Observation well WSA Verlo was constructed in 1964 to observe natural groundwater level fluctuations in a surficial aquifer in the Great Sand Hills area. The well was completed to a depth of 12.80 metres in lacustrine clayey silt overlain by approximately 6 metres of fine grained eolian (wind blown) sand. The well is developed in an interdunal depression. The direction of the groundwater flow is towards the north following the general slope of the topography.
Annual water level minimums typically occur in February or March with maximums in the May-June period. The Saskatchewan Research Council noted that the well shows a diurnal response in the summer that is attributed to evapotranspiration. Annual fluctuations vary from a maximum of about 0.5 to less that 0.01 metres with some years showing little to no recharge. From 1966 until 1972, water levels remained above 733 metres. Following that water levels went into a long term decline with only brief interruptions such as in 1996 and 1997. This resulted in record low water levels of about 730.2 metres in 2009/10, representing a decline of about 3 metres. Since then there have been some increases in the water level which is now around 730.3 metres. The cause of this decline is unknown.
WSA Verlo yields water of the calcium-bicarbonate type with a sum of ions concentration of approximately 419 mg/L.