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Under the weather The effect of climate change on our coastlines is not a just a matter of national concern - integrated coastal management now extends into Europe, reports Helena Russell, in the firs

Getting your beach towel down first on a sunny day is one of the many advantages of living by the coast. But it's not all ice creams and donkey rides - the risk of losing your home to coastal erosion is a real one and it is becoming more and more difficult to persuade insurers to take on such risks.

Climate change is a recognised phenomenon - long term trends show that water levels are indeed rising, just one of a number of factors caused by changes to the climate. But at the same time there are continuing advances in scientific understanding of coastal processes.

The European Commission is also funding development of a new data system which will give coastal managers access to a greater range of information.

Trying to predict the processes of coastal erosion is very much a developing science and, even with modern methods, coastal engineers can still be taken by surprise. Capital programmes for coastal flood defences might include a number of particular schemes, but often money has to be diverted elsewhere when other, more urgent problems come to light.

According to Environment Agency principal engineer Steve Hayman, design of sea defences now routinely takes rising sea levels into account. The Intergovernmental Panel on Climate Change forecasts a rise of 6mm per year over the next 50 year period, he explains, so a new sea defence scheme with a 50 year design life should be designed to account for a 300mm increase in sea level.

But rising sea levels are not the only change that is being seen - an increase in storminess is also noticeable. This means that it is the infrequent event which poses the greatest risk to sea defences.

Significant wave height - both the annual mean and the 50 year return period - is shown to be increasing. The annual mean is estimated to be rising by around 22mm per year.

Recent developments in coastal engineering have centred on the move to a more integrated way of dealing with designs and decisions. The introduction of 'literal cells' to address the fact that works at one site may affect the coastline some distance away, and the development of shoreline management plans, are both welcomed as important steps towards this goal.

A project now under development will widen the scope even further, so that integrated coastal management can be extended across Europe. The Decision Support for Integrated Coastal Zone Management scheme (DESIMA) is being developed with funding from two European Commission research organisations, and aims to provide a system which coastal managers can use to access a wide range of information. It is being led by French company Matra Systems & Information in conjunction with HR Wallingford, the UK's Satellite Observing Systems, and France's ACRI, which is concerned with risk management of sea pollution.

Coastal managers needing data input for projects will usually have access only to local information - from wave buoys, or by hindcasting from wind data for the area. But there is also a wealth of information available from satellites - wave data for remote areas all over the world - and other data such as coastal topographical information is planned to be available from aerial surveys by the Environment Agency.

The aim of DESIMA is to provide a server which coastal managers can log into. It will tell them what information is available and link them to the appropriate source - there will be charges for information from some of the sources. Historical data can be linked in, and there will also be the chance to introduce new scientific models or processing tools as they are developed.

At this stage of development, a demonstration project in the UK has been chosen which will be used as a trial for the system. HR Wallingford coastal engineer Paul Sayers explains that the site, at West Bay in Dorset, is ideal because it consists of a variety of different types of sea defences.

At the centre of the bay there are two harbour piers extending into the sea, and through which the River Brit flows. The east beach has a natural coastal defence in the shape of a shingle bank, and the west beach has hard defences in the shape of a seawall.

There are a number of different risks associated with these defences - the risk of a breach of the shingle bank, overtopping of the sea wall, damage to the sea wall or the harbour piers, and also the risk of blockage at the end of the harbour piers, leading to flooding from the river which meanders past the town.

Both nearshore and offshore wave data will be input into the model, along with wind information, bathymetry data and tidal levels. The responses of both the structures and the beach will be predicted, allowing the coastal manager to calculate the risks of overtopping or breach.

Topographical information and details of flood control structures will provide a basis for predicting the flood risk for the area. This will be used by the coastal manager - along with an economic appraisal of assets and a survey of the environmental impact and the erosion risk - to assess the possible options.

DESIMA is not the only Europe-wide coastal programme; consultant High Point Rendel's geotechnical division is working with the Isle of Wight Council on an EU funded programme looking at climate change and land instability. The seven-strong team also includes organisations from Ireland, France and Italy. During the three year project they aim to develop a reliable method of landslide forecasting and risk assessment based on ground movement monitoring.

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