Flood engineering · SEC1

The SEC1 perimeter barrier

Since May 2024 the whole SEC1 site has stood inside a barrier with its top at 19.5 feet: concrete wall on the street sides, an earth berm with a concrete core on the others, and seven gates that close its openings.

Plan

Plan of the SEC1 perimeter flood barrier The barrier runs around the whole site: concrete wall on the south and east sides, earth berm with a concrete core on the north and west. Seven gates close its openings: gates 1, 2 and 6 on the south side, 3 and 4 on the east, 5 on the north and 7 on the west. Gate 5, the north vehicle entrance, sits on higher ground and is the last to close. SEC1 Halls 1 to 3, Hall 4 above generators 1234567 Sedgebank Road wall berm Plan, not to scale. North is up.
Gates are numbered in the order they close. Gate 5, the north entrance, closes last, so that the site stays reachable as long as possible.

The gates

GateLocationTypeOpeningCrew
1South vehicle entranceAluminum stop logs, 10 bays24 ft 0 in6
2South vehicle entrance, exit laneAluminum stop logs, 6 bays14 ft 0 in4
3East pedestrian gateHinged flood door4 ft 0 in2
4East fuel fillHinged flood door6 ft 0 in2
5North vehicle entranceAluminum stop logs, 9 bays22 ft 0 in6
6Dock roadSwing gate, hydraulic28 ft 0 in3
7West service gateHinged flood door8 ft 0 in2

Stop logs are stored in a locked cage beside each gate, numbered by bay. Our standard is all seven gates closed and sealed within three hours of the order, by the staff on site, without help from outside.

Test record

DateTestAll gates sealed inNotes
2025-10-19Annual full test2 h 44 minGate 4 seal replaced.
2024-05-12Acceptance test (contractor)3 h 52 minPassed. Gates 1 and 2 flood-tested to 19.5 ft.

Partial deployments for tides and warnings are on the status history: gates 6 and 7, at the low south-west corner, are the ones a spring tide reaches first.