A Flood Alert was issued for River Thame, Horsenden Stream and Chalgrove Brook in Buckinghamshire, Hertfordshire, Oxfordshire between 25th February 2026 and 18th March 2026. Affected watercourses included the River Thame, Horsenden Stream, Chalgrove Brook.
During this event, FloodRadar monitoring gauges recorded notable rises. The River Thame at Dorchester rose 1.39m, peaking at 2.04m, while the River Thame at Stadhampton climbed 1.15m.
Environment Agency advice issued
High river levels may lead to flooding. River levels are high on the Chalgrove Brook through Chalgrove. River levels along the River Thame are below the flood risk threshold. Flooding of low lying land and roads in the Chalgrove area remains possible today, 18 March 2026. The forecast is for it to be dry today and tomorrow. We expect levels to remain high over the coming days. River levels are sensitive to further rainfall. We are monitoring rainfall and river levels. Avoid low lying footpaths and roads near rivers, which may be flooded. Go to River Levels Online for updates on current river l
Monitoring gauges during this event
| Station | River | Rise | Peak |
|---|---|---|---|
| Dorchester | River Thame | +1.39m | 2.04m |
| Stadhampton | River Thame | +1.15m | 2.28m |
| Wheatley | River Thame | +1.03m | 5.43m |
| Chalgrove | Chalgrove Brook | +0.98m | 1.38m |
| Aylesbury Thame | River Thame | +0.73m | 1.53m |
| Rowsham Bridge | River Thame | +0.69m | 0.96m |
| Thame Bridge | River Thame | +0.45m | 2.32m |
| Cuddington | River Thame | +0.20m | 1.56m |
| Aylesbury | Bear Brook | +0.18m | 1.34m |