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~~~ <br />~~ ~ Uv <br />DEPARTMENT OF NATURAL RESOURCES <br />DIVISION OF WATER RESOURCES <br />May 14, 2008 <br />RECEIVED <br />Cheryl Signs, P.E. <br />Cheryl Signs Engineering ~ MAY ~J Z~~ <br />109 East Fourth Avenue ®ivisiola of Rec4amatio~l, <br />Denver, CO 80203 ~~,~ <br />Re: Durham Pit, Substitute Water Supply Ptan <br />r~RMS File No. M-78-056 <br />Sections 3, 9, and 10, T5N, R65W, 6th P.M. <br />Water Division 1, Water District 3, Weld County, Colorado <br />Approval Period: January 1, 2008 through December 31, 2009 <br />Contact Phone Number for Ms. Cheryl Signs: 303-778-7653 <br />Dear Ms. Signs: <br />Bill Ritter, Jr. <br />Governor <br />Harris D. Sherman <br />Executive Director <br />Dick Wolfe, P.E. <br />Director <br />We have reviewed your letter dated March 9, 2008, requesting renewal of the above referenced <br />substitute water supply plan to cover depletions caused by an existing gravel mining operation. The <br />required fee of $257 for the renewal of this substitute water supply plan has been submitted. The <br />original plan was approved on May 24, 2004 and it was most recently renewed on March 6, 2007. <br />The anticipated net depletion for this plan is 51.96 acre-feet per year. The currently exposed <br />groundwater at the site totals 41 acres. According to the information submitted, 44.6 acres of water <br />surface was exposed within the reclamation permit boundary prior to January 1, 1981. The plan <br />anticipates that up to 60 acres of water surface could be exposed at the site in the next two years. <br />This results in up to 15.4 acres of exposed surface area that could require replacement of depletions <br />from evaporation. However, during the period of this plan, the 15.4 acres were reduced by 20 <br />percent to reflect the actual exposed ground water surface area. The 20 percent is an approximation <br />of the reduction in area from the ground surface to the water table. This reduction was developed by <br />measuring the pit perimeters and applying a 3:1 slope to reflect the surface area of the exposed <br />ground water surface area. Therefore, the potential exposed ground water surface area is 12.32 <br />acres. <br />You have provided a monthly breakdown of the annual depletions made up of 25.10 acre-feet of <br />net evaporative loss, 20.60 acre-feet of water lost with the mined product (which represents 700,000 <br />tons of mined product), 2.76 acre-feet of water used for dust control, and 3.50 acre-feet used for <br />concrete batching. Annual evaporation from 12.32 acres was estimated to be 33 acre-feet; however, <br />phreatophyte credits of 7.90 acre-feet per year have been applied to this plan, which reduced the net <br />evaporation depletions to 25.10 acre-feet per year. The evaporation calculations were based on the <br />entire exposed surface area in the event that the dewatering ceased. <br />The proposed source of replacement for this pit is 48.7 acre-feet (93.18 acre-feet of headgate <br />deliveries and 44.5 acre-feet of return flow obligations) of historic stream depletions from the dry-up of <br />33.7 acres of land historically irrigated with five shares of Greeley Irrigation Company's interests in <br />Greeley Canal No. 3 and 2.9 acre-feet (4.9 acre-feet of deliveries and 2 acre-feet of return flow <br />Office of the State Engineer <br />1313 Sherman Street, Suite 818 • Denver, CO 80203 • Phone: 303-866-3581 • Fax: 303-866-3589 <br />www.water.state. co.us <br />