PROJ00400

• Contract/PO #: C153588
• Contractor Name: Greeley, City of
• Contract Type: Loan
• Water District: 3
• County: Larimer
• Bill Number: SB 89-85
• Loan Projects - Doc Type: Feasibility Study

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Both bore holes and the test pit revealed approximately four to five feet of
fill overlying a one-foot layer of black, moist, organic material. The fill
consisted of light gray, loose to moderately dense, silty sand with pockets of
black organic clay and occasional cobbles to 8 inches in size. Below the
organi c 1 ayer, the test pi t encountered a 1 i ght gray, wet, loose, si 1 ty sand
with occasional gravel and boulders to 24 inches in diameter. Bore holes BM-4
and BM-5 penetrated these same materials to a depth of approximately 14 feet.
Underlying this material, the bore holes encountered a gray, wet, dense to
very dense, slightly silty sand with gravel, cobbles, and occasional
boulders. Bore hole BM-4 was carried to a total depth of 40 feet, and BM-5
was drilled to 35 feet. A slotted PVC standpipe piezometer was isolated in
the bottom five feet of each hole.

2.1.3.3 Service and Auxiliary Spillways

Bore hol e BM-6 was drill ed at the downstream toe of the auxi 1 i ary spi 11 way
dike immediately to the right of the service spillway apron. From the surface
down to nine feet, the hole penetrated a poorly graded, loose, saturated silty
sand with gravel, cobbles, and boulders. At nine feet, a boulder necessitated
switching to core drilling. To the bottom of the hole at 30 feet, boulders
composed of granite, gneiss, and schist in a silty sand matrix were
encountered. One small pocket of 1 i ght brown, dense, silty sand was noted at
25 feet. A slotted PVC standpipe piezometer was isolated between 22 and 27
feet.

Test pit BMP-5 was excavated on the crest of the auxiliary spillway dike about
ha If way between the servi ce spi 11 way and ri ght end of the di ke. No ri prap
protection was present at the surface. Compacted fill was encountered in the
upper two feet of the pit. It consisted of gray to tan, dry, silty sand with
gravel to four inches in size. It appeared to be loose near the surface and
became denser with depth. The foundation, from two to six feet, was composed
of moist, loose, poorly-graded silty sand with gravel and cobbles to six
inches in size. It was predominantly gray with multicolored cobbles. At a
depth of six feet, boulders to 24 inches in diameter in a silty sand with
gravel matrix were encountered. The pit excavation was stopped at eight feet
because of a large boulder.

1231 H

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