WSA Instow

WSA Instow was originally constructed as a water source well for secondary oil recovery with production from the well occurring from 1965 to 1978.  In 1980 it was incorporated into the observation well network in order to monitor water level fluctuations of the Judith River aquifer in southwestern Saskatchewan. The well is screened across the entire thickness of the Judith River Formation at this site, with the screens set from 401 to 554 metres. The aquifer is overlain by a thick sequence of silts and clays of the Bearpaw Formation and Quaternary deposits.  With a total depth of 554 metres, WSA Instow is the deepest well in the network.

The depth to water level in WSA Instow is over 190 metres, suggesting that recharge through the overlying low permeability shales and tills is very low compared to lateral flow in  the aquifer.  The initial portion of the hydrograph suggests that the well was still recovering from pumping.  However, in late 1985 water levels peaked at 736 .6 metres and then suddenly began to drop.  This has been attributed to pumping in the vicinity of WSA Instow.  The lowest water level of just over 726 metres occurred in 2005. 

The water is of the sodium-bicarbonate type with a sum of ions concentration of approximately 1970 mg/L.