UK floods: the facts

Risk

Since Friday 29 January, 1,135 homes have been flooded. During this time, more than 181,000 homes have been protected and more than 200,000 homes have been sent a flood warning following the wettest January since records began in 1766.

Around 5.2m (one-sixth) of properties in England are at risk of flooding. More than 2.4m properties are at risk of flooding from rivers or the sea, of which nearly 0.5m are at significant risk, and 1m of these are also vulnerable to surface-water flooding. A further 2.8m properties are susceptible to surface-water flooding alone.

Fifty-five per cent of those living in flood-risk areas know they are at risk, and of these, 60% have taken some action to prepare for flooding.

Cost

The clear-up costs after the latest floods could reach £1bn, according to accountancy firm PricewaterhouseCoopers.

The effects of flooding, and managing flood risk, costs the UK around £2.2bn each year. This is broken down into several areas: around £800m is currently spent annually on flood and coastal defences, while an average of £1,400m in damages are incurred.

Spending on flood defences would have to increase by £10-£30m plus inflation annually to maintain existing levels of flood protection to 2035. More funds of around £150m a year will also be needed for surface and groundwater flooding. These total costs could rise to as much as £27bn a year by 2080.

Previous costs: The Association of British Insurers has estimated the cost of the July 2007 floods, in insurance claims alone, at more than £3bn.

Flood warnings

There are 14 severe flood warnings currently in place along the Thames, as well as water levels in the area being extremely high. Two severe flood warnings also remain in place on the Somerset Levels.

Wettest January

This January has been the wettest since records began. In the UK there was 183.8 mm of rain, which is 151% higher than average. In the south-east and central southern England during December and January, there was 372.2mm of rain, the wettest two-month period since 1910.

Types of flooding

There are four types of flooding and in the past eight weeks the UK has experienced all of them:

Tidal From sea and tidal rivers. Often sudden and extreme.

Flash This surface-water flooding is usually worst when drainage systems in urban areas are overwhelmed by sudden heavy rainfall, exacerbated by the concreting over of large areas of soil and gardens.

Fluvial On floodplains when a river breaks its banks due to rainfall, snow or ice melt exceeding the capacity of the water course.

Groundwater When the earth is waterlogged and can no longer hold any more water.