Veleka River trapped: Dozens of barriers block fish migration

The Veleka River under the pressure of outdated infrastructure

Dozens of outdated weirs, sills, and spillways are blocking the free movement of fish along one of the best-preserved rivers in Europe – the Veleka. This became clear following a large-scale field expedition by the Bulgarian Biodiversity Foundation (BBF).

The "Veleka Without Barriers" project aims to create a database of river barriers to facilitate their removal and the restoration of the ecosystem by 2026.

Results from the field study

• 25 barriers along the Veleka River and its tributaries, the Katun and Aydere, were assessed.
• Most of the structures are past their expiration date or serve no real function.
• Accumulated trees around old barriers create a risk of flooding during high water levels.

The most serious problem

The largest barrier is a massive 4-meter concrete weir under the bridge of the Aydere River. The fish pass there is completely destroyed, making fish migration impossible throughout the year.

The data will be submitted to the Black Sea Basin Directorate to prioritize the removal of these obstacles. The project is funded by the Open Rivers program and will continue until September 2026.