Eco-friendly restoration and preservation of the Dutch coastline

Sea level rise, land subsidence and structural coastal erosion require vigorous management of our sandy coast. Rijkswaterstaat PPO is responsible for proper maintenance and restoration of our coastline and engages the Danish company Rohde Nielsen A/S to do so. For years they have been a familiar face in Dutch waters. The company is mainly involved in projects such as maintenance dredging of ports and waterways, port development, offshore dredging and, of course, beach and foreshore replenishment. 

"We have already carried out several replenishments in the Netherlands to the complete satisfaction of the client," says Hans Nicolaas, Area Manager at Rohde Nielsen A/S. "In the period from 2012 to 2015, for example, we were working along the entire Dutch coast at various locations from Ameland to Westkapelse Zeedijk. Last spring we again carried out repair and maintenance work at sites familiar to us at Westkapelse Zeedijk and in Domburg. We are currently doing work in Renesse and in the fall we will start work in Scheveningen. The latter location is a nice new challenge because we haven't worked there before."

The Trud R, a sister ship to the Magni R, will also be working in Renesse for a period of time.

Good and safe

"On the instructions of the Department of Public Works, the sand extraction areas are determined. Using our trailing suction hopper dredgers, we suck up the sand in the sand extraction area, transport it toward the coast and spray the sand on the beach." But not before the sand extraction area has been thoroughly surveyed. Nicolaas explains, "For example, a detection study is conducted from which appropriate measures follow, such as not dredging certain suspect areas because of the risk of explosives, for example." Ecological surveys must also be carried out, for which Rohde Nielsen hires an ecologist. "Of course, we do everything we can to ensure that our work is good, eco-friendly and above all safe."

Perhaps the largest and most versatile fission trailing suction hopper dredger ever built 

The total project of the four beaches should be completely finished by 2020. "But it will probably be finished before then," Nicolas said. "The contract gives freedom to the contractor to carry out the work in a certain time period, although there are also closed periods when work cannot be done (such as the July-August recreation period). From our available large fleet, we have deployed the Idun R and the Magni R at Renesse and the Njord R is being deployed at Scheveningen." The Njord R is a sleek, trailing suction hopper dredger and is probably the largest and most versatile split hopper dredger ever built. When placing a load of sand for underwater replenishment, it can be done very precisely and with high compaction, a method increasingly required. "With very high efficiency, relatively low energy consumption and a very high number of workable days, our vessels will do very well here and we expect to deliver faster."

The Idun R started work near the coast of Renesse in the first week of September.

Looking back and forward

"Last year we celebrated our 50th anniversary. Quite an achievement," Nicholas believes. "You can only achieve that if you offer the best service and quality at an affordable price. That's how we like to work. As a company and with our customers. But also with respect for the environment in which we work as well as the environment." Looking to the future, Nicholas sees an increasing emphasis on sustainability. "As the largest independent dredging contractor in Scandinavia, with dredging projects around the world, we are looking at what is going on and what we can contribute in terms of sustainability." For example, Rohde Nielsen is investigating whether its fleet could run on biofuels or what additional technical measures can be taken to make the footprint smaller. "But now first let's show our qualities on the busiest beach in the Netherlands!" concludes Nicolaas.