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<br />downstream of dams should be kept below a rate of 100 F per day. Where possible, the <br />bottom releases would be adjusted during spills to acclimate the fish to temperature <br />change. It is easier for trout to acclimate to temperature increases than to temperature <br />decreases. <br /> <br />Target: The target stream temperature for dam discharge while spilling is 50 to 600P <br />from June 1 through September 30 with a desired maximum of 650F. The target for <br />temperature fluctuations while spilling is less than 100 F per day. However, this will <br />demand the development of new operational guidelines which will take some time to <br />perfect. <br /> <br />~ Spinney Mountain Reservoir <br /> <br />The opportunities for temperature management at Spinney Mountain Reservoir are very <br />limited. The dam does not have a multi-level outlet structure that would permit releases <br />from a variety of elevations. The reservoir typically spills only in wet years, so blending <br />releases from the spillway and outlet works is not feasible. For reasons of dam safety as <br />well as water rights accounting, Aurora prefers to make releases through the outlet works <br />rather than over the spillway when the reservoir is fult <br /> <br />~ Eleven Mile Reservoir <br /> <br />Background: Eleven Mile Reservoir is typically kept full and spills water over the <br />spillway. Relatively warm surface water spilling from Eleven Mile Reservoir during the <br />summer can result in warmer discharge temperatures than are desirable for rainbow and <br />brown trout. Ideal operation for trout habitat would be continuous bottom releases from <br />the dam~ Since Eleven Mile is a drought reserve, the reservoir is typically full and <br />spilling which results in storage of over 5,000 acre-feet of additional supply in the <br />surcharge pool. The surcharge pool is important reservoir storage. <br /> <br />In 1988 and 1989, water temperature was measured directly below Eleven Mile Reservoir <br />dam (Station 1), at the mouth of Eleven Mile Canyon (Station 2), and at the Happy <br />Meadows campground area (Station 3). The water temperature exceeded 600 F from <br />June 24 through September 9 at Station 1; from June 6 through August 26 at Station 2; <br />and from June 6 through August 26 at Station 3 in 1988~ <br /> <br />Tasks: Within 5 years of acceptance of this Plan by the Forest Service, Denver Water <br />will install new outlet valves using stream temperature and minimum fish flow release <br />criteria in the design of the valves. The existing outlet valves do not allow for sustained <br />releases below approximately 100 cfs and cannot be used for temperature modification. <br />Denver Water will also install temperature gages in the spillway and outflow gage. If <br />possible, CDOW or USFS will install a temperature monitoring device about halfway <br />down Eleven Mile Canyon. <br /> <br />N :\Supply\ Waage\wildscen\attachb.doc <br /> <br />B-II <br />