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. . . a023~3 IFIM/PHABSIM and R2CROSS studies to support instream flow recommendations on highly controversial streams; eg., the Blue River in Summit County. The flexibility of the IFIM also makes it a good tool for developing instream flow recommendations for fish species that depend on stream habitats other than riffles and for developing recommendations for instream values other than fish. Tennant (Montana) Method The Tennant Method (Tennant 1976), also called the Montana Method, is an example of a non-field, standard setting methodology where instream flow recommendations are based on maintaining a predefined percentage of mean annual flow (Table 3). Sixteen states routinely use the Tennant Method to develop instream flow recommendations (Figure 1). Table 3. Instream flow regimens for fish, wildlife, recreation, and related environmental resources (Tennant 1976). Narrative Description of flows Recommended baseflow Recommended baseflow October - March April- September Flushing or maximum 200% of average flow 200% of average flow Optimum range 60%-100% of average. flow 60%-100% of average flow Outstanding 40% 60% Excellent 30% 50% Good 20% 40% Fair or degrading 10% 30% Poor or minimum 10% 10% Severe degrading 0% - 10% of average flow 0% - 10% of average flow The Tennant Method requires no field work. On gaged streams, estimates of mean annual flow are easily obtained from historic gaging records. On un gaged streams, mean annual flow can be estimated using accepted hydrologic techniques (Dunne and Leopold 1978; Kircher et al. 1985). The Tennant Method may be an appropriate methodology for developing instream flow recommendations on low priority stream segments or as a check on the reliability of R2CROSS- based flow recommendations. The "Flushing or Maximum" category may also provide an estimate of the channel maintenance or "out-of-bank" riparian flow requirements of a particular stream. 9