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share ownership in Prewitt Reservoir was also changed to augmentation use and included in the <br />plan. A junior exchange water right was decreed within the depletion reach up to the recharge <br />wells and ditches serving the eight recharge projects. <br />Per the decree, lagged well depletions and recharge accretions to the South Platte River are <br />accounted via the Glover method. Most of the irrigation wells are currently metered although <br />pumping is estimated for some irrigation wells based on power coefficients. Per the decree, out- <br />of-priority lagged well depletions are administered either with priority dates specific to the <br />ground water rights included in the plan or with the most junior ground water right if river <br />depletions are accounted for plan wells in aggregate. <br />Recommendations <br />Recommendations for representing the Lower Logan Well Users augmentation plan in the initial <br />development of the SPDSS StateMod Water Resources Planning Model input files are presented <br />below based on review of the decree and interviews with augmentation plan personnel and <br />Division 1 personnel. <br />Augmentation Plan Demands <br />To represent pumping for the entire SPDSS study period (1950 to present), well pumping to <br />supply irrigated lands should be estimated by the consumptive use algorithm in StateCU and <br />StateMod, to meet the irrigation water requirement less simulated surface water deliveries (if <br />applicable). Lagged well depletions affect river flows based on timing and location factors <br />defined in StateMod input files. Lagged depletions should be accounted in two Lower Logan <br />Well Users augmentation plan system depletions plan structures corresponding with <br />administration of the augmentation plans in two reaches: <br />• Above Harmony No. 1 Ditch (6402536_1) <br />• Below Harmony No. 1 Ditch (6402536_2) <br />Wells associated with the Lower Logan Well Users plan should be assigned to the various <br />administration reaches based on spatial location. <br />Augmentation Plan Supplies <br />Various sources are typically available to supply water to replace lagged well depletions. The <br />sources and the structures related to the Lower Logan augmentation plan recommended for <br />inclusion in the SPDSS model are summarized in Table 2. Augmentation supplies are as <br />follows: <br />Recharge rights from the river for the Lower Logan Well Users augmentation plan <br />system are summarized in Table 3. <br />Recharge well rights and augmentation well rights are summarized in Table 4. <br />Model operations to supply well depletions (stored under plan IDs 6402536_1 and 6402536_2) <br />are discussed in the augmentation plan operations section. <br />A-35 ofA-106 <br />