Canvey Island the 30 hectares known as West Canvey marshes, acquired by the RSPB in 2007, and the Canvey Wick nature reserve. Canvey Wick is a designated Site of Special Scientific Interest (SSSI) at the site of the abandoned and incomplete oil refinery. The foundations of the 100 hectare (0.4 sq mile) site were prepared in the 1970s by laying thousands of tonnes of silt dredged from the Thames; the abandoned and undisturbed area has flourished as a haven for around 1,300 species of wildlife, many of which are endangered or were thought to be extinct; including the shrill carder bee, the
Estuary this type of estuary in the U.S. are the Hudson River, Chesapeake Bay, and Delaware Bay along the Mid-Atlantic coast, and Galveston Bay and Tampa Bay along the Gulf Coast. Bar-built estuaries are found in place where the deposition of sediment has kept pace with rising sea level so that the estuaries are shallow and separated from the sea by sand spits or barrier islands. They are relatively common in tropical and subtropical locations. These estuaries are semi-isolated from ocean waters by barrier beaches (barrier islands and barrier spits). Formation of barrier beaches partially encloses the estuary, with only narrow