River Irwell

River Irwell
River
The River Irwell at Salford, looking towards Manchester city centre
Country	United Kingdom
Constituent country	England
Tributaries
- left	Croal
- right	Roch, Irk, Medlock
Source
- location	Cliviger, Lancashire
- elevation	400 m (1,312 ft)
- coordinates	53°43′54″N 2°11′49″W / 53.73167°N 2.19694°W / 53.73167; -2.19694
Mouth
- location	Manchester Ship Canal, Salford, England
Discharge	for Adelphi Weir
- average	17.72 m3/s (626 cu ft/s)

The River Irwell (/ˈɜːrwɛl/ UR-well) is a 39-mile (63 km) long river which flows through the Irwell Valley in North West England. Its source is at Irwell Springs on Deerplay Moor, approximately 1.5 miles (2.4 km) north of Bacup. It forms the boundary between Manchester and Salford and empties into the River Mersey near Irlam.

In the 17th and 18th centuries, the Irwell's lower reaches were a trading route that became part of the Mersey and Irwell Navigation. In the 19th century, the river's course downstream of Manchester was permanently altered by the construction of the Manchester Ship Canal which opened in 1896. The canal turned Manchester and Salford into a major inland seaport and led to the development of Trafford Park which became the largest industrial estate in Europe. Further changes were made in the 20th and 21st centuries to prevent flooding in Manchester and Salford, such as the Anaconda Cut in 1970 and the River Irwell Flood Defence Scheme in 2014.

The river became severely polluted by industrial waste in the Industrial Revolution, but in the second half of the 20th century a number of initiatives were implemented to improve water quality, restock it with fish and create a diverse environment for wildlife. Stretches of the river flowing through Manchester and Salford have attracted large-scale investment in business and residential developments, such as Salford Quays, and other parts have become important wildlife havens. The Irwell is used for recreational activities, such as pleasure cruising, rowing, racing and fishing.