Algal bloom occurring in the Ilz River

Increased concentration detected in Lake Hallstatt region

, and Administrator

2025 September 16 . 10:42 AM

2 min read

Algal bloom occurring in the Ilz River

In the picturesque Ilz river near Hofbauerngut, a swimming ban has been in place for several years due to insufficient water quality. On August 8, 2025, the Health Department of Passau reported an increased presence of blue-green algae, which is causing the reduced water clarity in the area of the Halser Dam.

The blue-green algae, a type of cyanobacteria, can pose a risk to both humans and animals. Young children should avoid the water, especially in the shoreline area, and swimming, as well as engaging in water sports, should be avoided in affected waters. Dogs and other warm-blooded animals are also at risk from blue-green algae.

Swallowing water from affected waters should be avoided, and intense skin contact may cause skin irritation or allergic reactions. Avoiding visible algal mats in affected waters is crucial for safety.

The report concerns the Ilz river near Hofbauerngut, and the issue is related to water clarity. Proposed projects for a floating structure in the Ilz valley between Hals and the Triftsperre are not currently known, and there are no relevant decisions from authorities in publicly accessible sources.

The Ilz river plays a significant role in the natural and water protection, and projects in this area would likely be reviewed by several authorities, including the Water Management Office in Deggendorf, the Lower Nature Conservation Authority at the Passau Landratsamt, the Bavarian Government (higher and upper nature conservation authority), and the Bavarian Environmental Office (LfU).

If you have specific questions about the project, the Landratsamt Passau (Water Rights, Nature Conservation, and Building Department) and the Water Management Office in Deggendorf are the first points of contact for such projects. For more information, you can also contact the Bavarian Government or request information under the Environmental Information Act if existing permits are available.

Without more details about the project, it is not possible to name a specific responsible authority. If the situation is a specific incident, please provide a detailed project description and timeline so that targeted research can be conducted. In standard procedures, the Landratsamt Passau (lower water authority) and the Water Management Office in Deggendorf are the initial points of contact for such projects. If you need help formulating a specific inquiry, I'm happy to assist!