Southwest Delta

In the Southwest Delta, the Rhine, Meuse, and Scheldt rivers flow into the sea. Following the disastrous flood of 1953, the Delta Works were constructed here to restore the area’s flood protection. The dams and storm surge barriers have considerably shortened the coastline. The process has created several types of water basins: freshwater and saline basins, with or without tidal movement. 

The area features several complex taskings in the fields of flood protection, freshwater supply, and spatial planning. In part, these taskings ensue from climate change. That is why a Preferential Strategy for this area has been drawn up under the national Delta Programme.  


The Delta Works have also caused new problems: erosion of intertidal areas and issues relating to water and soil quality. Every year, the freshwater Lake Volkerak-Zoommeer is prone to excessive growth of blue-green algae, as a result of excessive nutriment content and insufficient flushing. Lake Binnenschelde and Lake Markiezaatsmeer – which have become isolated due to the Delta Works – are also affected by recurrent water quality issues. The deeper sections of the Grevelingen lake bed are deprived of oxygen due to insufficient flow. In the Oosterschelde, sand continues to disappear due to erosion of the shoals (sand deficit of the channels).  

These issues have a negative impact on the sustainable development of the regional economy. In addition, climate change and the ensuing salinisation are jeopardising the balance between freshwater supply and freshwater demand. In the long run, the rising sea level will be posing new risks in terms of flood protection. All this calls for a knowledge programme to map out the bottlenecks and potential solutions.  

Preferential strategy

In order to address these challenges, a comprehensive Preferential Strategy for the Southwest Delta has been drawn up under the national Delta Programme. The Strategy sets out goals and measures aimed at preserving the flood protection, the proper ecological operation, and the utility functions of the area. With respect to the freshwater supply, a supplement has been drawn up: a further elaboration of the overall freshwater supply programme. 

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