The Association for Sewers and Waste Water (VKA) in Nidau is responsible for the waste water treatment plants from Port to Moeringen on the southern banks of Lake Bielersee. The Association manages several rainwater basins and pumping station. The Ipsach rainwater basin was built in the early 1990s. The unique feature is that this is a rainwater basin in a connected system. The receiving water cannot enter the lake by gravity but must be pumped into Lake Bielersee by four pumps of a combined discharge of 840 liters per second. The pumping station was repaired in the winter of 2011/2012.