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3.1.3 McKay Ditch The analysis of historic irrigation practices at MCR indicates that approximately 90 acres were irrigated by the McKay Ditch (see Figure A-4). As of the end of 2016, all of the 90 acres have been removed from irrigation due to gravel mining operations. The irrigation records show that, on average, 1,404 AF were diverted through the McKay Ditch during the period 1964 through 2009. The average annual diversion amount corresponding to the dry years of 1977 and 1994 equals 1,366 AF. Diversion records were adjusted so they would not exceed the decreed amount of 18.67 cfs; the adjusted diversions were then utilized as input data for the Soil Moisture Budget Model. The analysis of active call records shows that, on average, the McKay Ditch would be out-of-priority 6 days in May, 1 day in June, 5 days in July, 15 days in August, 20 days in September, and 20 days in October. Moreover, of the 1987-2010 period, only in 1994 was the South Rock Creek Ditch called out during the entire month of July. Therefore, for purposes of this study, it was conservatively assumed that the McKay Ditch would be out-of-priority beginning July 1st of each year. The Soil Moisture Model calculated that the historic irrigation C.U. for the McKay Ditch averaged 0.67 AF/acre over the 45-year study period, while the C.U. corresponding to the dry year equals 0.79 AF/acre. For this SWSP, the study period average of 0.67 AF/acre was selected (see Table 10, below). Table 10 Soil Moisture Budget Model- McKay Ditch Study Adjusted Conveyance Field Irrigation Irrigation Period Diversions Loss Delivery C.U.Rate C.U. (AF) Average (AF/acre) (AF/acre) (AF/acre) (AF/acre) Jan 0.00 0.00 0.00 0.00 0.00 Feb 0.00 0.00 0.00 0.00 0.00 Mar 0.00 0.00 0.00 0.00 0.00 Apr 0.00 0.00 0.00 0.00 0.11 May 0.57 0.06 0.52 0.13 12.08 Jun 5.77 0.58 519 0.53 47.76 Jul 0.00 0.00 0.00 0.00 0.00 Aug 0.00 0.00 0.00 0.00 0.00 Sep 0.00 0.00 0.00 0.00 0.00 Oct 0.00 0.00 0.00 0.00 0.00 Nov 0.00 0.00 0.00 0.00 0.00 Dec 0.00 0.00 0.00 0.00 0.00 Annual 6.34 0.63 5.71 0.67 59.95 Note: For purposes of this study, it was assumed that the McKay Ditch is out-of-priority beginning July 1st 3.1.4 Dry-Up Summary In total, 162 acres of historically irrigated fields have been removed from irrigation as a consequence of gravel mining operations within MCR.The irrigation consumptive use credits resulting from the dry-up totals 126.8 AF per year. It is important to note that MCR continues to divert water in-priority through the Famine 12 ::::;RESOURCE