Effective immediately, a ban has been implemented on accessing and swimming in both the Wiese and the Birs rivers as a result of the persistent heat and low water levels. This applies both to people and to domestic animals, so you are not allowed to let your dogs cool off in the rivers! The ban, which also includes the use of boats, stand-up paddleboards, or inflatable boats on these waterways, applies to the Wiese river between its mouth and the border with Germany, as well as to the Birs river between its mouth and the Reding Bridge. Fishing is also prohibited in these sections of the rivers. Swimming and fishing in the Rhein and in the remaining, unmarked sections of the Birs is still permitted. The ban remains in place until further notice, and violations will be punished with a fine of 100 francs.

The persistently high water temperatures, combined with low water levels, are causing significant heat stress for many fish species in the Wiese and Birs rivers. As temperatures rise, the oxygen content of the water decreases, while at the same time the fish’s metabolism increases, raising their oxygen demand. Heat-sensitive species are therefore seeking out cooler, more oxygen-rich sections of the water and retreating to the few remaining deeper areas. Due to the limited refuge, there is a high concentration of fish, leading to additional population density stress. Nase, grayling, and juvenile salmon are particularly vulnerable. Swimmers and pets represent an additional stress factor for these weakened fish. According to weather forecasts, no improvement in the temperature and water level situation is expected in the coming days, until at least early next week. To increase the survival chances of endangered fish, this ban on swimming and accessing the river for both people and domestic animals has been implemented until further notice.  

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