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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 <br />"Fishery surveys indicate that the stream environment is in good condition and supports a self- <br />sustaining rainbow trout and speckled dace fishery. Channel stability, bank stability, and water <br />quality are excellent for salmonids. However, limiting factors in this stream include a limited <br />supply of spawning substrates and occasionally high stream temperatures" (See BLM Fish <br />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 riffle stream habitat type. Riffles 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 riffle 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, 2 data sets were collected with the results shown in Table I below. <br />Table 1 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 1: Data <br /> <br />Part; Date Q 250%-40% Summer (3/3) Winter (2/3) <br />BLM 6/24/1997 7.60 19.3 - 3.1 8.4 1.0(1) <br />BLM 8/08/200 I 1.42 0.6 - 3.5 1.7 1.0 <br /> <br />BLM = Bureau of Land Management OOW = Division of Wildlife <br />(1) Predicted flow outside of the accuracy range of Manning's Equation. ? = Criteria never met in R2CROSS Staging Table. <br /> <br />Biologic Flow Recommendation <br />The summer flow recommendation, which meets 3 of 3 criteria and is within the accuracy range <br />of the R2CROSS model is 5.0 cfs (See Table I). This recommendation was developed by <br />averaging the results of two surveys that were within the confidence interval for the R2Cross <br />model. The winter flow recommendation, which meets 2 of 3 criteria and is within the accuracy <br /> <br />- 3 - <br />