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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 I from BLM to the CWCB <br />"Fishery surveys indicate that the creek supports a self-sustaining cu,tthroat trout fishery in the <br />upper portion of the creek in Deer Park, and the lower portion of the creek near the Animas <br />River supports a self-sustaining brook trout fishery. BLM has re~luested that the Colorado <br />Division of Wildlife re-introduce Colorado River Cutthroat Trout td the upper portion of the <br />creek. The creek is suitable because it is difficult to access and becau1se there are waterfalls that <br />create barriers to fish passage between the upper portion of the creek Jlnd the Animas River. The <br />stream environment is presently in excellent condition and provides imitable substrate, channel <br />stability, cover, water quality, and food supplies for salmonids. Hdwever, the stream is very <br />steep and high velocity, so pools and other feeding/spawning locationsl are limited. Accordingly, <br />it is important to provide stream flows that maintain the limited amount of physical habitat and <br />I <br />that maintain water exchange in pools during low flow periods. (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 rater 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 habi!tat type. Riffles are most <br />easily visualized, as the stream habitat types that would dry up first I should streamflow ceas.e. <br />This type of hydraulic data collection consists of setting up a trans1ect, 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, I biologic in stream flow <br />recommendation. This initial recommendation is designed to address the unique biologic <br />requirements of each stream without regard to water availability. Thrde in stream flow hydraulic <br />parameters, average depth, percent wetted perimeter, and average velbcity are used to develop <br />biologic instream flow recommendations. The CDOW has determin!ed that maintaining these <br />three hydraulic parameters at adequate levels across riffle habitat type!~, aquatic habitat in pools <br />and runs will also be maintained for most life stages of fish and aqua1tic invertebrates (Nehring <br />1979; Espegren 1996). <br /> <br />For this segment of stream, two data sets were collected with the results shown in Table 1 below. <br />I <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 ran~~e of the predicted Hows <br />based on Manning's Equation (240% and 40% of Q), the summer flo~w 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 /> <br />- 3 - <br />