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<br />Operations: Denver Water commits to release a minimum of 35 cfs August through <br />March and 40 cfs April through July or the computed inflow, whichever is less42 Denver <br />Water expects releases in April through July to stay above 50 cfs the majority of the time+ <br />Denver Water will strive to keep releases above 50 cfs (optimum) in August through <br />March and above 100 cfs (optimum) in April through July, realizing this will not always <br />be achieved4 <br /> <br />Storage releases may be made to meet the desired 35 and 40 cfs minimums, provided the <br />water can be recaptured without loss in Denver Water's downstream facilities, the <br />resulting lost storage in Cheesman can be recovered in the next runoff, and there is no <br />impairment of water rightS4 Future improvements (in~stream habitat structures and <br />modification or reducing width..to-depth ratios in areas that are currently wide and <br />shallow) in stream geometry and habitat may allow for lower minimum in-streamflows to <br />maintain or enhance trout population dynamics and structure. <br /> <br />b. Limit Streamflow Fluctuations <br /> <br />Providing stable streamflows is an important tool for enhancing fisheries4 Steady <br />transitions from low streamflow to high streamflow, and vice versa, allow fish time to <br />move into new habitats as water levels change4 Ideally streamflows would be adjusted to <br />match the life stages of trout as described in the next section4 Yet streamflow stability <br />must be placed in the context of many considerations for the South Platte River. Some of <br />these considerations include: <br /> <br />· ideal streamflow for rainbow and brown trout can be very different from natural <br />South Platte streamflow; <br />. native South Platte streamflows alternate between high snowmelt runoff and low <br />winter baseflow; and <br />. metro Denver's water use fluctuates from day to day and hour to hour as temperature, <br />cloud cover, precipitation~ humidity, and other conditions affect the level of use; and <br />. the unpredictability of streamflows is exacerbated by the ability of downstream senior <br />water users to ucalllt water past the upstream facilities at times that mayor may not <br />coincide with Denver area water use or weather patterns in the upper reaches of the <br />South Platte basin; and <br />. there is no substantial storage to act as a buffer between Denver Water's supply <br />(Cheesman) and customer water use downstream. The operating range of Denver's <br />terminal reservoir (Strontia) provides a space of only 2,000 acre-feet <br /> <br />Target: See optimum flow ranges in Table 2. <br /> <br />Operations: Denver Water commits to the guidelines in Table 3 for staging of outflow <br />changes (bottom releases) at Eleven Mile and Cheesman reservoirs. During emergencies, <br /> <br />2 Computed inflow is reservoir inflow minus reservoir evaporation4 Computed inflow:::: <br />change in storage + OUtflOW4 <br /> <br />N :\Supply\ W aage\wiIdscen\aUachb.doc <br /> <br />8-9 <br />