Estimation of Groundwater Recharge and Discharge by Using the Tritium-Helium-3 Dating Technique

Groundwater is an important source for clean drinking water and vital to human and ecological health. Its importance will continue to rise with increasing population and associated demands by agriculture, industry and urban development. Proper resource management requires information on rates of groundwater recharge and discharge into rivers and lakes. Both types of information combined provide better estimates on groundwater turnover times and therefore on aquifer properties and water dynamics. A quantification of both recharge and discharge rates can be performed using environmental tracer techniques, mainly based on use of the 3H/3He technique at suitable locations using multilevel wells or piezometers, springs and river sites in discharge areas. A comparison of tracers and methodologies will be performed to assess best suited methods depending on prevailing hydrological settings. This site-specific information will be compared to other estimates and results of numerical groundwater flow models to upscale information to the basin scale.