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Brannan Sand and Gravel Company — Valley's Edge Resource SWSP Renewal Request <br /> October 31, 2023 <br /> water surface. The total amount of groundwater exposure is likely to reduce over the <br /> period of the SWSP as area is backfilled,however,the exposed area will not exceed 16 acres <br /> during requested approval period. <br /> The annual net evaporation in the area is estimated to be 35.19 in (2.93 ft); this value is <br /> derived from the gross evaporation rate charged in the NWS 33 Atlas of 45 in (3.75 ft),the <br /> precipitation at the Brighton weather station of 14.04 in (1.17 ft), and a 70% credit for <br /> effective precipitation.The evaporative loss during the requested approval period is <br /> estimated to equal 46.91 AF as shown on Table 1. <br /> Brannan is not currently anticipating further significant mining at this point; however, <br /> some remaining product is anticipated to be recovered. The total water retained in mined <br /> product during the requested plan period is estimated to be 0.88 acre-feet. Brannan <br /> estimates that 3.98 AF of water will be used during the approval period for dust control at <br /> the site. <br /> The total anticipated consumptive use at Valley's Edge Resource, during the requested <br /> approval period,is estimated to be 51.78 AF. Due to the pit's location, consumptive uses do <br /> not instantaneously affect South Platte River but instead result in lagged depletions. A <br /> Glover lagging model (using IDS AWAS) was utilized for this site using the following lagging <br /> parameters: <br /> • Distance from centroid of site to stream (X) = 5,700 feet <br /> • Aquifer Transmissivity (T) = 70,000 gallons per day per foot <br /> • Specific Yield (S) = 0.2 <br /> • Aquifer Width (W) = 7,900 feet <br /> As shown in Table 1,the total lagged depletions for the requested approval period are <br /> estimated to equal 51.72 AF. Assuming a call year-round affecting this reach of the river, <br /> these lagged depletions are equal to the augmentation requirement and must be replaced <br /> to prevent injury to senior water rights. <br /> Please note that the include AWAS files are in water year,rather than calendar year, so the <br /> depletions for November and December of 2024 are shown in the AWAS file as 2 02 5. <br /> DINATALE WATER CONSULTANTS 3 <br />