New understanding and prediction of storm impacts on gravel beaches (NUPSIG)

The NUPSIG project is a research collaboration between the University of Plymouth and several governmental and private partners, with the aim of helping to protect gravel coasts in the United Kingdom against storms and rising sea levels.

Gravel beaches and barriers are found all around the United Kingdom and often provide a natural sea defence to low-lying land. Under storm conditions, the combination of waves and tides may lead to elevated water levels which can cause overtopping and flooding behind the gravel barrier. This can result in loss of habitat or damage to infrastructure such as property.

The aim of the NUPSIG project is to obtain new understanding of how gravel beaches are affected by storms, and to use this knowledge to develop coastal management tools to help protect the coast of the United Kingdom. The three-year research project is funded by the Engineering and Physical Sciences Research Council (EPSRC), in collaboration with the Channel Coastal Observatory, HR Wallingford and the Environment Agency.

Gravel beaches

Gravel, or shingle, beaches are made from sediments coarser than 2mm and are very common in England and Wales. They extend along more than 1,000km of its coastline and protect low-lying regions from flooding, and coastal cliffs from undercutting during storms. Collapse of these beaches can result in loss of habitat or damage to infrastructure such as property. The importance of healthy gravel coasts to society is therefore great, and coastal engineering structures (for instance seawalls and groins) and management techniques (recharge, recycling and reshaping) are extensively used at significant cost, to maintain and enhance their protective ability.

Storm impact

Regular breaching and extensive storm damage has occurred at many gravel barrier sites in the UK, and this is likely to increase as a result of sea-level rise and enhanced storminess due to climate change. Currently, limited guidance is available to beach managers to predict the response of gravel barriers and beaches to storms. Specifically, we are unable to predict under what conditions a gravel barrier will withstand a certain storm event, or whether the barrier will be overwashed, or even breached. Similarly, we have no means of evaluating the effect of certain management interventions (seawall construction, beach nourishment, profile reshaping) on gravel barrier stability.

Gravel barriers and beaches extend along more than 1,000km of the coastline of England and Wales and represent sustainable coastal defences that can protect low-lying back-barrier regions from flooding, and coastal cliffs from undercutting during storm events. Their societal role is widely acknowledged and coastal engineering structures (e.g. seawalls and groins) and management techniques (recharge, recycling and reshaping) are extensively used, at significant cost, to maintain and enhance their protective ability. Coastal erosion is widespread along gravel beaches in the UK and erosion rates are expected to increase as a result of sealevel rise and enhanced storminess due to climate change.

The need to understand and model morphodynamic processes on gravel beaches has been recognised by the Department of Environment, Food and Rural Affairs (DEFRA; responsible for coastal protection in the UK), which has commissioned a number of research projects concerning gravel barriers and beaches over the past few years. The key conclusion of the most recent project Understanding Barrier Beaches (FD1924) is that regular breaching and extensive storm damage has occurred at many gravel barrier sites in the UK and that limited scientific guidance is currently available to provide beach managers with operational management tools to predict the response of these beaches to storm conditions.