Research and analysis

Flamstead, north-west Hertfordshire: groundwater situation

Updated 9 May 2024

Applies to England

Groundwater levels – May 2024

Groundwater levels in the Flamstead area are considerably higher than expected for this time of year, which could result in groundwater flooding. Groundwater flooding occurs when underground water levels begin to rise above the surface.

The Environment Agency is monitoring levels and issuing a groundwater flood alert due to the risk of groundwater flooding in this area.

Current situation

The Flamstead area has seen high rainfall with 166% of the long-term average rainfall falling between October 2023 and April 2024. Groundwater levels have risen substantially in response to this and soils remain saturated across the area.

The River Hill Observation Borehole readings (which we use to monitor levels in Flamstead), show that groundwater levels are currently similar to previous wet springs and winters. This includes the winter of 2001, when minor flooding occurred in the Valley Lane area and in Delmer End Lane near Trowley Bottom.

Forecast risk of flooding

Due to the high groundwater levels, there is currently a risk of groundwater flooding which could result in localised surface flooding. It could also result in water flowing in usually dry chalk valleys and with fields becoming waterlogged in the area. The main area at risk is the Trowley Bottom Valley area around Flamstead.

We expect groundwater levels to continue to remain high for this month, though we do expect the situation the improve due to the drier and warmer spring weather. If groundwater flooding does occur it can often last for several weeks or months.

What we’re doing

We are monitoring the situation closely and will continue to do so. Our systems at the River Hill Observation Borehole are monitoring water levels every hour.  We will continue to monitor groundwater levels and their response to further rainfall, as well as assessing the risk of flooding.

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.

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. They 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

The next scheduled update is for Wednesday 15 May 2024. We will update this briefing note sooner if the situation changes significantly.

Groundwater levels may stay high for several weeks. Remember that flood water will also stay around for some time until 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: [email protected]
• Environment Agency National Customer Contact Centre: 03708 506 506
• Environment Agency Incident Hotline (freephone 24hr service): 0800 80 70 60