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
Exe Estuary on the west shore is the village of Dawlish Warren with its sand spit extending across the mouth of the estuary. Above this there are fewer settlements on the west shore, with just the villages of Starcross and Cockwood, both adjoining the lower portion of the estuary. The River Clyst also feeds into the estuary, just below Topsham. The River Kenn feeds into the estuary near Kenton. The soil is alluvial, derived from Devonian, Carboniferous and Permian rocks. The estuary is a Special Protection Area and SSSI. It is also a Ramsar site. The Exe Estuary is a site of