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<br />.' <br /> <br />87 % of the reach is located on federal lands. <br /> <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 <br />"Fishery surveys indicate that the upper part of the reach supports a migratory trout fishery, <br />while the lower part of the reach supports speckled dace. The stream environment is presently in <br />stable condition and improving, but it has had a history of human-caused erosion. Evidence of <br />improvement includes establishment of vegetation on point bars and gradual narrowing of the <br />channel. Channel stability, substrate, and cover are suitable for the fish population. However, <br />food sources are limited because of erosion and the stream experiences high temperatures at low <br />flow. Accordingly, it is important to provide stream flows that flush the system of sediments <br />and keep stream temperatures down. (See BLM Fish Survey 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 this segment of stream, two data sets were collected with the results shown in Table I below. <br />Table I shows who collected the data (Party), the date the data was collected (Date), the <br />measured discharge at the time of the survey (Q), the accuracy range of the predicted flows <br />based on Manning's Equation (240% and 40% of Q), the summer flow recommendation based <br />on meeting 3 of 3 hydraulic criteria and the winter flow recommendation based upon 2 of 3 <br />hydraulic criteria. <br /> <br />Table I: Data <br /> <br />Party Date Q 250%-40% Summer (3/3) Winter (2/3) <br />BLM 06/03/2003 9.96 4.0 - 24.9 8.80 3.08(1) <br />BLM 06/0 1/2004 8.99 3,6 - 22.5 5.79 5.28 <br /> <br />- 3 - <br />