Groundwater Quantity

Groundwater cannot be described by sub-watershed boundaries, as it does not respect these topographically defined areas. Rather, groundwater is placed in western and eastern groupings of sub-watersheds. In general, the western grouping has a shortage of high-yield freshwater aquifers. High-yield aquifers are typically associated with permeable sand and gravel deposits in the surficial geology, which allows groundwater to flow at significant rates. Groundwater resources in the eastern grouping appear to be abundant, but mapping this area is challenging.

The Mighty Peace watershed has less groundwater monitoring information available compared with the province's southern watersheds, such as the Bow River and Oldman River watersheds. But the water resource issues facing the watershed are also less urgent. Currently, the most comprehensive regional groundwater-monitoring program in place is ESRD's Groundwater Observation Well Network (GOWN). Twelve groundwater observation wells are active within the watershed, the majority of them located near Grande Prairie and the town of Peace River.

High yields and excellent water quality make the 600 km² Grimshaw Gravels aquifer one of the most important aquifers in the watershed. Located west of the town of Peace River and adjacent to Lac Cardinal, its general flow is in a southeasterly direction from the Whitemud Hills, which recharge the aquifer, to the Peace River. The aquifer provides drinking water for four municipalities: Berwyn, Grimshaw, Whitelaw, and Brownvale.

Water levels in the Grimshaw Gravels aquifer can change by about a metre following changes in precipitation and in the levels of Lac Cardinal. Because it is shallow, there is strong interaction between water in the aquifer, precipitation, and Lac Cardinal levels. Despite the aquifer's changing levels, supply from this aquifer continues to be good, and no long-term decline is apparent.

Groundwater Observation Well Network Locations