The decision to build an open barrier had several consequences. With a dam, tidal movements would have been completely eliminated. Without intervention, the tidal movements would have been remained. Because of the construction of the storm surge barrier, ebb and flood tides lost their power. The tidal movements were reduced by 25%. This meant that salt marshes stood clear of the water at many sites where they would have normally been flooded during high tide. To raise the water level, it was decided to reduce the Oosterschelde. The Oosterschelde had to be divided into compartments. The dams that were designed for this purpose were called compartment works for that reason. These dams are the Philips dam (between the Grevelingen dam and St. Philipsland), the Oyster dam (between South Beveland and North Brabant) and the Bath Spui canal (a Spui lock through South Beveland). Consequently, the closed waters (Krammer, Volkerak, Zoom lake and Markiezaat lake) turned fresh. Besides reducing the Oosterschelde, the dams were also built to guarantee a stable water level in the Scheldt-Rhine connection. A solid connection was of high importance to the accessibility of the port of Antwerp. Furthermore, the dams played a part in the water control and the environmental protection of, for instance, Western Brabant. By creating freshwater lakes between the former coast and empoldered land, water became available for the agriculture, which had been plagued by salinity for a long time.