Research and analysis

Groundwater situation: Sussex, 16 May 2024

Updated 16 May 2024

Applies to England

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This publication is available at https://www.gov.uk/government/publications/sussex-groundwater-situation/groundwater-situation-sussex-19-january-2024

Current situation

Other than January 2024, above average rainfall has been recorded in Sussex, each month between October 2023 through to and including April 2024. More than twice the average rainfall was recorded in October 2023 and both February and March 2024. Average rainfall has been recorded so far in May 2024.

Groundwater levels remain high, or higher than normal for the time of year. However, despite the rain, groundwater levels have been falling at all our indicator boreholes in Sussex since the middle of April 2024. Minor flood impacts are still occurring in parts of Sussex, with water affecting a small number of properties close to the village green in Stoughton. The sewerage network in the Lavant Valley (West Dean and Charlton) near Chichester remains affected.

Graph showing changes in groundwater levels in Compton Borehole in West Sussex from May 2022 to May 2024. The graph shows that groundwater levels are currently higher than normal but falling.

Graph showing changes in groundwater levels in Ladies Mile Borehole near Brighton from May 2022 to May 2024. The graph shows that groundwater levels are currently higher than normal but falling.

Weather forecast

Over the week ahead, most locations are forecast to see very little, or no, rain. Although brief periods of rain, or showers, are possible for some.

Long term weather forecasting is extremely difficult. There remains uncertainty and predictions might change, but currently, there are no strong signals of prolonged, extensive, or extreme rainfall, although the risk of showers continues into June 2024 too.

Forecast risk of flooding

We predict that groundwater should continue to slowly fall at all boreholes across Sussex. Possibly through to the autumn. Groundwater will initially not fall far, or fast, and minor groundwater flood impacts could persist through to June 2024 in Stoughton and possibly mid July 2024 near Chichester.

We cannot accurately predict the weather weeks or months ahead. The exact groundwater response will depend on the amount, intensity and distribution of any rainfall that occurs. However, it would require an exceptional amount of rainfall over the weeks ahead for groundwater to rise even a small amount again.

If we have an average or drier than average few months, groundwater might fall nearer to normal by August 2024. If persistent rain continues, groundwater levels will still likely fall, but could remain higher than normal going into next autumn and winter.

Next update

With groundwater levels expected to continue to fall, and flood risk reducing, we are not planning to update this briefing note next month. However, we will continue to monitor the levels and forecasts and will re-issue this situation report at any time when new instances of groundwater flooding are thought possible. We will likely re-issue this briefing note in autumn or winter 2024.

What we are doing

We continue to monitor groundwater levels and their response to rainfall.

Throughout autumn and winter, we will update this groundwater situation and our groundwater briefing notes.

We will issue and update flood alerts when there is risk of flooding affecting property.

We liaise with the local authority and other responding partners to ensure they are aware of the situation.

Our operational staff will remove blockages from main rivers to ensure they flow freely.

Actions and advice

Think and prepare now for what you’ll do if flooding occurs where you live. Do not wait until flooding happens.

Call Floodline on 0345 988 118 or visit check for flooding to find out if you can register to receive free flood alerts for flooding from groundwater.

Find out about:

Prepare a personal flood plan or community flood plan to help you and your community decide what practical actions to take before and during a flood, which will help reduce the damage flooding could cause.

Check pumps and any other flood protection equipment you have. Ensure valuables are moved from basements and other low parts of properties.

Where safe to do so, communities may wish to check and ensure there are no blockages in local watercourses and ditches.

Further information

You can read:

More detailed groundwater briefing notes are emailed as part of the flood alert service. Register for groundwater situation updates by email at ssdenquiries@environment-agency.gov.uk.

Contacts

For more information on the flood alert service and to find out what messages you are registered to receive, call Floodline on 0345 988 118.

Alternatively, you can contact the Environment Agency for more information:

If you have any questions, email enquiries@environment-agency.gov.uk.

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