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1000LORADO <br /> .0 Division of Water Resources <br /> Department of Natural Resources <br /> January 13, 2023 <br /> Jack Marvel, E.I.T. <br /> Civil Resources, LLC <br /> 323 Fifth Street <br /> P.O. Box 680 <br /> Frederick, CO 80530 <br /> Transmission via email: jack@civilresources.com <br /> RE: SLURRY WALL LINER APPROVAL - PROVISIONAL <br /> INOUYE PIT (EAST CELL) (WDID 0203984) <br /> INOUYE GRAVEL PIT, DRMS M-2018-037 (WDID 0210533) <br /> SW '/+ OF SECTION 31, TOWNSHIP 2 NORTH, RANGE 66 WEST OF THE 6T" P.M. <br /> WATER DIVISION 1, WATER DISTRICT 2, WELD COUNTY <br /> Dear Jack Marvel: <br /> The purpose of this letter is to provisionally approve the lining of the Inouye Pit (East Cell). The East <br /> Cell is located in the SW1/4 of Section 31, Township 2 North, Range 66 West of the 6t1 P.M. and is a <br /> part of the Inouye Gravel Pit (DRMS M-2018-037). The East Cell was lined with a soil bentonite slurry <br /> wall. The site is partially mined. This slurry wall liner leak test commenced on September 8, 2022 and <br /> concluded on December 7, 2022. A site inspection was performed by our office on July 12, 2022 to <br /> review site conditions and discuss the leak test plan. <br /> Your report dated December 12, 2022 provides the liner summary and leak test results. The test data <br /> provided indicates that liner meets the design standard referenced in the August 1999 State Engineer <br /> Guidelines for Lining Criteria for Gravel Pits (1999 SEO Guidelines). Meeting the design standard <br /> requires that during reservoir operations all water inflows and outflows for the liner perimeter <br /> enclosed area be accounted for on a monthly basis. <br /> This liner approval is applicable only during mining operations at the site and does not classify the <br /> structure as a reservoir capable of water storage. However, for the remainder of mining operations, <br /> water within the liner boundary is now classified as trapped native ground water. The trapped native <br /> ground water may be removed from within the lined area and returned to the stream system through <br /> surface flow or ground water recharge without the need for replacement so long as the operator does <br /> not put the water to beneficial use. All native trapped ground water remaining that is put to beneficial <br /> use (except for the water removed in product) must be replaced by the operator. All inflow of water <br /> into the liner boundary from any source, including precipitation and ground water inflows shall be <br /> removed by the pit operator so as not to cause out-of-priority storage. In order for the liner to be <br /> approved for water storage the operator must perform a final leak test once mining is complete <br /> and the site is at final grade. The final leak test will be allowed to have a modified duration of 45-days <br /> or less as long as the liner continues to satisfactorily operate during mining operations. <br /> Please contact me at 303-866-3581 x8246 or at ioana.comaniciu@state.co.us if you have any questions. <br /> Sincerely, <br /> 4j--)aWWr"� <br /> loana Comaniciu, P.E. <br /> Water Resource Engineer <br /> •a v, <br /> '3t 3 Sher-nan Street, Room 821 Denver, CO 80203 P 303 86b 3581 www colorado.;ov water <br /> Jared S Pons Governor , Dan Gibbs, Executive Duector Kevin G. Rein, State Engineer Director + +. <br />