2005-07-13_REVISION - M2000016 (42)

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Ms. Joanmx Williams RE: Combined South Platte SSP Renewal April 28, 2005 Page 3 oj6 After accounting for return flows, an excess of 43.9 ac-ft of lagged consumptive use credit may be applied towards meeting the total augmentation demand (Table No. 2). Table No. 3 shows the replacements made by the lagged timing of the historic consumptive use credit based on the results of the recharge model run during Water Year 2005. City of Greeley Lease A lease of 74.2 acre-feet of fully consumable water from the Ciry ofGreeley will make replacements from November 2004 through March 2005 and also October 2005 (Table No. 3). Replacements from this (ease began in November 2004 according to the schedule in Table No. 3. The point of replacement will be the Greeley W WTP. A copy of this lease agreement is included in Appendix B. In previous discussions with Bob Stahl, it was agreed that the South Platte River was a live stream from the site to the confluence with the Cache La Poudre River, and no water rights will be injured during the winter months. Also, due to the point of replacement located downstream from the mining operations, this source does not incur transit loss. Replacement Short fall Lafarge previously used a lease from Consolidated Mutual Water Company for summer replacements for these sites. This replacement source is presently not available. The currently replacement short-fall is 110.3 acre-feet from April 2005 through September 2005 (Table No. 3). AG will continue to work with Lafarge to secure replacement water to meet the remaining depletion volume. Once secured, the SEO will be notified of the additional source, and a copy of the lease agreement will be submitted. Again, it is requested this requirement be included as a condition of approval. If an additional source is not submitted by March 31, 2005, then the plan will become invalid. The water balance summarizing the total lagged depletions and replacement sources as well as the shortfall is shown in Table No. 4. This table will be updated after the additional summer replacement source is identified and submitted to the SEO. SITE DEWATERING The SEO is also concerned with the lagged effect to the stream system from dewatering operations and later allowing a groundwater lake to fill. The active mining operations at the Howe Pit, Tanabe Pit, Dunes Development Site, and Mann Lakes Pit all currently dewater to the South Platte River at a rate of approximately 1,500 gpm. As requested by the SEO, Lafarge will monitor the rate and duration of dewatering in the future. There is presently no dewatering at the For Lupton Pit. The mining operations have continuously dewatered directly back to the South Platte River for many years. Due to the long period of continuous dewatering, it is assumed the dewatering at this site has reached a state of equilibrium with the South Platte River. Since steady state conditions are reached, there is no longer a net accretion to the river from the dewatering operation. If changes in the dewatering operations at the four active mining sites occur during the projected term ofthis plan, an amendment will be submitted to the SEO with a new water balance and adequate replacements. C: (Documents and SettingslDonnaJ TaylorlLacal Se[[ingslTemparary Internet Fi[esIOLKBI[tr Lafarge SP Combined SSP !2 28 04. doc