Coastal flooding hazard by wave overtopping

A project to improve models of what happens when water levels rise above sea defences, so that they can be applied to all types of defences with greater certainty.

Documents

Coastal flooding hazard by wave overtopping SHADOW: Phase 1 (67KB) WORD

Coastal flooding hazard by wave overtopping SHADOW: Phase 1 - summary (44KB) PDF

Coastal flooding hazard by wave overtopping SHADOW: Phase 1 - extended summary (98KB) PDF

Coastal flooding hazard by wave overtopping SHADOW: Phase 1 - technical report (126KB) PDF

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Details

This project addressed a need for general methods of predicting what will happen when water levels rise up over sea defences. This included what can be applied to the range of defences found in the UK. Existing methods were limited to simple shaped defences, which means there were wide margins of uncertainty and different models produced different predictions.

This is especially important with regard to the expected sea level rise of at least 300mm over the next 50 years. There’s also a need for better levels of confidence around how sea defences will perform where public safety is concerned.

The project worked in collaboration with other European projects to improve numerical models of wave overtopping of coastal defence structures. It also worked to develop guidance on which designs are suitable for which circumstances.

The ‘Phase I’ interim report updated the existing EA Design and Assessment Manual on Overtopping of Seawalls (1999 Manual).

The project started in 2001 and was completed in 2002 at a cost of £140,000.

Published 12 February 2021