On Demand Release 



The 1982 runoff volume on the Middle Fork of the Poplar River at the Inter- 

 national Boundary from March 1 to May 31 was 27, ^^tO dam . Based on the 

 apportionment recommendations of the International Joint Commission, the 

 United States would be entitled to an on-demand release of up to a maximum 

 of 1,230 dam-^ during the period from June 1, I982 to May 31, I983. As of 

 December 31, 1982 no request had been received for this on-demand release. 

 All past commitments for on-demand releases have been met. 



SURFACE WATER QUALITY 



Surface water quality has been assessed using the data exchanged under the 

 terms of the Technical Monitoring Schedule. Additional data on conductivity, 

 collected by the United States Geological Survey from March to October, was 

 used in regression equations for determining flow-weighted concentrations. 



Flow-Weighted Concentrations ■ 



In order to assess compliance of the East Poplar River quality with the 

 recommended IJC objectives for boron and TDS, flow-weighted concentrations 

 must be computed. The IJC report recommends: (1) a long-term objective 

 computed as a five-year moving flow-weighted concentration, and (2) a short- 

 term objective for any given year computed as a three-month moving flow-weighted 

 concentration. The objectives apply to the March to October period which the 

 IJC determined to be the maximum time interval over the annual cycle in which 

 water may be used for irrigation purposes. Flow-weighted concentrations have 

 been computed using the following concept: 



^0 = 



C,Q, + C2O2 + C3Q3 + . . . C^Q^ 

 Q, + Q2 -^ O3 +. . . . 0^ 



where C^. = Flow-weighted concentration 



C. = Instantaneous concentration at mean daily flow Q. 



Q, = Mean daily flow for C, 



n = Last observation for the period of record 



