1482.01_390 Sunset Avenue North_ ZGA DFR 001_08-20-2015.pdf
Zipper Geo Associates
Daily Field Report
ZGA Project Daily Field
001
1482.01 Page: 1 of 2
No.: Report No.:
Project: Neuman Residence Location: 390 Sunset Ave North, Edmonds, WA
Client: Babbit Neuman Const. Co. Contractor: Babbit Neuman Const. Co.
ZGA Field Rep: James Georgis Permit No.: BLD20150223
Date: 08-20-2015 Arr./Dep. Time: 8:00am/9:20am & 11:00am/11:40am
Equipment Tracked excavator & end dump truck
Weather Overcast, 60 - 7
Used:
We completed two site visits at the request of Mr. Rick Neuman to observe receptor soil conditions for the site infiltration
facilities. A summary of our observations and recommendations is presented below.
Southeast Infiltration Facility
Upon arrival, we observed that the contractor had excavated the southern 15 feet of the SE infiltration facility. The
approximate extent of the excavation is shown on the attached site plan. The excavation was about 5 to 5½ feet wide and
extended about 4 feet below existing grade. The contractor indicated that the base of the excavation was at the design
bottom of facility elevation of 22 feet indicated on the project plans.
The sides and bottom of the excavation consisted of medium stiff to stiff sandy silt to silt. In our opinion these soils are
notsuitable for infiltration. At our request, the contractor excavated a test hole below the design subgrade elevation.
The test hole disclosed a two foot thick layer of brown sand underlain by about 6 inches of low permeability gray silt,
which in turn was underlain by brown, fine sand with some silt. This stratigraphy is consistent with the soils disclosed in
ZGA test pit TP-3 completed f
we recommended that the infiltration system be extended down about 2½ feet in order to fully penetrate the low
permeability silt layer. Two options appeared feasible to deepen the system 1) remove the unsuitable soil and lower the
entire system (crushed rock and StormTech structure) down about 2½ feet, or 2) remove the unsuitable soil and replace
it with clean crushed rock leaving the StormTech system at the design elevation. We contacted the project civil engineer
and owner regarding the site conditions and recommended that option 2 be considered. The civil engineer and owner
agreed that option 2 was the preferred alternative in order to maintain the intended continuity and connectivity between
the 4 cells of the infiltration system.
At the request of the contactor we returned to the site at 11:00 am. The excavation had been extended down about 2½
feet as recommended. The bottom of the excavation exposed medium dense, brown sand with some silt which is
consistent with the design receptor soils and project geotechnical report for the infiltration system. After our observation
of the subgrade, the contractor covered the bottom and sides of the excavation with a non-woven filter fabric and began
placing crushed stone backfill in general accordance with the project plans and our recommendations. The contractor
requested that we return to the site tomorrow morning to inspect the subgrade for the remainder of the SE infiltration
facility.
Reviewed by:
This field report presents the results of our on-
The contractor is responsible to complete the project in accordance with the approved plans and specifications regardless of our presence on site and our
subcontractors or responsibility for job site
safety.