2016-02-03_HYDROLOGY - M1979191 - Laserfiche WebLink

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Middle Poudre Combined SWSP Page 4 of 8 February 3, 2016 The 5.0 Lafarge BEDC shares were previously, and the 1.0 Steamboat Partners BEDC share will continue to be, diverted into a recharge pit (WDID 0302002) through an existing lateral from the ditch. The recharge pit was constructed on the un-mined portion of the Three Bells Pit site and was excavated to only the upper portion of the gravel deposit so as not to expose additional ground water. The estimated recharge pit size is one (1) acre. For the purposes of this plan, evaporation from open water was assumed for the entire surface area of the recharge pit for the number of days water was diverted into the recharge pit. Based on this approach, the proportion of days with water diverted into the recharge pit to the number of days per month was applied to the monthly gross evaporation rate, resulting in an evaporative consumptive use from the recharge pit of approximately 2.04 acre-feet. The dry-up acreage required for the 1.0 Steamboat Partners BEDC share would be 57.4 acres of the 344.3 historically irrigated acres on the Three Bells property. Mining on the property has resulted in sufficient de-facto dry-up of historically irrigated lands to cover the required dry-up associated with the 1.0 share being diverted to recharge during this plan period. The dry-up area attributed to the 1.0 Steamboat Partners BEDC share must be documented in accordance with the attached Administration Protocol "Dry-Up of Irrigated Land" to ensure that no other shares historically used on the Three Bells Farm are claiming credit for the same dry-up. From 2004 through October 2014, a cumulative volume of 4,697 acre-feet associated with the 5.0 Lafarge BEDC shares was recharged. An additional 189.11 acre-feet associated with the 1.0 Steamboat Partners BEDC share were recharged from November 2014 through November 2015. MMM is projecting to deliver the average headgate diversion of 91.4 acre-feet associated with their 1.0 Steamboat Partners BEDC share into recharge for 2016. A recharge model was used to determine the total monthly recharge accretion credits for 2016. The recharge model uses the following parameters: transmissivity (T) = 45,000 gallons/day/foot, the distance of centroid of the recharge pit to the Cache La Poudre River (X) = 1,600 feet, the distance from the parallel impermeable boundary to the Cache La Poudre River (W) = 5,000 feet, and the specific yield (S) = 0.2. The lagged accretions to the Cache la Poudre River are estimated to total 170.08 acre-feet for this approval period (includes carry over from recharge in previous years and projected recharge of the 1.0 BEDC during 2016), with return flow obligations totaling 45.59 acre-feet for this approval period. A monthly breakdown of projected lagged depletions, recharge credits, debits, and return flow obligations is shown on the attached Table 2. Actual recharge credits and return flow obligations will be based on the actual deliveries made for replacement purposes under this SWSP. 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. The DRMS letter (attached) identifies four approaches to satisfy this requirement. The Three Bells Pit is proposed to be reclaimed to Developed Water Storage. In accordance with approach no. 3, the bond for the Three Bells Pit has been increased to $3,294,000 to cover the cost of final reclamation.