Grading Ext Request, BLD20140317, Saunders, 15911 74th Pl W, Edmonds.pdft Group
1W
November 12, 2015
Northwest, Inc.
Mr. Leif Bjorback
City of Edmonds
121 - 5`h Avenue North
Edmonds WA, 98020
SUBJECT: REQUEST FOR NEW GRADING EXTENSION
New SFR at 15911 - 74' Place West, Edmonds, WA
BLD2014-0317
Dear Mr. Bjorback:
Geotechnical Engineers, Geologists
& Environmental Scientists
G-3598
On behalf of the client, Mr. Leroy Saunders, a new grading extension is requested. The
contractor was not able to finish the site earthwork within the allotted time period of the previous
grading extension. The following earthwork items need to be completed at the site:
1. Installation of the storm water detention pipe (installation started but not completed);
2. Backfilling and grading around the perimeter foundation.
3. Backfilling below the garage slab, and pouring of the garage slab;
4. Installation of the onsite storm drain CB's;
5. Final grading and rocking of the driveway;
6. Connection of street utilities to the house.
Completion Date
With weather and reduced light considerations, the anticipated completion date for the above
items is January 1, 2015. On January 1st, the site will be winterized in accordance with our
previous submittal. Any remaining earthwork will be stayed until after May 1', 2016, unless the
site is reevaluated by the geotechnical engineer of record to confirm that the site conditions are
stable and work may start without creating erosion issues or affecting site stability and the site
evaluation is submitted for approval by the City prior to re -commencing work.
Site Stability Evaluation
The site is currently stable and it is our professional opinion that the remaining earthwork will
not negatively impact the stability of the site and the earthwork may continue through the end of
December from a site stability and geotechnical perspective.
13240 NE 20th Street, Suite 10 Bellevue, Washington 98005
Phone 425/649-8757 Fax 425/649-8758
November 12, 2015
Grading Extension Request Page 2
New SFR, 1591174' Place W (BLD2014-0317)
Temporary Erosion and Sedimentation Control {TESL)
It is our opinion that the TEC methods used at the site up to this point have been satisfactory.
No offsite erosion control issues have been observed. We plan to continue monitoring the
effectiveness of the site's TESL, making modifications and replacing the TESL as needed. The
principal TESC measures being used include:
0 Silt fencing.
• Covering exposed soils with visqueen plastic and stabilizing the plastic with sand bags.
• Covering other areas of exposed soil with straw mulch.
• Maintaining the rock construction entrance and replacing the rock if contaminated with soil.
• Maintaining all erosion control measures in a good condition.
• Halting all earthwork activities during storm events and protecting exposed soils with
visqueen plastic.
The geotechnical engineer is monitoring the site weekly, or after storm events, and the reports are
being submitted to the City. It is our opinion that the erosion control measures being used are
sufficient to mitigate offsite impacts. From an erosion control perspective, it is our opinion that
completing the remaining earthwork this fall is better than waiting until next spring when the site
soils will be more saturated, be more difficult to work with, and have a greater erosion potential.
Sincerely
GEO GROUP NORTHWEST, INC.
Wade J. Lassey, LEG
Engineering Geologist
William Chang, P.E.
W=
GEO Group Northwest, Inc.
74 a S l' -7t4
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Wade JLassey