Canvey Island risks to London and the Thames estuary area. It is proposed that the western side of Canvey is developed as a site which is either temporarily flooded at times of risk, or transformed into a permanent wetland. Developments in the 20th century have produced a marked contrast between the environments in the east and west of the island. The eastern half of the island is allocated to residential areas, the main public amenities and a small holiday camp and seafront, while the western half of the island is mainly farmland, marshes and industrial areas. The marshes in the west include
Tamar–Tavy Estuary Seaweeds, green algae and communities of polychaete worms are all found in the estuary system; near Calstock is found the shrimp "Palaemon longirostris", which has been recorded in only two other estuaries in Britain. The estuary is also one of only two sites in the UK where the fish, allis shad, spawn. Other larger animals found in undisturbed parts of the SSSI include the European otter, the common kingfisher and dormice. Tamar–Tavy Estuary The Tamar–Tavy Estuary is a Site of Special Scientific Interest (SSSI) covering the tidal estuaries of the River Tamar and the River Tavy on the border between