Groundwater flood warnings and alerts

As a result of above average rainfall over the last six months, parts of the country are currently suffering from extensive flooding. This is primarily due to water in rivers, such the River Severn and River Wye, flowing out of their banks. The Environment Agency have issued a record number of river flood warnings and alerts, and these include warnings and alerts for groundwater flooding. The groundwater flood warnings and alerts cover parts of Dorset, Hampshire and Berkshire and are primarily on areas underlain by the Chalk aquifer.

Groundwater flooding typically occurs when groundwater rises up through the ground to meet the land surface. It can also result in flooded basements and the surcharging of sewers. Unlike flooding from rivers it may be slower to respond to rainfall, but once groundwater flooding occurs it may take many months to disperse. Due to the relatively wet winter, groundwater levels across much of the Chalk in southern England are already at above normal levels. As the soils are also currently fully saturated, should there be additional significant rainfall in the next month, there is the potential for more significant groundwater flooding in parts of southern England.

• BGS provides monthly summaries of the status of groundwater resources in the UK as part of the UK’s monthly Hydrological Summary
• Hydrological Outlook UK publishes forecasts of future groundwater resources
• BGS also researches groundwater flooding
• Practical advice from the Environment Agency to help reduce the impact of flooding from groundwater
• Visit the Environment Agency flood warning website for the very latest information on flooding
• Advice on how to prepare for flooding