The Humber
The Humber Estuary is the second-largest coastal plain estuary in the UK, and the largest coastal plain estuary on the east coast of Britain, coastal plain estuaries are formed when pre-existing valleys were flooded at the end of the last glaciation. The Humber estuary drains a catchment area of some 24,472 km2, around 20% of the total land surface of England. Water collected from this catchment flows to the estuary through many rivers and tributaries, the largest of which are the Aire, Derwent, Don, Ouse, Trent and Wharf.
A significant feature of the Humber is the large tidal range, this is due to its position within the North Sea basin; producing a mean spring tidal range of 5.7m at Spurn. The tidal range is amplified as it propagates up the estuary; it is 7.4m at Saltend, and 6.9m at Hessle which is 45km inland. Because of these large tidal ranges, the Humber is classified as a macro-tidal estuary.
The average width of the Humber Estuary is 4.3km and the average depth is 6.5m, it is 14km at its widest point and totals over 30,550 ha, (75,492 acres). The Humber's muddy appearance, known as turbity, is due to suspended sediment, which is derived mainly from the eroding boulder clay cliffs along the Holderness coast, but also from riverine sediments. Transport of this sediment is vital for the estuary's function, with over 1,500 tonnes carried in with every tide. It is estimated that up to 1.26 million tonnes of sediment may be present in the water column. The deposited sediments provide essential material to maintain estuary's important habitats such as, mudflats, sandflats and saltmarsh.
The Humber has an average of 40,000 ship movements per year and its ports and wharves handle 14% of the UK's international trade, it is the country's largest port complex. Industrial interest alongside the estuary include, chemical works, oil refinery complexes and power stations that dominate areas of its shores. Birds are a well known feature of the Humber with nine species of international importance using the estuary.
The Humber supports a rich variety of habitats and species and is recognised as one of the most important estuaries in Europe for overwintering birds as well as supporting 9 species of international importance. It is due to the presence of these important habitats and species that the Humber has been given a number of nature conservation designations under UK, European and International law.
