Groundwater: Measures for the Sustainable Use of a Contested Resource

Groundwater is a vital resource, yet its availability and quality are highly uncertain. Achieving sustainable groundwater management, therefore, requires creativity, collaboration, and a willingness to accept and navigate uncertainties.

Uncertainties in Groundwater Management

One of the biggest obstacles to sustainable groundwater use is the existing uncertainty. The current state of groundwater cannot always be clearly assessed, as monitoring networks provide only selective information on its qualitative and quantitative condition.

Moreover, human-induced contamination is often insufficiently researched. For instance, in many regions, the pathways and timing of nitrate infiltration or pesticide pollution remain unclear.

These uncertainties in the present are further amplified when trying to assess the future state of groundwater. Depending on the extent of climate change and the intensity of groundwater use, developments could vary significantly—from drastic declines in groundwater recharge to potential increases, both of which could have unpredictable effects on groundwater ecosystems and drinking water quality.
 

The Urgency of Sustainable Solutions

Even though many questions remain unanswered, decisive action is necessary. The consequences of a "business as usual" approach are already being felt. Increasing conflicts during drought periods in Germany, Europe, and worldwide underscore the need for effective groundwater management.

In Germany, water shortages during the drought years of 2018–2020 led to conflicts between municipalities, authorities, agriculture, and industry, particularly in the outskirts of major cities. In the Harz region, forest dieback has placed additional pressure on the operators of the West Harz and Elbaue-East Harz long-distance water supply systems. A similar challenge is evident on the Croatian island of Krk, where seasonal tourism demand puts enormous pressure on local water resources.
 

Principles for Sustainable Groundwater Management

Sustainable groundwater management under uncertain conditions requires clear guidelines. Four key principles can help address these challenges: participation, precaution, appropriateness, and adaptation.
 

1. Participation: Engaging Stakeholders

Successful groundwater management depends on the collaboration of various stakeholders—including authorities, farmers, scientists, and citizens. Their perspectives, needs, and knowledge should be incorporated into decision-making processes. Only through inclusive participation can conflicts be mitigated and viable solutions developed.

Our research in the junior research group regulate, involving these very stakeholders in Mansfeld-Südharz and Krk, provides examples of how multi-actor collaboration can pave the way for sustainable groundwater management.
 

2. Precaution: Minimizing Risks

The precautionary principle aims to identify and counteract risks to humans and nature at an early stage, even when their negative impacts are not yet fully understood. This means developing measures specifically tailored to potential future scenarios and their associated risks.

Even if the likelihood of a given scenario is uncertain, the precautionary principle calls for proactive action. In groundwater management, this can involve designating water protection areas to prevent contamination in the long term—regardless of whether the precise effects of certain pollutants on humans and ecosystems have been fully studied.
 

3. Appropriateness: Tailored Solutions

Measures should be adapted to local conditions and possibilities. Instead of one-size-fits-all approaches, flexible strategies are needed that take both ecological and economic realities into account.

For instance, different regional strategies may be required to address nitrate pollution. In one region, reducing agricultural fertilizer use may be the most effective and socially viable solution, while in another, technical water treatment measures—such as post-treatment to remove harmful substances—may be more appropriate.
 

4. Adaptation: Learning and Staying Flexible

The principle of adaptation, often referred to as "adaptive governance" or "adaptive management," emphasizes the need to continuously adjust measures based on new knowledge. In groundwater management, this could involve expanding monitoring systems and revising measures as needed.

Adaptation often requires creative approaches to infrastructure, regulations, and policies. In Sangerhausen, for example, different filtration methods were tested to address water contaminants, threshold and limit values were reviewed and adjusted, and regional supply networks were integrated.
 

Practical Measures in Groundwater Management

These principles can be translated into concrete measures that remain effective despite uncertainties. The following actions have been jointly developed by researchers and practice partners in regulate:

Designating Protection Areas: These prevent pollutants such as nitrates and pesticides from entering groundwater. Establishing groundwater protection zones—regardless of whether they are used for drinking water production—is a long-term precautionary measure.

Promoting Alternative Water Resources: In the tourism region of Krk, for example, alternative water sources have been explored to meet peak demand during the season. Potential solutions include collecting and using rainwater for irrigation and toilet flushing in hotels or filling swimming pools with seawater.

Expanding Monitoring: Installing additional measurement stations provides comprehensive data on groundwater levels and quality. If existing data is consolidated in a central data portal, it can serve as a solid basis for more flexible and precise decision-making.
 

Navigating Uncertainty Together

Sustainable groundwater management is achievable – but only through collaboration. The challenges are too complex to be addressed solely through technical expertise and innovation.

Knowledge exchange, cooperation, and the integration of diverse perspectives are crucial. Germany’s National Water Strategy provides a framework at the federal level to facilitate broader integration of knowledge into administrative practice. Here, the transdisciplinary approaches developed in regulate could serve as an example of how effective knowledge integration can work in practice.

This article was first published in German on Transforming Economies.