South Thames Estuary and Marshes are nationally scarce plants on dykes, and the diverse invertebra include nationally rare beetles, flies and true bugs. South Thames Estuary and Marshes South Thames Estuary and Marshes is a biological Site of Special Scientific Interest which stretches between Gravesend and the mouth of the River Medway in Kent. Part of it is a Nature Conservation Review site, Grade I, and part is a Royal Society for the Protection of Birds nature reserve. It is part of the Thames Estuary and Marshes Ramsar internationally important wetland site and Special Protection Area under the European Union Directive on the Conservation of
Grand Codroy Estuary estuary since 1974. The estuary consists of adjoining marine and intertidal habitats with an elevation no more than one metre. Four islands are located within the estuary, and the intertidal sandbars give way to mudflats "supporting rich growths of Zostera". The site is surrounded by cultivated grasslands. The marine area is shallow, at most two metres deep in intertidal areas, and somewhat deeper in the river channel. It is bounded by privately owned land, the Codroy Valley Provincial Park, and the Gulf of Saint Lawrence. Nearby are the Grand Codroy and Little Codroy rivers, which are popular fishing destinations. The