Towards a multi-scale understanding of groundwater quality interlinkages

• Applicant: Dr. Robert Reinecke
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management ; Physical Geography
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 559655498

Groundwater quality and quantity are central factors in preserving safe access to drinking water for humans, agriculture, and industry and sustaining ecosystem health. While groundwater depletion can limit the amount of available water, impaired quality may further restrict its use and lead to more resource competition. The changing climate is causing increased quality and quantity issues in groundwater systems. Increased drought occurrence, duration, and severity, as well as likely increasing groundwater abstractions, rising sea levels, and changes in groundwater recharge, combined with land use effects, affect groundwater quality. Understanding how long-term climatic changes impact the hydrologic cycle and, thus, groundwater quality-related processes (e.g., the exchange between surface water and groundwater systems, the change of recharge, or seawater intrusion through sea level rise) will be pivotal. To safeguard groundwater as an accessible source of drinking water for humans, ecosystems, agriculture, and industries, we need a multi-scale understanding of groundwater quality-related processes, which we currently lack. Multi-scale refers to the challenges in understanding processes at their respective temporal (e.g., long-lasting legacy effects vs. extreme events) and spatial (pore scale, catchment vs. large or even global scale) scales. Importantly, foundational research of methods to understand these multi-scales must be coupled with research insights on what spatial and temporal scales are relevant for water governance and management. The proposed TRAILS network will be a starting point for understanding which methods can be used to gain a multi-scale understanding of groundwater quality and which spatial and temporal scales are relevant for water governance and management. To achieve that, TRAILS assembles a unique network of experts in groundwater quality and quantity, groundwater-surface water interactions, coastal hydrology, karst systems, hydrology, modeling on various spatial scales with multiple methods, and governance. Rather than modeling or measuring variables of interest, TRAILS will focus on collecting, discussing, and synthesizing existing knowledge, data, and tools to identify fundamental research needs clearly.

• DFG Programme: Scientific Networks