The Story of the Iron Trunk Aquaduct
The Grand Union Canal, or Grand Junction Canal as it was called until 1929, was built between 1793 - 1805 to provide a vital link between London and the industrial Midlands.
The lowest point between the canal's two summits at Tring and Braunston was here at the River Ouse in Wolverton. William Jessop, the engineer for The Canal Company decided to cross
the valley on an embankment with an aqueduct across the river. This avoided the need to build a large number of permanent locks which would have been time
consuming wasteful of water and still would have required a special bridge or ferry for the horses.
A temporary flight of wooden locks was built between Wolverton and Cosgrove so
that the new canal could be used during the construction of the aqueduct. The site of these old locks can still be found in the copse to the west of the canal and south of
the river. The present Cosgrove Lock was part of that original flight.
The first aqueduct was built of brick. Work on it proceeded slowly and it was
plagued with problems even before it opened in 1805. It was, perhaps, no surprise when it collapsed on the night of February 18th 1808 and the temporary locks had to
be brought back into use to prevent interruption of trade.
As a result of these problems it was decided to replace the brick aqueduct with a
cast iron trough. This construction technique was first used only fifteen years earlier for a single span aqueduct for the Derby Canal and was, therefore, a relatively new
and advanced method. (In between the copse of the brick aqueduct and the construction of the iron one, a temporary wooden aqueduct was use, built by a local carpenter).
Benjamin Bevan of Leighton Buzzard, an engineer with the Canal Company, designed the aqueduct and it was manufactured by Reynolds and Company at their
Ketley Iron Works in the West Midlands. It was a success. The structure has remained solid since 21st January 1811. There have only been two 'stoppages' for
maintenance work to be carried out - first in 1921, and again in 1986.
One hundred and eighty years later, in March 1991, another complicated piece of
civil engineering resulted in the opening of an impressive new aqueduct in Milton Keynes. It was needed to carry the canal over Grafton Street to improve the access
from New Bradwell and Wolverton in to the south of the city.
There is a short canal branch at Cosgrove which is all that remains of the Stratford
and Buckingham Arm. This canal was opened in the early 19th century to link Buckingham with the main line of the canal. The most important cargoes were hay
and straw for London, where horse fodder was in short supply. The best known cargo on the Arm came from the Edward Hayes boatyard at Old Stratford where
steam boats and river launches were built for export all over the world. It was an amazing sight to see them being transported down Stony Stratford High Street to the canal.
The Grand Union Canal runs for a distance of 13 miles through the new city, following the river valleys of the Ouzel and Great Ouse. Some lengths flow through
the City's linear parks, others border the new housing areas, two of which are named after canal landmarks - Tinkers Bridge and Peartree Bridge.
The Grand Union Canal is part of a network of inland waterways that covers the length and breadth of England. From Milton Keynes the canal extends south to
Brentford where it joins the River Thames, and on to Birmingham, the centre of the canal network. Originally the building of this network was an important part of the
Industrial Revolution. The poor state of the roads in the 18th century meant that transport of goods by water was much quicker and therefore cheaper. A vast range
of goods, from bricks to barley, was carried by the horse-drawn narrowboats. The canal thrived during the first has of the 19th century, but with the coming of the
railways in the 1840's and 50's there began a slow decline.
Freight carrying continued to decline during the first half of the 20th century as the
network of roads improved. When transport was nationalised in 1947 ownership of the canals passed first to the British Transport Commission and then in 1963 to the
newly formed British Waterways. By this time construction of the motorway system had contributed to the end of profitable waterborne transport on the Grand Union
Canal. Today leisure activities such as boating, angling, birdwatching, sketching, walking, or just sitting have taken its place, and the canal is as busy during the
summer as it was in its commercial heyday.