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Nelson Mining Resource SWSP Page 3 of 8 February 3, 2015 Three separate models were developed for the period of 1950 -1965, 1966 -1990 and 1993 -2005 using the Integrated Decision Support Group Consumptive Use Model (IDSCU) and the Modified Blaney- Criddle method with TR -21 crop coefficients. Diversion records for 1991 and 1992 were missing from the Colorado Decision Support System ( "CDSS ") therefore these years were not included in the HCU analysis. Temperature and precipitation data were taken from the Longmont ESE weather station, which had continuous data from 1950 through 2006. Missing data were supplemented with data from the Fort Collins weather station. The ditch loss used the consumptive use analysis was 10 percent based on the ditch location, its length and previous experience and the irrigation efficiency was taken as 50 percent based on review of aerial photos of the farm and field visits to examine site specific conditions. Water in excess of the irrigation requirement was added to the soil moisture bank, which was assumed to have a water holding capacity of 1.95 inch /ft. The HCU analysis for the 1.55 shares from 1950 to 1993 and 1.5 shares from 1994 to 2005 averaged 160.6 acre -feet per year with a non - irrigation season return flow obligation of 14.6 acre -feet (see Table AI.7). The pro -rata historical consumptive use credit for the 0.434 shares is 48.18 acre -feet with a non - irrigation season return flow obligation of 4.34 acre -feet. This SWSP relies upon the changed shares starting the month of April 2015. The Applicant indicated that the measuring and recording device to measure the changed Last Chance Ditch shares back to the river has not been installed. Therefore, the Applicant is hereby notified that this SWSP is valid until March 31, 2015. The plan will be extended until October 31, 2015 if the necessary measuring and recording devices are installed and approved by the water commissioner by April 1, 2015. After applying the 0.434 shares of Last Chance Ditch water, there will be 12.85 acre -feet of uncompensated depletions. Additional replacements for depletions during the non - irrigation season and during months with insufficient credits will be made by releases of fully consumable wastewater treatment plant effluent or reservoir releases from a lease with the City of Longmont ( "Longmont "). The Applicant provided a copy of the renewed lease agreement with Longmont, dated November 25, 2014, to this office and the lease is attached to this letter. In accordance with the lease, Longmont will provide a total of 17.31 acre -feet of fully consumable water during the period of November 2014 through April 2015, and October 2015. The Longmont wastewater treatment plant is located approximately 10.5 miles upstream of this new mining operation. A 0.25 percent per mile transit loss (2.625 percent overall loss) has been accounted for in the amount of replacement water obtained from Longmont. The monthly depletions and replacement requirements are found on the attached Table AI1.4. 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 1, Asphalt Specialties Co. has submitted a financial warranty in the amount of $186,814.00 for the