2011-03-10_HYDROLOGY - M1981058 - Laserfiche WebLink

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Mr. Dick Wolfe March 1, 2011 Page 2 PROJECTED WATER USE AND CONSUMPTION The projected total depletions as a result of mining activities during the 2011 plan year are expected to be 27.29 acre-feet as shown in Table 1. Approximately 350,000 tons of material will be mined during the plan year resulting in 10.29 acre-feet of water lost with the mined material. Water consumed for dust control will not exceed 2.5 acre-feet per year. The exposed groundwater area during the plan year will not exceed 5.6 acres based on 3.6 acres of existing pond surface area and no more than 2 acres of dewatering trenches. Annual net evaporation from exposed water surface areas will be 38.35 inches minus a phreatophyte credit of 3.4 acre- feet per year based on the decree in Case No. 05CW076. Approximately 8 acres will be dewateed during the mining process. Figure 1 shows the existing 3.6 acre pond and the Lp location of the mining. STREAM DEPLETIONS The depletions to the Colorado River resulting from exposed groundwater at the Debeque Pit are based on the lagging parameters decreed in Case No. 05CW076. The total net depletions were lagged using the Glover Method in the IDS AWAS model with a distance from the mine area to the river of 150 feet, a distance from the stream to the edge of the alluvium of 2,000 feet, transmissivity of 50,880 gallons per day per foot, and a specific yield of 0.2. The model includes actual depletions due to mining and exposed water surface area through December 2010 and projected depletions for the remainder of the 2010 plan year (January 2011 through April 2011) and for the 2011 plan year (May 2011 through April 2012). The lagged stream depletions for the 2011 plan year are estimated to be 27.28 acre-feet as shown in Table 1. REPLACEMENTS Kirkland will make replacements for out of priority depletions affecting the Colorado River during the historical call period from April 1 through October 31. Kirkland has entered an agreement with the Lathams under which additional historical consumptive use credit from the Larkin Ditch will be dedicated to this SWSP to provide replacement water for the depletions described in this renewal. Previously, the Lathams have dedicated 2.0 shares of Larkin Ditch stock to the augmentation plan in Case No. 05CW076, corresponding to 6.0 acres of dryup based on rounding of the 3.13 acres per share historical ratio. Two shares at the historical average of 6.35 acre-feet per share results in 12.7 acre-feet per year of consumptive use credit. This 2011 plan includes historical consumptive use credits from an additional 4.1 shares resulting in a total of 6.1 shares dedicated to the plan. Dry-up of 19.1 acres is required for use of the 6.1 shares. Mining activity has resulted in dry-up of 20.1 acres as shown on Figure 2. Additional dry-up of 2.8 acres has occurred between the ditch and mine area and may be claimed in future plans. The consumptive use credit associated with 6.1 Larkin Ditch shares (at 6.35