12 



T 1 1 1 1 1 1 1 1 1 r 



JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 



1991 



Figure 3.2 Flow Hydrograph of the East Poplar River at the International 

 Boundary. 



were above the recommended minimum with the exception of January 1 . Icing as a 

 result of extremely cold weather reduced the flow to 0.026 mVs on this day. 



3.4 On-Demand Release 



In addition to the minimum flow, the IJC apportionment recommendation entitles Montana 

 to an on-demand release to be delivered during the 12 month period commencing June 

 1 , 1991. Based on the runoff volume of the Middle Fork Poplar River during the March 

 1 to May 31 , 1990 period, Montana was entitled to a release of 370 dam^ from Cookson 

 Reservoir. Montana requested this release be delivered between May 1 and May 30, 

 1991. A volume of 459 dam^ was delivered during this period. 



