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Ready Mix Concrete Substitute Water Supply Plan Page 4 of 9 <br /> November 24, 2020 <br /> maximum net evaporation volume is 7.25 acre-feet for October 2020 through December 2020 and <br /> 67.13 acre-feet for 2021, as shown in the attached Table 2, column 2. <br /> Mined Product <br /> In addition to the evaporation, water is lost with the mined product removed from the mine sites <br /> as shown in Table 2, columns 3a and 3b. RMCC projects that they will mine 343,300 tons of gravel <br /> for October through December 2020 and 1,379,000 tons of gravel for 2021 in a dewatered state in <br /> the lined portions of Stages 4, 5, and 6C/6D above the groundwater table, therefore 2% by weight <br /> of water is lost through mined product. RMCC projects they will mine 151,000 tons of gravel for <br /> January through November 2021 in a dewatered state in the unlined portion of Stage 6C below the <br /> groundwater table which will be subsequently washed, therefore 4% by weight of water is lost <br /> through mined product. The total water lost from gravel production and washing is projected to <br /> total 29.8 acre-feet (5.1 acre-feet for October through December 2020 and 24.7 acre-feet for 2021), <br /> as shown in Table 2, column 4. <br /> Dust Suppression <br /> The estimated water used for dust suppression is 4.4 acre-feet for October through December 2020 <br /> and 14.4 acre-feet in 2021, as shown in Table 2, column 5. RMCC will use water from Stage 2 for <br /> dust suppression purposes. <br /> Dewatering <br /> RMCC will continue to dewater Stages 1, 2, 4, and 6B during the period of this SWSP. The dewatering <br /> pumping volume is projected to be 14 acre-feet per day at each unlined pit and 0.5 acre-feet per <br /> day at each lined pit and will be continuous at one or more stages throughout the SWSP request. <br /> The total combined dewatering volume for all stages is estimated at 19,697 acre-feet (4,002 acre- <br /> feet for October through December 2020 and 15,695 acre-feet for 2021), shown in Table 2, column <br /> 6. <br /> Refill <br /> Stage 2 will be allowed to refill through groundwater inflows to a depth of 15 feet and a total surface <br /> area of 10 acres, resulting in 75 acre-feet used for refill in January 2021. <br /> Reservoir Construction <br /> Construction to convert Stage 4 to a storage reservoir will begin in November 2020. Water will be <br /> used for dust control, compaction, and diversion from the South Platte to fill the reservoir. <br /> Estimated water for construction is estimated based on assumed operating hours and days per <br /> month. Assuming construction will occur through August 2021 it is estimated that 61.6 acre-feet will <br /> be fully consumed with no lagged depletions (5.7 acre-feet in November and December 2020 and <br /> 55.9 acre-feet for January through August 2021). <br /> Total Consumptive Use <br /> The total consumptive use at the site for the period of this SWSP is 233.7 acre-feet (22.4 acre-feet <br /> October through December 2020 and 211.3 acre-feet 2021). The dewatering pumping volume to be <br /> discharged to Big Dry Creek during the period of this SWSP is estimated at 19,697 acre-feet, as <br /> shown on the attached Table 2, column 6. <br />