San Miguel River Appendices - Laserfiche WebLink

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.. , ii II I, II " Land Status Review Total Length I Land Owne:rship Upper Terminus Lower Terminus (miles) % Pnivate % Public South Fork San I Bear Creek Miguel River 6.4 77% 23% , I 23% of the reach is located on public lands managed by eit~er the USFS or the Town of Telluride and the other 77% of the reach is located on private lands. I I 1 Biological and Field Survey Data , The CDOW has conducted field surveys of the fishery resources on tl1is stream and have found a I natural environment that can be preserved. As reported in the letter from CDOW to the CWCB "The existence of a natural environment was established by the GWCB in Case Number 4- 1 84CW427. The upper San Miguel River is classified as a medium st~eam (between 20 to 35 feet wide). Aquatic sampling shows that a self sustaining brook and rainbow trout tishery exists in the upper San Miguel River Basin. In addition to the trout fishery, t~e upper basin also supports a population of mottled sculpins" (See CD OW Fish Survey in Appenoix B). I Field Survey Data CDOW staff used the R2CROSS methodology to quantify the amount of water required to I preserve the natural environment to a reasonable degree. The R2CROSS method requires that stream discharge and channel profile data be collected in a riffle strciam habitat type. Riffles are I most easily visualized, as the stream habitat types that would dryl up first should streamflow cease. This type of hydraulic data collection consists of setting Lp a transect, surveying the I stream channel geometry, and measuring the stream discharge. Appendix B contains copies of field data collected for this proposed segment. : Biological Flow Recommendation The CWCB staff relied upon the biological expertise of the coop1erating agencies to interpret output from the R2CROSS data collected to develop the ini~ial, biologic instream flow recommendation. This initial recommendation is designed to address the unique biologic requirements of each stream without regard to water availability. lihree instream flow hydraulic parameters, average depth, percent wetted perimeter, and average ivelocity are used to develop biologic instream flow recommendations. The CDOW has determined that maintaining these three hydraulic parameters at adequate levels across riffle habitat types, aquatic habitat in pools and runs will also be maintained for most life stages of fish and a~uatic invertebrates (Nehring 1979; Espegren 1996). 1 , I For this segment of stream, seven data sets were collected with ~he results shown in Table 1 below. Table 1 shows who collected the data (Party), the date the ~ata was collected (Date), the measured discharge at the time of the survey (Q), the accuracy:range of the predicted flows based on Manning's Equation (240% and 40% of Q), the summer flow recommendation based on meeting 3 of 3 hydraulic criteria and the winter flow recommendation based upon 2 of 3 hydraulic criteria. 1 - 3 -