Deltares: On the Anatomy of Nearshore Sandbars

On 17 June 2016, Deltares researcher Dirk-Jan Walstra will be awarded a doctorate for his research into the anatomy of (submerged) sandbars off the coast.

“Walstra’s study, entitled ‘On the anatomy of nearshore sandbars’, offers insight into sandbanks’ behavior and how we can reinforce our coastlines through the targeted positioning of underwater sand deposits,” Deltares said in its announcement.

“For my dissertation, I studied the behavior of the sandbanks. The next step for me will be to take a targeted look at the designs of the sand deposits,” said Walstra.

“I intend to apply this model to a variety of deposit designs, in order to identify opportunities for increasing efficiency. In the Netherlands, most sand replenishment is handled by Rijkswaterstaat. Looking abroad, I believe this research could be put to good use in Florida, for example, since most of the coastal management there is based on offshore sand deposits too.”

Deltares added that “in the Netherlands, we already have many years of experience using sand replenishment to preserve our coastline. One way to do this is by depositing sand on the beach itself, but since the early 1990s, we are increasingly depositing sand off the coast, under water.”

This is cheaper than beach nourishment, meaning that a larger volume of sand can be deposited with the same budget.

Another advantage of this approach is that the beach is no longer disrupted by the work.