PROJ00504

• Contract/PO #: C153334
• Contractor Name: Henry Waneka Mutual Reservoir Company c/o City of
• Contract Type: Loan
• Water District: 6
• County: Boulder
• Bill Number: FSA
• Loan Projects - Doc Type: Feasibility Study

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The existing dam consists of a 3000 foot long horseshoe shaped earth fill
embankment with two gated outlets and an emergency spillway. The height of the
embankment at the maximum section is approximately 35 feet. The present reservoit
surface area is approximately 55 acres. Deficiencies in the embankment and other
appurtenant structures have been identified by the State Engineer's Office (SED),
beginning in 1977. A letter from the SEO to the HWMRC restricting the storage
in the reservoir to 3 feet below the crest of the emergency spillway was issued
May. 23, 1979, until the deficiencies were corrected. Subsequently, the City
of Lafayette and the HWMRC through the Colorado Water Conservation Board (CWCB)
entered into an agreement with WRC to evaluate the feasibility of improving the
dam.

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The investigation of the structure by WRC verified the deficiencies noted
by the State (see Chapter V). The investigation included a geologic drilling and
testing program, a slope stability analysis, and seepage analysis. A hydrologi-
cal analysis was previously performed by WRC. Several alternatives were considered
which improved the structure and increased the storage capabilities. Two alter-
natives were selected for detailed evaluation, rehabilitation and enlargement
(refer to Section V-C of this report). The project costs (Chapter-VI) and the
economic feasibility (Chapter-VII) were then evaluated for the alternatives.
The enlargement alternative has been found to be financially sound (Table-Il) and
is therefore recommended by WRC for construction. Other recommendations (Chapter-
VIII) included additional stock purchased by the City of Lafayette and continued
water conservation measures by the Lafayette water users.

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