PROJ01784

• Contract/PO #: FS0059FX
• Contractor Name: Melvin L. Thiebaud
• Contract Type: Miscellaneous
• Water District: 0
• Loan Projects - Doc Type: Feasibility Study

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ROY ROMER
Governor

HAL D. SIMPSON
Acting State Enginee

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DIVISION OF WATER RESOURCES
WATER DIVISION IV

Keith C. Kepler
Division Engineer
1 540 East Niagara
P.O. Box 456
Montrose. Colorado 81402
[phone]
July 24, 1992

RECErVED
JUL 3 1 '92

WATER Ht.~vur/CES
STATE ENGINEER
COLO. --

Melvin Thieboud
1490 2420 Drive
Cedaredge, CO 81418

Re: Eureka li1
W. Div. 4, DAMID: 400229

Dear Mr. Thieboud:

The purpose of this letter is to summarize the major points of our meeting of
June 8, 1992, my follow-up tele?hone conversation with you on June 23, 1992, and
outline remedial repair alternatives to correct the problems with the Eureka #1
dam.

Since the apparent source of leakage through the embankment which caused the
slide on the downstre~m slope was traced to rodent activity, the emb~nk~ent
material in the area of leakage must be removed and recompacted. The area of the
slide must also be removed and recompacted to achieve a stable slope.

As I indicated, maximum compaction can be achieved only when the soil moisture
content is at an optimum. The optimum moisture content can be determined most
accurately in a laboratory compaction test, and varies according to soil type.
Acceptable results in the field can be achieved provided the moisture content is
within 1 to 2 percent of optimum, sufficient compactive effort is applied to the
soil and the thickness of each lift of soil is small enough to receive complete
compaction throughout. A field density test can be performed to determine the
amount of compaction achieved rela~ive to the laboratory maximum density. For
most small dams a density equal to 957. of the laboratory maximum density provides
reasonable confidence in the performance of the dam.

Even though non-jurisdictional dams like the Eureka #1 are exempt from design and
construction standards set forth in the rules and regulations, the exemption does
not reduce your exposure to liability should the dam fail. It is my prOfeSSiOnal}
opinion that the dam is currently unaafe for full storage. Based on the actions
and observations by the water commissioner, the reservoir should not be operated
above gage height 6.0 until repairs are made. Furthermore, it is the policy of
the State Engineer's Office not to impose a formal storage restriction on Class
II , non-jurisdictional dams such as the Eureka IiI, but advise the owner on
technical matters related to needed repairs.

In addition to repair of the leakage area, two other problems should be corrected

A-P