2012-12-07_HYDROLOGY - M1994005 - Laserfiche WebLink

Home Browse Search

Mr. Peter Foster December 6, 2012 Colona Gravel Pit, Substitute Water Supply Plan Page 3 of 7 REPLACEMENT WATER The primary source of replacement water for this pit during the irrigation season of April through October is consumptive use credits from the dry-up of 29.2 acres historically irrigated by 2.5 shares in the Ouray Ditch (see Table 1, March 27, 2009 for the water rights dedicated to the plan). Based on Ouray Ditch diversion records, assuming a ditch loss of 10% and an irrigation efficiency of 50 %, the average annual historical stream depletion associated with the Applicant's 2.5 shares is estimated to be about 49.1 acre -feet per year, as shown in the attached Table 3. A portion of the water diverted to irrigate the 29.2 acres property historically accrued to the Gunnison River in a form of surface and ground water return flow. You have completed a delayed depletion analysis to determine the amount and timing of the ground water return flow. According to this analysis it was determined that 50 percent of the total return flow accrues to the Uncompahgre River as surface return flow within the same month as the diversion and 50 percent accrues to the Uncompahgre River as ground water return flow. The timing of the ground water return flows was lagged to the Uncompahgre River using the Glover method with the following aquifer parameters: X = 1,880 feet, W = 3,180 feet, S =0.15, and T = 50,000 gpd /ft. After applying the 2.5 shares of Ouray Ditch water to Year 1 (since depletions for Year 1 are greater than Year 2) there will be 33.8 acre -feet of uncompensated depletions. However, out -of- priority depletions, determined based on the percentages of days the Gunnison River fell below 750 cfs during the year 2002 (worst case scenario), for the Year 1 of operation total 18.6 acre -feet (Table 3, column 14). A water lease (copy attached) from the Tri- County Water Conservancy District (Tri- County) for reservoir releases of 6 acre -feet per year of fully consumable water from Ridgway Reservoir will be used to supplement the consumptive use credits for the month of October. A 1.65% transit loss will be applied to all deliveries from Ridgway Reservoir as specified in Column 3 of your Table 4. The proposed source of replacement water for this pit during the non - irrigation season of November through March is fully consumable water released from Blue Mesa Reservoir by the U.S. Bureau of Reclamation. The Applicant has two contracts (copies attached) for Blue Mesa water, one for 5.0 acre -feet and another for 13.0 acre -feet. An 8.9% transit loss will be applied to all deliveries from Blue Mesa Reservoir as specified in Column 2 of your Table 4. CONDITIONS OF APPROVAL I hereby approve the proposed substitute water supply plan in accordance with § 37 -90- 137(11), C.R.S., subject to the following conditions: 1. This plan shall be valid from October 1, 2011 through September 30, 2013 unless otherwise revoked or modified. If this plan will not be made absolute by a water court action by the plan's expiration date, a renewal request must be submitted to this office with the statutory fee (currently $257) no later than August 15, 2013. 2. The Applicant must provide the name, address and phone number of the person who will be responsible for the operation of this plan to this office, the Division Engineer, Bob Hurford, and the Water Commissioner, Luke Reschke (both at PO Box 456, Montrose, CO, 81402, telephone 970 - 249 - 6622), within 20 days of the receipt of this approval, and same must be provided on the accounting forms submitted to the division engineer and the water commissioner. 3. Well permit no. 66447 -F was issued for the maximum total exposed surface area in the pit of 6.28 acres, 8.8 acre -feet of water lost with the mined aggregate and 3 acre -feet of