Groundwater recharge rate estimation using remotely sensed and ground-based data: A method application in the mesoscale Thur catchment

Abstract

Study region: The mesoscale Thur catchment located in the north‐eastern part of Switzerland is a study site in which a range of hydrological research has been conducted. Study focus: Groundwater recharge is challenging to quantify due to the complexity of hydrogeological processes and limited observations. Because of its spatiotemporal availability, remotely sensed data present an attractive water management tool. Its application in mesoscale catchments (10 – 104 km2) however, remains limited. This study investigated the use of satellite products used in conjunction with ground-based data to determine spatiotemporal variations in water available for groundwater recharge. Gridded components from readily available precipitation, evapotranspiration, and hydrological discharge data were used to generate spatiotemporal maps over a 20-year period. New hydrological insights for the region: Closure of the water balance found that monthly data displayed a moderate correlation, with improved correlations of obtained seasonal and annual intervals, suggesting that over the long-term the Thur catchment is in a steady state. Maps were generated and trends for the 20-year period assessed. Examination of the gridded water balance components for different hydrological years emphasized the limiting effect of precipitation on recharge. This study highlights the value of remotely sensed data in groundwater recharge estimates, but emphasises the importance of continued ground-based monitoring; the lack of which is a limiting factor in water management where mesoscale catchments are concerned.

Keywords

• Mesoscale catchments
• Groundwater recharge
• Spatiotemporal
• Evapotranspiration
• Water balance