00428t -
J
w
RECf
1977
of Edmonds
city pevel. ROO.
Community
Y
Kegel & Associates Inc.
yy' August 22, 1977
1
Planning Division
' City of Edmonds
City Hall
Edmonds, Washington 98020
Re: Storm Drainage Analysis of Proposed Park Mere West Development
Our Job No. 6886
Gentlemen:
Proposed Design:
A. Storm water runoff will come from two main sources:
.1. Road surfaces
2. Roof areas.
Runoff from road surfaces will be intercepted by roadside gravel
filled `trenches. These trenches will detain the water until it
can be leached into the underlying soil
Runoff from roof surfaces will be intercepted by standard roof
and footing drains. This water will also be detained and eventually
will leach into the soil by means of gravel sumps located on each
lot. On slopes exceeding 25%, these sumps will take the form
of trenches running parallel to the contours. Such an arrangement
will prevent slippage due to high concentrations of subsurface
Water on steep slopes.
B. The accompanying soils analysis and percolation rates indicate
a suitable depth and quality of material that should adequately
absorb the storm water runoff as ground water recharge. Therefore
extensive clearing and regrading for an additional detention area
in the common space may be entirely eliminated or scaled down
in size from that originally designed.
C. The existing culvert under 68th Avenue West and the drainage
channel running east -west across the subject property will not
be altered.
Soils:
A percolation test and a soil log on each lot were performed
by Mr. Warren Williams, a registered sanitarian (See Appendix).
ENGINEERS • SURVEYORS • PLANNERS
9800 EVERGREEN WAY (U.S. 99), EVERETT, WASHINGTON 98204 • PHONE (206) 353-1119/ 775-5424