Influence of past and future atmospheric and oceanic climate change on groundwater levels, recharge, discharge, and salinity

Atmospheric climate change in cold regions can impact groundwater resources through alterations to snow-rain partitioning, mid-winter thaws, and evapotranspiration. Also, sea-level rise can drive elevated coastal water tables and saltwater intrusion, which can deleteriously impact coastal groundwater resources and coastal infrastructure. We investigate these processes in the coastal province of Nova Scotia, Canada, where 40% of the population relies on vulnerable private wells. We consider impacts of past climate change by conducting statistical analyses of hydrometeorological data and find that late-summer significant negative trends are apparent in net precipitation, groundwater levels, and groundwater discharge (baseflow). To assess the impacts of future climate change we are developing province-wide coastal groundwater vulnerability maps (salinization and water table rise) based on a coastal groundwater analytical solution parameterized and forced with geospatial data. We are also using downscaled climate projections to drive a physically-based hydrologic model to investigate how groundwater recharge may respond to changing temperature and precipitation in different hydrologic response units. Our preliminary results provide critical insights into the impacts of climate change on groundwater resources and lay the foundation for better risk identification to underpin sustainable groundwater management.