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Mr. William Berg, P.G. December 19, 2017 Page 3 of 5 and lagged to the stream. An instantaneous credit of 2.75 acre-feet from dewatering the cell prior to mining was removed from stream depletions in March 2017 and March 2018. Table 2 shows that under Scenario B, the lagged stream depletions during the period January 2017 through December 2017 are estimated to be 20.27 acre-feet and the lagged stream depletions during the period January 2018 through December 2018 are estimated to be 20.27 acre-feet. These estimates are based upon evaporative losses from the settling and washing ponds and mined cell (see attached Table 1B). REPLACEMENTS The proposed source of replacement water for this pit is a ten year lease (through 2020) to deliver 27 acre-feet annually of fully consumable water from the Board of Water Works of Pueblo (“PBWW”). The lease water will be provided from the Board’s stored water at Clear Creek Reservoir, Turquoise Reservoir, Twin Lakes Reservoir, Pueblo Reservoir, from direct flow transmountain water, reusable return flows from transmountain water, or from any other reservoir or place from which the Board may legally deliver water, and will be delivered to the Arkansas River Near Avondale USGS stream gage. The monthly depletions and replacement requirements are provided on the attached Table 2. A transit loss of one percent was applied to the required monthly replacement amounts, as shown in Table 2. CONDITIONS OF APPROVAL I hereby approve the proposed SWSP in accordance with §37-90-137(11), C.R.S., subject to the following conditions: 1. This SWSP supersedes the SWSP approved on April 25, 2017 and shall be valid for the period of December 19, 2017 through December 31, 2018, unless otherwise revoked or superseded by decree. If this plan will not be made absolute by a water court action by the plan’s expiration date, a renewal request must be submitted to this office with the statutory fee (currently $257) by November 1, 2018. 2. Well permit no. 62251-F was obtained for the current use and exposed pond surface area of the gravel pit in accordance with §37-90-137(2) and (11), C.R.S. 3. The maximum amount of ground water exposed under this plan shall not exceed 5.77 acres at times when mining is not occurring and 4.57 acres at times when mining is occurring. Documentation of pond size may be required by the Division Engineer in the form of an aerial photo evaluation or survey by a Professional Land Surveyor during the plan year or years covered by subsequent renewals of this plan. 4. The maximum annual evaporative loss associated with this mining operation shall not exceed 16.46 acre-feet under Scenario A and shall not exceed 20.27 acre-feet under Scenario B, as listed on the attached Tables 1A and 1B. 5. Under Scenario A, the maximum operational loss associated with this mining operation shall not exceed 10.44 acre-feet, as listed in on the attached Table 1A. The total product mined below the ground water table at the St. Barbara Sand and Gravel Mine shall not exceed 270,000 tons per year resulting in an annual amount of 7.92 acre-feet of water lost in the mined aggregate (270,000 tons of sand mined below the ground water table and 414,000 tons of rock, chip, and waste mined above the ground water table). The annual amount of water used for dust suppression shall not exceed 2.52 acre-feet. Under Scenario B, there shall be no operational loss associated with this mining operation.