Environment Agency Issues Flood Alert for Upper River Ems Valley in West Sussex

Alert Details

The Environment Agency has issued a Flood Alert for groundwater flooding in the upper River Ems Valley. This alert was raised on March 20, 2026, following observations of high groundwater levels at the Compton borehole.

Affected Areas

The alert specifically covers the upper River Ems Valley within the Solent and South Downs area of West Sussex. Specific geographic impacts include:

• Stoughton: Main road and a small number of cellars.
• Walderton: Between Cooks Lane and Barley Mow, and a small number of cellars.
• East Marden: The road leading from East Marden.
• B2146: Areas near Woodlands Lane.

What You Should Do

Residents in the affected areas are advised to take the following actions:

• Exercise caution on flooded roads, specifically in the Stoughton and Walderton areas.
• Ensure that any groundwater pumps are in good working order and operational.
• Monitor local conditions as springs may continue to appear in fields and water may flow across roadways.

Expected Conditions

Groundwater is currently very close to the surface. While levels at the Compton borehole are slowly falling, water is expected to continue appearing in fields and flowing down roads. No rainfall is forecast for the next five days (through Tuesday, March 24, 2026), which should allow groundwater levels to continue their gradual decline. However, groundwater remains high enough to impact a small number of cellars in Stoughton and Walderton.

Timeline

The alert is currently active. While groundwater is expected to fall throughout the remainder of March, the Environment Agency notes that flood impacts may not fully reduce until April. If persistent or exceptional rainfall occurs in late March, these impacts could be prolonged. An update to this message is scheduled to be provided by 18:00 on March 24, 2026.