Indicator: Ecological status of rivers | Umweltbundesamt

At a glance

• In 2021 only around 8 % of German streams and rivers were in at least a good ecological status or had at least a good ecological potential.
• According to the European Water Framework Directive, by 2015 with a time extension to 2027 all rivers must have achieved at least a good ecological status or potential.
• The time up to 2027 must be used to reach these demanding targets.
• The measures taken to date require more time to take effect. Other measures are also required.

Environmental importance

Streams and rivers are an important part of the environment. The landscapes away from the coastsare mainly shaped by rivers. Their status has deteriorated seriously in the past. Due to water engineering works over the last few centuries, around half of all streams and rivers are now considerably modified or artificial. Rivers are also polluted by contaminants and nutrients from industry, private households and agriculture.

Water pollution causes changes in the original species composition. The indicator primarily reflects the degree to which the current species composition in the rivers corresponds to the original composition. The closer the species diversity to the original status, the better the ecological status and therefore the more resilient the ecosystem. The ecological potential, on the other hand, is specified in significantly modified or artificial water bodies, because a comparison with the natural species composition is not possible in such cases.

Assessing the development

In 2021, the share of rivers in at least good ecological status or with at least good ecological potential has increased slightly by about 1 % compared to 2015. This share was just almost 8 % when last measured. The most important reason for this is that species communities which have been disturbed on the long term require time to recover. This was initially underestimated. However, the share of running waters in a bad or poor status declined further between 2015 and 2021. At the same time the share of running waters in a moderate ecological status increased slightly.

The European Water Framework Directive (WFD, EU Directive 2000/60/EC) was agreed in 2000. This set a target for all water bodies in Europe of a good or very good status by 2027 at the latest. The Federal States drew up management plans defining measures for improving water quality. Germany was not the only country that missed the 2021 target for most streams and rivers by a large margin. The current and subsequent management cycles under the WFD must now be utilised in order to achieve the ambitious targets as soon as possible.

Methodology

The ecological status of a stream or a river is primarily defined on the basis of the presence of different species and their abundances. This is compared with the species composition which would naturally be present in this type of water body. Five status classes are defined, depending on the degree of divergence, from ‘very good’ to ‘bad’. An ecological potential is assessed for artificial and heavily modified water bodies. The highest potential is present when all measures to improve the environmental quality have been taken which do not have a significant negative effect on use. The classification is laid down in the Surface Waters Ordinance (cf. water protection policy in Germany).

More detailed information: 'Ökologischer Zustand der Fließgewässer' (in German only).