2011-02-03_HYDROLOGY - M1978052 - Laserfiche WebLink

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Jared Dains February 3, 2011 Page 2 The consumptive use at the Riverbend East will consist from evaporation from exposed groundwater, aggregate production, dust control, and dewatering which is scheduled to begin in March 2011. The gravel pits are located as shown on attached Figure 1. This plan identifies replacement sources to cover depletions from the multiple mine sites. The following table lists the sites that are involved in this combined replacement plan: Tea! F e - l`nAARINFn QFPI ArFMFNT PLAN SITES Previous Current Well New Permit Exposed Surface Site Name DRMS # Approval Permit No. Required acres NA* Howe Pit M-78-052 10/27/2009 67261-F No Mann Lakes M-82-147 10/27/2009 56354-F No 0.0* Riverbend M-00-016 03/27/2009 55577-F No 4.0** Operation Lupton Lakes 28.1 (pre-dewatering) (Riverbend M-04-078 10/27/2009 66625-F Yes 25.2 (post-dewatering) East *Lining was approved on August 1, 2006 for Howe Pit and September 10, 2009 for Mann Lakes. Denver Water will be responsible for replacement of evaporative depletions at the Howe Pit site from any unlined lakes **Area exposed under the Fort Lupton Lakes, M85-088 but incorporated by the Riverbend Operation M-00-016 In accordance with the letter dated April 30, 2010 (copy attached) from the Colorado Division of Reclamation, Mining, and Safety ("DRMS"), all sand and gravel mining operators must comply with the requirements of the Colorado Reclamation Act and the Mineral Rules and Regulations for the protection of water resources. The April 30, 2010 letter from DRMS requires that you provide information to DRMS to demonstrate you can replace long term injurious stream depletions that result from mining related exposure of ground water. The DRMS letter identifies four approaches to satisfy this requirement. For the Riverbend Operation and the Lupton Lakes Pit (Riverbend East), it is our understanding that approach no. 1 or no. 3 will be utilized as evidenced by the Applicant's bond in the amount of $808,415.87 through DRMS for the Riverbend East and $3,150,000.00 through DRMS for the Riverbend Operation. For the Mann Lakes site there is no need for a long term replacement requirement since all depletions for the Mann Lakes site were replaced in November 2010. Depletions The total annual losses resulting from evaporation, aggregate washing, dust control and concrete batching are shown in the following table: TABLE B - LOSSES Evaporation Aggregate Dust Concrete Total Total Site Name Losses Washing Control Elatching (ac-ft) Lagged (ac-ft) (ac-ft) (ac-ft) (ac-ft) (ac-ft) Howe Pit 0 0 0 25.0 25.0 25.0