Mersey

River in northwest England; length 112 km/70 mi. Formed by the confluence of the Goyt and Tame rivers at Stockport, it flows west through the south of Manchester, is joined by the Irwell at Flixton and by the Weaver at Runcorn, and enters the Irish Sea at Liverpool Bay. It drains large areas of the Lancashire and Cheshire plains. The Mersey is linked to the Manchester Ship Canal. Although plans were announced in 1990 to build a 1,800-m/5,907-ft barrage across the Mersey estuary to generate electricity from tides, these were abandoned in 1992 for financial reasons.

The river lies entirely below 45 m/150 ft. It is artificially modified (as part of the Manchester Ship Canal) as far as Warrington, where it becomes tidal. The Mersey is polluted by industrial waste, sewage, and chemicals.

The Mersey became an artery of communications from the 18th century. Boats for passengers and goods used the river, with its major tributary the Irwell, between Liverpool and Manchester from 1720; the Bridgewater Canal acquired this traffic in the late 18th century. The Mersey had passenger services until the development of the railway in the middle of the 19th century. In the estuary (which has an area of over 78 sq km/30 sq mi), steam ferries provided transport for commuters from the residential areas of Cheshire to Liverpool from 1815. In 1934 the first road tunnel under the Mersey was opened. Until the 1920s the river formed the boundary between Lancashire and Cheshire.