Department Surface Waters - Research and Management

Pollution, embankments, hydropower – rivers and their biological communities are severely degraded, in Switzerland and elsewhere. With climate change, the pressure on river ecosystems is increasing. For example, the frequency of floods and droughts is expected to increase.

To cope with these extreme conditions, many insect larvae, fish and aquatic plants depend on refugia. Refugia are areas in the river where organisms retreat, for example to avoid drift by increased flow velocities. Refugia can be found, for instance, in submerged banks, backwaters, side channels or tributaries. Channelization has transformed many rivers and streams into monotonous channels without refugia.
The aim of restoration projects is to increase the diversity of habitats in the rivers, both at medium flow and during extreme events.

In subproject 2 of the “Resilient Rivers” project of the “Hydraulic Engineering and Ecology” research programme, we investigate the availability of refugia and the community composition of macroinvertebrates, aquatic plants and riparian vegetation in channelised, restored and (semi-) natural river reaches. We use extensive field surveys and hydraulic modelling, in close collaboration with partners from science and practice.
Our studies contribute to a better understanding of refugia as key habitats for survival and ecosystem functioning.