Determining the causes of groundwater warming and its effects on groundwater quality in Israel's coastal aquifer

Climate change is expected to raise groundwater temperatures, affecting more than 100 million people living in areas where temperatures exceed national drinking water standards. However, many of these projections are based on models rather than observations. As more countries implement continuous monitoring programs for the sustainable management of groundwater systems, analyzing trends in water level and quality data related to climate change is becoming more feasible. Therefore, the goal of this study was to utilize a 30-year record of water level and water quality data collected from 1,600 wells drilled into the unconfined and unconsolidated coastal aquifer of Israel.  We sought to identify trends in groundwater warming and explore their potential sources. High temperatures were generally related to wells in urban areas, while temperatures were lower under open fields and agricultural areas. However, the increasing trend in groundwater temperature was clear in both areas. We will investigate the correlation between well temperature and unsaturated zone thickness using well logs, and analyze temperature changes with distance from the Mediterranean Sea. Major ion data and a Piper diagram will be used to assess shifts in concentrations related to temperature changes. Although in its infancy, this study would shed light on some groundwater geochemical processes impacted by climate change.