Veleka River trapped: Dozens of barriers block fish migration

13.05.2026 | Ecology

A BSPB expedition revealed that dozens of outdated weirs and spillways along the Veleka River are blocking river connectivity and threatening the ecosystem.

Снимка от Pudelek, Wikimedia Commons, под лиценз CC BY-SA 3.0

The Veleka River under the pressure of outdated infrastructure

Dozens of outdated weirs, sills, and spillways are blocking the free movement of fish along one of the best-preserved rivers in Europe – the Veleka.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

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.