WSA Simpson 16-05

Observation well WSA Simpson 16-05 was constructed in 1964 to a depth of 6.04 metres in an unconfined surficial aquifer formed by fluvio-lacustrine sands. The surficial sand is approximately 6 metres thick and is only partially saturated.  This aquifer is underlain by till and stratified drift that forms part of the complex Nokomis Aquifer System.  WSA Simpson 13-04 is completed several hundred metres away into the same surficial aquifer allowing comparison of water table fluctuations between the two wells. 

Recharge from precipitation moves laterally through the aquifer and then discharges in a topographically low area that drains into Last Mountain Lake.  The head in the underlying aquifer system is higher than in the surficial aquifer so some flow from the deeper aquifer system into the shallow one can be expected.  The trend in both wells is very similar with each well typically reaching its seasonal minimum in March.  However, maximums for Simpson 16-05 are reached in April while the maximums in Simpson 13-04 do not occur until August-September.  This difference is possibly due to a thicker unsaturated zone at 13-04.  The aquifer is sensitive to annual climate fluctuations with some years showing very little recharge.  The minimum water level of about 490.75 metres occurred in 1989.  Strong recharge in 2010 and further recharge in 2011 led to a record high peak water level of about 492.6 metres in 2011.  Water levels in the well remain high.     

Water from the well is of the calcium-bicarbonate type with a total dissolved solids concentration of around 325 mg/L.