Reka River barrier inventory, Slovenia

Inventorying all barriers in the Reka River catchment to identify and prioritise potential future feasibility studies and dam removal projects.


Meandering through a complex karst landscape, the Reka River carves the world-famous Škocjan Caves Park inscribed in the UNESCO World Biodiversity Heritage list. The fragile biodiversity of the caves, home to the fascinating and endemic olm, is under increased pressure due to numerous barriers on the Reka River that intensify the pollution in the river and fragment its populations of several Natura 2000 species, including marble trout and stone crayfish.

The river is still mostly natural, and its floodplains are mainly occupied by agriculture, which allows room for removal and restoration. Its ecological status is currently estimated as good, but fish populations are not included in the assessment. However, according to the local Fishing Club, many regulations are planned in the near future or are already on the way, so there is a clear need for immediate action. The local community, the fishing club and the Škocjan Caves authorities all favour dam removals and have already suggested several barriers to be removed.

At a glance

Project typeBarrier identification and prioritisation
Project statusLive
Key speciesItalian barble, Danube barble, marble trout and stone crayfish
Project websiteOzivimo

Project context and opportunity

A desktop survey identified 1145 barriers in the Reka River catchment. Still, these data are highly uncertain and outdated and only locations are known, which greatly limits the capacity to identify potential dam removal sites. The true distribution of barriers in the catchment, together with the key data (size, status, etc.), can help to understand the impacts on the riverine ecology and identify the most damaged barriers. This will lead to identifying the most ecologically suitable or socially acceptable dam removal sites to focus on.

Moreover, highlighting the lack of an official national database on river barriers can help encourage relevant authorities to increase their interest and engagement. This is urgently needed, as awareness about the negative effects of river barriers is low to non-existent among the general public in Slovenia, even among most of the fishermen. The results of this project will be published in Slovenian scientific and local journals as well as at two national conferences, this can help gain financial support for upscaling the inventory to the national level, start a public discussion about dam removal, start using prioritization methods etc., thus paving the way for dam removal movement in Slovenia. All large campaigns start small. Our experience with the citizen-science approach from the Reka River will help us replicate the same approach in other areas in Slovenia and/or eventually build a nationwide barrier inventory campaign.

Project aims

The project is focused on inventorying all barriers in the Reka River catchment through a citizen-science approach. A database of the barriers with the most important information, such as location, type of barrier, height, length, working condition, structure, photo etc. will be produced. This info is essential to identify potential low-hanging fruits and to perform prioritization so that future feasibility studies and dam removals can be planned and implemented as efficiently as possible. A local campaign will be performed to engage local people for barrier tracking and to build support for dam removal. The project team will train at least 50 people (locals, fishermen, students) to track barriers during three field workshops. Barrier Tracker will be presented, together with field protocols, to collect the key barrier data. Barriers will then be recorded during ten joint field tracking events.