Engineering Response Letter_20180426.pdfOGROUPFIOURinc.
P.O. Box 1059
Lake Stevens, Washington 98258
(425) 408-1152
Fax (425) 877-1341
e-mail: info@grp4.com
Brad Shipley, Associate Planner
City of Edmonds Development Services Department
1215t" Avenue North
Edmonds, WA 98020
Re: Meadowdale Short Plat; PLN20170057
Group Four No. 17-0523
Dear Mr. Shipley,
April 25, 2018
APR 2,-
DEVo U. 4,' ,
CES
I am responding to the comments in your Planning Review Comments letter dated April 11, 2018,
for the project referenced above. The comments are addressed as follows:
Engineering Review:
Please see the attached comments from the Engineering Division, including Storm water.
1. The project does not appear to be satisfying the retrofit requirement per ECDC
18.30.060.D.b.i; the project must mitigate storm water using MR #5 for 25% of the existing
impervious surfaces on Lot 1 in addition to mitigation for new plus replaced surfaces on Lot 2.
The proposed plan & report have been revised to include the retrofit requirement, as noted.
2. It is unclear why the engineer selected rain gardens as the most appropriate BMP for the site;
List 1 must be reviewed in -order (top to bottom) and it appears that the design infiltration
rate above 5 in/hr allows for the full use infiltration and pervious pavements on -site. Revise
design to implement first feasible BMP option on list and/or revise report to expand on the
infeasibility of each BMPs not selected for use.
The plan & report have been revised, the rain gardens have been replaced with infiltration and
pervious pavements, and the infeasibility of methods not selected is provided.
3. Per Edmonds Addendum Checklist #4, an additional correction factor of 0.9 (for influent
control) is required to be applied to the design infiltration rate; revise drainage report as
needed to use corrected design infiltration rate.
The drainage report is revised to include the correction factor applied to the design infiltration
rate, as noted.
Meadowdale SP; #17-0523 Page 1 of 2
LAND SURVEYING CIVIL ENGINEERING LAND USE PLANNING PROJECT MANAGEMENT
Planning Review:
1. Lot Area. Access easements do not count toward lot area. The proposed 25" access and utility
easement reduces the proposed Lot 2 below the minimum required lot area of 12,000 sf.
€ Revise the proposal to meet this criterion.
The proposed lot configuration has been revised to delete the access easement across
Lot 2, and the proposed lot area for Lot 2 does meet the minimum of 12,000 SF.
2. Site Plan.
€ Add names of adjacent property owners.
The names of the adjacent property owners have been added to the short plat map, as
requested.
€ Setbacks are measured from the property line or access easement. Adjust the southern
side setback for Lot 2. Side setbacks are 10 feet. Additionally, correct the western side
setbacks for both lots from 25 feet to 10 feet.
The setback lines for both lots have been corrected on the short plat map, including the
western side yard setback for Lot 1. Lot 2 is a corner lot, which requires a street setback
for each frontage, and allows side yard setbacks for interior lot lines. There is no longer
a setback required from the access easement, as it has been deleted.
Please feel free to contact me with any questions or additional comments.
Sincerely,
GROUP FOUR, INC.
Ken Williams
Senior Project Manager
Meadowdale SP; #17-0523
LAND SURVEYING CIVIL ENGINEERING
LAND USE PLANNING
Page 2 of 2
PROJECT MANAGEMENT