Beaverhead River - Reach #2 ^. • 



Summary flow statistics for a 49-year period of record 

 were derived from data collected at the USGS gage at Barretts. 

 Since 1964, flows at this gage reflect regulation by Clark 

 Canyon Reservoir. 



The absolute minimum recommendation of 150 cfs is avail- 

 able in at least 9 of 10 years for the months of October 

 through April, and at least 8 of 10 years for the months of 

 August and September. Overall, the absolute minimxom is readily 

 obtainable in most water years. 



On a monthly basis, the most desirable minimum of 300 cfs 

 is available in at least 4 of 10 years and appears generally 

 obtainable in average and above average water years. 



The East Bench Irrigation District, which has assum.ed 

 operation of Clark Canyon Dam from the Bureau of Reclamation, 

 presently has an informal agreement with the Montana Depart- 

 ment of Fish, Wildlife and Parks to provide a minimum flow of 

 about 225 cfs in reach #2. The Clark Canyon project only pro- 

 vides a guaranteed minimiim instream flow of 25 cfs for fish 

 and wildlife benefits- 



Gallatin River - Reach #2 



Summary flow statistics for a 39-year period of record 

 were derived from data collected at the USGS gage at the head 

 of reach n2 (near Gallatin Gateway) . Flows at this gage re- 

 fl^i^ct the natural flow regime since it is located upstream of 

 all irrigation diversions. The flow depletions throughout 

 much of reach #2 occur only during the irrigation period from 

 about July 1 through October 15. 



During the non-irrigation months when no depletions oc- 

 cur, the absolute minim\jm recommendation of 250 cfs is avail- 

 able in at least 8 of 10 years. If no depletions occurred 

 during the irrigation season, the absolute minimum would be 

 available in all water years. At the present level of irri- 

 gation depletions, an absolute minimum of 250 cfs is even 

 unobtainable in above average water years in some sections 

 of reach #2. 



The most desirable minimum recommendation of 52 3 cfs is 

 unavailable during most of the low water months, even under 

 the natural flow conditions. During December through March 

 the most desirable minimum is never available and available 

 in less than 4 of 10 years during April, September, October 

 and November. 



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