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Reservoir storage during the 1981-90 period was supplemented by ground 

 water pumping for purposes of mine dewatering. In most of those years, 

 the pumping exceeded the amount of water contributed by natural flow. An 

 average of 5,400 dam 3 was pumped from the mine annually. 



Apportionment 



In 1976, the International Souris-Red Rivers Engineering Board, through 

 its Poplar River Task Force, completed an investigation and made a rec- 

 ommendation to the governments of Canada and the United States regarding 

 apportionment of the waters of the Poplar River basin. Although not 

 officially adopted by the two countries, Canada has attempted to follow 

 the apportionment recommendations. 



The apportionment of the East Poplar River is determined on the basis of 

 the natural flow of the Poplar River. Through 1990, the recorded flow of 

 the Poplar River at the International Boundary was considered to be the 

 natural flow. The recorded flow for the March-May period each year is 

 used to determine the minimum flow and on-demand release requirements on 

 the East Poplar River for the succeeding 12 months. Generally, the 

 greater the flow in the Poplar River, the greater the releases into the 

 East Poplar River. The complete apportionment recommendation is given in 

 Annex 4 . 



Minimum Flows and On-Demand Releases 



During the ten-year period, the flow in the East Poplar River has gen- 

 erally exceeded minimum flow requirements. However, flows did drop below 

 the recommended minimum for short periods in 1982, 1986, and 1990. Main 



