Alpine lake is named 2021 water body type of the year

Nearly all German Alpine lakes in "good" ecological condition - but threatened by climate change

Der EibseeClick to enlarge
The Eibsee, an Alpine lake
Source: Thomas Gürke

The Chiemsee, Ammersee, Tegernsee, and Starnberger See are a few of the 14 impressive alpine lakes in Germany that enjoy popularity beyond the borders of the Alpine foothills. Clear, cold and comparatively oligotrophic water is their common property. Excessive algal growth is rare. Thanks to the extensive treatment of wastewater in sewage treatment facilities - and thus the minimisation of pollution - almost all alpine lakes now enjoy a "good" or "very good" ecological condition. However, changes occurring in the course of continuing climate change will also put a strain on alpine lakes and their ecosystems in the future. In order to strengthen their resilience, other human pressures such the diffuse inputs of nutrients and pollutants, bank reinforcement or the destruction of reed beds must be reduced as much as possible.

Alpine lakes are less polluted in particular in comparison to lakes in the North German Lowlands. Inputs of nutrients are especially low, which means little algal growth and a high degree of water transparency. This is mainly due to the alpine tributaries, which are naturally low in nutrients. The now widespread treatment of wastewater at sewage treatment plants in Germany, however, also contributes to the water quality, which is also reflected in a diverse flora and fauna. Stoneworts can once again be found growing in at even great depths in alpine lakes. Other typical species are the European crayfish, whose population is classified as " threatened" in Germany, and the alpine newt.

The task in the coming decades will be to preserve the Alpine lakes for future generations and to protect their ecological structure. To achieve this aim, all substance inputs should be drastically reduced and - where possible - built-up shoreline areas should be restored to their natural state so that shallow water areas can develop again in a semi-natural way. Climate warming and the resulting increase in water temperatures are changing the mixing regime and the water volumes of tributaries. Making the lakes more resilient to these changing environmental conditions must be the primary goal of reducing the other anthropogenic pressures to the extent possible.

World Water Day

For the eleventh time, the German Environment Agency is declaring the water body type of the year on the occasion of the United Nations World Water Day on 22 March. The observance day aim to draw attention to the diversity of water bodies in Germany, also as a contribution to the United Nations Water Action Decade (2018-2028). Intact water bodies are the lifeblood of a landscape and extremely valuable for people. This year's World Water Day is being held under the motto "Valuing Water".

EU⁠ Water Framework Directive ⁠

Monitoring the status of water bodies, identifying shortcomings and developing appropriate measures for their protection has been regulated uniformly in the European Union since 2000 by the EU Water Framework Directive. Many water bodies in Germany fail to achieve good ecological status due to excessive pollution and a multitude of structural changes. Continual efforts are called for to reduce these shortcomings and to ensure that water bodies remain ecologically intact.