2013-07-25_HYDROLOGY - M1979059 - Laserfiche WebLink

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Peter Wayland Brownwood SWSP December 31, 2012 Page 2 of 5 Depletions The anticipated net depletion for this plan is 27.78 acre -feet per year for up to 13 acres of exposed ground water. Gross evaporation at this site is taken from NOAA TR -33 Map 3 and is estimated to be 39 inches per year with an effective precipitation amount of 10.58 Inches. The lagged depletions from evaporation at the Brownwood Pit were estimated by the Applicant's consultant using the Integrated Decision Support group's Alluvial Water Accounting System (IDS AWAS) stream depletion model. The aquifer characteristics used in the model are; transmissivity (T) = 44,883 gallons per day per foot, specific yield (SY) = 0.2, the distance from the centroid of the exposed around water to the stream = 798 feet, and the location of the parallel impermeable boundary was estimated to be 2,000 feet from the stream. The stream depletions model was taken to a steady state condition and show that the stream depletions will equal the yearly evaporation of 27.78 acre -feet at a monthly rate as shown in the attached Table AI.1 Replacements The proposed source of replacement for this pit includes historical consumptive use credit from 0.24 shares of Big Thompson Ditch & Manufacturing Co ( "BTDMC ") water rights from the dry-up of 16.76 acres of land, and a water lease with the City of Loveland. The applicant has a 25 -year Water lease with the City of Loveland ( "Loveland ") for 100 acre -feet of fully consumable water which is used for replacement purposes for six gravel pits operated by the Applicant, including the Brownwood Pit. Loveland will deliver this water to the Big Thompson River at their waste water treatment plant (WDID 0402300) which is adjacent to the Brownwood Pit. Therefore a transit loss will not be assessed on releases made for this plan. Transit losses are subject to change at the water commissioner's discretion. The monthly depletion and replacement requirements, based on an average year are found on the attached Table AI.4. Under the terms of the Loveland lease, replacements can be made using a variety of water owned by Loveland including, but not limited to, Windy Gap reusable effluent, Loveland Storage Reservoir water as decreed in case no. 82CW202A, and Colorado Big Thompson ( "C- BT') Project water. In the event that Loveland plans to use C -BT water as a replacement source, Loveland shall comply with the Interim Rule issued by the Northern Colorado Water Conservancy District ( "Northern District ") in May 2005, regarding the use of C -BT Project water in substitute water supply plans. Prior to the use of C -BT Project water, Loveland is required to notify this office, the division engineer and the water commissioner of the amount of C -BT Project water dedicated to this plan and provide a copy of the Northern District's approval letter as required by paragraph 1(g) of the Northern District's May, 2005 Interim Rule. A review of the irrigation practices at Brownwood Farm indicates that 2 shares of the BTDMC were used to irrigate approximately 139.68 acres. Of these shares, the Applicant owns 5/6 of a share and is claiming a credit based on 16.76 acres of dry up. The dry up of 16.76 acres is associated with 0.24 shares of the water right. The average year analysis shows that on an average year the historic net stream depletions as a result of the 0.24 shares are 22.03 acre -feet per year. This would provide a credit of 24.39 acre -feet during the irrigation season, and a return flow obligation of 2.36 acre -feet during the non - irrigation season (see attached Table A1.3). During a dry year, the current 25 -year lease with Loveland may not be sufficient during the irrigation season. The Applicant has stated they are currently negotiating with the City of Loveland to lease a storage water right, which could be released In real time during dry years to provide coverage to this gap. Any final lease or agreements with the Applicant and