2011-09-20_HYDROLOGY - M1985218 - Laserfiche WebLink

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Mr. Jared Dains September 19, 2011 acre -foot from the sanitary/miscellaneous well). During the April 1, 2011 through March 31, 2012 plan year, the site excavations will not expose any additional ground water. No mining or dewatering will take place during this plan year unless an amendment to this plan is approved. Stream depletion analyses for both the Active Pit area and the Unused Wash Pond (attached) used the Stream Depletion Factors of 7.3 days for the Active Pit and 120 days for the Unused Wash Pond, obtained from the USGS Publication 72 -192 "Stream Depletion Factors, Arkansas River Valley, Southeastern Colorado ". REPLACEMENTS The 'source of replacement water is the Arkansas Groundwater Users Association (AGUA), and the 1 -year lease agreement covering this plan year has been submitted as verification to this office. The terms of the lease are 60 acre -feet of fully consumable water, commencing April 1, 2011. Per the lease agreement, this volume of water will be delivered to a point on the Arkansas River in Sec. 34, Twp. 20S, Rng. 63W, which is directly adjacent to the Rich Pit; therefore, transit losses will not be assessed. The lease with AGUA will provide sufficient replacement water for depletions at the Rich Pit over the plan year, and will be delivered according to the schedule outlined in Column E of the attached Table 3. A new lease agreement must be provided for any renewal of this SWSP in the coming years. In accordance with the letter dated April 30, 2010 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, or provide bonding for an alternative method to mitigate, the long term injurious stream depletions that result from mining related exposure of ground water. A source of renewable Tong -term replacement water sufficient to cover evaporative depletions has not been secured for this plan. Lafarge West, Inc. was negotiating with the City of Aurora to purchase the site and install a slurry wall liner for use as water storage. However, according to your September 8, 2011 email to this office, the City of Aurora's option to purchase the site has expired. Therefore, as stated in your April 28, 2011 letter to DRMS, Lafarge is considering bonding this site to install a liner with a preliminary estimated cost of $271,320. Lafarge anticipates that it will have up to three years to phase in the additional financial warranty. CONDITIONS OF APPROVAL Page 2 I hereby approve the proposed substitute water supply plan in accordance with §37 -90- 137(11), C.R.S., subject to the following conditions: 1. This plan shall be valid through March 31, 2012 unless otherwise revoked or modified. 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 February 15, 2012. 2. The exposed ground water surface areas, consumption of water, and river depletions due to operation of this plan may not exceed those listed in Tables 1, 2, and 3, unless an amendment is approved in advance by this office. Documentation of pond size may be required by the Division Engineer in the form of an aerial photo evaluation or survey by a