HomeMy WebLinkAboutBLD2012-00174 Geological Addendum - BLD Letters / Memos - 5/4/2012 r - -
ALL AMERICAN GEOTECHNICAL
O0 GEOLOGY ADDENDUM LETTER
DAMON ERNST
P.O.Box 484
UNION,WASHINGTON 98592
RE: GEOLOGICAL VISIT !
9980 STATE ROUTE 106
SHELTON,WASHINGTON
PARCEL 32236-51-00032
MAY 04,2012
AAG12-007
Dear Mr Ernst:
As per your request, I am sending you a geological addendum for the above- parcel. The results of my visit,
together with my recommendations, are to be found in the following letter. I have provided three copies for your
review and distribution.
GENERAL
Curtis D Cushman visited the site on May 3, 2012. The owner was on-site. I was shown the bluff area below the
single family dwelling on site where the client wishes to place a small garage which will shelter a boat.. The site
is located by a drive at Pebble Ridge directly off SR 106 east of Alderbrook.
The site overlooks Hood Canal to the northwest. The area is one of extensive shoreline residential development.
The proposed site is the only one on the lower property suitable for construction.
All other general information may be taken from the original geotechnical report by Harold Parks of GTL and by
the update by Curtis D Cushman.
GEOLOGY
According to the original report, the area is Vashon advance outwash. Site inspection seems to indicate that the
actual area of construction is Vashon till. In any event,the site is cut, with no fill, and is bottomed by"hardpan",
which is common in the till. Either unit is suitable for construction.
AAG 12-007 8947 Buttonwood Lane NE,Olympia, WA 98516 1
Phone#: (360)481-6677 Fax#: (360)754-4848
ALL AMERICAN GEOTECHNICAL
SOILS
The Alderwood soil has essentially been removed and graveled over at this time. The soils on the lower slope are
densely vegetated with well-rooted plants. The area above the slope, outside the proposed building site, is
developed with grass, shrubs,and retaining walls.
OBSERVATIONS
The property is largely developed. The addition of a shelter for a boat will not adversely impact the slope nor the
environment as currently designed.
RECOMMENDATIONS
It is my professional opinion that the proposed structure, as a non-residential structure with no new grading
footprint, and located as it is on firm ground, should be approved as designed. Construction should be in keeping
with earlier recommendations and regulations of the county.
Drainage should always be directed away from the vegetated slope, and proper safeguards used to ensure there is
no discharge of sediments downslope. A silt fence is recommended.
Respectfully Submitted,
ALL AMERICAN GEOTECHNICAL,INC.
7
243 �o ` Curtis D Cushman,L.G.,L.E.G.
SQ eo Senior Engineering Geologist
Curtis Dean Cushman
AAG 12-007 8947 Buttonwood Lane NE,Olympia, WA 98516 2
Phone#: (360)481-6677 Fax#: (360)754-4848