2013-01-09_HYDROLOGY - M1977344 - Laserfiche WebLink

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s Ms. Lindsay M. Griffith, P.E. Page 3 January 8, 2013 Operational losses include dust suppression and water removed in the mined product. Projected dust suppression needs for the 2013 are estimated to total 80.31 acre -feet. The total pumping from the Duck Pond in Case No. 92CW35 for dust suppression is limited to 55 acre -feet per year. Therefore the additional 25.31 acre -feet of water used for dust suppression will be pumped from the other ponds under this SWSP (Table 2). Water removed in the mined product was calculated using a value of 2% water content by weight, as the mined product is being removed from below the water table, but in a dewatered state. You have estimated the depletion associated with water removed from the mined product to be 29.51 acre -feet of water lost with approximately 1.8 million metric tons of mined material. Note, that under § 37 -90- 137(11), C.R.S., the State Engineer may approve SWSPs to replace depletions in connection with the extraction of "sand and gravel" by open mining as defined in § 34 -32- 103(9), C.R.S., when such mining operation exposes ground water to the atmosphere. Your SWSP request for the Holcim Quarry indicates that the material mined at the site is "limestone" that originates from below the water table but in a dewatered state, and according to the General Guidelines for Substitute Water Supply Plans for Sand and Gravel Pits ( "SWSP Guidelines for Sand and Gravel Pits ") has a moisture content of 2% by weight. You also indicated that although Holcim has elected to follow the guidance of the SWSP Guidelines for Sand and Gravel Pits, you believe that this is a conservative position that may not be consistent with the local hydrology and therefore this is an issue that requires further discussion with the Division of Water Resources. Although this SWSP has been approved under § 37 -90- 137(11), C.R.S., for 2010- 2012, this proposed operation does not qualify for a substitute water supply plan under the provisions of § 37 -90- 137(11), C.R.S., and any future requests for SWSPs should be submitted pursuant to § 37 -92 -308, C.R.S. Unless you can document that this proposed operation will qualify as a "sand and gravel" mining operation as described in § 37 -90- 137(11), C.R.S., future SWSP requests must be submitted under the provisions of § 37 -92- 308, C.R.S. If a substitute water supply plan is submitted pursuant to § 37 -92 -308, C.R.S., proof of proper notification and the $300 filing fee must be provided. The total depletions for this SWSP, as shown in the attached Table 2, are estimated to be 54.82 acre -feet. The 54.82 acre -feet does not include the evaporation losses since these depletions are covered by the evaporation loss component of the changed Porter Ditch water right from Case No. 92CW35. Depletions to the Arkansas River have not been proven to be instantaneous, merely assumed to be instantaneous due to the geologic formation (fractured limestone) and the proximity to the river. According to Condition No' 7 of the previous SWSP approval you were required to demonstrate that depletions to the Arkansas River are instantaneous, or if not, provide the schedule of the lagged depletions and a post - pumping replacement plan. In the SWSP request you indicated that since the Holcim Quarry is not located in a typical alluvial geology you did not have sufficient time to determine if lagged depletions occur. Therefore you are requesting an extension of one year to investigate this issue. To allow additional time to investigate the timing of depletions, the deadline to prove that these depletions are instantaneous, or a lagged depletions schedule is required is hereby extended to December 31, 2013 by way of this letter.