2011-11-16_HYDROLOGY - M1977522 - Laserfiche WebLink

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Mr. Jared Dains, E.I. Page 2 November 16, 2011 Your SWSP renewal request indicates that approach 1 or 3 will be pursued, and that new bonds are pending. The State Engineer's Office will limit the mining operation so that additional ground water cannot be exposed until sufficient bonds, as determined by DRMS, have been posted. Depletions Consumptive uses at the Feit Pit consist of evaporative and operational losses. Operational losses will include water lost in mined product, intermittent fills, and water used for dust control. The on -site concrete batch plant and the use of the well with permit no. 57724 -F has been =sold to Varra Companies. All depletions associated with future use of the batch plant and well 57724 -F are the responsibility of Varra Companies and are not included with this SWSP. Lagged depletions from the well's previous use are included in this SWSP renewal and are accounted for in Table 3. The estimated lagged stream depletions for the term of this SWSP are 109.80 acre -feet per year. The total exposed groundwater at this site is 40.2 acres, of which 34.1 acres are considered post -1981 and require augmentation to offset evaporation. According to the information from the previous plan, a total of 6.1 acres of groundwater was exposed within the Feit Pit reclamation permit boundary prior to January 1, 1981. Based on the Division 1 Water Court decision in case no. 2009CW49, the replacement of evaporative depletions is not required for ground water exposed to the atmosphere prior to January 1, 1981 through open mining of sand and gravel, regardless of whether open mining operations continued or were reactivated on or after that date. Accordingly, the evaporative depletions for the Feit Pit were calculated based on an exposed surface area of 34.1 acres exposed after December 31, 1980. The area receiving the pre -1981 credit is shown on the attached Figure 3 tabled "Proposed Feit Pit Pre -1981 Credit Allocation Location (Not to be considered final) ". Please note, these credits are no longer allowed to be re- allocated to other areas of ground water exposure. The applicant has 30 -days after this SWSP approval to submit to our office a final Pre - 1981 map. If nothing is received in that time frame, Figure 3 will become final. In addition, as required by the General Guidelines for Substitute Water Supply Plans for Sand and Gravel Pits, updated April 1, 2011, the Applicant must provide a GIS compatible file that has a shape file for the final re- allocated pre -81 area. The estimate of evaporative losses under this plan was also reduced during the ice covered period. You have assumed the ice covered period to occur during the months of December and January based on the average temperatures of 29.4 °F for December, 28.6 °F for January. Temperature data were obtained from the Greeley UNC weather station (053553) for the time period of 1967 through 2005. The ice covered periods may be used to reduce the amount of evaporative losses that need to be replaced; however, for the purpose of this SWSP, the Applicant shall replace the net evaporation depletions from the exposed ground water surface area that may occur during the assumed ice covered period (December and January) for any time that the pits are not completely covered by ice. Computation of the net evaporation during any time that the pits are not completely covered by ice shall be determined as the pro - rata amount of the monthly gross evaporation rate distribution amount identified in the State Engineer's General Guidelines for Substitute Supply Plans for Sand and Gravel Pits, subtracting the pro -rata amount of the effective precipitation for that period. The projected depletions requiring augmentation from evaporation for WY 2012 is 94.08 acre -feet. The attached Tablet identifies the estimated monthly depletions from evaporation.