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<br />000810 <br /> <br />Cimarron DredJ:inJ: Environmental Assessment <br /> <br />The gravel bar deposited by the Cimarron River is not considered spawning habitat, primarily <br />because of large fluctuation in releases from Morrow Point Dam (between 0-5.000 cfs) and the <br />water is too cold for spawning. <br /> <br />Brown and rainbow trout may be affected by the proposed action if significant sediments are <br />transported and deposited in key spawning areas downstream of Crystal Reservoir during critical <br />time periods. This could result in eggs laid in redds (nests) being covered with fine silts and <br />depriving the eggs of oxygen. Large amounts of transported sediment could greatly reduce <br />rainbow and brown trout recruitment. <br /> <br />. <br /> <br />In addition. brown trout and rainbow trout are affected if flows in the Gunnison River are <br />lowered below 300 cfs. Crystal Reservoir will continue to operate as the regulating reservoir. <br />wirh releases being made based on projected hydrology. Therefore. flows in the Gunnison River <br />below Crystal will be unaffected by the proposed action. Releases from Morrow Point Dam will <br />continue to operate to produce peaking power; however, dredging activities will be limited to <br />periods when water is not being released from Morrow Point Dam. This should aid in limiting <br />the amount of sediments being transported in the Gunnison Ri ver. It is also anticipated that most <br />increases in suspended sediments as a result of the dredging activity would settle out in Crystal <br />Reservoir and not affecr the Gunnison River downstream. Water quality samples would be taken <br />daily during the dredging activity as described in the Water Quality section of this chapter to <br />monitor changes in water quality. <br /> <br />Dredging activities would be conducted after October 1 and completed no later than November <br />30 to avoid conflicts with CDOW's annual monitoring program. The CDOW would continue the <br />annual fall sampling of the Gunnison River and would be able to measure effects on brown and <br />rainbow trout recruitment. <br /> <br />To assist in dewatering the dredging site, Crystal Reservoir's water surface elevation would be <br />maintained at or below 6,743 feet. Except while releases are being made from Morrow Point <br />Dam during the project, the first 1.200 feet of the tailrace would be drained. CDOW does not <br />consider the tailrace suitable fish habitat because of the high flows released from Morrow Point <br />Dam (Hebein 2001). <br /> <br />Once the dredging is completed, the backwater pool created by the deposited material will no <br />longer exist. Water in the channel from the dam to the upper end of Crystal Reservoir would be <br />dependant on releases from Morrow Point Reservoir and the water surface elevation of Crystal <br />Reservoir. <br /> <br />Local wildlife may avoid the area during dredging activities; however effects are projected to be <br />short-term and the project would not alter existing wildlife habitat. <br /> <br />\3 <br />