FEB MAR APR MAY JUNE JULY AUG SEPT CXJT NOV DEC 



Figure 3.2 Flow Hydrograph of the East Poplar River at the Interaational Boundary. 



3.2.4 On-Demand Release 



In addition to the minimum flow, the UC apportionment recommendation entitles Montana to an 

 on-demand release to be delivered during the twelve-month period commencing June 1 . Based on 

 the runoff volume of 2 110 dam? recorded at the Poplar River at the International Boundary 

 gaging station during the March 1 to May 31, 1995 period, Montana was entitled to an additional 

 release of 370 dam' from Cookson Reservoir during the twelve month period commencing June 

 1, 1995. Montana requested this release to be made between May 1 and May 30, 1996. A 

 volume of 339 dam' , in addition to the minimum flow, was delivered during this period. This 

 delivery was 31 dam' less than the entitled release. 



3.2.5 Water-Quality 



The 1981 report by the UC to Governments recommended: 



For the March to October period, the maximum flow-weighted concentrations should not 

 exceed 2.5 milligrams per litre (mg/L)for boron and 1500 mg/Lfor TDSfor any three 

 consecutive months in the East Poplar River at the International Boundary. For the 

 March to October period, the long-term average of flow-weighted concentrations should 

 be 2.5 mgIL or less for boron, and 1000 mg/L or less for IDS in the East Poplar River 

 at the International Boundary. 



