A storm surge coinciding with high tides raised the level of the Humber Estuary. The water flooded the gates of the port and filled the port to overflowing. A Seveso-classified chemical and hydrocarbon storage terminal was under 1 m of water. Following the weather alerts, the site shut down its operations and isolated its electrical power supplies. The terminal’s non-essential employees were evacuated; the rest were moved to the safety of the upper floors of the operations building.

The walls surrounding the retention tanks were not flooded and remained dry during the flood event. Although mobile equipment was carried around by the water, the fixtures on the site suffered little mechanical damage. All the site’s switching stations were flooded and the wastewater treatment system was out of commission. None of the tanks were breached.

Due to the site’s altitude, most of the water flowed back into the river bed and the port. The remaining water was then pumped to the river. The flood had knocked out the electricity, so mobile generator sets were brought in. Most of the terminal remained out of commission during this immediate resumption phase. The priority systems were restored to working order thanks to heavy repairs to the main mechanical and electrical systems. However, the electrical power supply was severely damaged. The backup electrical power supply therefore remained in place for these priority systems.

A flood investigation report listing the events that occurred before and during the flood was drafted to draw lessons for the future. The electrical power supply was fully restored after each switching station was repaired and tested.

The site is located in an area that is highly prone to flooding because while the river’s flood protection and defence level is at 6 m OD (ordnance datum), the entrance to the port is at only 3.37 m OD.

To prevent flooding in the future, the outer entry gates to the port have been raised to a protection level of 6.5 m OD. This now gives the site a less than 1 in 1000 annual probability of flooding (<0.1%).

A petrochemical site (46146), a cement works (46151), and a chemical terminal (46144) were also flooded that day.

Download the detailed report in .pdf format (1.6 Mb)