Nearshore Beach Replenishment Trial: Final Report 2018

‘Delivering benefits through evidence: Trialling a new approach to beach replenishment in Poole Bay’ is the Environment Agency’s 2018 report of a year-long programme of fieldwork by the Borough of Poole Coast Protection Team.

Project Summary

The Nearshore Beach Replenishment Trial, endorsed by the Environment Agency both locally and nationally, tested a new approach to beach replenishment in Poole Bay. The concept was to make use of locally dredged sediment and place it near the shore, allowing the prevailing waves and tidal currents to move material toward and along the beach. A similar approach, has been used widely in the Netherlands and more recently in Denmark. The trial was the first of its kind in the UK.

After 15 months, some material had replenished the beach but both a larger quantity of source material and more time would be needed demonstrate long-term viability of this technique. The success of the technique elsewhere would depend on site-specific conditions.

Method

The Marine Management Organisation granted the licence to allow the placing of sand in the sea. The works were undertaken between the 9th and 14th February 2015, when 30,000m³ of sand was placed on the sea bed approximately 400m offshore at Canford Cliffs Chine, in water between 5-8m deep.

Poole Harbour Commissioners provided the sand from maintenance dredging of Poole Harbour entrance, thereby recycling beach material back into the system, rather than dumping it offshore at a disposal site.

Seven survey sets were collected by the Channel Coast Observatory over time. Each set consisted of a topographic survey of the beach and a bathymetric survey of the sea bed. Fluorescent tracer studies were also undertaken to establish a link between the sediment deposited on the sea bed and the beach. An Acoustic Doppler Current Profiler (ADCP) measured the speed, direction and turbidity of water currents using sound waves. 

• The original (archived) project pages include further project details, photos, and videos
• A short report on the trial’s aims & methods was produced by the project team in July 2016

The Results

The Environment Agency published their final report in March 2018.