Opinion ID: 2543527
Heading Depth: 2
Heading Rank: 3

Heading: the percentage of priority 12 water golden may apply to lawn irrigation under the 60s decrees

Text: Golden did not then, and does not now, identify any one of its water rights for any particular use within the Golden municipal water system. Therefore, Wheeler assumed that the percentage of Priority 12 water applied to lawn irrigation would be the same as the percentage of Golden's total water usage that was applied to lawn irrigation. This assumption allowed Wheeler to predict the percentage of Priority 12 water that would be applied to lawn irrigation from the actual historic use of Golden's water supply in 1956. In 1956, Golden used a total of 1372.8 acre-feet of water. Wheeler assumed that all the water used during the non-irrigation season, November through April, was used for household purposes. From this six-month amount, Wheeler then extrapolated the in-house use for the entire year. By subtracting the total in-house use from the total annual use, Wheeler derived the amount of water Golden applied to lawn irrigation during the six-month irrigation season in 1956. That amount was 491.4 acre-feet. 491.4 acre-feet is 36% of Golden's total annual water usage in 1956 of 1372.8 acre-feet. Thus, Wheeler testified that assuming Priority 12 water was diverted 365 days a year, 36% would be used for lawn irrigation. 491.4 acre-feet is 53% of the 932.1 acre-feet of water Golden used during the six-month irrigation season in 1956. Thus, Wheeler testified that assuming Priority 12 water was diverted continuously during the irrigation season, approximately 50% would be used for lawn irrigation. Wheeler explained that to calculate the percentage of Priority 12 water that would be applied to lawn irrigation during the irrigation season, we assume that the 2.86 [14] would be used 100 percent of the time if transferred. Then we went through and took actual requirements per month to be equivalent to the 2.86, and that was distributed between the domestic supply, purely domestic supply or household supply, and the irrigation supply. Accordingly, the water court's conclusion that the testimony of W.W. Wheeler in the 1959 change proceeding established that Golden could only apply 36%, or 611 acre-feet, [15] of the water it is entitled to divert during the irrigation season to lawn irrigation is erroneous. Wheeler's testimony that, based on Golden's pattern of municipal use in 1956, 36% of the Priority 12 water transferred would be applied to lawn irrigation assumed that Golden would divert Priority 12 water continuously 365 days a year. The water court's calculation fails to account for this assumption. The 36% to which Wheeler referred in his testimony is only relevant if Golden is diverting Priority 12 water continuously throughout the year [16] ; this is not the case. Golden only diverts Priority 12 water during the irrigation season, and Wheeler's calculations and testimony make clear that he concluded Golden can divert 4.66 c.f.s. of Priority 12 water continuously from May through October and apply 53% of that water to lawn irrigation without injuring junior appropriators. Thus, Golden may apply up to 53% or 900 acre-feet of the water it is entitled to divert from May 1st through October 31st to lawn irrigation. [17] We now consider whether Golden has exceeded this limit. The water court found that the best evidence of the actual percentage of Priority 12 diversions applied to lawn irrigation is set forth in the affidavit of Golden's water expert Gary Thompson. We do not disturb this factual determination as it required the water court to assess the credibility of competing evidence presented by the parties. Farmers Reservoir & Irrigation Co., 33 P.3d at 812; see also City of Thornton v. Bijou Irrigation Co., 926 P.2d at 88. To calculate the percentage of Golden's water supply that is used for lawn irrigation, Thompson relied on the monthly water use data contained in Exhibit G 155 and the method described in Golden's augmentation plan (Case No. 83CW361). According to the water court, Thompson assumed that the average diversions for the months of December-February were applied to in-house use, only. He subtracted this monthly average from Golden's total monthly diversions for each month of the period, May through October.... The resulting differences are the volumes of water applied each to lawn irrigation and other outside uses. Dividing these differences by the total diversions, and multiplying by 100 yields the percentage of total diversions that were applied to outside use. [18] Petitioners claim that in 1994 Golden enlarged its use of Priority 12 water by applying more Priority 12 water to lawn irrigation than Wheeler anticipated. We therefore apply Thompson's methodology as described by the water court to determine whether Golden applied more than 900 acre-feet of Priority 12 water to lawn irrigation in 1994. Golden used 2719.4 acre-feet of water during the irrigation season in 1994. Of this, according to Thompson's methodology, 55%, or 1500 acre-feet, was applied to lawn irrigation. [19] Because Golden does not identify any one of its water rights for any particular use within the Golden municipal water system, we assume that an equal percentage of the Priority 12 water diverted during the 1994 irrigation season was applied to lawn irrigation. [20] Thus, Golden applied 55% of the Priority 12 water it diverted during the 1994 irrigation season to lawn irrigation. However, the water court found that Golden only diverted 866 acre-feet of Priority 12 water in 1994 just over half of its entitlement. [21] Accordingly, Golden only applied 476 acre-feet (.55 × 866) of Priority 12 water to lawn irrigation in 1994, only about 28% of the 1698 acre-feet it is entitled to divert and 424 acre-feet less than the 900 acre-feet (.55 × 1698) it is entitled to apply to lawn irrigation in any given year. Therefore, Golden did not expand its use of Priority 12 water in 1994 by applying a greater amount than Wheeler anticipated to lawn irrigation.