Dartford Creek is one of the last remaining natural tidal creeks in London. It was built in 1981 to minimise flood risk from the Thames Estuary to Crayford and Dartford. There are two gates that travel vertically and are driven by a chain system. The gates are balanced by two water-filled counterweights. When they close, the barrier is able to withstand up to 7 metres of water above average sea level. Most of the time the gates are raised but when flooding is predicted by the Met Office both are closed. Raised embankments along the lower reaches of the Thames estuary also act as flood defences. Before the barrier was built Dartford flooded significantly in 1953 and 1968. In the face of global warming should we be worried about Dartford flooding once more? There is certainly a lot of new housing on floodplain and reclaimed marshland. Take a look at this map and judge for yourself. It shows the land projected to be below annual flood level in 2030. Climate Central: Coastal Risk Scr