Tunnel leak 'forced York flood barrier to be raised'
Water leaking into a service tunnel forced the opening of a flood barrier in York that led to hundreds of homes in the city being flooded, a report has found.
The Environment Agency (EA) launched an investigation into the incident at the Foss Barrier on 26 December.
Its report said water entering the pumping station led to the decision to raise the barrier to prevent the control room flooding.
The EA is now upgrading the barrier.
The barrier consists of a 16.5 tonne moveable gate that can be raised and lowered. It stops the flow of the River Foss and pumps water around the barrier into the nearby River Ouse to maintain a steady water level.
The report said the service tunnel, housing power cables, control systems and drainage pipes, became overwhelmed as water levels in the River Foss rose during heavy rain.
It identified an opening in a construction joint as "providing a route for water to leak into the service tunnel".
As the water leaked in, a pump designed to clear it from the tunnel was unable to cope. The barrier was raised and the water pumps were switched off.
The report recommends that "openings between the building and the service tunnel should be sealed so that when water enters the service tunnel it cannot rise and flood the building," and that "there is a risk that without undertaking the remedial steps a repeat of the event would compromise the facility."
In March, the EA said it was installing more powerful pumps and constructing a new control room as part of part of a £13m project to be completed by November 2017.