Canvey Island barriers spanning Benfleet Creek to the north and East Haven Creek in the west. The drainage system consists of sewers, culverts, natural and artificial dykes and lakes which feed seven pumping stations and gravity sluices that discharge the water into the Thames and creeks. Four of the discharge sites are "high flow" stations capable of discharging 600 litres of water per second at any tide level. The levels within the system are managed by a further five "low flow" pumping stations. The Environment Agency's Thames Estuary 2100 flood defence plan includes Canvey Island as one site for alleviating the flood
Canvey Island location of land areas in Ptolemy's ancient work have led modern researchers to question the correlation between Ptolemy's island and contemporary Canvey. MacBean and Johnson, 18th century historians, contend "Counus Island" would have existed much further out to sea (or even likely to be the Isle of Sheppey), so any similarity between the names is mere coincidence. Without any suitable island matching Ptolemy's Counus Island, 20th century historians White and Yearsley posit the documented island to have been lost or reduced to an insignificant sandbank by subsidence and the constant effects of the sea. The settlement and agricultural development of