Stream: Blue Creek Executive Summary

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measurements indicate flows that are approximately double the current instream flow water right. Instream Flow Recommendation The BLM recommended an increase of 4.5 cfs (April 1 to July 31), based on its data collection efforts. The modeling results from this survey effort are within the confidence interval produced by the R2Cross model. Land Status Review Upper Terminus Lower Terminus Total Length (miles) Land Ownership % Private % Public Confl. w/ Big Blue Creek & Little Blue Creek Confl. w/ Morrow Point Reservoir 3.53 0% 100% 64% of the public lands are managed by the National Park Service and the remaining 36% are managed by the BLM. Biological Data This segment of Blue Creek is a moderate to high gradient stream, with moderate to large substrate size, punctuated by large boulders. The proposed reach is confined by a narrow canyon, and some portions of the creek are further confined by the construction and maintenance of U.S. Highway 50. The riparian community is in good condition and composed of willow, alder, and spruce. The creek provides a good mix of pools, riffles, and runs for fish habitat. The riparian community often provides good shading for the water column. Fishery surveys indicate that the creek supports a self - sustaining population of brook trout, rainbow trout, and speckled dace. Field Survey Data BLM staff used the R2Cross methodology to quantify the amount of water required to preserve the natural environment to a reasonable degree. The R2Cross method requires that stream discharge and channel profile data be collected in a riffle stream habitat type. Riffles are most easily visualized, as the stream habitat types that would dry up first should streamflow cease. This type of hydraulic data collection consists of setting up a transect, surveying the stream channel geometry, and measuring the stream discharge. Biological Flow Recommendation The CWCB staff relied upon the biological expertise of the cooperating agencies to interpret output from the R2Cross data collected to develop the initial, biologic instream flow recommendation. This initial recommendation is designed to address the unique biologic requirements of each stream without regard to water availability. Three instream flow hydraulic parameters, average depth, percent wetted perimeter, and average velocity 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 aquatic invertebrates (Nehring 1979; Espegren 1996). -3-