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Transect 1 was located within a typical riffle section and was used in a standard R2CROSS analysis. The modeling results from these efforts are within the confidence interval produced by the R2CROSS model (see Table 1). Biological Flow Recommendation CDOW and BLM staff, using a combination of PHABSIM/RHABSIM and R2CROSS methodologies, developed the proposed instream flow recommendations for the San Miguel River (see Appendix H for copies of the hydraulic modeling data). Board staff relied upon the biological expertise of the cooperating agencies to interpret the output from the PHABSIM/ RHABSIM and R2CROSS Methodologies to develop the initial, biologic instream flow recommendations. These initial recommendations are designed to address the unique biologic requirements of each stream without regard to water availability. In addition to the criteria developed using the PHABSIM Methodology and RHABSIM Software, the three standard instream flow hydraulic parameters used in R2CROSS (average depth, percent wetted perimeter and average velocity) were also used to calculate and predict the biologic instream flow recommendations (see Table 1 Below). For this segment of stream, several data sets were collected with the results shown in Table 1 below. Table 1 shows who collected the data (Party), the measured discharge at the time of the surveys (Q), the accuracy range of the predicted flows based on Manning's Equation (240% and 40% of Q), the method used, the summer flow recommendation based on meeting 3 of 3 hydraulic criteria and the winter flow recommendation based upon 2 of 3 hydraulic criteria. Table 1: Data Party Measured Q's 250 % -40% Method Summer (3/3) Winter (2/3) PHABSIM 500 (Bluehead) DOW & BLM 450, 325, 175, 100 1125-40 / 325 (Flannelmouth)� 3 - -- RHABS IM DOW & BLM 450, 325, 175, 100 1125-40 l 650 115 ard Standard DOW = Division of Wildlife; BLM = Bureau of Land Management Biologic Flow Recommendation The CDOW and BLM evaluated all of the data collected to date and determined that best flow recommendation would come from using the results from a combination of methods. PHABSIM is a widely accepted method for quantifying the suitable versus unsuitable hydraulic habitat attributes of selected species and life stages as a function of discharge. R2CROSS is best suited for identifying flows with specific hydraulic criteria across riffle type habitats. The State of Colorado has used R2CROSS extensively in the past to appropriate instream flow water rights. s The PHABSIM/RHABSIM analysis was used to only quantify the suitable versus unsuitable hydraulic habitat attributes of bluehead and flannelmouth sucker adults as a function of discharge. Amounts shown reflect the discharge which produced the maximum amount of useable habitat based on the measured mesohabitat types.