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Jared Dains Page 3 <br />February 3, 2011 <br />Mann Lakes 0 0 0 0 0 0.44 <br />Riverbend 11 <br />7 0 0 0 11.7 9.1 <br />Operation . <br />Lupton Lakes 74 <br />9 22.1 18.3 0 115.2 101.9 <br />Riverbend East . <br />TOTAL 86.6 __ ?22.11 18.3 25.0 151.9 136.4 <br />Lafarge does not anticipate dewatering any of the sites during the period of this SWSP, except <br />Riverbend East for which dewatering is schedule to start in March 2011. Lupton Lakes (Riverbend <br />East) site was dewatered from May 2008 through September 2008. The lagged dewatering depletions <br />after the dewatering stopped from November 2010 through February 2011 equal 0.64 acre-feet as <br />shown in the attached Table 2. The timing of the lagged depletions from the dewatering operations <br />starting in March 2011 was determined through a stream depletion model for the Riverbend East site. <br />The model addresses the lagged depletions from the Howe and Riverbend West sites by accounting <br />for the net accretion credits at the river that occur due to the dewatering operation at the Riverbend <br />East site. These accretions are applied to this plan against depletions from the Howe and Riverbend <br />West sites as shown in the attached Table 2. <br />As long as the pit is continuously dewatered, the water returned to the stream system should be <br />adequate to offset the depletions, however once dewatering at the site ceases, the river will experience <br />a net depletion as the pits gradually fill. At least three years prior to completion of mining, a plan must <br />be submitted that specifies how the post pumping dewatering depletions (including refilling the pit) will <br />be replaced in time, place and amount. The Applicant is hereby notified that if dewatering at this <br />site occurs only during the summer months and the pond is allowed to fill during the winter <br />months the depletions that will have an effect on the stream as a result of refilling the pit, must <br />be addressed in any subsequent SWSP renewal for this pit. <br />Due to water quality issues, Lafarge uses water from five wells at the Riverbend East site for <br />washing material and dust control of road and stock piles. Lafarge will pump water for industrial uses <br />from the following wells: 1657-RR (WDID 0208500),2819-FR (WDID 0208639),19944-RR (WDID <br />0205187), 20317-RR (WDID 0207417) and 20583-R (WDID 0205190). All of the wells are located <br />within the gravel permit boundary in sections 18 and 19, Township 1 North, Range 66 West, 6t' P.M. <br />Well Nos. 1657-RR, 2919-F, 19944-FR, 20317-R and 20583-R are permitted for irrigation purposes <br />and they are included in the Ground Water Management Subdistrict of the Central Colorado Water <br />Conservancy District ("Central GMS") augmentation plan approved by the Division 1 Water Court in <br />case no. 2002CW335. Lafarge obtained new well permit for these wells as follows: 70135-F (1657- <br />RR), 70136-F (20583-R), 70137-F (19944-RR), 70138-F (20317-RR) and 70139-F (2819-FR). <br />The water pumped for dust control is considered to be 100% consumptive, thus the <br />consumptive use for dust control is 18 acre-feet. For the purpose of this SWSP a 4% moisture loss <br />was calculated to account for the resulting moisture content of aggregate. The estimate of the total <br />moisture losses was based upon the projected washing schedule associated with the projected <br />aggregate sales. The consumptive use for the washing is 22.1 acre-feet (Appendix A). Return flows <br />from the aggregates washing is delivered back to a settling pond on the Riverbend East site. The <br />evaporation from the settling pond is accounted for in the SWSP.