sheehangeoltr.pdfNELSON GEOTECHNICAL
NGA
ASSOCIATES, INC.
GEOTECHNICAL ENGINEERS & GEOLOGISTS
Main Office Engineering -Geology Branch
17311 — 135`h Avenue NE, A-500 112 Olds Station Road, Suite C
Woodinville, WA 98072 r Wenatchee, WA 98801
.(425)48.6-1669 . FAX (425) 481-2510 ' 509
(425) 33-1669 Snohomish County ` ( ) 6 65-7686 (Phone/Fax)
)MEMORANDUM
DATE: October 5, 2006
TO: Tom Sheehan
CC: Ed Baker — Baker Engineers, Inc. (fax)
w
FROM: Khaled Shawish, PE
Bala Dodoye-Aiali
RE: Sheehan Pool Repair
Slope Stability Issues
Edmonds, Washington
NGA File No. 712905
Y
06
We have been requested to comment on potential impacts to a steep slope adjacent to your planned pool
repair project at your residence in Edmonds, Washington. We previously prepared a geotechnical report
for the project titled "Geotechnical Engineering Evaluation — Sheehan Pool Repairs — Edmonds,
Washington," dated July 27, 2005- For our use in preparing this memo, we have been provided with a
letter from the City of Edmonds dated August 17, 2006 requesting our review comments.
Project plans include replacing a failing wall that currently provides support for your pool. The pool will
be emptied and braced during wall replacement. A steep slope is located off the property, across an access
driveway, and as a result, we have been informed that the site is mapped within a Steep Slope Hazard
Areas and Erosion Hazard Areas as defined by the City of Edmonds. We have reviewed Section 23.80.050
in the Edmonds Community Development Code. Base on our review, site observations, and our
understanding of the project, it is our opinion that the planned improvements should not have an adverse
impacts on the off-site slope, providing all recommendations presented in our previous report are followed.
Erosion control measures will be implemented during construction to keep muddy water from leaving the
site and reaching the slope. Also, permanent drains will be incorporated into the pool and tightlined away
from the slope. The slope will be monitored during construction. When the project is completed, all
Memorandum
Sheehan Pool Repairs
Edmonds, Washington
October 5, 2006
NGA File No. 712905
Page 2
exposed surfaces will be covered and therefore there should be no increased potential for long-term
erosion. The final product should result in less risk to the slope compared to the current conditions created
by the failing wall_
We trust this memorandum should satisfy your needs at this time. Please call if you have any questions
or require additional services.
NELSON GEOTECHNICAL ASSOCIATES, INC.