After the Deltaworks

Battle against the sea

Village of Serooskerke, Schouwen
Village of Serooskerke
After the construction of the Deltaworks, the inhabitants of the Delta area were finally able to catch their breath. A disaster such as the one in 1953 would not occur again in the near future. The chance of such a disaster happening again was drastically reduced. During the five decades following the disaster, other opportunities and threats faced the nation. The Deltaworks were an important chapter in the history of the Dutch battle against the sea, but it was not the final word. To keep the Delta area and the rest of the Netherlands safe, a lot more will have to be done than simply giving the dams a new lick of paint every now and then.

A broad approach

Nederlands landschap
Since the flood disaster of 1953, the Dutch have developed a new sense for water management. It was realised that not only is the sea a threat, but that water in general can be very dangerous. Water also comes from the rivers and the sky. Due to climate changes, the amount of water will increase, especially in the winter. On the basis of data collected by the KNMI, the Royal Dutch Meteorological Institute, it was calculated that the summer of 2004 was the wettest summer since 1951. On average, the precipitation was 314 mm for the whole of the Netherlands, whereas it is normally only 202 mm. So, the summer was extremely wet. Flooding occurred at many places, and rivers had to process large quantities of water. These, and other developments, have made the Dutch water management more than just the protection of the coast. Moreover, the image of the sea as an enemy has been proved wrong, or rather incomplete. Safety for people living in coastal areas is still top priority, but factors such as nature, recreation and habitation also have to be taken into account. 

The Oosterschelde as a starting point

The choice for an ‘open’ storm surge barrier in the Oosterschelde, instead of an ‘closed’ dam can be regarded as a turning point in the conception of water. Firstly, the Oosterschelde would be dammed. That was the best solution to provide safety for the people living in this area. However, different social powers campaigned against the damming of the Oosterschelde. They stressed that although safety was an important issue, other factors had to be taken into account as well. The unique freshwater environment of the Oosterschelde was one of these factors. After a long discussion and balancing the pros and cons of each alternative, it was decided to build an open barrier. Water quality, the environment, nature, fishery, recreation, agriculture, shipping and industry were all considered. These kind of policies in which as many factors as possible are taken into account are called ‘integral water management’. The Oosterschelde project proved that it was possible to unite different stakes.

Consequences of the Deltaworks

Although a barrier was built in the Oosterschelde, the tidal movement was reduced by about a quarter. As you can imagine, the influence on the nature of the other dams was even greater. Except for the Oosterschelde and Westerschelde, all the estuaries were closed. Where the salty seawater could originally stream back and forth, the water behind the dams was brought to a halt. The tidal movement stopped and the saltwater became fresh. Some areas that had always been flooded during high tide were uncovered. Other areas of tideland on the other hand were always covered by water. Channels, streams and coves became silted up and mud flats and shallows caved in. Saltwater fish died and birds moved away. Gradually, other species replaced them. These developments can never be reversed. What humans can do, however, is give nature plenty of room, within certain borders. In for instance the Haringvliet, the Hollandsch Diep and the Biesbosch, people try not to interfere with nature any more. However, the way in which the province of Zeeland looked, will never be the same again. It is shocking, but not insuperable. Other plants and animals, which are not any less unique, have replaced the ones that disappeared.

Example projects

Salt marshes near Sint Philipsland
Salt marshes
Since 1985, several nature development projects have been carried out. On the former artificial island Neeltje Jans, beaches, dunes and bird islands arose or were created. The concrete and steel of the Deltaworks have become home to all kinds of shells and seaweeds. Another example of a good project is the Haringvliet. When this estuary was closed in 1970, the water gradually turned fresh. Fish, such as eels, stickleback and smelt died, since suddenly, they could no longer make their way back to the North Sea. The freshwater fish that replaced these saltwater fish were discharged into the sea when the Haringvliet outlet sluices were used. After extensive research and much debate, it was decided to open the Haringvliet sluices for 95 percent of the time. The sweet water fish will disappear again, but the original inhabitants will return for good. Until now, the sluices have only been set ajar, since many things had to be dealt with first. Only after the drinking water supply is secured and agreements made with adjacent municipalities, local farmers and fishermen, can the Haringvliet become a barrier instead of a dam.

The future?

Stormvloedkering during a storm in the end of 1986
Due to climate changes, the sea level will rise by 10 to 90 centimetres in the next century. Significant higher quantities of precipitation are also expected. At the same time, the west of the Netherlands is sinking because of long-term geological processes. The ground is sinking even more, since the Dutch are experts at draining water (and soil!) into the sea. So, the threats are two-fold: on one side, sea levels are rising, and on the other side, the ground is sinking. To protect the Netherlands, the Oosterschelde and Maeslant barriers will have to be closed more often in the future. In order to keep the Oosterschelde open, the dikes around the estuary will have to be reinforced as well. However, bigger and broader dikes need more space – space that is currently being used for nature, habitation or recreation. The Deltaworks have surely solved the safety problem, but they have simultaneously created another problem. Water management goes far beyond the construction of more and more dams and dikes.