Much of the water in Switzerland no longer flows naturally. Nearly one quarter of the total length of watercourses is artificial, covered over, or impaired by the construction of obstacles.

Many lakes also have artificial embankments to protect against erosion. But at the same time, they hinder the lakes' self-cleansing mechanism.

Dramatic and repeated flooding of some rivers in the 19th century led to a widespread movement to channel them and to straighten their courses.

The best known examples are the Linth correction, between Lake Walen and Lake Zurich, and the Jura waters correction in the area of Lakes Biel, Murten and Neuchâtel. This solved a chronic problem for people living in these areas and created large tracts of usable land.

Since then many Swiss rivers have been channelled and embanked. This has led to a reduction in the natural habitat and aa loss of biodiversity. It has also tended to push the problem of flooding further downstream as the floodplains were drastically reduced.

Today many rivers are being returned to their natural state.