storinivater manual, the project would be exemptfromthis
requirement. However, based on discussions with the Cite ofEdinonds storinwater
engineer, there have been flooding probleins in this basin. Due to these problems, the City
indicated that they have been requiring flow control on all development projects in the
basin. In response to this requirement, flow control will be design and constructed for the
project. Sizing for the LID flow control.BMPs will follow the City of'Edflionds Simplified
Sizing Handout
PO -(206)484-3495
Harter Residence ADU
Response to 1St Review Comments
November 17, 2014
#E72B (Table S), and calculations are shown in the Drainage Report. Four trenches will be
constructed to manage runoff from the roof, and from pavement areas.
S. Clearly show/label impervious surface areas and proposed materials on the drainage
plan. Include a. Driveway surface material, b. will there be a walkway connection
between the new driveway and the ADU entry?, and c. Label the deck on the drainage
plan and note as pervious or impervious.
Response: Driveway surface is asphalt, now called out on the plan. No walkway
connection is proposed with the addition. The deck is labeled on the drainage plan.
6. As the proposed retaining wall supports a surcharge, the design and calculations will
need to be prepared by a licensed engineer and submitted to the City.
Response: A response to this requirement will be provided by the Architect.
7. The wall drain outlets are shown both in the right-of-way and on private property at or
near property lines and sloping toward adjacent properties. Stormwater runoff shall be
managed on site and not directed to a neighboring parcel. Please revise plans as needed.
Response: Wall drains (weep holes) are now shown entirely on site, discharging to rock
pads, in accordance with the DOE manual. These discharges are allowed to occur and
be directed toward neighboring parcels, as that is their natural discharge location. As
long at the discharge meets DOE requirements (Dispersed via rock pads), they are
allowed.
8. It appears as though the existing CATV location maybe in conflict with the proposed
addition. Please indicate rerouting as needed.
Response: A note has been added to the drainage plan to address this comment.
We trust that we have address all of the comments in this letter, as well as the revised plans and
report submittal herewith. If you have any questions regarding this response, please call me at
(206) 484-3495.
Regards,
Cecil & Associates, LLC `
Roger J. Cecil, P.E.