WATERSHED-SCALE STUDY OF GROUNDWATER RECHARGE IN THE CANADIAN PRAIRIES

Understanding of groundwater recharge and its spatio-temporal variation is important as it sets the constraint on water balance of aquifers, particularly in regions characterized by dry climate such as the Northern Great Plains of North America. We established a hydrological observatory in a small (250 km²) agricultural watershed in Alberta, Canada to examine how groundwater recharge-discharge processes respond to variation in meteorological conditions. The watershed is part of the unique community-based groundwater monitoring system using a citizen-science approach, which has enabled us to monitor long-term variation of aquifer water levels and engage community groups in the discussion of water management and regulation. Stream baseflow analysis indicated a decadal-scale shift in groundwater recharge in response to a shift in meteorological condition. Using the chloride concentration measured in monitoring wells, we estimated the spatial distribution of groundwater recharge flux, and used it to improve the performance of three-dimensional groundwater flow model for the watershed. The methodology developed in this study will provide a useful tool and framework for groundwater management in rural watersheds in southern Alberta, where increasing demands on groundwater resources are anticipated.