C153705 Feasibility Study

• Contract/PO #: C153705
• Contractor Name: Beaver Reservoir Company
• Contract Type: Loan
• Water District: 59
• County: Gunnison
• Bill Number: SB 94-029
• Loan Projects - Doc Type: Feasibility Study

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Beaver Reservoir Company
Attention: Mr. Neil Thompson
February 4, 1993
Page 10

abutment near the apparent top of a thick sandstone bed from a point near the downstream
end of the outlet pipe to near the bend in the creek.

SUMMARY AND CONCLUSIONS

The following is a summary and conclusions of the data gathered from our field
investigation and a review of previous investigations:

I. The left abutment of the dam was constructed on coal beds showing evidence of
burning which resulted in loss of volume and disturbance to overlying bedrock
layers.

2. In the right abutment, a zone of crushed or sheared shale was observed at a depth
of approximately 24 to 32 feet'in'test hole WCC~2.
, .

3. The embankment soil is classified as a clayey sand. The material shows no signs
of dispersive tendencies and appears to have been generally well compacted during
placement.

4. The results of the geophysical survey are inconclusive with respect to seepage, as
a result of the reservoir having been drawn down at the time of our survey.
However, ttrree areas were identified as potential seepage areas. These areas are
near coordinates 50N, 140E, along the east and west ends of 2ooN, and along the
east endof,ON, 50N, and 2ooN.

5. Based on the' results of our investigation, our feasibility study will focus on
~mediation of the foundation to reduce the seepage through the darn.

GENERAL INFORMA nON

The test hole drilled for this study was located to obtain a reasonable picture of subsurface
conditions for design purposes. Variations from the conditions portrayed frequently occur.
These variations are sometimes sufficient to necessitate modifications in design and
construction. Thus, it is important we observe subsurface materials exposed in excavations
to take advantage of all opportunities to recognize differing conditions and reduce the risk
of having undetected conditions which could affect the future performance of the structure.

23067/LEIO 02-04-93(4:24pm)/RPT