The UK Environment Agency
began building the River Foss Barrier near its junction with the River Ouse in the centre of York in 1987 and it was opened in 1989. Its objective was to protect that part of York drained by the River Foss from excessive water flow in the River Ouse backing up the Foss valley. Despite this defensive work, the Foss Barrier was overwhelmed on 26 Dec 2015 when the electrical plant controlling the pumps and the barrier mechanism was also threatened.
Compounding the disaster was the apparent immaturity of the official coordination of the response and the flooding on 27 Dec of the Stonebow telephone exchange cutting off services and making communications more difficult.
Once the Major Incident Response Team requested military assistance it started to appear within 12 hours. An RAF Chinook was provided from 28 Dec and other resource assisted with warning, plant, evacuation and flood protection tasks until 31 Dec 2015.