Grading Ext Request BLD2014-0317 Saunders 15911 74th Pl W.pdfGeotechnical Engineers, Geologists
Group Northwest, Inc. & Environmental Scientists
GEO
December 31, 2015
Mr. Leif l3jorback
City of Edmonds
121 - 5h Avenue North
New SFR at 15911 - 74' Place West, Edmonds, WA
BLD2014-0317
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On behalf of the client, Mr. Leroy Saunders, a new grading extension is requested. The
contractor was not able to finish all the site earthwork within the allotted time period of the
previous grading extension. The following earthwork items need to be completed:
1. Placement of rock and fabric in the seepage zone area east of the catchment wall;
2. Construction of the swale on the east side of the catchment wall and house;
3. Installation of the two stormwater CBs at the end of the swale east of the house;
4. Connection of street utilities to the house (power, gas, phone and cable);
5. Reshaping the slope between the driveway and west side of house.
6. Normal erosion control, including cleanup and rocking the driveway entrance.
Completion Date
With weather and reduced light considerations, the anticipated completion date for the above
items is January 31, 2015. On January 31st, the site will be winterized in accordance with our
previous submittal. Any remaining earthwork will be stayed until after May I't, 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
January from a site stability and geotechnical perspective.
13240 NE 20th Street, Suite 12 Bellevue, Washington 98005
Phone 425/649-8757 FAX 425/649=8758
December 31, 2015
Grading Extension Request Page 2
New SFR, 1591174' Place W (BLD2014-0317)
Temporary Erosion and Sedimentation Control (TESC)
It is our opinion that the TESC 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 TESC, making modifications and replacing the TESC as needed. The
principal TESC measures being used include:
9 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.
• Maintaining the erosion control measures in a good condition.
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• 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 as soon as possible 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.
Principal
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of WASp,
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GEO Group Northwest, Inc.
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