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<br />"Fishery surveys indicate that the stream environment is presently in stable condition, and <br />supports a self-sustaining brook trout fishery. Channel stability, bank stability, and water quality <br />are good for salmonids. However, limiting factors in this reach include a limited supply of <br />spawning substrates and pools, along with occasional low flows and high stream temperatures. <br />Accordingly, it is important to provide stream flows that protect the limited amount of available <br />habitat if the continued existence of the fishery is to be assured" (See BLM Fish Survey in <br />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, three data sets were collected with the results shown in Table 1 <br />below. 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 />Party Date Q 250%-40% Summer (3/3) Winter (2/3) <br />BLM 6/24/1997 8.57 22.3 - 3.6 1.9(1) 1.2(1) <br />BLM 10/15/2004 1.00 0.4 - 2.5 2.4 1.30 <br />BLM 10/15/2004 1.05 0.4 - 2.6 ? 0.7 <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 />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 2.4 cfs (See Table 1). The winter flow recommendation, which meets <br />2 of 3 criteria and is within the accuracy range of the R2CROSS model, is 1.0 cfs if the two <br />wiihill-l"Ungt: n::suiis an:: avtaagt:u (St:t: Tabit: 1). Ii is UUl" ut:iit:[ ihai n::cuIIuIlt:lluaiiulls ihai [ail <br /> <br />- 3 - <br />