REVIEWED BLD RESUB 1 BLD2021-0895 Geotech updateCOBALT
G E 0 S C I E N C E S
October 18, 2021
Sue Eastman King
Eastman.kings P gmail. com
RE: Plan Review
131 Skyline Drive
Edmonds, Washington
Cobalt Geosciences, LLC
P.O. Box 82243
Kenmore, Washington 98028
In accordance with your authorization, Cobalt Geosciences, LLC has prepared this letter to
discuss our plan review and to provide additional erosion control recommendations.
We have reviewed the updated civil plans and discussed the project with the civil engineer. It is
our opinion that there are no significant geologic hazards on the site other than erosion hazards.
Our recommendation for effective setbacks for foundation elements from slopes of 30 percent
magnitude or more still apply; however, there are no areas where the building requires a setback
or buffer from landslide hazard areas as defined by the Edmonds municipal code. These hazards
are not present.
The approximate 10 feet tall rockery in the southwest portion of the property (property to the
south) is currently stable. The proposed site development adjacent to this rockery includes steps
and local walls. This work will not require significant grading and is located at least 5 feet from
the rockery. The proposed wall and landscaping construction will not adversely affect the rockery
on the adjacent property.
Typical erosion control measures are likely suitable for the site development; however, we suggest
the following items be considered as a contingency for work that occurs during the wet weather
season (if conditions warrant their use):
• Any temporary slopes and soil stockpiles should be covered with plastic sheeting when
work is not taking place. This will require sandbags and other systems to maintain their
locations.
• Ability to excavate a temporary sediment pond with the ability to pump standing water
into a Baker tank (or similar) if required.
• Cover bare soils with straw and rock (with waddles in slope areas) to prevent sheet flow
when work is not taking place.
• If erosion is resulting in sediment buildup at the silt fences, it should be removed, and the
sources of the erosion must be mitigated as soon as possible.
We should be on site during grading and excavation work to verify temporary excavations, soil
bearing, foundation drains, fill compaction, and if required, erosion control measures.
www.cobaltgeo.com (2o6) 331-1097
October 18, 2021
Page 2 of 2
Limited Geotechnical Evaluation
Closure
The information presented herein is based upon professional interpretation utilizing standard
practices and a degree of conservatism deemed proper for this project. We emphasize that this
report is valid for this project as outlined above and for the current site conditions and should not
be used for any other site.
Sincerely,
Cobalt Geosciences, LLC
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Phil Haberman, PE, LG, LEG
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www.cobaltgeo.com (2o6) 331-1097