Optimizing river restoration: A multi-scenario approach to barrier removal prioritization

Area of Science:

• River ecology
• Conservation science
• Spatial planning

Background:

• River barriers fragment ecosystems, disrupting connectivity, sediment transport, water flow, and biodiversity.
• The EU Nature Restoration Law (NRL) mandates river connectivity restoration through barrier removal.
• Effective implementation of the NRL requires data-driven prioritization strategies for barrier removal.

Purpose of the Study:

• To develop and apply a multi-scenario spatial optimization framework for prioritizing river barrier removal.
• To identify areas that maximize ecological benefits (biodiversity, erosion reduction) while minimizing socio-economic impacts.
• To support effective river restoration planning by balancing ecological and socio-economic considerations.

Main Methods:

• Utilized a multi-scenario spatial optimization framework combined with multi-criteria decision analysis.
• Evaluated seven conservation scenarios focusing on biodiversity, erosion, and human impact mitigation.
• Applied the framework to the Morava sub-basin within the Danube Basin.

Main Results:

• Prioritization of barrier removal varied significantly across scenarios due to differing costs.
• Identified consistent high-priority areas crucial for improving connectivity and riparian restoration.
• Potential to restore 1011 km of free-flowing river and 604 ha of riparian zones by removing barriers in identified priority areas.

Conclusions:

• Scenario-based spatial optimization offers a structured approach to balancing ecological restoration with socio-economic constraints.
• Addressing data gaps for small barriers and expanding analysis to larger scales are crucial for future refinement.
• Transboundary cooperation is vital for achieving large-scale river restoration goals, such as the NRL's target of 25,000 km.