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Mr. Peter Foster, P.E. Page 3 <br />June 28, 2012 <br />Replacement <br />The proposed source of replacement water for this pit during the irrigation season (April <br />through October) is a portion of the Applicant's interests in the Seventy -Five Ditch. The Seventy - <br />Five Ditch diverts water from Gunnison River and it was decreed in CA1325 (Priority No. 1) for <br />14 cubic feet per second ( "cfs "), to irrigate 560 acres, providing a duty of water of 1 cfs per 40 <br />acres of land. United owns 31 percent of the senior water right in the Seventy -Five Ditch or 4.33 <br />cfs which is proposed to be used as a replacement water source in this plan. Based on United's <br />pro -rata ownership of the Seventy -Five Ditch, the 4.33 cfs could irrigate up to 173.3 acres. The <br />State Consumptive Use model with the Upper Gunnison High Elevation Calibration Coefficient <br />was used to determine the historical consumptive use for lands irrigated under the Seventy -Five <br />Ditch, Priority No. 1. In addition based on the decreed duty of water of 1 cfs per 40 acres of land <br />you determined the historical consumptive use for the lands under the Seventy -Five Ditch as 1.7 <br />acre -feet per irrigated acre (Table 3A). Based on the average depth to groundwater of <br />approximately 5 feet below ground surface, the historical consumptive use for subirrigation was <br />reduced by 15 percent, resulting in an adjusted historical consumptive use value of 1.5 acre -feet <br />per acre. For the purpose of this plan, United plans to dry-up 3.0 acres which will create a credit <br />of 4.42 acre -feet. <br />The only major water right in the vicinity of Gunnison West is the Gunnison River <br />Whitewater Course. The Gunnison West irrigated lands and associated return flows are located <br />downstream of this Recreational In- Channel Diversion water right. The historical calling water <br />rights downstream of the Gunnison West operation are the Gunnison Tunnel and the Redlands <br />Power Canal. In 2002 the Gunnison Tunnel placed a call from July 7 to September 19 and from <br />September 25 to September 27. The Redlands Canal has not historically placed a call, but could <br />potentially place a call when stream flows are not adequate to meet their water rights. The <br />Seventy -Five Ditch, Priority No. 1 water right is senior to both Gunnison Tunnel and Redlands <br />Canal water rights. The Applicant asserts, per their discussion with Division 4 Engineer Bob <br />Hurford, that the historical call period on the Gunnison River is limited to the period from July <br />through September, during which the historical consumptive use credit exceeds depletions to <br />the river. April and October are the only months in which plan depletions would not be exceeded <br />by historical consumptive use, but with no call on the river, no water will be owed during those <br />months. <br />Blue Mesa Reservoir is located immediately downstream of the Gunnison West <br />operation, with a decreed capacity of 1,064,744 acre -feet, and provides releases to Gunnison <br />River for power and upper Colorado River storage purposes. The operation of the Blue Mesa <br />Reservoir typically determines the downstream call regime, therefore the timing of return flows is <br />not necessary to consider in this plan. This is because the timing of return flows will be offset by <br />storage and operation of the Blue Mesa Reservoir, which does not require lagging of return flows <br />to the river to avoid injury. <br />Conditions of Approval <br />I hereby approve the proposed substitute water supply plan in accordance with §37 -90- <br />137(11), C.R.S., subject to the following conditions: <br />1. This SWSP shall be valid for the period of January 1, 2012 through December 31, 2013, <br />unless otherwise revoked, modified, or superseded by decree. If this plan will not be <br />made absolute by a water court action by the plan's expiration date, a renewal request <br />