2014-03-19_HYDROLOGY - M1979097 - Laserfiche WebLink

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Mr. Jared Dains East Rigden Pit Substitute Water Supply Plan (M -79 -097) March 19, 2014 Page 3 Depletions at the East Rigden Pit do not instantaneously accrue to the Cache La Poudre River, but instead result in a lagged depletion. The monthly evaporative and operational depletions to the Cache la Poudre River were lagged from the pit using the Alluvial Water Accounting System (AWAS) program developed by the Integrated Decision Support (IDS) Group at Colorado State University with the following parameters: • Distance from the gravel pit centroid to the river (X) = 2,100 feet • Alluvial aquifer width (W) = 5,800 feet • Specific yield (S) = 0.2 • Transmissivity (T) = 55,000 gallons per day per foot The stream depletion model shows that the East Rigden Pit's stream depletions will total approximately 155.12 acre -feet during the SWSP period, as shown on the attached Table 1. Replacements The City of Fort Collins will provide replacements for the depletions using its portfolio of reusable water rights, as evidenced in its commitment letter that was provided with the SWSP request. Potential sources of reusable water will be Joe Wright Reservoir (WDID 0303678, located in Section 24, T7N, R76W on Joe Wright Creek) water, Southside Ditch water, or supplies stored in the Fossil Creek Reservoir (WDID 0303774, located in Section 10, T6N, R68W). The decree in case no. 92CW129 provides information about the systems referred to as "Southside Ditches Water Rights ", which include the following: • Fort Collins Arthur Water Rights (WDID 0300918, aka Fort Collins Irrigation Canal, located in Section 34, T8N, R69W) • Fort Collins Larimer County No. 2 Water Rights (WDID 0300914, located in Section 29, T8N R69W) • Fort Collins New Mercer Water Rights (WDID 0300913, located in Section 29, T8N R69W) • Fort Collins Warren Lake Water Rights (WDID 0303804, located in Section 31, T7N, R68W) Southside Ditches water owned by Fort Collins was changed in case no. 92CW129 for all municipal uses including augmentation. The water delivered to Fossil Creek Reservoir will be either Southside Ditch water as changed in 92CW129 or Southside Ditch effluent. The Southside Ditch decree lists the Fossil Creek Reservoir Inlet Ditch as an alternate point of diversion and Fossil Creek Reservoir as an alternate point of storage. Also Fort Collins diverts Southside Ditch water for use by its treated water customers. The effluent produced by this use is first delivered from Fort Collins's Drake Water Reclamation Facility to Fossil Creek Reservoir before ultimately returning to the river through the Fossil Creek Reservoir Outlet Ditch. Acceptable accounting must be provided and approved by the Division Engineer prior to using water stored in Fossil Creek Reservoir. All replacement will be based on actual depletions determined from tracking actual diversion volumes and sources. The replacement will be reported in the Fort Collins existing accounting. Transit losses will be provided based on an assumed transit loss rate of 0.25 percent per mile, unless otherwise required by the Water Commissioner. In the event that delivery of the replacement water must be delivered past headgates which sweep the river, Applicant is required to install a bypass structure or use an existing bypass structure by agreement with a third -party, Applicant is responsible for either installing a new bypass structure or securing an agreement with a third -party to use an existing bypass structure.