Third advice

On February 27th, 1954, the Deltacommission gave its third piece of advice, in which they would focus on damming the sea arms. Closing the sea arms would cause coastal reduction, and reduce the number of places that the sea has a direct effect upon. Damming the Haringvliet, the Brouwerhavense Gat, the Eastern Schelde, and the Veerse Gat would prevent high water levels arising in the sea arms.

The advantages of closing the tidal inlets
Closing the tidal inlets had a number of advantages compared to raising the current dikes:
1. Raising the current dikes would be more expensive, more difficult, more dangerous, and less effective compared to damming the tidal inlets.
2. Damming the sea arms would prevent the water remaining brackish
3. Building dams between different islands would provide good connections with the rest of the Netherlands
4. Raising the current dikes would cost land, while building dams would actually reclaim a modest amount of land.
5. By implementing the Deltaplan, a unique recreation area would be created

Firstly, in the case of raising the dikes, 1000 kilometres (!) of dikes would need to be raised. Since the sea level is continually rising, the dikes would need to be raised again after two years. Not only would the risk of flooding remain, but raising the dikes would also involve a lot of maintenance. By damming the sea arms, only some tens of kilometres of dunes, dikes and dams would remain, which means far less maintenance. Moreover, the raising of dams would be very easy to carry out.
Secondly, water around the Zeeland islands would remain brackish in the case of raising the dikes. The Deltaplan (in the form of damming the sea arms) would prevent the water from remaining brackish, and a large freshwater basin would be created. This would have a positive effect on the entire Dutch freshwater economy, because of a good source of river water.  
Thirdly, by carrying out the Deltaplan, the islands would be connected to the mainland of the Netherlands via roads on top of the dams. In the case of raising the dikes, the islands would keep their isolated position.
Another advantage of the Deltaplan is the modest reclamation of land, compared to raising the dikes. The dikes would be raised and broadened inland over a distance of hundreds of kilometres, which would have cost a large area of arable land. By building the dams, land is reclaimed.
Carrying out the Deltaplan would also create a unique recreation area, something which would not be achieved by raising the dikes.
The Deltaplan seems to be a plan with nothing but advantages. However, there is one big disadvantage: the crustacean and shellfish fishing industry would be lost. If closed, the Eastern Schelde would be supplied with fresh water instead of salt water. Mussels, oysters, and other crustaceans, and shellfish, cannot survive in freshwater. The Deltacommission therefore advises to investigate the possibility of moving the crustacean and shellfish to other places.