Free-flowing rivers

Free-flowing rivers is still a new concept under European legislation, but it is expected to become an important driver for river and floodplain restoration. Free-flowing rivers have the potential to support multiple policy objectives through improved delivery of ecosystem services:

• Improved achievement of biodiversity objectives, including improved conservation status of riparian habitats and species.
• Improved achievement of ecological status of the Water Framework Directive
• Improved carbon sequestration in floodplain soils
• Improved use of natural water retention measures for disaster risk reduction

For a river to be free-flowing, neither transversal nor lateral barriers are to be in place. Transversal barriers, such as dams and weirs, disrupt the flow from upstream to downstream, and cut the longitudinal connectivity. In contrast, lateral barriers such as dikes, river bank stabilization, or drainage alter the natural movement of water and sediments, to and from the floodplain, and cut the lateral connectivity.

The relationship between river hydrology and morphology, also known as river hydromorphology is formally recognized as critical for the quality of aquatic environment. It is one of the supporting quality elements under the Water Framework Directive. The reporting under the Water Framework Directive has shown that for about one third of Europe’s surface water bodies it is a reason for not achieving good ecological status.