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y Central Weld County Water District -Proposed Dry Creek Reservoir Agenda Item 20g <br />November 25-26, 2002 <br />Alternative No. 1 -The no action alternative does not provide raw water storage for the Districts, <br />leaving them vulnerable to service interruptions caused by limited supply from Carter Lake, as well <br />as the high cost of obtaining supplemental water from other entities. For 2003, LTWD has <br />budgeted $500,000 for'rental water to meet the needs of its customers, and CWCWD has budgeted <br />$1,000,000 for rental water. Additionally, it is expected that the Northern Colorado Water <br />Conservancy District carry-over policy will be limited or discontinued in the near future, leaving the <br />Districts vulnerable to annual climate fluctuations and water yield quota fluctuations. <br />Alternative No. 2 -This alternative consists of constructing a reservoir, including an earthen dam <br />and water delivery system, at the location 2-3 miles southeast of Carter Lake. The dam would <br />impound up to 5200 ac-ft of water for use by the Carter Lake Filter Plant. An existing 20-inch steel <br />pipeline would be used to transport water between the filter plant and the reservoir, and a new <br />pumping facility would be constructed to deliver water from the reservoir. <br />Alternative No. 3 -This alternative consists of constructing a dam, closer to the Filter Plant, at the <br />location about 0.5 miles to the northeast. The dam would impound approximately 800 ac-ft of <br />water. This alternative was ruled out following preliminary geological, geotechnical, and <br />environmental evaluation due to considerable geological complications and environmental issues. <br />The combination of small storage capacity and high cost also made this alternative unfeasible. <br />The selected alternative. Alternative No. 2 -Alternative 2 was selected because it is the most <br />feasible alternative for meeting the Districts' need for raw water storage. It would consist of the <br />following: <br />1. Construction of an approximately 5200 acre-foot reservoir including a 40-foot high earthen <br />dam with emergency spillway and outlet works. <br />2. Conversion of an existing 20-inch treated water line to a raw water line to connect the <br />reservoir to the Carter Lake Filter Plant. <br />3. Construction of a 5000 GPM pump station to pump water from the reservoir to Carter Lake <br />Filter Plant. <br />Smith Geotechnical Engineering Consultants has conducted feasibility-level design work for the <br />proposed dam, and TEC Engineering has conducted feasibility-level design work for the proposed <br />pump station. Geotechnical investigation, testing, and analysis indicates that the site is suitable for <br />the construction of the proposed reservoir. A geologic assessment indicates no geologic conditions <br />or other physical features that would complicate the construction of a dam. A spillway of <br />approximately 350 feet will be provided. The outlet works would consist of a 48-inch diameter outlet <br />pipe, constructed with a gate on the upstream end for control of the outlet and a gate tower within <br />the dam to facilitate operation and maintenance. <br />Total Project cost (including contingency and inflation) is estimated to be: <br />1. Engineering Fees $ 805,000 <br />2. Land Acquisition $2,750,000 <br />3. Construction Cost $6,945,000 <br />TOTAL $10,500,000 <br />Schedule - If the loan is approved, project construction would begin in Fall 2004. <br />Page 3 of 7 <br />