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Mr. Paul Bruss, P.E <br />March 24, 2016 <br />Page 2 of 6 <br />Well perrinit no. 61509-F corresponds to Phases 1 and 2 and limits that portion of the <br />operation to evaporation from 12.0 acres of exposed water, water removed from 900,000 <br />tons of material (26.52 acre-feet annually), and dust control (17.76 acre-feet annually). <br />Application receipt no. 3664433 was received by this office to change/expand the use of well <br />Permit no. 61509-F and will be evaluated subsequent to approval of this SWSP. Well Permit <br />No. 75997-F corresponds to Phase 7 and limits that portion of the operation to evaporation <br />from 5 acres of exposed water and 29.4 acre-feet annually (4% water content by weight of <br />1,000,000 tons) of water removed from mined material (or the amounts covered under a <br />Water Court approved plan for augmentation or SWSP approved by the State Engineer, <br />whichever is more restrictive). <br />In accordance with the letter dated April 30, 2010 from the Colorado Division of Reclamation, <br />Mining, and Safety ("DRMS"), all sand and gravel mining operators must comply with the <br />requirements of the Colorado Reclamation Act and the Mineral Rules and Regulations for the <br />protection of water resources. The April 30, 2010 letter from DRMS requires that you provide <br />information to DRMS to demonstrate you can replace long term injurious stream depletions <br />that result from mining related exposure of ground water. According to the renewal request, <br />the long term plan for the site is for a storage reservoir in Phase 2, which already has an <br />approved slurry wall, and to backfill Phases 1 and 7 to a ground surface elevation at least two <br />feet higher than the ground water table. Therefore, please provide an explanation and/or <br />documentation that a financial warranty sufficient to cover the cost of backfilling Phases <br />1 and 7 that meets the Division of Water Resources requirements for preventing ground <br />water exposure has been filed, in accordance with approach no. 1 of the April 30, 2010 <br />letter from DRMS, with the next SWSP renewal request. <br />DEPLETIONS <br />Annual site depletions consist of 154.3 acre-feet of gross evaporative losses, 11.0 acre-feet of <br />pumping for dust control, and 7.4 acre-feet of water removed in the mining product, for a <br />total depletion of 172.7 acre-feet for each of the plan years (February 1, 2016 through <br />January 31, 2017 and February 1, 2017 through January 31, 2018). The monthly distribution <br />of the values and the lagged effects on the Arkansas River, are detailed on your Tables 1-4, <br />which are attached. The lagged depletions were calculated individually for each Phase of the <br />operation based on the characteristics below. <br />Location <br />Transmissivity <br />(gpd/ft) <br />Specific <br />Yield <br />Distance to <br />River (ft) <br />Distance to Alluvial <br />Boundary (ft) <br />Phase 1 <br />97,100 <br />0.15 <br />1,032 <br />2,647 <br />Phase 2 <br />97,100 <br />0.15 <br />964 <br />2,206 <br />Phase 7 <br />97,100 <br />0.15 <br />420 <br />2,250 <br />Lagging factors for each of the Phases were calculated using the Glover Method, normalized <br />to the number of months required for 95% of depletions to affect the river, and are provided <br />in the following table. <br />1313 Sherman Street, Room 821, Denver, CO 80203 P 303.866.3581 F 303.866.3589 www.water.state.co.us :i <br />John W. Hickentooper, Governor 1 Robert Randall, Interim Executive Director ,,v'( , h ,,/ .f <br />•\-k fir» <br />' } 1876 ` <br />