The Dartford Creek Barrier resembles a giant concrete guillotine, bridging the River Darent just before it meets the Thames. The barrier supports two 160-tonne gates which can be dropped to hold back the rising tide. In 2019 it was used about 12 times, whenever water levels threatened to overwhelm the river embankments.
The surrounding marshland and fields lie several metres below the maximum tidal height of the river. The vulnerable floodplain stretches into the nearby towns of Dartford and Crayford (along the River Cray tributary).
Upriver, the much larger Thames Barrier protects central London. On the north bank, the Barking Creek Barrier, a similar (but larger) drop-gate barrier, protects the floodplain of the River Roding.
The Environment Agency usually closes Dartford Creek Barrier when high ‘spring’ tides (which occur roughly once a month) combine with stormy weather. In 2019, the Dartford Creek Barrier closed about 12 times. 2018 saw seven closures and 2017 saw eight. The barrier closed 12 times in 2016 to prevent flooding.