But the focus is not only on bathing suitability, the general condition of the lakes has also been observed for 15 years. The quality of Mondsee and Traunsee went up again.
Even if Upper Austria’s bathing lakes are consistently of high water quality, some even have drinking water quality, the ecological and nutrient-related conditions of 14 lakes were also surveyed in a series of measurements. The aim was to record toxic pollution, such as that caused by blue-green algae, or to record the heat development in the water. In addition, water components were analyzed and trends recorded. The result: 70 percent of the bodies of water correspond to “the targets of the Water Framework Directive” and are at least in “good ecological condition,” explained Sabine Kapfer from the Water Management Department at a press conference with Environment Councilor Stefan Kaineder (Greens) on Tuesday.
Too many nutrients
However, 20 percent of lakes have too many nutrients. Traunsee and Mondsee, for example, had quality problems. In the Traunsee, a saline, low-oxygen layer had formed at a depth of 80 to 100 meters due to long-term discharges from soda production, which is why there was no longer full circulation of the water, according to Kapfer. After soda production stopped, it took 13 years until that layer was thinned enough in 2018 for the water to circulate from the surface to the bottom again.
Critical visibility depth
The Mondsee, on the other hand, had a critical visibility depth due to the nutrient conditions. Above all, agriculture was challenged. Quality control for agriculture was extended to Mondsee in 2013 and more attention was paid to the proper application of liquid manure. But the phosphorus precipitation in the association’s sewage treatment plant has also been optimized. The Mondsee has been in good ecological condition since 2015.
Kaineder once again named climate change as a challenge for the future of water bodies. He warned that an increase in water temperature would have a massive impact on the water ecosystem. In order to prevent the rivers from heating up too much, they have started to let the riparian trees grow again. Natural shading counteracts the warming of the water.
Source: Nachrichten
