2016-02-17_HYDROLOGY - M2000016 - Laserfiche WebLink

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Mr. David M. Heintz Page 2 of 8 MMM South Platte Combined Replacement Plan February 10, 2016 All remaining lagged depletions associated with the Howe Pit were replaced under the previous SWSP and therefore Howe Pit is not included under this SWSP renewal request. In addition lining was approved on August 1, 2006 for Howe-Haller A Reservoir and September 24, 2008 for Howe-Haller B Reservoir. Denver Water is now responsible for replacement of evaporative depletions at the Howe Pit site from any unlined lakes. Mining at Riverbend West continues to be temporarily ceased and MMM will resume mining when it becomes economically feasible. MMM does not plan on mining material from the Riverbend West Site throughout the duration of this SWSP renewal. An amendment to this SWSP must be made should MMM wish to reactivating mining at the site during this approval period. The consumptive use at Riverbend West will consist only of evaporation from exposed groundwater. The consumptive use at the Riverbend East will consist of evaporation from exposed groundwater, aggregate production, dust control, and dewatering which is anticipated to continue during the duration of this SWSP. MMM is the operator of this site but Denver Water is the DRMS permit holder and has reclamation responsibility at the site. The replacement water will be supplied by a long-term lease of reusable effluent from the City of Aurora. Depletions The total annual losses resulting from evaporation, aggregate washing, and dust control are shown in the following table: TABLE B - DEPLETIONS' Evaporation Aggregate Dust Total Site Name Losses Washing Control Total (ac- Lagged (ac-ft) (ac-ft) (ac-ft) ft) (ac-ft) Riverbend West 26.37 0 0 26.37 26.37 Riverbend East 82.04 67.90 34.80 184.74 168.79 TOTAL 108.41 67.902 34.80 211.11 195.16 ' This table does not take into affect dewatering depletions. 2 Depletions associated with mining of 2,307,000 tons of aggregate Due to water quality issues, MMM uses water from five wells at the Riverbend East site for washing material and dust control of road and stock piles. MMM will pump water for industrial uses from the following wells: 1657-RR (WDID 0208500), 2819-FR (WDID 0208639), 19944-RR (WDID 0205187), 20317-RR (WDID 0207417) and 20583-R (WDID 0205190). All of the wells are located within the gravel permit boundary in sections 18 and 19, Township 1 North, Range 66 West, 61h P.M. All five wells are permitted for irrigation purposes and they are included in the Ground Water Management Subdistrict of the Central Colorado Water Conservancy District ("Central GMS") augmentation plan approved by the Division 1 Water Court in case no. 2002CW335. Lafarge obtained new well permits to cover industrial uses at these wells as follows: 70135-F (1657-RR), 70136-F (20583-R), 70137-F (19944-RR), 70138-F (20317-RR) and 70139-F (2819-FR). These well permits remain under Lafarge