Graphical Analysis of Publicly Available Monitoring Well Databases to Evaluate and Categorize Groundwater Recovery Across Alberta, Canada

Abstract

A graphical analysis method is applied over the province of Alberta, Canada using publicly available water level data from standard monitoring wells to evaluate and categorize aquifer recovery. Agriculture in the province relies heavily upon surface water for irrigation, which is increasingly unreliable due to climate change and increasing climate variability. Due to an expected future reliance on groundwater, it is necessary to better understand groundwater flow and aquifer characteristics across Alberta to prevent over-allocation of groundwater resources. Water level data from provincial monitoring well hydrographs are examined and graphically analyzed to broadly characterize recovery in agriculturally significant regions of the province of Alberta, Canada. Through this analysis, the presence of a recharge boundary within a recovery curve can be ascertained. Of the 292 monitoring wells originally screened, recovery curve analysis is conducted on 49 monitoring wells. Using graphical analysis of recovery curves within monitoring well hydrographs, the presence or absence of recovery or aquifer replenishment in an area immediately surrounding monitoring well screens is determined. 785 recovery curves from the 49 monitoring wells are subsequently categorized as either “enhanced recovery”, “normal recovery”, or “inconclusive”, with continuing discussion and analysis focusing on results from 36 wells located in three significant aquifers within the province. These aquifers include the Paskapoo aquifer, aquifers within the irrigation districts of southern Alberta, and surficial aquifers within agriculturally rich regions of the province. Results demonstrate the presence of a potential recharge signal deviating from standard Theis recovery curve in 97.22% of the 36 monitoring wells studied. In individual wells, recovery curve classifications vary over time, with some recovery curves being classified as “normal recovery”, and some being classified as “enhanced recovery”, showing signs of a possible recharge boundary. This classification depends on the characterization of late-time recovery curve behavior, as pumping signals transition to regional aquifer signals over time. Analyzed hydrographs show the influence and effects of changes in groundwater pumping on surrounding water levels, including through change in water policy. This method provides information about the presence or absence of recharge over a large area, in contrast to traditional methods of determining recharge which cover smaller areas in comparison. However, a comprehensive database of monitoring well data are required to facilitate analysis, as 48.76% of recovery curves analyzed were classified as “inconclusive”. It is recommended that results from this method are paired with data such as climate indices or agricultural usage, to help determine possible correlations between results and climatic, geographic, or agricultural factors.