The Philips Dam
Even though the Oosterschelde Barrier has an open character, it was inevitable it would reduce the Oosterschelde estuary. less seawater could flow in and out the Oosterschelde, which reduced the contrast between low tide and high tide. Salt marshes and mud flats came into jeopardy despite the good intentions. To overcome this, two more dams were built on the eastern part of the Oosterschelde: the Philips Dam and the link: the Oester Dam. First of all these dams reduced the surface of the Oosterschelde and supported the ebb and flow of the tides in the remaining area. These dams meant salvation for not only the salt marshes and mud flats but also for the oyster farming in Yerseke. To a greater extent oyster farmers are dependent on the tidal movements for the harvest. Secondly, tidal free water arose behind the dams which was a part of the Scheldt-Rhine Link. Thirdly the two dams, together with the Oosterschelde Barrier, protected the area behind them against high water levels. The so-called compartmentalisation works belong the Markiezaatkade, the Bathse Spuikanaal and the Bathse Spuisluis.
The Philips Dam can be divided into two parts. The northern part runs from the lock complex on the Plaat van Vliet (in the Volkerak) to the connection on the Grevelingen Dam. The southern part runs from the lock complex to Sint-Philipsland. The dam was placed as far back as possible on the Oosterschelde, because otherwise the salt marshes of Sint-Philipsland would have ended up behind the dam. The stagnant freshwater would have meant the end of the salt marshes. The construction of the Philips Dam was facilitated by temporarily closing down the Oosterschelde Barrier. This method was also used for the construction of the Oester Dam.
In the years 1977 and 1978 an artificial island of 96 hectares (0,96 km²) was built on the Plaat van Vliet. The building excavation on the island covered an area of 19 hectares. In order to build the excavation, 100 hectares were dug up and 130 hectares were filled in. A total of approximately 370,000 m² of concrete was poured in, containing 27,000 tons of armoured steel. The locks were finished in the middle of 1984 and the dam in 1987. In the meantime a large amount of sand was raised on the route between Sint-Philipsland and the Grevelingen Dam.