Laserfiche WebLink
Mr. Jeff Deatherage <br />March 2011 <br />Page 2 <br />Depletions that occur due to evaporation at the Colona Pit have a lagged effect on the <br />Uncompahgre River. WWE used the Glover Stream Depletion Method to determine the lagged <br />effect, assuming that the depletion rate from the river has reached a steady state. The lagged <br />depletions are shown in Table 2, Column 1. <br />WATER SUPPLY AND REPLACEMENT SOURCES <br />Historical Consumptive Use Credits <br />United owns 2.5 shares in the Ouray Ditch, which were previously used for the irrigation of 29.2 <br />acres. A historical consumptive use (HCU) analysis was performed and included in the previous <br />renewal letter. The HCU credits total 49.1 AF per year. <br />Historical Return Flows <br />WWE calculated the return flows associated with the historically irrigated area. The return flows <br />are assumed to have returned equally as one-half surface water and one-half ground water. <br />Surface returns are assumed to accrue back to the river in the same month. The groundwater <br />returns were lagged from the centroid of the historically irrigated area to the Uncompaghre River <br />using the Glover Equation and equal 110.3 AF/yr. (Table 2, Column 2). The combined total of <br />the lagged historical return flow pattern and evaporative depletions total 121.6 AF (Table 2, <br />Column 3). <br />WATER REPLACEMENT PLAN IF OPERATIONS CEASE <br />To offset depletions from evaporation and meet historical return flow obligations, United <br />proposes the following plan. The Ouray Ditch will continue to divert United's share of HCU <br />credits, ditch loss (10 percent of diversions), and groundwater return flows (see Table 3). Except <br />for the ditch loss, the water would be delivered to the pit and lagged from the centroid of the pit <br />to the river. Table 2, Column 7 shows the difference between the total obligation to the river <br />(Table 2, Column 3) and the total lagged replacement supply available (Table 2, Column 6). <br />Based on our analysis, United has sufficient dry-up credits and lagged return flows from the pit to <br />meet their obligations to the Uncompaghre River. <br />,.y.::.-,os -u, •.x?a;Y?.,i.„ "?:?, .? ..- .w•u.-:?r.?aai?•. ,?„?.:?_ ?:.. z:.?ti?di?-?s-u_.. ?-s.f?', ??wc--'O?? F