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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 presently in stable condition, and <br />supports a self-sustaining brook trout and white head sucker fishery. In the portions of the <br />reaches managed by BLM, the stream provides good food supplies, pools, channel stability, bank <br />stability, and substrate for salmonids. However, the fishery is limited by a lack of cover, <br />occasional high water temperatures, and by bank erosion and silt in some locations. Late <br />summer and fall flows are adequate to support fisheries, but further diversion could endanger the <br />fish population" (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 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 each of these segments of stream, two data sets were collected with the results shown in <br />Table 1 below. Table 1 shows 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 />T bl 1 D <br /> <br />u <br /> <br />R h <br /> <br />a e ata - Jpper eac <br /> Party Date Q 250%-40% Summer (3/3) Winter (2/3) <br /> BLM 4/29/1997 3.28 8.4 - 1.3 2.5 1.0\') <br /> BLM 9/19/2001 0.7 0.3 - 1.8 1.2 1.1 <br /> BLM 9/19/2001 0.57 0.2 - 1.4 2.2 1.0 <br /> <br />ELM = Bureau of Land Management DOW = DlvlslOn ofWlldltfe <br />(1) Predicted flow outside of the accuracy range of Manning's Equation. ? = Criteria never met in R2CROSS Staging Table. <br /> <br />-4- <br />