Groundwater could be an increasingly important water supply in the Canadian interior with global warming and declining summer runoff; however, not enough is known about the behavio of groundwater under climatic variability. Groundwater levels at two wells in southern and central Alberta are analyzed in order to document long-term variability of groundwater levels and their sensitivity to climatic events. The instrumental well records span more than 40 years. Strong correlations (r > 0.7, p < 0.01) between mean annual groundwater levels and tree-ring chronologies suggested the use of regression models to reconstruct historical water levels for more than 300 years. From the estimated groundwater levels several periods with five or more consecutive years of low levels were identified (i.e. periods centered on 1698, 1720, 1855, and
