or normal water yoar. 



'' it'ld Met hods 



The inflection point flows for the single and multiple transect methods 

 and tlie flows that maximize the total available habitat for adult brown and 

 rainbow trout, as derived from the IFG method, are compared to the range of 

 flow recommendations derived from the trout-flow data in Table 3. These recom- 

 mendations are intended to satisfy the flow needs of adult trout and are only 

 applicable to the low flow or non-runoff period. The recommendations of the 

 three field methods will not be listed by month nor adjusted to fall within the 

 constraints of water availability for a median water year as in Table 2. 



3 

 Table 3. Flow recommendations (m /s) of the single transect, multiple transect, 



and IFG incremental methods compared to those derived from the trout 

 standing crop and flow data for five reaches of the Madison, Beaver- 

 head, Gallatin and Big Hole Rivers. 



Flow Recommendations (m /s) 



a/ 



Upper limit presently undefined. 



Singl e Tran s ect Method. The inflection point flows for three of the 

 reaches (Madison ill, Madison //3 and Gallatin //2) are approximately equal to the 

 lower limits of the flow ranges generated by the trout-flow data. For the 

 Beaverhead #2 reach, the inflection point flow occurs midway between the lower 

 and upper limits and in the remaining reach (Big Hole #1) the inflection point 

 flow is somewhat less (2.1 m /s) than the lower limit. In general, the single 

 transect recommendations compare favorably to those derived from the trout-flow 

 data. 



M ultiple T ran sect Method . Only three of the multiple transect recommen- 

 dations (Madison //I, Beaverhead //2 and Gallatin //2 reaches) are judged accep- 

 table based on the comparison with those of the trout-flow data. -The recommen- 

 dation for the Madison //3 reach is unacceptable since it is 5.7 m /s less than 

 the lower limit of the flow range derived from the trout-flow data. For the 

 Big Hole //I reach, a recommendation is unavailable since two inflection points 

 (at 7,8 and 17.0 m /s) are present on the wetted perimeter-discharge curve. 



