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Peter Foster and Jonah Howe, Wright Water Engineers Page 6 of 14 <br /> Re: Gunnison West Gravel Pit SWSP <br /> December 8, 2025 <br /> The gravel mining operations at Gunnison West Pit have resulted in the dry-up of 30.9 acres <br /> of the mining property outside of the pit ponds, as shown on attached Figure 2. Applying the <br /> adjusted HCU value of 1.5 acre-feet/acre to this area produces an HCU credit of 45.6 <br /> acre-feet/year, which exceeds the estimated depletions of the gravel pit operations of 21.7 <br /> acre-feet/year during the term of this SWSR <br /> Call Analysis and Return Flows <br /> The only major water right in the vicinity of Gunnison West is the Gunnison River Whitewater <br /> 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 <br /> water rights downstream of the Gunnison West operation are the Gunnison Tunnel and the <br /> Redlands Power Canal. In 2002 the Gunnison Tunnel placed a call from July 7 to September <br /> 19 and from September 25 to September 27. The Redlands Canal has not historically placed a <br /> call, but could potentially place a call when stream flows are not adequate to meet their <br /> water rights. The Seventy-Five Ditch, Priority No. 1 water right is senior to both Gunnison <br /> Tunnel and Redlands Canal water rights. The Applicant asserts, per discussion with Division 4 <br /> Engineer Bob Hurford, that the historical call period on the Gunnison River should be <br /> expanded by adding December through April to the presumed call period of July through <br /> September. Adding April introduces the expectation of adding depletions. A potential call <br /> scenario is shown in column 7 of attached Table 3, indicating that out-of-priority depletions <br /> will be replaced with the exception of April. <br /> If a call is placed in April, and historical consumptive use credits are not available to replace <br /> all depletions, additional replacement water will have to be obtained from Blue Mesa <br /> Reservoir. 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 the <br /> Gunnison River for power and upper Colorado River storage purposes. <br /> The operation of the Blue Mesa Reservoir typically determines the downstream call regime; <br /> therefore, the timing of lagged depletions and return flows is not necessary to consider in <br />