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1 <br />1 <br />1 <br />1 <br />1 <br />Substitute Supply Plan for the <br />1 (; Everist ApOr~gate Clneratinn <br />from the dry-up of historically irrigated lands. This pond will provide storage of excess irrigation <br />rights for replacement during the non-irrigation season. <br />Evaporative Losses <br />Fond evaporation represents the largest depletion to the Blue River resulting from the proposed <br />mining operation. Evaporative losses have been quantified for the proposed fvst yeaz groundwater <br />exposure of 3 surface acres and the proposed total groundwater exposure of 13 surface acres during <br />the second yeaz of the operation. Estimates of net montlily evaporation was calculated by <br />distributing the annual gross evaporation from the National Oceanic and Atmospheric <br />Administration Technical Report 33 (NWS 33) according to the State Engineer's Office's (SEO's) <br />monthly distribution percentages for sites above 6,500 feet msl (Gravel Pit Genera! Criteria for <br />Substitute Supply Plan, February 28, 1995) and subtracting 70 percent of the average mont}ily <br />precipitation (1950-1992) from the Dillon weather station. The net evaporation calculations are <br />shown in Table 1. <br />Consumptive Use From Extraction and Washing, Dust Control, and <br />Concrete Batching Operations <br />Consumptive use from aggregate extraction and washing are the result of the retention of water on <br />the aggregate. The SEO assumes a loss of 4 percent by weight of the aggregate produced based on <br />previous experience unless site-specific information is available. L.G. Everist assumes a peak <br />capacity of 200,000 and 450,000 tons of aggregate mined during the first and second yeazs, <br />respectively. No concrete batching will occur during the first yeaz while an estimated 60,000 yd' is <br />expected to be batched the second yeaz. L.G. Everist assumes an average of 30 gallons of water <br />and 1.55 tons of aggregate per cubic yazd of concrete batched. ]n an effort to handle the water used <br />in concrete production separate from the retainage loss from aggregate mining, the estimated <br />93,000 tons of aggregate used in the proposed concrete batching has been subtracted from the total <br />aggregate mined for purpose of the retainage loss calculation. As a result, the estimated retainage <br />881-025.110 Wright Water Engineers, Inc. Page 3 <br />1 <br />