2015-07-09_HYDROLOGY - M1977439 - Laserfiche WebLink

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Upper Poudre Combined SWSP Page 5 of 11 June 26, 2015 This SWSP relies on a quantification of average historical farm headgate delivery, consumptive use, and associated return flow approved in previous SWSPs based on an analysis for 5.75 shares that was performed for Lafarge West, Inc. by the Applegate Group, Inc. The 5.75 shares were determined to have been used to irrigate a total of 104.5 acres. The historic average farm headgate delivery was determined to be 41.79 acre-feet per share (2.30 acre-feet per irrigated acre). The historic consumptive use was determined to be 21.36 acre-feet per share (1.17 acre-feet per acre). For 2015, the Applicant proposes to dry -up, or to irrigate exclusively with non -Taylor ft Gill Ditch water, a total of at least 239.5 acres associated with the subject 13.175 shares. The location of the lands to be dried up for the 2015 irrigation season is shown on the attached Figure 2. The dry -up will provide a total of 550.63 acre-feet of farm headgate delivery or 295.84 acre-feet of consumptive use credit to be used for replacement of out -of -priority depletions under this SWSP. The maximum monthly and annual volumetric farm headgate diversion limits for the subject 13.175 shares, based on the average monthly and annual farm headgate deliveries determined for the 5.75 shares, are shown in Table D below. Table D - Maximum Volumetric Farm Headgate Diversion Limitations (acre-feet) Apr May Jun Jul Aug Sep Oct Annual 5.75 shares 2.94 41.78 53.79 56.73 48.88 31.47 4.73 240.31 Pro -rated for 13.175 shares 6.74 95.73 123.25 129.99 112.00 72.11 10.84 550.63 It is anticipated that 357.42 acre-feet of farm headgate delivery associated with the Taylor Et Gill Ditch shares will be delivered to the Upper Poudre Recharge Ponds (WDID 0302004) during the period of May through October. Daily deliveries of the shares will be measured and any excess deliveries will be sent directly back to the river without claiming augmentation credit. Excess water will be returned to the river via the Taylor Et Gill Wasteway, as described in more detail below. Evaporative losses from the water delivered to a series of three recharge ponds is estimated to total 6.84 acre-feet for this plan period, based on a maximum recharge pond surface area of 3.0 acres. The net recharge accretions were lagged to the river using the AWAS model with the following parameters: a distance (X) from the centroid of the exposed ground water surface to the river of 2,300 ft; a width (W) of the aquifer of 6,500 ft; a transmissivity (T) of 160,000 gpd/ft; and a specific yield (S) of 0.2. Taylor Et Gill Ditch shares have been diverted into the recharge ponds to produce accretions to the stream for replacement purposes for the subject sites under previous SWSPs since 2004. Lagged recharge accretions from past and projected (2015) deliveries are anticipated to total 297.10 acre-feet during this plan period. The return flow obligations associated with the use of the Taylor Et Gill Ditch shares will be calculated using the return flow factors shown in the attached Table 4, column E. Return flow obligations during the summer period of April to September will be calculated by multiplying the monthly delivery to recharge by its respective monthly factor. Obligations during winter months (October through March) will be calculated by multiplying the previous year's annual delivery to recharge (141.58 acre-feet for 2014) by its respective monthly factor. Any farm headgate delivery of the Taylor Et Gill Ditch shares made in October will be included in the October return flow requirement in addition to the amount calculated based on the monthly return flow factor. Return flow obligations will be calculated based on the actual timing of diversions. After accounting for return flow obligations, the Taylor Et Gill Ditch shares delivered to recharge are projected to generate a total of 138.02 acre- feet of available replacement water during this plan period. The remaining 193.21 acre-feet of farm headgate delivery associated with the Taylor Et Gill Ditch shares will be delivered directly to the Cache La Poudre River for replacement purposes during the period of April through August. Deliveries will be made at the Taylor Et Gill Wasteway located as shown in Figure 1. The wasteway is a headgate on the ditch that flows to an approximately 8.5 -acre pond.