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<br />land Status Review <br /> <br /> Total Length Land Ownership <br />Upper Terminus Lower Terminus (miles) % Private % Public <br />Unnamed Tributary Willow Creek 3.1 0% 100% <br />Willow Creek South Arkansas 1.6 43% 57% <br />River <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 stream environment is presently in stable condition, and <br />supports a self-sustaining brown trout fishery. Substrate and cover is good for salmonids. This <br />type of stream environment has steep gradients that typically limit the available pool habitat and <br />food supply. Accordingly, it is important to provide stream flows that protect the limited amount <br />of available habitat if the continued existence of the fishery is to be assured" (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, seven 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 />- 3 - <br />