Where should the dam be placed?
Initially, there were four possible places the Grevelingen dam could have been placed. At each position, the dam's purpose, the price, and the traffic between Schouwen-Duiveland and Goeree-Overflakkee, were taken into account.
- Position 1 had the disadvantage that the dam would have to bridge three deep canals in the Grevelingen lake. Moreover, the dam would be too long, and unfeasible for financial reasons. Lastly, the dam would be built in a place where the current would regularly change direction. For this reason there was a risk that the bed beneath the dam could move.
- The disadvantages of position 1 also apply to position 2. The only difference was that the port of Oude Tonge would be spared with position 2.
- The third position was much shorter and cheaper than the first two options. The dam would cross the water directly to the north, via the Island of Oude Tonge.
- The last position was a variant of position 3. In the plan of position 3, the dam would cross the point where two current canals of the Grevelingen lake come together. In position 4 however, the dam would cross these canals one by one.
Research showed that there was no difference between positions 3 and 4 from a safety point of view. Position 3 was eventually chosen because it was so much cheaper than position 4.