River Foss Barrier

The Foss Barrier consists of a retractable floodgate and pumping station owned and managed by the Environment Agency. It straddles the River Foss in York, just above the confluence of the Foss with the River Ouse. The barrier’s purpose is to prevent water from the Ouse flowing upstream into the Foss, raising water levels and flooding properties along the River Foss. The pumps next to the flood gate move water around the barrier via a side culvert so that it can continue to drain into the Ouse. This prevents water levels on the Foss rising when the barrier is closed. The Ouse’s normal water level at York is approximately 5 metres (16 ft) AOD (Above Ordnance Datum). When the river level reaches 7.5 metres (25 ft) AOD, the barrier is lowered into the Foss, shutting it off from the Ouse. The electrically driven barrier takes less than five minutes to lower into position. The barrier operates as a ‘turn and lift’ gate (see below) so it opens and closes in a similar way to a garage door. The pump-house attached to the barrier maintains the water level in the Foss at around 6.5 metres (21 ft) AOD. When the flood subsides and the level of the Ouse drops back to 6.5 metres (21 ft), the levels in both rivers are equalised so the barrier opens, and the pumps shut down.