Question: For what purpose was the oldest canal in England initially constructed?

Context articles: Spencerport Methodist Church
Thomas Phillips Mill Complex
Zippin Pippin
Mount Lavinia Hotel
Pelletier House
Bagdad Bypass
Foss Dyke
Castlefield
Brayford Pool
MS Windoc (1959)

Spencerport Methodist Church, also known as Spencerport United Methodist Church, is a historic Methodist church located at Spencerport in Monroe County, New York, United States.
 It is a Romanesque style, three- by seven-bay church building constructed of brick on a foundation of Medina sandstone.
 Initially constructed in 1870-1871, the interior was updated in 1909 to the Akron Plan precepts for church design.
Thomas Phillips Mill Complex is a historic mill complex located at Newark in New Castle County, Delaware.
 The complex includes a late 18th-century mill owner's house, a circa mid-19th-century miller's house, and a grist mill that was initially constructed in 1795.
 The mill is a banked, 2 ⁄ -story, gable-roofed building that is constructed of uncoursed rubble fieldstone at its basement and first floor levels, and of weatherboarded frame at its second story and attic levels.
The Zippin Pippin, formerly called the Pippin, is one of the oldest existing wooden roller coasters in the United States.
 It was initially constructed in the former East End Park in Memphis, Tennessee, in either 1912, 1915, or 1917 by John A. Miller and Harry C. Baker of National Amusement Devices.
 The construction material was pine wood.
 As the park declined in popularity, the coaster was dismantled and relocated adjacent to the horse track in Montgomery Park, later known as the Mid-South Fairgrounds.
 For a time it was incorporated as an attraction in the now-closed Libertyland amusement park there, until that park closed in 2005.
 Purchased by the city of Green Bay, Wisconsin, in 2010, it was installed at the Bay Beach Amusement Park, where it is once again in operation.
The Mount Lavinia Hotel, in Mount Lavinia, Sri Lanka, is a 275-room hotel, situated at 100 Hotel Road in Mount Lavinia.
 It is recognised as one of the oldest and most famous hotels in the country.
 It has been continuously operating as a hotel since 1947, but was initially constructed as the Governors Residence in 1806.
The Pelletier House is a historic home and national historic district located at Jacksonville, Onslow County, North Carolina.
 Built in the 1850s by Rufus Ferrand Pelletier in the Greek Revival style, it sits atop Wantland Spring on the banks of the New River.
 Initially constructed as a one-room dwelling to serve as home and office, additional rooms were built onto the structure during later years.
 The house itself was originally part of a turpentine lot owned by Rufus Pelletier and his brother William Pelletier.
 These rooms were damaged during a fire in the early 1950s.
 The house was occupied by Pelletier's daughter Eliza until her death in 1954.
 Subsequently, the Onslow Historical Society acquired and maintained the structure until January 25, 2013 when Onslow County took over ownership.
 The house is opened for public viewings on special occasions.
 It is the oldest standing structure in Jacksonville.
The Bagdad Bypass is a proposed bypass of the Midland Highway, through Bagdad, Tasmania.
 While not a new proposal, the idea began gaining momentum on the release of the Southern Transport Investment Program in 2007.
 The road will be initially constructed as a two-lane highway with extra earthworks undertaken to facilitate future duplication of the bypass.
 The road will be constructed as a grade separated highway and has been designed to seamlessly connect to the Brighton Bypass.
The Foss Dyke, or Fossdyke, connects the River Trent at Torksey to Lincoln, the county town of Lincolnshire, and may be the oldest canal in England that is still in use.
 It is usually thought to have been built around 120 AD by the Romans, but there is no consensus among authors.
 It was refurbished in 1121, during the reign of King Henry I, and responsibility for its maintenance was transferred to the city of Lincoln by King James I.
 Improvements made in 1671 included a navigable sluice or lock at Torksey, and warehousing and wharves were built at Brayford Pool in the centre of Lincoln.
Castlefield is an inner city conservation area of Manchester in North West England.
 The conservation area which bears its name is bounded by the River Irwell, Quay Street, Deansgate and the Chester Road.
 It was the site of the Roman era fort of Mamucium or Mancunium which gave its name to Manchester.
 It was the terminus of the Bridgewater Canal, the world's first industrial canal built in 1764, with the oldest canal warehouse opening in 1779.
 The world's first passenger railway terminated here in 1830, at Liverpool Road railway station and the first railway warehouse opened here in 1831.
The Brayford Pool is a natural lake formed from a widening of the River Witham in the centre of the city of Lincoln in England.
 It was used as a port by the Romans - who connected it to the River Trent by constructing the Foss Dyke - and has a long industrial heritage.
MS "Windoc was a Lake freighter or laker, initially constructed as a bulk carrier in West Germany in 1959.
 Entering service that year as Rhine Ore, the ship was renamed Steelcliffe Hall" in 1977 and reconstructed as a laker.
 In 1988 the laker was renamed "Windoc" and in 2001, was involved in a collision with a bridge on the Welland Canal which caused the ship to catch fire.
 The ship was declared a constructive total loss.
 While undergoing repairs in Ontario, the ship broke free of its moorings and grounded.
 Later pulled free, the vessel was eventually converted into a barge.