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<br />Biological Data <br /> <br />The BLM has conducted field surveys of the fishery resources on this stream and have found a <br />natural environment that can be preserved. As reported in the letter from BLM to the CWCB for <br />the upper reach, "Fishery surveys indicate that the stream environment is presently in stable <br />condition, and supports a self-sustaining rainbow trout fishery. Channel stability, bank stability, <br />and substrate is good for salmonids. However, this stream has a wide, typically shallow channel <br />that limits the amount of physical habitat available. In addition, low flows make it difficult for <br />fish to pass between pools if depth is not sufficient. Accordingly, it is important to provide <br />stream flows that protect the limited amount of available habitat if the continued existence of the <br />fishery is to be assured." As reported in the letter from BLM to CWCB for the lower reach, <br />"Fishery surveys indicate that this stream segment provides important important spawning <br />habitat during snowmelt runoff for flannelmouth sucker and blue head sucker, which are sensitive <br />species in decline. BLM is working to keep these species off the list of threatened and <br />endangered species by protecting suitable habitat. During the remainder of the year, this stream <br />segment provides habitat for speckled dace and migrant rainbow trout. (See BLM and other fish <br />surveys in Appendix B). <br /> <br />Field Survey Data <br /> <br />BLM staff used the R2Cross methodology to quantify the amount of water required to preserve <br />the natural environment to a reasonable degree. The R2Cross method requires that stream <br />discharge and channel profile data be collected in a rime stream habitat type. Rimes are most <br />easily visualized, as the stream habitat types that would dry up first should streamflow cease. <br />This type of hydraulic data collection consists of setting up a transect, surveying the stream <br />channel geometry, and measuring the stream discharge. Appendix B contains copies of field <br />data collected for this proposed segment. <br /> <br />Biological Flow Recommendation <br /> <br />The CWCB staff relied upon the biological expertise of the cooperating agencies to interpret <br />output from the R2Cross data collected to develop the initial, biologic instream flow <br />recommendation. This initial recommendation is designed to address the unique biologic <br />requirements of each stream without regard to water availability. Three instream flow hydraulic <br />parameters, average depth, percent wetted perimeter, and average velocity are used to develop <br />biologic instream flow recommendations. The CDOW has determined that maintaining these <br />three hydraulic parameters at adequate levels across rime habitat types, aquatic habitat in pools <br />and runs will also be maintained for most life stages of fish and aquatic invertebrates (Nehring <br />1979; Espegren 1996). <br /> <br />For these two stream segments, data sets were collected with the results shown in Table 1 and <br />Table 2 below. Tables I & 2 show who collected the data (Party), the date the data was collected <br />(Date), the measured discharge at the time of the survey (Q), the accuracy range of the predicted <br />flows based on Manning's Equation (240% and 40% of Q), the summer flow recommendation <br />based on meeting 3 of 3 hydraulic criteria and the winter flow recommendation based upon 2 of <br />3 hydraulic criteria. <br /> <br />-4- <br />