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Ms. Jennifer S. Lindhat Page 4 June 8, 2016 1976) and Brighton 1 NE (ID 950, record 1976-2014) NOAA weather stations. The net evaporation rate for the exposed water surface is estimated to be 2.92 acre-feet/acre, as shown on the attached Table 1. In addition to the evaporation, water is lost with the mined product removed from the mine sites. RMCC is projected that they will produce 955,000 tons of gravel in 2016 and 1,500,000 tons of gravel in 2017. Gravel mined will be in a dewatered state and will be washed therefore the ground water lost with the mined product is estimated at 4 percent by weight. The water lost with the mined product is projected to total 28.12 acre-feet in 2016 and 44.16 acre-feet in 2017. The estimated water used for dust suppression during the Stage 1, 7 and 2 total 10.82 acre-feet in 2016 and 14.36 acre-feet in 2017, as shown in Table 2, column 5. As described above, RMCC will dewater the northern 12-acre portion of Stage 1 from April through September of 2016. The dewatering pumping volume is projected to be 14 acre-feet per day. The northern 12-acre portion will fill with water when RMCC stops dewatering, which is estimated to be May 2017. Therefore the first fill of the 12-acre portion of Stage 1 will create an additional depletion at the site. The first fill volume is estimated as the volume of the pit less the pore volume and the water retained in the mined product. You estimated that the volume of the pit will be 357 acre-feet based on a depth of 30 feet and a surface area of 11.9 acres. The mid-point of typical gravel porosities is 27.5 percent. The pore volume was determined to be approximately 98.5 acre-feet by multiplying the volume of the pit by the gravel porosity (357 acre-feet x 27.5 percent). The ground water volume that has been filled the gravel pores was previously dewatered and already accounted for in the dewatering pumping volumes. Additionally 4 percent of the mined gravel by weight or 17.1 acre-feet (from 580,300 tons from April through September mining) has already been accounted for as ground water depletions. Therefore the first fill volume that will occur in June 2017 is 241.7 acre-feet (357 acre-feet-98.2 acre- feet-17.1 acre-feet). Prior to allowing Stage 1 to flit dewatering will commence at Stage 7, which is located immediately west and adjacent to Stage 1, and will continue to deliver dewatering water to Big Dry Creek. The total consumptive use at these sites for the period of this SWSP is 404.7 acre-feet. The dewatering pumping volume to be discharge to Big Dry Creek during the period of this SWSP is 5,992 acre-feet in 2016 and 9,800 acre-feet in 2017 (Table 2). The IDS AWAS stream depletion model was used to determine the lagged depletions from dewatering, evaporation and operational tosses at the Holton Lakes and Morton Lakes sites to Big Dry Creek, using the following Glover parameters: • specific yield = 0.2 • transmissivity = 150,000 gpd/ft based upon 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 7 mining area to Big Dry Creek= 1,150 feet • distance from centroid of the Stage 2 mining area to Big Dry Creek = 700 feet • distance from Big Dry Creek to alluvial boundary = 7,250 feet for Stage 1 and 7, and 7,830 feet for Stage 2, based upon CDSS South Platte River alluvial aquifer boundary mapping Based upon this analysis 95 percent of the depletions accrue to the stream within 5 months for Stage 1, within 14 month for Stage 7 and within 11 months for Stage 2. Normalized lagged factors