WSA Estevan No. 1 and No. 2
Observation well WSA Estevan 2 was completed in 1971 to replace Estevan 1 which had been constructed in 1964 to serve as an observation well for studies of the Estevan Valley aquifer (EVA). Both wells were completed in Empress Group sand and gravel of the EVA with Estevan 2 having a completion depth of 145.08 metres. The hydrograph represents a combined plot for data from Estevan 1 and 2. The general direction of the groundwater flow in the aquifer in this area is west and south toward the Souris River near Outram where this part of the aquifer is believed to discharge.
Water levels in WSA Estevan 2 have been heavily impacted by large scale groundwater withdrawals from September 1988 until May 1994. This water was used during a major drought as supplementary cooling water at Boundary and Shand Power Stations. The impact of this pumping is clearly evident on the hydrograph with almost 24 metres of water level
drawdown occurring. Prior to pumping, only minor fluctuations in water level had occurred. Since 1994 the aquifer has not been utilized for any large scale uses and water levels have been recovering and are still rising slowly, but remain approximately 5 metres below the pre-pumping levels. This slow recovery illustrates that the rate of recharge to the aquifer through the overlying glacial till is very slow. The hydrograph also shows the smaller impacts of a 72 hour pumping test in late 1982 and a 29 day test in late 1984.
Water from WSA Estevan 2 has a sum of ions concentration of approximately 1590 mg/L, is of the sodium-bicarbonate type and is characterized by the virtual absence of sulphate.