PROJ00414

• Contract/PO #: C153326
• Contractor Name: Fruitland Mesa Water Conservancy District
• Contract Type: Grant
• Water District: 0
• County: Montrose
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

I,

I
I

1. Field reconnaissance of the dam site area performed by a
PRC/ECI geologist.

I

2. Test pitting and sampling of the potential borrow areas to

define the quantity and quality of locally available embankment

construction materials.

I

In addition to the field investigations, a review and analysis of
available data pertaining to the original embankment construction was
performed. Laboratory testing of the construction materials was also
carried out.

I
I

I
I

B. Materials
Borrow Areas Field Exploration

I

A field exploration program was conducted (during the period of
July 30, 1980, to August I, 1980) in Borrow Areas A and B (land owned
by Fruitland Mesa Conservancy District> as indicated on the property
map (Figure 6). The exploration program consisted of test pitting at
selected locations in areas A and B and surface geological mapping.
Test pitting was accomplished by a 650 Allis Chalmer's backhoe.
Borrow Area A is composed of residual weathered shale with the influ-
ence of some sandy interbeds. Borrow Area B is a high knoll composed
of residual highly weathered to moderately weathered shale with
interbedded sandstone that protrudes into the southern end of the
reservoir. Each test pit was logged in the field and soil samples
from representative stratum were taken and tested to determine their
engineering properties.

I

I
I
I

I
I
I
I
I

Seven test pits were excavated in Borrow Area A and five in Borrow

area B as shown in Figure 7. The thickness of clayey soils ranges

from 11.5 to more than 13 feet in Borrow Area A and from 3 to 12 feet

in Borrow Area B. Summary logs of these test pits are also given in

the same Figure.

Analyses of available construction materials based on isopach maps
of the residual soils overlying bedrock indicate that about 934,000
cubic yards of clayey soils exist in borrow area A and 350,000 cubic
yards of clayey soils exist in borrow area B.

II-7