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000157 , South Platte River Minimum flow recommendations for all life stages of brown trout are 50 cfs, while optimum flow recommendations for brown trout range from 50-150 cfs, depending upon the life stage. Minimum spawning, incubation, hatching, and adult flows for rainbow trout are 100cfs, while 50 cfs is the minimum flow recommendation for rainbow fry and juvenile life stages. Optimum flow recommendations for rainbow trout range from 50-225 cfs for,the various life stages. See Table 3 for details. , ~~intenance of reasonable minimum flows during the most vulnerable life stages (spawning, incubation, hatching, and fry) are of paramount importance in maintaining thriving rainbow and brown trout populations in the South Platte River below Cheesman Reservoir, which is owned and operated by the 'Denver ,Water Department (DWD) as part'of its water storage and supply system. However, maintenance of stable minimum flows for trout (or any other sort of recreation) has not been the hallmark of the DWD's flow management regime in the South Platte River. The DWD would like the environmental community, angling groups; and the ,Colorado Division of Wildlife to believe that their water management plan .and Cheesman Dam, in particular, are the primary reasons for the gold medal trout fishery that exists in Cheesman Canyon. However, nothing could be further from the truth. Rather, the catch-and-release regulation' implemented on the Cheesman Canyon section of the South Platte in 1976 is the primary reason for the development of the world-class trout fishery. Tanner (1954) found that the average size of rainbow and' brown trout caught in Cheesman Canyon was ll.9 inches and lO.4 inches, respectively. Anglers harvested an estimated 390 pounds of,trout per mile in a 90-day period, which is a harvest estimate of about 50 pounds/acre'in a 90-day period. Under the present catch-and- release regulation, the average size of rainbow trout in the populatiOn has been in the 13-14-inch range, while the browns average about 12 inches in the population. Total'estimated catch in 1954 from June, 15 through,September l5was 2,352 for 8,75l'hoursofangling effort. Thus, total catch-per-man-hour (CPMH) was 0.27.' A creel census in '. Cheesman, Canyon, for June-September 1986 (Nehring 1987) revealed 'anglers caught an estimated 39,900 trout while angling for 34,600 hours of effort ,for an average CPMH of 1.15. The operation of Cheesman Reservoir by the DWD has not changed measurably between the 1950's and 1980's, but the management of the Cheesman Canyon fishery has with the implementation of catch-and-release angling regulations in 1976. Anglers caught an estimated 46;600 trout 12 inches and larger and l2,700 trout l5'inches and larger in the Cheesman Canyon section of the South Platte River from May through September 1986 (Nehring 1987). In the eventuality that Two Forks or some alternative Two Forks is built, whatever portion of the South Platte below Cheesman Reservoir remains a free-flOwing stream should be protected with true minimum flow requirements that are adhered to by the DWD. Examination of the USGS discharge records reveal the way in which the DWD operates Cheesman Reservoir. Flows are operated totally towards maximization of the water yield and benefit of the DWD's water supply system. Winter flows regularly drop into the 20 cfs range, periodically to less than lO cfs. April spawning flows for rainbows often are as high as 300-400 cfs and then flows "'. I [W002394