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<br />Arkansas River Water Needs Assessment - Section 1. Executive Summary <br /> <br />Turquoise Reservoir and Twin Lakes <br /> <br />Turquoise Reservoir and Twin Lakes are primarily <br />managed for lake trout and rainbow trout. Both <br />reservoirs are oligotrophic, meaning that they are <br />low in plant nutrients and oxygen is typically <br />distributed evenly throughout the water body. <br />Lakes of this type are typically suited to salmonids, <br />which are oxygen sensitive. Primaty and secondary <br />production is relatively low in both lakes, trans- <br />lating into limited food supplies for fish species. <br />Highest production occurs in the warmer months <br />of July and August in the euphotic zone, where <br />there is sufficient penetration of sunlight into the <br />water column to support plant growth. Thermal <br />stratification at this time, coupled with major <br />adjustments in water levels, increases flushing of <br />nutrients from the reservoir. Maintaining lake <br />levels and controlling flushing rates is critical for <br />successful fishety management, particularly for lake <br />trout. To foster maximum biotic production in <br />these reservoirs and to protect and maximize littoral <br />habitat during the summer months, water surface <br />elevation should be held at some stable level. <br /> <br />Filling and maintaining water levels in Twin Lakes <br />and Turquoise Reservoirs as much as possible prior <br />to October 1 ensures inundation of shorelines, which <br />provide spawning habitat for lake trout adults. Lake <br />trout spawn during October and November in Twin <br />Lakes. Although frequently not possible, mainte- . <br />nance or continued filling during the winter ensures <br />eggs remain inundated until hatching and fty <br />emergence in February or March. Stable water levels <br />from March to June provide habitat for fty and <br />juveniles until they move to deeper water by June. <br />Adjustments to water levels from June to August of <br />more than 10 feet from full pool decrease primary <br />and secondary production. Maintaining stable water <br />levels from August to October lends stability to the <br />reservoir, further enhancing productivity. <br /> <br />Clear Creek Reservoir <br /> <br />Management for kokanee salmon and rainbow trout <br />are emphasized in Clear Creek Reservoir. Clear <br />Creek Reservoir is the most productive of the three <br />upper basin impoundments; however, it is still <br /> <br />considered oligotrophic. Clear Creek Reservoir does <br />not experience the daily adjustments to its water <br />level that Twin Lakes and Turquoise Reservoirs do. <br />As a result, Clear Creek Reservoir shows better <br />survival and growth rates, including overwintering, <br />of key species. Fish population needs are best met if <br />Clear Cteek Reservoir is maintained as full as <br />possible on a year-round basis. <br /> <br />PuebbJ Reservoir <br /> <br />Pueblo Reservoir is managed as a warm-, cool-, and <br />coldwater fishery. The coldwater fishety consists <br />mainly of tainbow trout maintained by annual <br />stocking. The warm- and coolwater fishery is <br />comprised primarily of black basses, crappie, <br />bluegill, walleye, wipers, and channel catfish. <br />Walleye, wipers, and channel catfish are stocked, <br />while bass and crappie are not. <br /> <br />At times, the fluctuation of water levels in Pueblo <br />Reservoir has been very severe. Major drawdowns <br />have dropped the water level up to 49 feet below <br />conservation pool. Depending on when these <br />occur, they can have a major effect on the produc- <br />tion of SpOrt and fotage fish. <br /> <br />Gradually filling Pueblo Reservoir from November <br />rhrough March allows for the inundation of vegeta- <br />tion and shoreline, which will provide food, covet, <br />and spawning areas in the spring. A full reservoir <br />from March to mid-July allows for good spawning <br />habitat, high plankton levels to feed fty, and cover <br />for adults, juveniles, and fty. Rapidly drawing the <br />reservoir down from mid-July to mid-August <br />exposes shoreline for recolonization of annual <br />(nonriparian) vegetation and concentrates forage <br />species for maximum utilization by sport species for <br />growth. Maintaining stable water levels from mid- <br />August to November lends stability to the reservoir, <br />further enhancing productivity. <br /> <br />Water Preferences for Terrestrial Wildlife <br /> <br />Arkansas River <br /> <br />The wildlife values associated with the Arkansas <br />River corridor and its riparian habitats, wetland <br /> <br />1-22 - Water Needed to Protect or Promote Critical Resource Values <br />