C150122 Feasibility Study

• Contract/PO #: C150122
• Contractor Name: Central Weld County Water District
• Contract Type: Loan
• Water District: 4
• County: Larimer
• Bill Number: SB 03-110
• Loan Projects - Doc Type: Feasibility Study

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customers and CWCWD has budgeted $1,000,000 for rental water to meet the
needs of its customers. Additionally, it is expected that the North'ern Colorado
Water Conservancy District carry-over policy will be limited or discontinued in the
near future. Subsequently, the Districts would be extremely vulnerable to annual
climate fluctuations and NCWCD water yield quota fluctuations. This alternative
was deemed undesirable because it does not meet the need for raw water
storage.

Alternative 2

This alternative consists of constructing a reservoir including an earthen dam and
water delivery system at the location labeled Dry Creek Reservoir on Figure 2.
The dam would impound up to 5200 ac-ft of water for use by Carter Lake Filter
Plant. An existing 20-inch steel pipeline would be used to transport water
between the filter plant and the reservoir. A new pumping facility would be
constructed to deliver water from the reservoir to the Carter Lake Filter Plant.
This alternative was selected as the most effective means of meeting the needs
of the Districts.

Alternative 3

This alternative consists of constructing a dam at the location labeled Alternative
3 on Figure 2. The dam would impound approximately 800 ac-ft of water. This
alternative was ruled out following preliminary geological, geotechnical, and
environmental evaluation due to considerable geological complications and
environmental issues. The combination of small storage capacity and high cost
also made this alternative unfeasible.

SELECTED ALTERNATIVE

The proposed Dry Creek Reservoir as described in Alternative 2 was selected
because it is the most feasible alternative for meeting the Districts' need for raw
water storage. It would consist of the following:

1. Construction of an approximately 5200 acre-foot reservoir including a 40-
foot high earthen dam with emergency spillway and outlet works.
2. Conversion of an existing 20-inch treated water line to a raw water line to
connect the reservoir to the Carter Lake Filter Plant.
3. Construction of a 5000 GPM pump station to pump water from the
reservoir to Carter Lake Filter Plant. The pump station will include a 24-
inch pipeline connecting to the existing 20-inch line and a 36-inch pipeline
connecting to the reservoir outlet works.

Smith Geotechnical Engineering Consultants has conducted feasibility-level
design work for the proposed dam and TEC has conducted feasibility-level
design work for the proposed pump station. The site description for the selected

Dry Creek Reservoir Feasibility Study

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