A Risk Assessment Approach to Drinking Water Safety: Integrating EU Water Policy Principles in Estonia

Ensuring safe and sustainable drinking water supplies is a global challenge, particularly in regions reliant on groundwater, where contamination risks are increasing due to human activities. In Estonia, groundwater provides most of the drinking water supply, yet contamination from agriculture, and industry poses significant risks. To address these challenges, frameworks aligned with the EU Water Framework Directive are needed to identify vulnerabilities for groundwater bodies and implement targeted risk management strategies.

Static protection zones have traditionally safeguarded groundwater, but dynamic, data-driven approaches better manage risks by understanding catchment areas and contamination pathways. This study introduces a comprehensive risk assessment methodology designed specifically for Estonia's hydrogeological conditions, focusing on contamination risks associated with drinking water abstraction areas.

Using hydrodynamic modeling (MODFLOW-6) and GIS tools, groundwater flow was calculated to 28-year period to identify catchment areas and link contamination sources with indicators and substances specified in regulations. Conceptual models were developed to help water operators describe the natural chemical composition of drinking water sources and the dynamic characteristics of catchment areas during risk assessments.

The methodology was validated across diverse hydrogeological settings in Estonia. Results show that integrating advanced modeling with stakeholder-driven tools significantly improves the accuracy of risk assessments compared to static approaches. This framework enables targeted management strategies to reduce contamination risks and effectively protect drinking water quality.

By aligning with EU water policies and providing user-friendly tools, this approach offers a scalable solution for similar groundwater challenges elsewhere. Empowering stakeholders ensures long-term water resource protection and sustainable governance.