About project

RARE-G is a cross-border initiative co-funded by the Interreg Central Baltic Programme. It aims to reduce pollution and hydraulic loads from urban wastewater and stormwater systems entering the Baltic Sea. The project runs from June 2026 to May 2029 and brings together five partners from Latvia, Estonia and Finland.

Urban drainage systems across the Central Baltic region face a shared set of pressures. Ageing infrastructure, rainwater and groundwater entering wastewater networks, hydraulic overloads during heavy rainfall, and gaps in data and digital capacity increase the likelihood of overflows, flooding and untreated discharges. Climate change is intensifying these risks and making proactive infrastructure management increasingly important.

RARE-G responds by linking practical nature-based investments with a common, geo-enabled approach to risk assessment. Partners will combine network, spatial, hydraulic, monitoring and water-quality information in a GIS-based framework. The framework will support the identification of vulnerable network sections and pollution pathways, comparison of intervention options, and transparent prioritisation of future investments.

Project approach

• Assess partners’ data availability and digital maturity, establish a shared data structure and identify information gaps.
• Survey and design pilot sites and define common monitoring and maintenance requirements.
• Develop and apply a GIS-based network risk assessment and resilience evaluation framework.
• Construct nature-based solutions and install the monitoring needed to assess hydraulic and water-quality performance.
• Compare pre- and post-intervention data, document effectiveness and prepare transferable guidance for replication.
• Exchange experience across borders through partner cooperation, a mid-term event in Viimsi and a final conference in Jūrmala.

Pilot solutions

Jūrmala, Latvia

A rain garden will be developed in the Ķemeri/Durbe area near the Durbes Street wastewater pumping station. The solution is intended to reduce hydraulic pressure in the Vēršupīte catchment, lower overflow and pollution risks, and improve water quality near the buffer zone of Ķemeri National Park. Monitoring and sensors will provide evidence for network operation, maintenance and investment decisions and help identify abnormal flows, infiltration and overloads earlier.

Viimsi, Estonia

Viimsi Municipality will implement a stormwater treatment solution combining a man-made waterfall and retention pond. The pilot will manage flows, support pollutant removal and demonstrate how engineered and nature-based elements can be integrated in an urban drainage system.

Kaarina, Finland

The City of Kaarina will implement two nature-based stormwater management pilot sites. Their performance will contribute to the project’s joint evidence base and provide practical experience that can be compared and transferred across the partnership.

Main outputs and lasting value

• Four improved urban load sources across the three participating countries.
• A tested, transferable GIS-based risk assessment and resilience evaluation framework.
• Digital maturity assessments, structured spatial and monitoring data, and risk maps supporting intervention priorities.
• Technical documentation, monitoring methods, effectiveness findings and maintenance guidance for nature-based solutions.
• Stronger capacity among municipalities and water utilities to plan climate-resilient, evidence-based urban water investments.

Why cross-border cooperation matters

Urban wastewater and stormwater pollution does not stop at administrative or national borders: loads from local systems ultimately affect shared coastal waters and the Baltic Sea. Latvia, Estonia and Finland bring complementary operational, municipal and research expertise. Applying a common approach in different urban and environmental settings makes the framework and pilot lessons more robust, comparable and transferable than solutions developed at a single site.

For more information, contact:

Project Management – Lead partner:
Aivars Kamaruts
📞 +371 29 209 695
📧 aivars.kamaruts@jurmalasudens.lv