They decided to construct two parallel dams. Between these two dams the lake will have a constant water level. From the Kreekrak-sluizen in Zuid-beveland to the Hollands Diep there will be an immense fresh water buffer. This buffer is mainly used to control subsoil water levels in Noord-Brabant. Of course this lake became popular by tourists for recreational purposes for the water must have a high quality. It is not easy to keep this quality for the lake can be polluted with salt water by the locks from the Kreekrak-sluizen in the Philips-dam. Therefore an ingenious system is developed to keep fresh water and sea water separated. When the pollution with salt water is unacceptable all the water can be flushed by the channel .