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
Hilbre Islands some of which are privately owned. The most southerly building on the island is the Hilbre Bird Observatory, from which birds are continuously monitored in connection with a national network of observatories and ringing stations. In January 2011 it was announced that there would be no permanent ranger. Wirral Council said that they had had difficulty finding a ranger prepared to live without mains electricity or running water on the island. Hilbre Islands The Hilbre Islands ( ) are an archipelago consisting of three islands at the mouth of the estuary of the River Dee, the border between England and