Research and analysis

Chesham Vale, Buckinghamshire: groundwater situation

Updated 2 May 2024

Applies to England

Groundwater levels – May 2024

Groundwater levels in the Chesham Vale area are high for the time of year after the high levels during the winter and early spring. As a result of this there was a risk of groundwater flooding earlier in the year but this has now receded. Groundwater flooding occurs when underground water levels begin to rise above the surface.

The Environment Agency previously issued a Groundwater Flood Alert due to the risk of groundwater flooding in this area. As groundwater levels have now receded and no flooding is being observed on the ground we have removed the groundwater flood alert.

Current situation

The Chesham Vale area has seen high rainfall with 166% of the long-term average rainfall falling between October 2023 and April 2024. Groundwater levels rose substantially in response to this and soils were saturated across the area. Due to recent lower rainfall and soils become drier the situation has now improved.

The Ashley Green Observation Borehole readings show that although groundwater levels are currently high, they are still over 2 metres below the levels reached in the flooding incident of 2001, where there was significant and widespread flooding. Fortunately, due to the recent warmer and drier spring weather, groundwater levels are now declining resulting in lower risk of groundwater flooding.

Forecast risk of flooding

Due to the high groundwater levels, there was a risk of groundwater flooding which could result in localised surface flooding. The main area at risk was Vale Road, Chesham. Nearby areas in and around Chesham have also been affected by groundwater in previous wet winters.

As indicated above although levels are still high, they are declining and groundwater flooding is not likely during the next few weeks. We have therefore removed the groundwater flood alert. We will continue to monitor the situation and continue to talk to our partners to improve preparation for future events.

What we’re doing

We are monitoring the situation and will continue to do so. Our systems at the Ashley Green Observation Borehole (which we use to monitor levels in Chesham) are monitoring water levels every hour.

We will be talking to the local authority and other responding partners as the situation changes to make sure they are aware of the latest updates. We will support our partners’ responses in managing any flooding impacts during future spring and winter events.

Local Buckinghamshire advice

Check the:

• groundwater flood maps
• flood risk strategies, plans and assessments

You should report groundwater flooding to Buckinghamshire Council.

Actions and advice

The following information could help you to reduce the impact of groundwater flooding. To find out more about your flood risk and prepare for future flooding:

• read practical advice to help you reduce the impact of flooding from groundwater
• sign up for flood warnings to receive free flood alerts and warnings for flooding from groundwater
• read advice about what to do before or during a flood

Groundwater can infiltrate sewer systems. If you have problems flushing your toilet or sewage is emerging, contact Thames Water Utilities on 0800 316 9800.

Some practical steps you can take to prepare for flooding and minimise the impact to you, your property and possessions are to:

• prepare a flood kit including a torch, batteries, mobile phone, warm clothes, water, food and any prescription medicines you may need
• move valuables from basements and cellars
• check pumps and any other flood protection equipment you have
• keep drains and gullies around your property free of debris
• keep an eye on local water levels and weather conditions

Unfortunately, there are no measures available to lower the water table during a groundwater flood. Residents and businesses:

• must be prepared for groundwater levels remaining high
• should undertake measures to protect their property until the water table naturally lowers

The most important thing to do to prepare for groundwater flooding is to have a personal flood plan.

Groundwater flooding can be difficult as homes, roads and community spaces can all be affected for long periods of time. If you are struggling and would like someone to talk to, the National Flood Forum is a charity to help, support and represent people at risk of flooding. You can call them on 01299 403 055.

Project Groundwater supports communities to be more resilient to groundwater flooding. The project aims to increase engagement with communities to help build understanding and awareness of groundwater flooding. We are working to: 

• improve monitoring of when and where groundwater emerges
• develop a better groundwater flood warning service that will support residents to act
• investigate what nature-based solutions could be used to reduce groundwater flood risk

Defra is funding Project Groundwater as part of the Flood and coastal resilience programmes – Engage Environment Agency. The Environment Agency is managing the programmes. They will drive innovation in flood and coastal resilience and adaptation to a changing climate.

Find out more about Project Groundwater.

Next update

We will update this briefing note if the situation changes significantly.

Groundwater levels may stay high for several weeks. Please remember that flood water will also stay around for some time until the groundwater levels recede.

Further information

Check the latest flood alerts and warnings.

Read our weekly and monthly water situation reports for England.

Contacts

• Floodline: 0345 988 1188
• Environment Agency Hertfordshire and North London (HNL) area enquiries: hnlenquiries@environment-agency.gov.uk
• Environment Agency National Customer Contact Centre: 03708 506 506
• Environment Agency Incident Hotline (Freephone 24hr service): 0800 80 70 60