ZAGREB – A river barrier appeared on Wednesday in Gajeva Street in Zagreb. Seemingly blocking pedestrians’ passage, this symbolic barrier is actually meant to illustrate how obstacles on rivers and streams disrupt natural processes.

“This barrier slowed down pedestrians for just one day in the city center to draw attention to the serious problem posed by hundreds of old, neglected, and decaying barriers that are harming our rivers and streams — and costing nature dearly,” said Matea Jarak from WWF Adria, the WWF's regional branch, which erected the barrier to mark European Dam Removal Day. In doing so, Zagreb joined numerous European cities that are raising their voices in support of restoring the free flow of rivers.

Barriers in nature are more than just unnecessary structures — they obstruct fish migration, reduce biodiversity, and, when poorly maintained, pose risks to human safety. Across Europe, more than 1.2 million barriers fragment rivers. Tens of thousands of them are outdated and degrade waterways by blocking the natural flow of water, sediment, nutrients, and species. This disruption weakens ecosystem resilience and the services they provide, contributing to a catastrophic loss of nature, including a 75% decline in migratory freshwater fish populations in Europe since 1970, according to the Living Planet Report 2024.

So far, WWF has managed to achieve several positive results in our region as well. In the area of Plitvice Lakes National Park, eight outdated barriers were removed from the Bijela River in cooperation with the park, restoring nearly 8 km of the river’s flow and ensuring better migration for endangered species such as the Danube salmon. In Montenegro, we carried out the first barrier removal in our region by demolishing three barriers on the Vezišnica River, a tributary of the Ćehotina, which has recently been designated a natural monument.

“Removing barriers on watercourses is one of the activities that most contributes to the implementation of the Nature Restoration Law, and it is being carried out worldwide. We have demonstrated that barrier removal has a positive impact on ecosystems through the project on the Bijela River, where during the first monitoring of the Danube salmon we observed young individuals using newly liberated sections of the river,” concludes Jarak. More about the barrier removal in Plitvice Lakes National Park can be found in the report published today, Progress in Barrier Removal in Southeastern Europe.

In addition to actively removing barriers, WWF, in cooperation with numerous organizations and with public support, has also succeeded in preventing the construction of two new hydropower plants on the Drava River, which would have further threatened natural water flows and biodiversity.