The Donnersbach is an alpine, crystal-clear and mostly undeveloped, well-structured mountain stream with a wide variety of flow characteristics, small pools as well as a short dammed-up area.
The total length is 9 km, extending from the reservoir at the entrance to the valley to the weir next to the Lahrerweg, and is exclusively for fly fishing using barbless hooks. The fishing area comprises all of Donnersbachwald Valley and flows right past Gasthof Pension Appartements "Zur Gams".