WSA Duck Lake No. 2

Observation well WSA Duck Lake No. 2 was constructed in 1964 to a depth of 124.6 metres in coarse grained Empress Group sands, which are believed to be hydraulically connected to the Hatfield Valley aquifer.  The purpose of the well is to monitor natural groundwater level fluctuations in a deep aquifer and to investigate the vertical hydraulic gradient between the shallow and deep aquifers present at this site.  The two aquifers are separated by an 82 metre thick till layer formed by the overlying Saskatoon Group and Sutherland Group tills.  There is a pronounced vertical gradient between the two aquifers with the water level in the upper aquifer being approximately 20 metres higher than in the lower aquifer. 

Due to the very low permeability of the overlying till, the rate of recharge to the deep aquifer is extremely low.  Annual fluctuations of the water level are not due to recharge to the aquifer but are caused by the change of total weight acting on the aquifer due to snow accumulation on the ground surface during the winter and changes in the total water in the overlying surficial sand. Thus the water level record for WSA Duck Lake No. 2 shows an increase during the winter of generally a few centimetres to 20 centimetres corresponding to snow accumulation and decline during the summer as the surficial sand loses water by evaporation and discharge of water to McFarlane Creek. The record low water level of about 478.9 metres occurred in 2003 at the end of the 2001-2003 drought, while the record high of about 479.75 occurred in 2013 after several years of heavy snowfall and greater than normal summer rain.   

The aquifer yields water of the sodium-sulphate/chloride type and has an average Total Dissolved Solids concentration of approximately 5470 mg/L