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1578 2. Turquoise Reservoir, Twin Lakes. and Clear Creek Reservoir Water Level Preferences The various resource values have similar Water level needs at Turquoise Reservoir and Twin Lakes. A.1I resources are benefitted by maintaining full reservoirs as much of ,he rime as possible. and with as little Water levd Huctuation as possible. However, resource maIlagers recognize rhar reser~ voir operations must com:inue in order to make water deliveries [Q water users. With this in mind. resource values are best suppon:ed when the: reser- voirs are kepr as full as possible during May. when the vegetation growing se::lSon begins and when water temperatures become warm enough to sup~ pOrt significanr biological acrivity among fish popularions. Once the reservoirs are full at the end of spring runoff (typicallv around July! 5) resource values are best supported if reservoirs are nor drawn down by more than 10 feer between the fill dare and Ocwber 1. Drawdowns of more than 10 feet reduce rhe primary productivity (basic food pro- ducrion) of the reservoirs, and reduce ,he area of feeding habitat for tish. In addition, drawdowns of more rhan 10 feer affect the scenic quality of the lakes for recreation use. and can make some boat ramps unusable. Gradual drafting during the Ocwber - March period is prderred over drafting from July through Seprember. Drafting during rhe Julv-Seprember period can have negarive impacts on fish population producrivity, while Ocwber- March drafting avoids these impacts. Clear Creek Reservoir supporrs a good quality, diverse fish community, because reservoir water levels are fairly srable throughour the growing sea- son, and because me reservoir ropographv pro- vides an extensive shallow littoral zone. Srable reservoir levels. good access, scenic qualiey, and a high quality fishety also make Clear Creek Reservoir an attractive location for angling md boating. However. even small variations in reser- voir levels can crC::lte signitlcmt changes in bank exposure because of rhe shallow areas near the edges of the reservoir. Division ofWildlite recent- ly consrructed a boar ramp exrension ro address this prob~em. All resources at this reservoir are best supporced by a coneinuarion of rhe currene operacion pattern, which minimizes Water level fluctuations during the growing season. Please see the charrs on the following page for an overview of warer level needs at Twin Lakes and Turquoise Reservoir. No chart is preseneed for Clear Creek Reservoir because typically there is not a significant fluctuation of water levels at that reservOlr. 3. Pueblo Reservoir Water Level Preferences Operations to satisfy water storage and w:uer delivery needs are significantly different at Pueblo Reservoir than at Twin Lakes and Turquoise Reservoir. Insread of lowest reservoir levels in late wineer and peak reservoir levels in July, Pueblo Reservoir rypically reaches its lowest elevation in early November and its mil.."(imum elevation on approximately April \5. From April 15 ro late Ocrober, the reservait is gradually drafted. Recognition of these operational par::unerers. along with a longer growing se:.1Son and year- round recreational use, produce different water level needs at Pueblo Reservoir. A.s a result, regardless of what plan of operations is imple- men[ed for Pueblo Reservoir, warer level needs for various resources values will be in conflicc during significant portions of the year. November - Mid-Aptil Boaring and angling use are low during [his period, and rhe riparian com- munity is largely dormant. While ,he best water levels tor rhe warm Water fishery would be full as possible during this period, the fishety can survive if there is a sufficient pool of water during ,he fall and filling occurs during the wimer. Mid-April- October (Growing Season) Warer level needs are in conflict during rhis period. The optimal warer levels co suPPOrt boating would be a full re.servoir all season, but this contlicrs with operational demands on the reservoir. W,ldlite and riparian needs are best supported by a full reservoir on l\'ray 15, with sligh[ drawdown scarc- ing any time between Mav 15 and Julv 15. A slight drawdawn allows rhe roo ring zones of ripar- ian plants [Q remain in concact wich groundwater levels, but allows exposure of the some teservair substrare [Q grow mnual vegetarion species. The 26