On the side of the lake facing Braunsen, there is an upstream impoundment that was turned into a nature reserve in 1976.
This area is now a haven for water birds ('red list' of endangered species) such as mallard, teal and grey heron as well as many other animals and plants.
There are two observation stations for watching endangered water birds right in the nature reserve. Information panels provide details about the diverse bird life in the area.
The first bird watching station can be reached from the Vorstau car park in the Braunsen direction; the second one from the hiking and cycling trail towards Braunsen.