Groundwater is essential for drinking water provision and food production while hosting unique biodiversity and delivering key ecosystem services. However, overexploitation and contamination are prevailing threats in many regions worldwide. Even integrated governance schemes like the European Union Water Framework Directive often fail to ensure good quality and quantity conditions of groundwater bodies. Contributing factors are knowledge gaps on groundwater characteristics, limited financial, staff and land resources, as well as policy incoherencies. In this paper, we go further and argue that current groundwater challenges cannot be understood when considering the local situation within hydrologic boundaries only. New long-distance processes are at stake—so called telecouplings—that transgress watershed and administrative boundaries and significantly influence the state of local groundwater bodies. We provide three literature-based examples of European groundwater systems that are impacted by telecouplings, and we show how research and solution perspectives may change when acknowledging the de-localization of groundwater(s). We elaborate on virtual water trade, remote water supply, and seasonal tourist flows that connect sending, receiving and spillover systems. These processes can induce groundwater depletion and contamination but may also help to conserve the resource. Our hypothesis calls for a new spatial paradigm to groundwater management and highlights the need for transdisciplinary research approaches as envisioned in socio-hydrogeology.

<p>Groundwater resources are essential for human water supply and ecosystem functioning. Against the background of climate change, groundwater use becomes increasingly important, as it serves as a buffer during dry periods and is often less polluted than surface water. However, changing socio-economic factors influence groundwater use patterns (e.g. demographic transition, economic development and efficiency gains) and can lead to high demands during (dry summer) periods of low availability. In addition, there are climate change-related changes in groundwater recharge due to altered precipitation patterns and increased potential evapotranspiration. Therefore, it is necessary to consider scenarios of future groundwater availability and use to support sustainable groundwater management in Europe. We combine groundwater recharge and societal water demand in Europe to identify spatial patterns of groundwater availability and demand mismatches. For the current situation, we use data from the global hydrological model WaterGAP to quantify, with a spatial resolution of 0.5°, groundwater stress across Europe as the ratio of total groundwater abstractions to groundwater recharge. For future recharge estimation, we compile a multi-model ensemble with data from the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) that includes four global climate and eight global hydrological models to assess the uncertainties that are inevitable in analyzing the future impacts of climate change. We quantify scenarios of future domestic water demand using water use data, population scenarios and climate variables on a national and sub-national scale. By combining current groundwater stress with trends in future groundwater recharge and domestic water demand, we identify hotspots of future stress on domestic water supply. Our approach contributes to the understanding of human-water interactions and highlights the importance of combining physical conditions and human influences. The methodology can be easily adapted to other regions of the world (if data on water use and population are available) to support sustainable groundwater management.</p>

<p>The past droughts uncovered that groundwater resources in Germany are finite. Ecosystem degradation and restrictions in public water supply were the consequences of reduced groundwater recharge, particularly in 2018. This event only exemplifies the challenges for groundwater governance under climate change. Current frameworks like the European Water Framework Directive often fail to ensure the envisioned targets of good quantity and quality of (ground)water. Besides known contributing factors (limited resources, policy incoherencies), we see new supra-regional social-ecological interactions that transgress watershed boundaries and significantly influence local groundwater systems. In our research, we look through a telecoupling lens and thus reframe groundwater challenges.</p><p>Here, we present the findings of an ongoing inter- and transdisciplinary project on sustainable groundwater management in the federal state of Saxony-Anhalt, Germany. More and more municipalities shutdown local water supply facilities and connect themselves to a remote water supply network. In our case, nitrate and uranium contamination of groundwater as well as drought-induced low groundwater levels created public pressure to switch to the remote water supply network. Thus, a complex web of social-ecological interactions affects local and remote (ground)water resources. These processes can, however, not be explained by hydrology alone – they require a socio-hydrology approach. Here, we investigate the groundwater situation from an interdisciplinary perspective to better understand both societal and environmental phenomena locally and in remote places using the telecoupling framework.</p><p>In collaboration with stakeholders, we apply a methodologically guided transdisciplinary process of problem framing, interdisciplinary collaboration and knowledge integration. Therein, we particularly shed light on how the remote water supply network affects local groundwater bodies. Representatives from local and remote water suppliers, agriculture, nature conservation, regional planning, local and federal state agencies join this process to create a shared vision of sustainable groundwater management. Against the background of climate change and the evolvement of societal water demand, scenarios of specific measures are collaboratively developed with stakeholders to conserve the resource.</p><p>This ongoing research showcases, how stakeholder involvement can enrich a purely scientific perspective on groundwater challenges as local particularities and problem perceptions come to the forefront that offer options for applicable solutions.</p>

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