Sediment Tracer Technique from Fugro

Fugro is participating in a nearshore replenishment trial that aims to reduce the cost of beach maintenance.

Sustaining Poole Bay’s wide sandy beach is hugely important for the protection of seafront properties and infrastructure against regional coastal flooding and erosion.

Maintaining these sands has historically relied on traditional replenishment schemes; dredging material from the harbor and physically pumping or spraying this ashore. In December 2014 the Borough of Poole spent around £2 million carrying out such works.

A nearshore replenishment trial is now underway with the aim of determining if dredged material which is deposited offshore, naturally makes its way to the beach, thus eliminating the need for costly mechanical pumping and land operation to reduce the cost of beach maintenance.

To assist in this trial, Fugro released 1,000 kilograms of tracer sand approximately 400 meters offshore. This tracer material was placed on top of the deposited sand as part of the trial. It closely matches native sand characteristics but has been colored to allow detection and tracking of its movement.

Following the release of the fluorescent tracer material, Fugro is conducting a survey to collect sediment samples from the seabed and beach in the region around the deposit zone. The movement of the fluorescent particles is tracked through a campaign of sediment sampling.

If onshore movement of the material could be proved, significant cost savings can be made in future by utilizing natural, onshore wave action to carry sediment ashore, thus providing continued protection for this stretch of coastline.