Colorado - Old Dillon Reservoir Enlargement_Application & Scope of Work

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Water Supply Reserve Account - Grant Application Form Form Revised May 2007 (30 acre-feet) and Summit County (120 acre-feet) share a 150 ac-ft Old Dillon Reservoir First Enlargement storage right that was adjudicated in Case No. 93CW288. The decree in Case No. 93CW288 also adjudicated a separate right of exchange to storage for Summit County in the amount of 53.4 acre-feet and a change of water right for 11.87 acre-feet of Silverthorne's Valaer Ditch water right. The parties may adjudicate additional storage and exchange rights. Dillon and Silverthorne have limited existing raw water storage, which makes the development of this reservoir enlargement project extremely important to protect the Towns from the possibility of drought and potential pollution in the Straight Creek and Blue River watersheds. This reservoir will also provide important security and flexibility in the use of the parties' rights in Clinton Gulch Reservoir and Dillon Reservoir. Summit County and the Town of Dillon share a 10 cfs direct-flow right from Salt Lick Gulch to Old Dillon Reservoir that was appropriated in 1939 in Civil Action No. 1806. Dillon owns 2.0 cfs and the County owns the remaining 8.0 cfs. The ODR group plans to rehabilitate the ditch between Salt Lick Gulch to Old Dillon Reservoir to allow for delivery of the full 10 cfs. capacity when water is available. The Town of Dillon plans to store a combined total of 96.14 acre-feet of water (as previously described) in the enlarged reservoir for use as an alternate supply for the Town of Dillon in the event that the Town's Straight Creek water supply would become contaminated due to forest fire or pollution from an incident along the 1-70 corridor. In order to convey this water to the Town of Dillon, the Town plans to construct a siphon below new Dillon Reservoir to the Town or utilitize a water bridge across the new reservoir. The Town presently serves 1682.6 EQRs (Equivalency Quotient Ratio) or single family equivalents and needs to serve 2,100 EQRs at build out. Town staff estimates that the Town will need approximately 2.5 ac-ft of raw water per day to meet the peak summer demand at build out. The Town of Silverthorne plans to store approximately 20 acre-feet in the enlarged Old Dillon Reservoir. The approximately 20 acre-feet are comprised of 11.87 acre-feet of Valaer Ditch water, which have been changed to storage in the enlarged Old Dillon Reservoir by decree of the District Court, Water Division 5 in Case No. 93CW288; with the remainder being additional water decreed for storage in the enlarged Old Dillon Reservoir. The Town of Silverthorne will use this water to enhance the reliability of the Town of Silverthorne's municipal water supply system primarily by inclusion of such water in a court approved augmentation plan for the purpose of replacing otherwise out-of-priority depletions caused by the Town of Silverthorne's municipal wells. It is contemplated that the Town of Silverthorne's use of this water will be accomplished by the direct release of water stored in the enlarged Old Dillon Reservoir to Salt Lick Gulch at those times and in such amounts as needed to replace the Town's otherwise out-of- priority depletions to the Blue River below its confluence with Salt Lick Gulch caused by operation of the Town of Silverthorne's municipal wells. 6