2011-11-29_HYDROLOGY - M1982131 - Laserfiche WebLink

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Mr. Jared Dains Page 2 November 29, 2011 In accordance with approach no. 4, you have provided an affidavit dated October 4, 2010 that dedicates five of the Applicant's shares of GIC water as replacement water solely for this SWSP for as long as there are depletions at this gravel pit site or until such time as another replacement source is obtained. A copy of the affidavit is attached to this letter. For the purposes of this SWSP, this affidavit will be accepted for the dedication of the shares; however, if the State Engineer determines that a different affidavit or dedication process is necessary to assure proper dedication of the shares, additional information may be required prior to future SWSP approvals. Depletions Depletions from the Bucklen Pit will result from exposed groundwater evaporation and operational losses resulting from mining activity. Currently there are a total of 17.81 acres exposed at the Bucklen Pit site. The pit is presently being dewatered to allow for dry mining in Amendment Area A. The majority of the current exposed surface area consists of a large pond of 17.65 acres and the additional 0.16 acres of exposed surface area consists of the dewatering trenches. Based on the information from previous SWSPs, 5.27 acres of ground water was exposed within the reclamation permit boundary prior to January 1, 1981. You indicated that the 5.27 acres exposed within the reclamation permit boundary prior to January 1, 1981 was backfilled. The WY 2010 & 2011 SWSPs did not allow this pre -81 credits based on administrative policy which did not recognize any pre -81 areas in gravel pits which continued to be mined after 1981. In accordance with water court case 09CW49 and current administrative policy found in the State Engineer's General Guidelines for Substitute Water Supply Plans for Sand and Gravel Pits (Updated April 2, 2011), this SWSP will once again recognize 5.27 acres of exposed ground water as being pre -81 because the court found that a gravel pit operator or property owner does not need to replace depletions that occur due to evaporation from ground water exposed prior to January . 1, 1981 regardless of whether mining continued after December 31, 1980. Additionally, although this area was already backfilled, the WY 2009 SWSP allowed the credit to be taken, and thus approved a reallocation of the pre -81 area. The location of the pre -81 area is now permanently tied to the location depicted in Figure 2. The net evaporative area is therefore 12.54 acres (17.81 total acres less 5.27 "pre -81" acres). Computation of evaporation under this plan was 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 monthly temperatures of 29.4 °F for December, and 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 pit is not completely covered by ice. Computation of the net evaporation during any time that the pit is 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 attached Table 1 identifies the estimated monthly depletions from evaporation. The total projected evaporative consumptive use for WY 2012 is 34.60 acre -feet. Operational losses associated with mining activities will include water removed with the mined product and water used for dust control. Approximately 50,000 tons of material is projected