The Sösestausee was built from 1928-1931 and is located on the road from Osterode to Riefensbeek-Kamschlacken. On the one hand, it serves to regulate the water in the prairie in order to avoid the annual spring floods. Furthermore, it supplies, together with the Granetalsperre, large parts of Lower Saxony and Bremen with drinking water. With a capacity of more than 25,000,000 m³ and a 56 meter high and 500 meter long dam wall, it was for a long time the largest drinking water dam in Germany.
Therefore, it is also closed to water sports of all kinds. Fishing is allowed though. The dam with its length of approx. 3 km can be negotiated by bicycle or on foot. On the dam there are more interesting hints to the dam and drinking water production;