Scour holes formed on both sides of the Eastern Scheldt storm surge barrier close to the edges of the existing soil protection. These scour holes developed on both sides of the barrier in a straight line and were not only very deep in places (deeper than AOD – 50 metres) but they also had steep walls (steeper than 1:5).
As a result, sliding or settlement flows could occur and cause damage to the soil protection. In order to be able to guarantee the stability of the piers from the storm surge barrier, it is necessary for the soil protection to remain intact and to prevent it from weakening, eroding, washing away, sliding or being damaged. Because of that, Herbosch-Kiere carried out rock dumping at the location of the scour holes.
A new rubble layer of 98,000 tons of steel slag (size 45-180 mm), 25,000 tons of rubble (40-200 kg) and 10,000 tons of rubble (60-300 kg) was installed over an area of +/- 75,000 m2 using ATLANTIS. The bottom of the Eastern Scheldt in that area lay at a depth of 55 to 60 m below the surface of the water.