Every dam needs a flood relief system so that even exceptionally large floods do not overflow the dam crest. At the Oderteich it is the flood relief system at the eastern end of the dam and is also called the large outflow.
In the reservoir in front of the outflow, a few menhir-like steles made of granite, about 2.50 meters high, stand out. They are used to keep ice floes away from the overflow, as they could block the drain cross-section, i.e. move it. The protection system of the old outflow was made in 1895 by the royal central smithy in Clausthal. It makes it possible to increase the storage target by another meter.
Originally, the outflow continued straight ahead for almost 100 meters in a southerly direction before the water could tumble down into the valley. This route is still recognizable to the trained eye in the field. When, towards the end of the construction work in 1722, stones were still missing for the completion of the dam wall, the steeply sloping and approximately 80 meter long Great Outflow was blasted out of the rock about 60 meters below the protection system at a right angle to this outflow, with which one could probably get a cheaper hydraulic one expected performance. The firing range carved into the rock is very impressive, especially when in operation.
In 1886/87 it was concluded that the efficiency of the outflow had to be further increased. To this end, a few meters to the east of the existing outflow, another outflow, twelve meters wide at the inlet, was built, the overflow sill of which is about one meter above the sill of the old main outflow. It crosses under the B 242 parallel to the main outflow and merges with it shortly before the overflow gauge and the subsequent chute. As a result, the capacity of the spillway system could be increased by around 50%.