The Barriers of Istria Project will deliver the first systematic identification and prioritisation of obsolete river barriers in Istria County, with the explicit goal of enabling one or more viable barrier removals supported by ORP within a reasonable timeframe.
Istria County’s catchment encompasses three principal rivers – Mirna, Raša and Dragonja – covering approximately 2,813 km². The region features a Mediterranean climate, karst geology and fertile soils supporting agriculture, viticulture and olive production. Istria is Croatia’s most visited tourist destination, with relatively low poverty rates and a diverse economy combining tourism, shipbuilding and agriculture.
The rivers support 36 recorded fish species, including several endemic and critically endangered species such as Adriatic sturgeon (Acipenser naccarii), Adriatic brook lamprey (Lethenteron zanandreai) and the globally significant olm (Proteus anguinus). The region faces significant pressures from seasonal tourism, water infrastructure demands and widespread fragmentation caused by undocumented weirs, small dams and culverts that obstruct fish passage and river connectivity.
| Project status | Live |
|---|---|
| Project type | Barrier identification and prioritisation |
| Country | Croatia |
| River | Mirna, Raša, Dragonja |
| Focal species | Acipenser naccarii, Acipenser sturio, Lethenteron zanandreai, Barbus plebejus, Padogobius bonelli, Anguilla anguilla, Proteus anguinus |
| Organisation | WWF Adria in partnership with Natura Histrica |
| Website | wwfadria.org/hr/ |
Despite Istria County’s exceptional ecological significance as home to endemic fish species of the Adriatic basin and the rare olm, there has never been a systematic inventory or prioritisation of artificial barriers fragmenting its freshwater systems. This critical knowledge gap prevents effective planning and implementation of barrier removals, which are essential for restoring river connectivity, improving water quality and enhancing biodiversity.
Current public funding sources in Croatia are limited and typically directed toward larger infrastructure projects rather than barrier mapping preparatory work. The Open Rivers Programme offers a unique opportunity to fill this foundational gap and create a replicable model for barrier identification and restoration planning that can be adapted throughout the Adriatic region and Western Balkans.
The Barriers of Istria Project will systematically identify, document and prioritise obsolete river barriers across Istria County, creating a robust, field-verified database and a transparent prioritisation framework. Key goals include:
delivering the first comprehensive inventory of barriers using systematic field surveys and e-DNA methodology;
developing a georeferenced database with ecological and technical attributes;
identifying 5-10 high-priority barriers suitable for removal, with 1-2 candidates prepared for immediate ORP-supported demolition;
building local and regional capacity through stakeholder engagement and training;
creating a replicable methodology applicable across Croatia and the Adriatic basin.
Expected outcomes include restored river connectivity (10-20 km of river segments reopened), enhanced habitat quality for endemic species and a sustainable framework for ongoing river restoration aligned with EU Biodiversity Strategy targets.
Funded by
