Preparatory work for barrier removal on the Bijela and Trešanica Rivers, Bosnia and Herzegovina

Introduction

The Neretva River Basin is one of the most important freshwater biodiversity hotspots in Southeast Europe, supporting a high number of endemic fish species. The upper Neretva, particularly within the municipality of Konjic, includes around 60 km of largely free-flowing river, along with key tributaries such as the Bijela and Trešanica.

These tributaries play a crucial ecological role as spawning and refuge habitats for endemic salmonid species. Despite their relatively preserved condition and high water quality, river continuity is disrupted by several small barriers, including concrete weirs and ramps constructed decades ago.

Many of these structures are no longer functional or are only partially used, yet they significantly hinder fish migration and sediment transport. Their proximity to key spawning areas further increases their ecological impact.

Project context and opportunity

River restoration and barrier removal initiatives in Bosnia and Herzegovina are still at an early stage, with limited institutional support and no dedicated funding mechanisms. At the same time, increasing pressure from hydropower development threatens the remaining free-flowing rivers.

Previous field research identified 11 barriers across the Bijela, Bukovica, Baščica, and Trešanica rivers. This project focuses on two priority sites, selected based on ecological importance, feasibility, and stakeholder acceptance.

By initiating concrete preparatory steps, the project lays the foundation for future large-scale restoration efforts in the Neretva Basin

Project aims

The main goal of the project is to prepare concrete restoration measures for priority barriers on the Bijela and Trešanica rivers, including both removal and ecological improvement interventions.

Specific objectives include:

• Developing feasibility studies and technical documentation for each site
• Designing appropriate solutions for barrier removal and fish passage
• Conducting ecological assessments, with a focus on fish migration and habitat connectivity
• Initiating permitting procedures in cooperation with relevant authorities
• Engaging stakeholders, including local communities, fishing associations, and public institutions
• Raising awareness of the importance of river connectivity and restoration

By the end of the project, the selected sites will be fully prepared for implementation. The project thus contributes to restoring ecological connectivity, improving spawning conditions for endemic fish species, and strengthening local capacity for river restoration.