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3^.2.1.1 Exploration Activities 



Given the continuing low water levels in Cookson Reservoir SaskPower Corporation continued to 

 evaluate the Frenchman (Hell Creek) formation as an additional supplementary supply. The 

 exploration efforts by SaskPower Corporation have essentially taken place in two phases. The first 

 phase included test drilling, observation and test well installation, and a 36-day pump test. The 

 pumping rate during the test was initially set at 150 U.S.gpm. but eventually had to be reduced to 

 80.8 U.S.gpm. Using the information obtained, a numerical model (MODFLOW) was constructed, 

 and various pumping scenarios modelled. Model results indicate that at a production rate of 1 000 

 dam'^/year, significant drawdowns at the International Boundary would occur. A copy of the 

 investigation report was submitted to the Montana Bureau of Mines and Geology. 



Following the first phase which was completed in 1993, SaskPower Corporation constructed two 

 additional wells utilizing alternative well designs in order to increase production rates. A pump test 

 using all three wells was initiated on March 30, 1994 and continued until September 27, 1994 (181 

 days). An initial pumping rate of 982 m^/day was obtained, but within a few days the rate had to be 

 reduced to 806 m^/day due to high drawdowns in the production wells. Following the pump test, a 

 modelling study using MODFLOW was undertaken. 



Based on the results of the pump test and subsequent modelling, SaskPower Corporation found that 

 the overall hydraulic conductivity and thus productive potential of the Frenchman aquifer are 

 significantly lower than were expected at the start of the investigation. Initially, SaskPower 

 Corporation had hoped for a supplemental supply of 2 000 dam^/year, but the investigation indicates 

 that this would require a well field of at least 24 and perhaps as many as 40 wells. A pipeline to 

 transport the water would also be required. 



