South Thames Estuary and Marshes 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 Wild Birds. Over 20,000 waterfowl use this site, and some species are present in internationally important numbers. There
Columbia River Estuary mouth of the Columbia River. Settlements on the estuary include Astoria and Warrenton in Oregon, and Ilwaco in Washington. The gathering and retail/wholesale distribution of seafood is a prominent local industry and producer of jobs in the estuary. Columbia River Estuary The Columbia River Estuary is an estuary and a bay on the Oregon–Washington border and the Pacific Coast of the United States. If the Columbia River Estuary is defined by the region that experiences ocean tides, then the estuary extends up the Columbia River to Bonneville Dam and up the Willamette River to Willamette Falls (south of Portland at