2013-01-02_HYDROLOGY - M2008017 - Laserfiche WebLink

Home Browse Search

Ms. Michelle Hatcher Derr SWSP December 31, 2012 Page 2 of 4 consumptive use from evaporation. The average precipitation for this time period is 14.27 inches. No phreatophyte credit has been applied to this SWSP. A stream depletion model was used to determine the lagged depletions to the Cache La Poudre River. The following parameters were used in the model: harmonic transmissivity (T) = 76,056 gallons per day per foot, specific yield (SY) = 0.2, the distance of the exposed ground water to the river X = 2,126 feet, and the location of the parallel impermeable boundary was estimated to be 22,900 feet from the stream. Because this is a new proposed mining operation, no ground water was exposed at this location prior to January 1, 1981. The stream depletion model shows that the Applicant must replace 8.54 acre -feet from January 2013 through December 2013. Replacements The source of replacement water to be used for this SWSP is a lease of 8.57 acre -feet of reusable effluent from the City of Greeley ( "Greeley "). A copy of the signed lease agreement with Greeley for 8.57 acre -feet of fully consumable effluent from Greeley's Wastewater Treatment Plant ( "WWTP ")(WDID 0302312) to be used at the Derr Pit was forwarded to this office on December 31, 2013 and is attached to this letter. Greeley's WWTP discharge point is located approximately 0.8 miles upstream from the depletion point for the Derr Pit. Transit losses of 0.5% for 0.8 miles are included in the lease amount. If Broken Arrow needs to get water past the Ogilvy Ditch headgate, they will use the Central Colorado Water Conservancy District's ( "Central ") augmentation station located at the headgate of the Ogilvy Ditch. Broken Arrow is in the process of getting an agreement with Central for the use of the augmentation station. The Applicant is required to submit a copy of the agreement with Central to this office and the division engineer prior to requesting to pass water past the headgate. However, Greeley can also make releases from its Lone Tree WWTP (WDID 0102342). If effluent from the Lone Tree WWTP is used for replacement purposes, Central's augmentation station would not be required to deliver replacement water. The monthly depletions and replacement requirements are found on the attached Table 3. Long Term Augmentation) In accordance with the letter dated April 30, 2010 from the Colorado Division of Reclamation, Mining, and Safety ( "DRMS "), all sand and gravel mining operators must comply with the requirements of the Colorado Reclamation Act and the Mineral Rules and Regulations for the protection of water resources. The April 30, 2010 letter from DRMS requires that you provide information to DRMS to demonstrate you can replace long term injurious stream depletions that result from mining related exposure of ground water. In accordance with approach number 3, a total bond amount of $1,362,889, which includes the cost of installing a slurry wall, has been set. DRMS approved a phased mining plan operation which allows the bond to be posted in phases. Prior to opening a new phase the operator will submit an increased financial warranty so as to hold enough bond at any given time to construct a slurry wall around the actively mined phases. The current bond amount for Phase 1A is $49,132. Groundwater shall not be exposed as part of Phase 2 until the bond is increased to $1,282,080. Prior to the exposure of ground water at this site, the Applicant is required to provide proof to this office (the Division of Water Resources) that such a bond has been obtained and the requirements of the April 30, 2010 letter from DRMS have been satisfied. Conditions of Approval Based upon statutory requirements, I hereby approve the proposed SWSP in accordance with § 37 -90- 137(11), C.R.S. subject to the following conditions: