After the reconstruction of the steel mill in Witnica, which had been destroyed by the Russian army in 1758 during the Seven Years’ War, the water demand of the facility increased. Under the supervision of F. B. Brenckenhoff, a great hydroengineer of the Frederician Prussia, a channel was built between Poritz See lake and the Witna spring in order to increase the water flow in the Witna. The gradually lowering of the water table in the lake resulted in the historic Poritz See lake being divided into the smaller reservoirs, known today as Lake Dzikie, Lake Łabędzie and Lake Gęsi. A section of the channel can be seen from a dirt road from Mostno to Witnica.