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<br />. <br /> <br />.' <br /> <br />. <br /> <br />Biological Data <br /> <br />The CDOW has conducted field surveys of the fishery resources on this stream and have found a <br />natural environment that can be preserved. As reported for this reach of stream in CDOW'S <br />recommendation letter to the CWCB, no fish were collected; this is not to be interpreted in such <br />a manner to say that Groundhog Gulch is incapable of supporting fish. Groundhog Gulch <br />supports a wide variety of aquatic macroinvetebrates indicative of high quality water and it <br />supports a healthy riparian community. The geology of the Telluride area is unique in that the <br />water of many the San Miguel's tributary streams have extremely low conductivity; in other <br />words, the water quality of nearly all of the San Miguel's tributary streams is extremely pure - <br />pure to the point that electro fishing is not possible with standard electro fishing equipment. Fish <br />may exist in these streams but they are not readily sampled with standard electro fishing gear. <br />The CDOW believes that the lower reaches of these streams are used by fish that are residents of <br />the mainstem San Miguel River and are important to the San Miguel's fish community during <br />some periods of the year (i.e. spawning, rearing, and refugia from high flow events). Dissolved <br />levels of heavy metals in the San Miguel River continue to be a problem for the river's fishery <br />but conditions are improving; the high quality water from tributary streams such as Groundhog <br />Gulch are vital to the continued improvement of water quality and the San Miguel's fish <br />population. <br /> <br />Field Survey Data <br /> <br />CD OW and CWCB staff used the R2Cross methodology to quantify the amount of water <br />required to preserve the natural environment to a reasonable degree. The R2Cross method <br />requires that stream discharge and channel profile data be collected in a riffle stream habitat type. <br />Riffles are most easily visualized as the stream habitat types that would dry up first should <br />streamflow cease. This type of hydraulic data collection consists of setting up a transect, <br />surveying the stream channel geometry, and measuring the stream discharge. Appendix B <br />contains copies of field data collected for this proposed segment. <br /> <br />Biological Flow Recommendations <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, one data set was collected with the resu1t~n Table 1 below. <br />Table 1 shows who collected the data (Party), the date the data was colYected (Date), the <br />measured discharge at the time of the survey (Q), the accuracy range of the predicted flows <br />based on Manning Equation (240% and 40% of Q), the summer flow recommendation based on <br />meeting 3 of 3 hydraulic criteria and the winter flow recommendation based upon 2 of 3 <br />hydraulic criteria. <br /> <br />- 3 - <br />