Key to managing the water level in the Floating Harbour (and Bathurst Basin) are the sluices at Underfall Yard which have been operating since 1840. In December 2021 a Bristol City Council Cabinet report recognized that the sluices were in urgent need of repair but work has yet to start. A Cabinet meeting on 4th April confirmed that ‘the sluices are not operating correctly and need investment to repair and prevent potential flooding, damage to the dock’s infrastructure and local businesses.’ The City Council application to the Environment Agency for funding for the work has been successful and a budget of £1.7 million has been allocated for the repair of the sluices.
The failure of the sluices would leave the Harbour Authority without the ability to control the harbour level:
- If the sluice gates fail in an open position the harbour water level will fall, causing the harbour walls to collapse.
- If the gates fail in a closed position, the harbour authority will be unable to prevent the water level from rising due to fluvial flows entering the Floating Harbour via the Frome and Feeder Canal.
A Cabinet report in December 2021 stated that only one of the two available sluices was operational between March and July 2021 because of the failure of the second sluice. The City Council commissioned Arup to analyse the flood risk if both sluices failed in a closed position. They found that ‘the failure of the sluices in a fluvial event would cause significant flooding around the Floating Harbour and the Victoria Street area and would significantly increase flooding from the Feeder Canal in the St Philips Marsh area and flooding from the Frome at Cabot Circus.’ The case for repairing the sluice gates is a compelling one.
Environment Agency funding will, in the words of Cllr. Nicola Beech (Cabinet member with responsibility for flood resilience) ‘allow us to deliver improved sluice gate arrangements fit for the 21st century.’