Laserfiche WebLink
Sclont.Me Evaluation of R10109picnl Qpinlans; on rndan@crcd and Thm=ncd rlchoa In the iclamsth Rivor MIa : interim Rcport (2002) <br />hRp: thoay. �a�. cd�7/ nNnnnnrJUUr) pty37A��lumlrl nEtat. c° tENDANGERED ANn 'THREA- MNEDFISFIFSIN THE KLAMA"[H BIM 13ASIN <br />they are high. As a result, mixing as a cause of water quality conditions loading to <br />mortality cannot be interpreted at this time its terms of lake level. <br />While there is no clear evidence, despite a monitoring record of substantial length, <br />for connection between lake levels and the welfare of the two surlier species in Upper <br />Klamath Lake, lake levels cannot be reduced below those observed in the last ten years <br />without risk of the occurrence of adverse events that are not described in the detailed <br />monitoring record (1990 - present; analyses complete through 1995). A negative <br />association between welfare of the species and lake level could emerge if lake levels are <br />reduced below those of recent historical experience_ The absence of any presently <br />evident empirical connection between the observed lake levels and the welfare of the <br />endangered suckers cannot be taken as justification for continuous or frequent operation <br />of the lake at the lowest possible levels, given that the effects of operating the lake at <br />lower levels arc undocumented. Thus, while the observational record contradicts <br />important underlying assumptions of the RPA, it does not provide an endorsement for the <br />lake levels proposed in the USBR biological assessment, which if implemented could <br />take interannual mean lake levels well below those of recent historical observation. <br />Potential benefits of higher lake levels in Clear Lake, Gerber Reservoir, and Tule <br />Lake sump are more difficult to evaluate because the record of analysis and observation <br />for these water bodies is not so extensive as it is for Upper Klamath Lake. These lakes <br />have not suffered notable mass mortality in association with low lake levels, but Clear <br />Lake populations showed poor body condition following severe drawdown in the early <br />1990s, The USFWS gives reasonable support for lake levels in Clear Lake no lower than <br />the recent drought - related minimum (1992 -1993: 4519 feet). The RPA reasonably adds a <br />margin of two feet (4521) to allow for water loss in the absence of withdrawals under <br />drought conditions. <br />16 <br />9BB -d BE0 /6ZOA 9EZ -1 89SE99BEOE sannosm innIVN 100 -woad Ev:[[ ZOOZ- 80 -93d <br />