The Manchester Ship Canal is an inland waterway 36 miles (58 km) long in the North West of England. Starting at the Mersey Estuary near Liverpool, it generally follows the original routes of the rivers Mersey and Irwell through the historic counties of Cheshire and Lancashire. Several sets of locks lift vessels about 60 feet (18 m) up to Manchester, where the canal's terminus was built. Major landmarks along its route include the Barton Swing Aqueduct, the only swing aqueduct in the world, and Trafford Park, the world's first planned industrial estate and still the largest in Europe.The rivers Mersey and Irwell were first made navigable in the early 18th century. Goods were also transported on the Runcorn extension of the Bridgewater Canal (from 1776) and the Liverpool and Manchester Railway (from 1830), but by the late 19th century the Mersey and Irwell Navigation had fallen into disrepair and was often unusable. In addition, Manchester's business community viewed the charges imposed by Liverpool's docks and the railway companies as excessive. A ship canal was therefore proposed as a way of giving ocean-going vessels direct access to Manchester. The region was suffering from the effects of the Long Depression, and for the canal's proponents, who argued that the scheme would boost competition and create jobs, the idea of a ship canal made sound economic sense. They initiated a public campaign to enlist support for the scheme, which was first presented to Parliament as a bill in 1882. Faced with stiff opposition from Liverpool, the canal's supporters were unable to gain the necessary Act of Parliament to allow the scheme to go ahead until 1885.Construction began in 1887; it took six years and cost £15 million (equivalent to about £1.65 billion as of 2011). When the ship canal opened in January 1894 it was the largest river navigation canal in the world. Although it enabled the newly created Port of Manchester to become Britain's third busiest port—despite the city being about 40 miles (64 km) inland—the canal never achieved the commercial success its sponsors had hoped for. Ships often returned to sea loaded with ballast rather than goods for export, and gradually the balance of traffic moved to the west, resulting in the closure of the terminal docks at Salford. Although able to accommodate a range of vessels from coastal ships to inter-continental cargo liners, the canal is not large enough for all modern vessels. As of 2011, traffic had decreased from its peak in 1958 of 18 million long tons (20 million short tons) of freight each year to about 7 million long tons (7.8 million short tons). The canal is now privately owned by Peel Ports, whose plans include redevelopment, expansion, and an increase in shipping from 8000 containers a year to 100,000 by 2030, as part of their Atlantic Gateway project.