C153804 Feasibility Study

• Contract/PO #: C153804
• Contractor Name: Left Hand Ditch Company
• Contract Type: Loan
• Water District: 5
• County: Boulder
• Bill Number: HB 95-1155
• Loan Projects - Doc Type: Feasibility Study

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Executive Summary

In response to an order from the State Engineer's Office the Left Hand Ditch Company is

seeking to make certain modifications to the dams at Left Hand Valley Reservoir to increase the

spillway capacity. The Company is seeking funding from the CWCB for a portion of the

construction costs associated with the improvements. This feasibility study examines the

feasibility of one non-structural and seven structural alternatives and demonstrates the technical,

financial and institutional feasibility of constructing a new stepped roller compacted concrete

spillway over the north dam of the reservoir.

The spillway will be constructed over the north dam forming the reservoir and will have
a 95 foot crest width converging to a 70 foot stilling basin at the bottom of the 2.25:1 slope. The
existing spillway will remain in place providing capacity for storms up to I in 100 years
recurrence interval. The new spillway will have a fuse plug section constructed on its crest to be
overtopped during storms of greater than I in 100 year recurrence intervals. In concert the two
spillways will provide a total capacity of 11,025 cfs, sufficient to pass the runoff from a storm
equal to 75 percent of the Probable Maximum Precipitation without overtopping the dams.

The construction cost estimate for the new spillway, including construction engineering
and contingencies, is $490,400. The Company will finance 75 percent of the construction cost
through a construction fund loan from the CWeB and will finance the remaining 25 percent of
the construction cost through a bank loan. Assessments charged to the shareholders of the
Company will provide the funds necessary to repay the loans. Assessments were increased from
$5.00 per share to $7.50 per share for 1994 in anticipation of this project. Assessments will
further be increased from $7.50 per share to $8.00 or more per share to fund the repayment
beginning in 1995. Construction will begin in September 1995 with completion in
approximately six to eight weeks.