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<br />~ Eleven Mile Reservoir <br /> <br />Background: Low streamflows (particularly less than 20 cfs) drastically reduce habitat <br />for all trout life stages in the reach from Eleven Mile canyon downstream through Happy <br />Meadow campground. Maintaining adequate winter streamflow for adults is a priority for <br />fisheries. Eleven Mile is normally full and bypassing the inflow~ <br /> <br />Target: The minimum requested by the CDOW for Eleven Mile Reservoir outflow is <br />20 efs with an optimum range of 50 to 100 efs (see Table 2)~ <br /> <br />Operations: Denver Water commits to release a minimum outflow of 32 cfs or the 7-day <br />running average of computed inflow) whichever is less" 1 Using a 7-day running average <br />will help to reduce fluctuations in streamflows. <br /> <br />If computed inflow is less than 32 cfs, then a bottom release may be made to meet the <br />desired 32 cfs outflow. Bottom releases will be made provided they can be recaptured <br />without loss in Denver Water's downstream facilities, the resulting lost storage in Eleven <br />Mile can be recovered in the next runoff, and there is no impairment of water rights~ <br />Bottom releases will not be made if it would cause the reservoir to stop spilling4 Starting <br />no later than May 1, bottom releases will be discontinued to allow the surcharge pool to <br />fill and complete the cycle. However, while the surcharge pool is being filled the <br />minimum streamflow will be maintained as described in this Plan. The limited volume of <br />water available for supplemental bottom releases will first go towards maintaining <br />minimum streamflows and be used secondarily for temperature moderation4 <br /> <br />Future improvements (in-stream habitat structures and modification or reducing width...to- <br />depth ratios in areas that are currently wide and shallow) in stream geometry and habitat <br />may allow for lower minimum streamflows to maintain or enhance trout population <br />dynamics and structure~ <br /> <br />~ Cheesman Reservoir <br /> <br />Background. Releases from Cheesman Reservoir have been managed in more recent <br />years such that winter streamflows are not a limiting factor for trout popu]ations~ Winter <br />streamflows (November through March) below Cheesman have averaged 98 cfs in the <br />1985 - 1996 period, but 9% of that time the streamflow was less than 40 cfs~ <br /> <br />Target: The minimum release desired is 35 cfs Augu~t through March with the optimum <br />range of 50 to 150 cfs. For the period April through July the minimum desired release is <br />40 cfs with the optimum range of 100 to 225 cfs. <br /> <br />] Computed inflow is reservoir inflow minus reservoir evaporation. Computed inflow = <br />change in storage + outflow ~ <br /> <br />N;\Supply\ Waage\wildscen\attachb.doc <br /> <br />B-g <br />