deishergeotech.pdfAssociated Earth Sciences, Inc.
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September 11, 2006
Project No. KE060468A
Land Planning Northwest
1002 nd Avenue South, Suite 170
Edmonds, Washington 98020
Attention: Larry Deisher, P.E.
Subject: Evaluation of Top of Slope Setback
Detached Garage
7025 174th Street SW
Edmonds, Washington
Dear Mr. Deisher:
RESUB
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CIV o.
As requested, Associated Earth Sciences, Inc. (AESI) is pleased to present this letter
providing our recommendations for top of slope setback for the above -referenced site.
This fetter has been prepared for the exclusive use of Land Planning Northwest, Mr.
Larry Deisher, and their agents for specific application to this project. Within the
limitations of scope, schedule, and budget, our services have been performed in
accordance with generally accepted geotechnical engineering and engineering geology
practices in effect in this area at the time our letter was prepared. No other warranty,
express or implied, is made. It must be understood that no recommendations or
engineering design can yield a guarantee of stable slopes. Our observations, findings,
and opinions are a means to identify and reduce the inherent risks to the owner.
This letter is based on our visit to the site on May 25, 2006 and our review of the
following documents:
1. "Geotechnical Engineering Evaluation, Deisher Short Plat," prepared by Nelson
Geotechnical Associates, Inc., dated May 26, 2004.
2. "Memorandum, Slope Protection, 7023 174th Street SW, Edmonds, WA,"
prepared by Nelson Geotechnical Associates, Inc., dated May 26, 2004.
3. "Drainage Plan," single sheet site plan stamped "Approved as Noted," dated
August 6, 2004 and signed by Jamie Hawkins.
4. "Short Subdivision Site Drainage Plan," prepared by Land Planning Northwest,
dated May 18, 2006.
Kirk6nd. Office • 911 Fdtk Avenue, Suite 100 • Kiddand, WA 98033 • P (4.25) 827-7701 • F (425) 827-5424
Everett Office • 29111/2 Hewitt Avenue, Suite 2 • Enema, WA 98201 • P (425) 259-0522 • F j (425) 252-3408
www.aesgeo.com
We also reviewed a V=40 feet site plan that showed the location of the proposed
detached garage.
The subject lot contains a steep slope (43 percent) on the north side. The slope is
heavily vegetated and contains evergreen trees with straight trunks. The slope does not
exhibit indications of ground water seepage or past or present shallow or deep-seated
slope movement.
We have reviewed the above -referenced geotechnical report and memorandum
prepared by Nelson Geotechnical Associates, Inc. and are in general agreement with
their geotechnical recommendations. In our opinion, the recommended 25 -foot top of
slope setback presented in the geotechnical report could be reduced to 20 feet without
impacting the stability of the neighboring slope. This setback should apply to all
structures and the on-site storm water spreader trench.
We understand that the structure planned for the lot will consist of a manufactured
home supported on a standard post and pad foundation. In our opinion, the native soils
are suitable for support of this type of foundation using an allowable soil bearing
pressure of 2,000 pounds per square foot (psf). To attain this allowable soil bearing
pressure, all footings have to extend down to medium dense to dense native soil.
Foundations should not bear upon existing site fill.
We appreciate the opportunity to be of service to you on this project. Should you have
any questions regarding this letter, please contact us at your earliest convenience.
Sincerely,
ASSOCIATED EARTH SCIENCES, INC.
Kirkland, Washington
:ion
Jon N. Sondergaard, P -G., P.E.G.
Principal Engineering Geologist
KE060468AI
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