CoStructNet / Beach Processes Network Workshop

HR Wallingford 4/6/03
BEACH STRUCTURE INTERACTION

Welcome by Tom Bruce (500kB download)
Introduction to DEFRA / EA research programme Mike Thorn (EA/DEFRA TAG Theme leader)
Rock structures for beach control
Current practice in designing rubble structures on beaches Kevin Burgess (Halcrow) (3MB download)
Performance of simplified rock structures Andrew Bradbury (NFDC) (6MB download)
Guidance on use of simplified rock structures Matt Crossman (speaker) (DEFRA) / Silvia Segura (HRW) (3MB download)
The revised "Rock Manual" - Jonathan Simm / Kirsty McConnell (HRW) (3MB download)
Suffusion of fine materials in rock mounds and beach / foundation materials - William Allsop (HRW / Southampton) (3MB download)
Rock armour re-shaping modeling - John-Paul Latham(speaker) / Sebastien Dupray (Imperial College)
A possible coast protection system - John Loveless (Bristol)
Lunch
Beaches and scour
Toe scour in front of coastal structures James Sutherland (HRW) (1MB download)
Laboratory measurements of scour using different sediments RR Simons (UCL) (1MB download)
Use of Boussinesq model to drive sediment transport / morphological evolution in front of sea walls, for coarse grained and mixed grained beaches Andrew Chadwick (Plymouth) (1MB download)
Liquefaction around marine structures: the LIMAS project Scott Dunn (HRW) (1MB download)
Behaviour of beach drainage systems Heidi Shaw (Southampton) (4MB download)
Lowering of cohesive foreshores & interactions with beaches David Brew (Posford Haskoning) (1MB download)
Break-out discussions
Gaps in knowledge on effects of structures on beaches
Gaps in knowledge on effects of foundations on structures
Plenary discussion / conclusions
The meeting made the following conclusions about toe-scour: Beach lowering takes place over a wide range of time-scales and length-scales. Toe scour may be small compared to longer-term and larger-scale beach processes, but it may trigger a failure when larger-scale processes reduce beach levels. Toe scour may fill in quickly (hours) leaving little trace of its existence, so it is unlikely to be revealed by routine surveys. Beach lowering combines cross-shore and longshore hydrodynamics and sediment transport Monitoring of beach levels to identify long-term and seasonal trends is needed. Large-scale experiments and/or field experiments are needed to be able to predict toe scour better. Improved representation of the effects of seawalls and groynes on sediment transport is needed.
Close

Coastal defences and breakwaters -
Beach - structure interactions

Organised by COZONE: CoStructNet and Beach Processes network
Supported by EPSRC, DEFRA / EA, HR Wallingford

Many coastal and estuarial defences use rubble structures such as nearshore breakwaters, reefs, groynes, and revetments constructed on beach material. There are considerable gaps in design tools to describe the interactions between beach materials (principally sand or shingle) and these structures. The main interactions can be described at two levels:

• Macro - far and near field effects of the structure on beach movement, particularly planshape and profile
• Micro - local effects of the structure on sediment movement (local scour), and of the sediment on the structure (foundation support / settlement).

This workshop was organised by the Coastal Structures and Beach Processes networks to inform coastal engineers on recent and current research on coast defences, to assist DEFRA / EA and EPSRC in the definition of future research needs / activities, and to assist in the development of focussed research proposals to EPSRC.

The meeting was intended for engineers working in analysis, design, construction, maintenance and operation of coast defences, but also applicable to researchers in wave processes, beach modelling, coastal structure performance, marine / coastal foundation engineering.