2012-11-07_HYDROLOGY - M1982155 - Laserfiche WebLink

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Jared Dains Page 2 November 6, 2012 137(11), C.R.S., for 2010 -2011 and 2011 -2012, this proposed operation does not qualify for a substitute water supply plan under the provisions of Section § 37 -90- 137(11), C.R.S., and as a plan used primarily to change water rights for various uses, including dust control at an operation that does not expose ground water, this plan should be submitted for approval pursuant to Section § 37 -92 -308, C.R.S. Unless you can document that this proposed operation will qualify as "open mining ", that ground water will be exposed during the life of the substitute water supply plan, and that the amount of consumptive use generated from the water rights changes is necessary for the operations at the Fountain Pit, a future SWSP request for approval will be denied and a substitute water supply plan under the provisions of Section § 37 -92 -308, C.R.S., will be required. If a substitute water supply plan is submitted pursuant to Section § 37 -92 -308, C.R.S., proof of proper notification and the $300 filing fee must be provided. DEPLETIONS According to the submittal, the only consumptive uses of water are from dust control, which you have estimated to be approximately 3.5 acre -feet per year, and from evaporation from the storage pond, estimated to be 1.45 acre -feet per year, using the estimated water surface area of 0.5 acres. The total of 4.95 acre -feet per year would be withdrawn from well permit no. 59834 -F and piped approximately one mile to the storage pond. Gross evaporation from the storage pond surface area, was determined using NOAA Technical Report NWS -33, Evaporation Atlas for the Contiguous 48 United States. You have proposed to replace only the net evaporation from the storage pond, however under Colorado statutory law, ET credit can be utilized to offset the exposure of ground water only for streambed reservoirs and gravel pit ponds created as a result of "open mining ". Since the storage pond is not a streambed reservoir nor a gravel pit pond created as a result of "open mining ", the SEO's position is that the ET credit allowed pursuant to C.R.S. § 37 -80- 120(5) does not apply to the storage pond since it cannot be considered open mining as described in C.R.S. § 34 -32- 103(9). Accordingly, for the purposes of this SWSP, Schimdt is required to replace gross evaporation from the ground water exposed in the storage pond. Based on the NOAA Technical Report NWS -33, gross annual evaporation at the location of the storage pond is approximately 46.0 inches (3.83 acre -feet per surface acre), or 1.91 acre -feet per year for the storage pond (based on a pond surface area of 0.5 acres).Therefore a total of 5.41 acre - feet would have to be withdrawn from well no. 59834 -F and piped approximately one mile to the storage pond. As required by Condition No. 5 of the previous SWSP approval the Applicant was notified that assumption of instantaneous depletions is not accepted in any subsequent renewal request of the SWSP, therefore the timing of depletions to Rock Creek attributable to pumping from the sump well no. 59834 -F were calculated using the Integrated Decision Support System AWAS program utilizing the following lagging parameters: X =390 feet, transmissivity= 30,000 gallons per foot per day, aquifer width =3,500 feet and specific yield =0.2. Due to the location of the sump and the lagging parameters used, the stream depletions were determined to be 4.66 acre -feet. However, since the lagged depletions were calculated based on your proposal to only replace the net evaporation from the storage pond, the lagged depletions will have to be recalculated based on the amount of the gross evaporation from the storage pond. 4