In 2013 a tracer study was implemented over a six-month period at three sites: Solent Breezes, Lee-on-the-Solent and Stokes Bay. This tracer study formed part of a wider coastal processes study, River Hamble to Portchester Coastal Flood and Erosion Risk Management Strategy (RHPS), which was designed to improve the current understanding of sediment transport along the open coast. Results have also since been used to inform a new Hill Head to Portsmouth Harbour Beach Management Plan.
Figure showing the location of the deployment sites at Solent Breezes, indicated by the yellow stars
Figure showing the location of the deployment sites at Lee-on-the-Solent, indicated by the yellow stars
Figure showing the location of the deployment sites at Stokes Bay, indicated by the yellow stars
The tracer pebbles were deployed in batches of 100 pebbles, with 500 pebbles deployed in total at each site during March 2013. The pebbles were deployed at pre-defined locations, approximately equal distances apart and designed to highlight the localised coastal processes along that stretch of frontage. At Solent Breezes, the pebbles were deployed either side of a proposed drift divide along this stretch of coastline. At Stokes Bay, part of the deployment focused on the outlet of the River Alver and the movement of material within the vicinity of this zone.
Figures: Deployments at the sites Solent Breezes, Lee-on-Solent and Stokes Bay
At all sites, pebbles were deployed at the location of profile lines monitored by the Regional Monitoring Programme and released at the approximate point of Mean Sea Level (MSL). This would ensure a consistent release elevation across all beaches, with the pebbles spread approximately evenly over this point.
Surveys to detect these pebbles were conducted in March, April, May and August 2013. The results successfully show the movement of pebbles along the beach frontage, including around structures such as groynes, and have been instrumental in helping to inform our knowledge of sediment transport within these areas.
Full details of this study, including the results from the retrieval surveys can be found in the following report