ENG SI REPORT INFILTRATION PITSCOBALT Cobalt Geosciences, LLC
GEOSCIE P.O. Box82243
Kenmore, Washington 98028
December 16, 2021
Wayne Malmberg
waynem@windstarconstruction.com
RE: Drywell Observations
1001 Olympic Way
Edmonds, Washington
In accordance with your authorization, Cobalt Geosciences, LLC has prepared this letter to
discuss drywell excavation work at the site.
We visited the site in December 2021 to observe excavation of two large drywells west of the
residence. The soils encountered in the excavations were mixtures of sand, silt, and gravel and
were locally caving. These soils would be consistent with a Medium Sand to Loamy Sand per
USCS textural triangles.
The areas excavated with dimensions of 20 feet by 8 feet by 8 feet and 10 feet by 8 feet by 8 feet. We
observed 48 cubic yards of washed rock installed for drywell #1 and 24 cubic yards for drywell #2.
We observed the wash rock being wrapped with a sediment control mat and covered.
Sincerely,
Cobalt Geosciences, LLC
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A. Haberman
12/ 16/2021
Phil Haberman, PE, LG, LEG
Principal
www.cobaltgeo.com (2o6) 331-1097