2025-01-14_HYDROLOGY - M2008082 - Laserfiche WebLink

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Morton Lakes Substitute Water Supply Plan Renewal January 10, 2025 Page 6 of 14 relatively constant rate until the end of the SWSP period. All dewatering will be accurately metered so as to properly determine the lagged dewatering depletions to the stream that will result once dewatering ceases. As long as all water is pumped from within the lined pits and is returned to the stream without consumptive use, there are no new lagged depletions from dewatering that need to be replaced under this SWSP for Stages 5, 613, 6D, 7A, and 7B. Reservoir Construction at Stage 5 It is projected that the final reservoir construction for Stage 5 will require 67.02 acre- feet of water during 2025 as shown on attached Table 2, Column 6. Since water will be pumped directly from the stream for storage in Stage 5, no lagged depletions will occur from this use. Total Consumptive Use (Uniaq_qed Depletions) The total consumptive use at the site for this plan period is 181.51 acre-feet, as shown on attached Table 2, Column 7. La_q_qed Depletions The IDS AWAS stream depletion model was used to determine the lagged depletions from dewatering, evaporation, and operational losses at the Morton-Holton Lakes site to Big Dry Creek and the South Platte River, using the following Glover parameters: • Specific yield = 0.2 • Transmissivity = 150,000 gpd/ft based on pumping test data in Colorado Ground Water Circular No. 11 • Distance from centroid of the Stage 1 mining area to Big Dry Creek = 300 feet • Distance from centroid of the Stage 2 mining area to Big Dry Creek = 1,150 feet • Distance from centroid of the Stage 5 mining area to Big Dry Creek = 318 feet • Distance from centroid of the Stage 6A mining area to the Big Dry Creek = 1,356 feet • Distance from centroid of the Stage 6B mining area to the Big Dry Creek = 1,724 feet • Distance from centroid of the Stage 6D mining area to South Platte River = 643 feet