A new interdisciplinary study developed within the ClimEx-PE project examines how legal and institutional frameworks can either support or hinder aquifer resilience and the wider implementation of Managed Aquifer Recharge (MAR). Published in Groundwater for Sustainable Development, the research brings together expertise in law, hydrogeology and socio-economic sciences to compare water governance in the Netherlands, Ireland, Spain and Hungary.
The study, led by István Hoffman of Eötvös Loránd University (ELTE), starts from a simple but important observation: water does not follow the administrative and regulatory boundaries created to manage it. Rainwater, surface water and groundwater are interconnected components of the same hydrological cycle, yet they are often governed by separate laws, institutions and policy objectives.
The same water, different rules
Modern hydrological science recognises precipitation, surface runoff and groundwater as parts of an interconnected system. Water regulation, however, frequently treats them as separate domains.
The authors describe these fragmented arrangements as regulatory “silos”. Such silos can occur in sectoral legislation, institutional responsibilities and the separate governance of rainwater, stormwater and groundwater. As a result, decisions concerning one component of the water cycle may fail to consider their consequences for the others.
This becomes particularly important under increasing climatic variability. Aquifer resilience depends not only on how much groundwater is abstracted, but also on how effectively groundwater resources are replenished. The study therefore argues that groundwater recharge governance should receive much greater attention alongside the regulation of abstraction.
Drain the water – or retain it?
Stormwater management illustrates this challenge particularly well. During intense rainfall, urban water management understandably focuses on preventing flooding and damage by draining excess water rapidly. Yet the same water may also represent a valuable resource for replenishing groundwater.
Responsibilities for these two objectives are often divided between different institutions and levels of governance. Stormwater management may primarily be a municipal responsibility, while groundwater management is regulated at regional or national level. This fragmentation can make it difficult to retain water locally and use rainwater or stormwater as a source for Managed Aquifer Recharge (MAR) where hydrogeological conditions allow.
The potential is substantial. Previous research from Hungary’s Danube–Tisza Interfluve estimated that rainwater collected from rooftops in five settlements, each with approximately 6,000–7,000 inhabitants, could provide around one million cubic metres of water per year that could potentially contribute to groundwater recharge.
Four countries, different governance approaches
The study compares countries with markedly different climatic, hydrological and administrative settings. The Netherlands and Ireland have oceanic climates, Hungary has a continental climate with increasing drought pressures in some regions, while Spain faces water-management challenges characteristic of Mediterranean conditions.
Their governance structures also differ considerably. Hungary has a relatively centralised water-management system, the Netherlands has a distinctive system of water authorities, and Spain operates through a multi-level structure involving river-basin organisations and autonomous regions.
Among the four countries examined, Spain has one of the most explicit MAR-related regulatory frameworks, although implementation still varies between river basins. In Ireland and Hungary, MAR remains less explicitly incorporated into water legislation. The comparison nevertheless shows that some degree of regulatory fragmentation persists across all four jurisdictions.
Aquifer resilience is not only a technological challenge
The study highlights that groundwater serves multiple and sometimes competing societal needs, including drinking-water supply, agriculture, industry and ecosystem services. Recharge policies must therefore consider not only water quantity but also water quality, environmental protection and public-health risks.
This is why the research adopts an explicitly interdisciplinary perspective, combining hydrogeological understanding with legal and policy analysis. The approach is closely aligned with the “One Water” paradigm, which treats surface water, groundwater, rainwater and other components of the water cycle as parts of an interconnected system rather than as separate resources.
The study concludes that the principal barriers to wider implementation of MAR are not primarily technological, but institutional and regulatory. Regulatory frameworks that separate interconnected components of the water cycle can reduce recharge opportunities and limit the capacity of aquifers to buffer increasing climatic variability.
Towards more integrated groundwater governance
Based on the comparative analysis, the authors call for aquifer recharge objectives to be more explicitly integrated into national water legislation and sectoral policies. They also emphasise the need for stronger coordination between authorities responsible for groundwater, rainwater and stormwater, flood management and land use.
Where hydrogeological and water-quality conditions are suitable, rainwater and stormwater should be considered more systematically as potential sources for MAR. Planning, regulation and permitting should bring together legal, hydrogeological and technical expertise from the outset.
The findings reinforce a central principle of the ClimEx-PE project: strengthening groundwater resilience under hydroclimatic extremes requires more than technological solutions. Effective adaptation also depends on governance frameworks capable of recognising and managing the natural connectivity of the water cycle.
The article, “Regulatory obstacles to aquifer resilience: A comparative legal-policy analysis of hydrogeological connectivity and managed aquifer recharge governance in Europe”, was authored by István Hoffman (Eötvös Loránd University), Katalin Sulyok (Durham University), Jessica J. Lillquist (Utrecht University), and Judit Mádl-Szőnyi (Eötvös Loránd University) and published in Groundwater for Sustainable Development.