WSA Melfort

Observation well WSA Melfort was constructed in 1967 to a depth of 10.64 metres to observe natural groundwater level fluctuations in a shallow aquifer.  It is completed in medium grained sand of the basal portion of fluvio-lacustrine sediments deposited during the final deglaciation of the area. The aquifer is overlain by 5.2 m of silty clay and clay, which acts as a confining layer.  Water infiltrating into the ground moves from the surface downward into the aquifer with the groundwater flow direction determined by the topography. It is believed the aquifer discharges laterally into local depressions and may also be discharging into a tributary of the Carrot River.

The hydrograph shows a large range of responses to climatic conditions, both in terms of magnitude and timing.  Total fluctuations in a year are often less than 0.1 metres, but occasionally may be in the range of 0.3 to 0.5 metres.  In 2010, the well experienced an increase of about 0.8 metres, but some years have shown very little recharge resulting in a continual decline through the year.  The record low of about 443.6 metres occurred in 2004, which was followed by strong recharge over the next three years resulting in water levels approaching historic high levels.  Further strong recharge in 2010, 2011 and 2012 resulted in record high water level peaks of around 445.75 metres over the past couple of years.

The well yields water of the calcium/magnesium-sulphate type with a sum of ions concentration of about 3540 mg/L.