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Division of Water Resources" ' <br />RE:,Greetey Pit SWSP. : <br />May.-25,:2010 .. <br />': PaJie.2 of 4:: <br />:Consumptive uses at the Greeley-Pit consist of evaporative and operational losses. -Evaporative <br />losses; are calculated Based on exposed groundwater: surface area. As.: shown on Figure .2, of <br />the 676' acres <br />`:currently exposed; "approximately 31.0 sores =were. exposed prior to _ 1981 <br />,.. <br />(corresponduig to the 21.2 acre southwest pond, the.5.7 acre southeast <br />pond, and 4.1 acres of_the <br />40. acre north pond):. Also, according to "Joe Kuntz of-Mountain Constructors (who operated the <br />gravel, pit during: the "19$0 t6:1981. period) there wa -4 additional 8.8 acres of excavated area <br />which is not:shown as being filled with groundwater in the aerial photograph in Figure 2 because . <br />that:area was being tlewatered at the time., .He believes that dewatering may have ceased and the <br />: additional 8:8 acres would. have filled' i exposed groundwater prior .to.January 1; 198:1:. In <br />accordance with DWR policy, Hiner requests a credit for the pre-1981 exposed area; this r'esults. <br />m.a current net -exposed areo:0 21.8 acres. No additional :groundwater. will be exposed during.. ; <br />the:plari.period. <br />According to NOA,A,Technical Report. NWS 33, the gross evaporati on for the area is 45 inches. - <br />.:. Evaporation'i as &stributed.o ' <br />n,a <br />monthly basis pursuant to values recommended by the DWR <br />for. "elevations: below 6,500 feet- MSL, ""Accounting for: an effective precipitation credit.and <br />anticipated ice-covered:periods; the annual. net. evaporation is estimated to equal .311.1 inches.. <br />Miner anticipates that no dewatering will occur during WY 2010; therefore, for a net exposed <br />water surface. of 27.8 acres, the evaporative. loss during the plan period is estimated: to' equal <br />70.22 "acre-feet as shown in Table No. .1. <br />.Operhtional losses. At the pit will occur from water removed with the mined, product "and water. <br />lased for "dust control. -This operational consumptive use is quantified- in Table -No. 2. " -Hiner <br />expects that no more -than 100,000 tons of material will be -mined. in WY 2010 according to . <br />.;ho monthly percentages provided in Column (A) of Table No.- 2.. The material. will be: mined <br />:..;. above the :water table, and. the material will not be -washed. Pursuant. to the State Engineer's " <br />"guidelines, ".the assumed moisture content is: 2% by weight, but 0'/ is charged because the <br />sture .is not-a-groundwater diversion. The water removed with the mined product is therefore - <br />estimatedao.bezero aaft in the plan period. " <br />Water :withdrawn, from the pit: is also used for .dust control: Hiner -estimates that a minimal <br />. ariount of:dust control water will-be use4 from March to October, corresponding to.-1.00 ac-ft, <br />leer: year..: As shown in Column ,(E) of Table No. 2, .the total. operational consumptive -use is : <br />estimated. to be 0.9 ae-ft during theplan period, . <br />`Total Augmeniatlon Requirement - <br />The: total augmentation :requirement, defined. as the sum of the. -evaporative. consumptive..use <br />Opera. or' , consumptive. use, and GIC return flow obligation, is estimated to equal 71.12 acre- <br />feet"during-the plan period. The Greeley Pit is directly-adjacent to the Cache la Poudre River and <br />therefore the depletions. are. considered instantaneous. and .do not have a lagged impact to the -