A Flood Alert was issued for Groundwater flooding in the Alton area in Hampshire on 10th March 2026. Affected watercourses included the Groundwater.
During this event, FloodRadar monitoring gauges recorded notable rises. The Petersfield Stream at Winchester Road rose 0.08m, peaking at 64.89m, while the River Wey at Passfield Mill climbed 0.06m.
Environment Agency advice issued
Groundwater levels are high but stable at our Farringdon borehole near Alton, and flooding of low-lying areas and roads is possible. We expect levels to remain high over the coming days and levels will remain sensitive to further rainfall. Due to the nature of groundwater flooding, this situation could continue for several weeks or longer. We are closely monitoring rainfall and groundwater levels. Residents are advised to prepare property flood resilience measures and ensure that pumps are working where they have been installed. Take particular care when driving through floodwater both for you
Monitoring gauges during this event
| Station | River | Rise | Peak |
|---|---|---|---|
| Winchester Road | Petersfield Stream | +0.08m | 64.89m |
| Passfield Mill | River Wey | +0.06m | 1.11m |
| Kings Pond | River Wey | +0.05m | 0.32m |