Laserfiche WebLink
Ms. Kristina Wynne <br />Greeley 35th Ave /Iverson Combined SWSP <br />July 16, 2012 <br />Page 4 <br />99CW232; or f) any other release and measurement point that Greeley and MMM agree upon. <br />The Applicant is required to coordinate with the water commissioner the delivery location of <br />replacement water to ensure out -of- priority depletions are adequately replaced to prevent injury to <br />other water rights. Conveyance loss for delivery of augmentation water is subject to assessment <br />and modification as determined by the water commissioner or division engineer. A copy of the <br />lease with Greeley was previously submitted to this office and is attached to this letter. A monthly <br />breakdown of depletions and replacements is shown in the attached Table 3. <br />Additional replacement supplies will come from two additional short term leases with the <br />City of Greeley. The first lease provides 4.0 acre -feet of fully consumable in September 2012 and <br />October 2012. The second lease provides for 6.0 acre -feet of fully consumable replacement <br />water in March through May 2013. Dewatering, as explained below, will also be used to offset <br />depletions at Iverson and 35th Ave Pits. <br />Dewatering <br />The commencement of dewatering at the Iverson Pit will generate credits to the river in <br />excess of the lagged depletions for the first 9 months of dewatering operations. This is based off <br />an assumed dewatering rate of 1,500 gpm at the same lagging parameters for the Iverson <br />depletions, and takes into account some water being diverted for dust control uses. Dewatering is <br />projected to commence by the end of June 2012 and reach a steady state condition, where <br />dewatering accretions equal dewatering lagged depletions, in March 2013. The applicant has <br />estimated that once dewatering ceases, depletions will occur to the river during the subsequent <br />four months. <br />A dewatering depletion analysis must also include water removed from the tributary <br />stream system by the 'first fill' or any `intermittent fills' of the gravel pit. The first fill or intermittent <br />fill is the water that fills an unlined gravel pit and occupies the volume previously occupied by the <br />removed sand, gravel, or other solid material. For pits that are dry mined through dewatering, the <br />first fill normally occurs at the conclusion of mining. This volume must be calculated and applied <br />to the mining operations water consumption pursuant to paragraph 14 of the General Guidelines <br />for Substitute Water Supply Plans for Sand and Gravel Pit (update April 1, 2011). At least three <br />years prior to the cessation of dewatering, the applicant must provide a complete analysis <br />showing the lagged depletions that will result from the cessation of dewatering and the first fill of <br />the pit and the anticipated replacement water source. <br />A Totalizing Flow Meter is required to be installed to record monthly dewatering volumes <br />with meter readings reported on the submitted monthly accounting. <br />Long Term Depletions <br />In accordance with the letter dated April 30, 2010 from the Colorado Division of <br />Reclamation, Mining, and Safety ( "DRMS "), all sand and gravel mining operators must comply <br />with the requirements of the Colorado Reclamation Act and the Mineral Rules and Regulations <br />for the protection of water resources. The April 30, 2010 letter from DRMS requires that you <br />provide information to DRMS to demonstrate you can replace long term injurious stream <br />depletions that result from mining related exposure of ground water. <br />The Reclamation Plan filed with DRMS for the Iverson Pit includes MMM leaving an <br />unlined pond. Unlined ponds will create long term injurious stream depletions unless otherwise <br />augmented. According to the mining lease MMM has with the landowners ( "The Iversons "), the <br />