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Pete Conovitz August 10, 2011 Page 2 of 5 the Fort Morgan Water Company during the winter months. According to paragraph 5(c)I of the water court application in case no. 2006CW229, CDOW may utilize augmentation credits from the Riverside Irrigation District or water available from another plan for augmentation. You indicated that in 2009 CDOW acquired a 20% interest in the Goodrich Farms recharge and augmentation plan decreed in case no. W -2919. Therefore for the purpose of this SWSP, CDOW intends to utilize augmentation credits from Goodrich Farms recharge and augmentation plan. Depletions The current surface area of the Chartier Pond is 6.2 acres. An additional 2.3 acres (for a total of 8.5 acres) may be exposed in the future. DRMS permit no. M84 -040 allows for a maximum exposure of 8.5 acres of ground water at this site. In the previous SWSP approval Mr. Chartier anticipated mining an additional 50 -foot by 150 -foot section of the pond (0.17 acres surface area in 2010). This mining activity did not occur and over time Mr. Chartier plans to mine up to the maximum surface area of 8.5 acres allowed under DRMS Permit no. M84 -040. Therefore this SWSP will account for the evaporation losses from the maximum exposed surface area of 8.5 acres and the water lost with the mined product assuming that the actual amount of mining will not exceed 0.17 acres in any one year. Evaporative depletions to the South Platte River were calculated as the gross Chartier Pond evaporation less a portion of the historical consumptive of native vegetation prior to pond construction. Gross evaporation from the pond is estimated to be 50 inches per year, for a total evaporative loss of 25.83 acre -feet per year. A phreatophyte credit of 18.10 acre -feet from 6.2 acres of native cottonwoods has been applied to this SWSP (Table 4). In the previous SWSP approval, computation of evaporation was also reduced during the ice cover period. You have assumed that the pond will not freeze during the 2011 -2012 winter season and you have proposed to replace the net evaporation depletions during the winter season. Mr. Chartier anticipates mining a 150 -foot by 50 -foot section of the pond (0.17 acres surface area). Assuming an average mining depth of 15 feet and a depth to ground water of 4 feet, approximately 0.19 acre -feet of water would be lost with the mined product. The additional mining during the term of this SWSP will increase the exposed surface area from 6.2 acres to 6.36 acres. • However as mentioned above this SWSP will account for evaporation losses from the maximum exposed surface area of 8.5 acres. The evaporation for the 8.5 acres during the months of November through March was calculated as the difference between gross evaporation and the effective precipitation, where the effective precipitation is equal to 70% of the total precipitation. According to the new "General Guidelines for Substitute water Supply Plans for Sand and Gravel Pits "water consumption by the mining operation will also need to include water removed from the tributary stream system by the "first fill" of the gravel pit. The "first fill" is the water that fills the gravel pit and occupies the volume previously occupied by the removed sand and gravel. For the Chartier Pit the "first fill" was estimated based on a surface area of 0.17 acres multiplied by the mined aquifer depth of 11 feet multiplied by the percentage gravel matrix (75% assuming a porosity of 25 %) and then subtracting the volume of water lost with the mined product. Based on the above, the water removed by the "first fill" was determined to be 1.13 acre -feet. No water is proposed to be used for dust control and the applicant has not proposed to wash the mined gravel, thus no additional water uses are included in this SWSP. The anticipated net depletion for this SWSP is 11.01 acre -feet. This amount breaks down into 9.69 acre -feet of evaporation from up to 8.5 acres of exposed ground water surface, 0.19 acre -feet of water lost with the mined product and 1.13 acre -feet of water occupied by the "first fill ". The timing of