Thirty of 35 Tirol lakes rated excellent for bathing

Thirty of 35 bathing waters in Tirol received an excellent rating in the fourth water-quality survey of the summer, ORF reported. Five bathing sites were rated good. The waters can recover quickly, officials said.

The latest measurements were carried out between August 3 and 8. Surveys are conducted several times during the summer to track and assess changes in water quality. They examine microbiological and hygiene parameters, as well as pH levels, oxygen saturation and water visibility.

Five sites receive good rating

The Stimmer See lake in Langkampfen, the Natterer See lake in Natters and the Reither See lake in Reith im Alpbachtal were rated good. Two bathing sites at Walchsee, in the camping area and at the lakeside promenade, also received a good rating.

The assessment considered indicator bacteria that can point to possible faecal contamination, along with water visibility and temperature.

Heat puts pressure on lakes

Experts said persistent high temperatures and lower water levels were leading to warmer water this summer. Smaller, shallower and more heavily warmed waters respond more quickly to prolonged periods of heat than large, deep lakes because their lower water volume allows them to heat up faster.

Andreas Murrer, head of the water ecology department at the Tyrol provincial government, said the sensitivity of each lake depended on several factors, including its depth, water exchange, inflows, shade, nutrient levels and use.

Water conditions can change during the bathing season, and individual measurements can improve again. At Natterer See, visibility measured with a Secchi disc was more than two metres in the latest survey, compared with one metre in the third survey. Murrer attributed the varying changes from lake to lake partly to the prolonged heat and dry period.