Main rivers () are a statutory type of watercourse in

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe ...

and

Wales Wales ( cy, Cymru ) is a country that is part of the United Kingdom. It is bordered by England to the east, the Irish Sea to the north and west, the Celtic Sea to the south west and the Bristol Channel to the south. It had a population in ...

, usually larger streams and rivers, but also some smaller watercourses. A main river is designated by being marked as such on a main river map, and can include any structure or appliance for controlling or regulating the flow of water in, into or out of a main river. Every other open watercourse in England and Wales is determined by statute as an ' ordinary watercourse'.

England

The Environment Agency carries out maintenance, improvement or construction work on main rivers to manage flood risk as part of its duties and powers as defined by the Flood and Water Management Act 2010. The Environment Agency's powers to carry out flood defence works apply to main rivers and the sea only; they do not apply to ordinary watercourses. The Environment Agency does not ''have'' to maintain or construct new works on main rivers or the sea and it is unlikely to maintain a watercourse to improve its amenity or to stop erosion that does not increase flood risk. Main rivers in England are designated by the

Environment Agency The Environment Agency (EA) is a non-departmental public body, established in 1996 and sponsored by the United Kingdom government's Department for Environment, Food and Rural Affairs, with responsibilities relating to the protection and en ...

; Defra statutory guidance, issued under section 193E of the Water Resources Act 1991, advises that the Environment Agency should classify a watercourse as a main river if it is likely to have flood consequences for significant numbers of people or properties, or if it is likely to contribute to significant flooding across the catchment.

Wales

Natural Resources Wales Natural Resources Wales ( cy, Cyfoeth Naturiol Cymru) is a Welsh Government sponsored body, which became operational from 1 April 2013, when it took over the management of the natural resources of Wales. It was formed from a merger of the Coun ...

decides which rivers are classified as main rivers, and carries out works to manage flood risk in the main river catchments.

Map

The main river maps for England and Wales are freely available to the public for viewing.

References

Bodies of water Rivers Flood control in the United Kingdom {{Hydrology-stub