English: A map of Dagenham Breach (1707-1719), based on Perry, "An Account of the Stopping of Daggenham Breach", (London, 1721) and Smiles, "Lives of the Engineers" .

The breach was in the Thames river wall; the tidal waters scoured out a large lake. The pink area denotes further land flooded at high tide. 'A' denotes the dam built by Captain Perry, who fixed it after 12 years' ruinous expense. The River Beam is on the right.

"Horseshoe" areas ,marked 'U' ,have nothing to do with Dagenham Breach. They are typical examples of reclaimed land lost to the river in the past, and turned into reed beds.