When Richmond Lock and Weir and its footbridge were opened in 1894 by the Duke and Duchess of York there were cheers and celebrations in St Margarets. Now they had a short cut to Richmond on their doorstep. (Twickenham Bridge would not be built for another 39 years.)
There were celebrations in Isleworth as well. They were cheering because they didn’t have a short cut to Richmond on their doorstep.
When the old London Bridge was demolished in 1832, with its 19 cramped piers and protective palisades, it resulted in the tides on the Thames rising and falling far more rapidly than they had done before. With the bridge no longer holding the river back water levels at Teddington dropped by 30 inches. The river flowing through Twickenham and Richmond became a stream running between mud banks. For much of the time the upper river was unnavigable by anything but the smallest craft.
To restore the river to its former state the Thames Conservators petitioned Parliament for permission to construct a barrage, a tidal lock and weir, across the river at Isleworth. The good people of Isleworth were not impressed by this idea at all. Although they recognised that it would help navigation through Richmond and Twickenham they also could see that a tidal lock and weir across the river at Isleworth wouldn’t be of any use to them whatsoever. Their objections were simple and direct…
- The sand and gravel subsoil upon which Isleworth stood was drained every time the tide went out. If the river level was maintained artificially high by a barrage the town would soon be waterlogged and cellars flooded. At spring tides the entire community would under water!
- Isleworth was the location of Messrs Kidds’ Flour Mill, an important local industry and a major employer. The Mill used a waterwheel driven by the Duke of Northumberland’s River as it emptied into the Thames. If the level of the Thames was maintained artificially high there would be insufficient fall on the water to drive the wheel. Result? No grinding, no flour and no employment.
- People living in Isleworth suspected that the real reason river levels upstream were so low was because the water companies were removing vast amounts of drinking water from the Upper Thames by it had even reached Teddington, Twickenham and Richmond.
In short, as attractive at the idea of a tidal barrage might have seemed to the land locked boat owners of St Margarets, Richmond or Twickenham, it had no appeal for the riverine residents of Isleworth who asked this one question…
“Why should the inhabitants of Isleworth be victimised for the sake of the boat builders and pleasure seekers upstream from us?”
In 1890, after common sense and intelligent engineering had come up with a satisfactory solution to the problem, permission was granted to build a half tide lock and weir across the river at St. Margarets, half a mile upstream of Isleworth and clear of its Mill, barge quays and boat yards. Honour was satisfied.
The working principal of the Richmond Half Tide Lock is relatively simple. As the tide comes in from the sea the water is allowed to flow past the lock up to Teddington. With the sluice gates (weirs) raised there is no impediment to river craft. At a certain point after the tide has turned and begins flowing back to the sea again the weirs are lowered. This holds the water between the lock and Teddington at the level of a half tide, a minimum depth of 1.72 metres. This allows boats to navigate safely up river to Teddington. Any large boat wishing to pass down river below the lock can use the large conventional barge lock. Owners of smaller boats can pull their boats over the weir on a series of rollers.
When the next incoming tide starts to fill up the river again the weirs are raised once again to allow the water to pass through up to Teddington - and so it goes. When the lock was originally built the weirs were raised by hand. The teams of lock keepers required to do this arduous job lived with their families in the buildings underneath the pedestrian steps on both sides of the river.
The engineer who designed the main lock, the sluices and the weirs was F.G.M Stoney. His work on Richmond Lock is of considerable importance in the history of hydraulic engineering as he first introduced here floating sluice gates. He also used Richmond Lock to pioneer the apparatus for turning the vertical gates in the tide to the horizontal position for storage. Stoney used the same design principals on his later work on the Manchester Ship Canal in 1894 and the Aswan Low Dam in 1902.
RICHMOND HALF TIDE LOCK - VITAL STATISTICS
Technically, Richmond Lock is a half-tide lock and barrage, which also incorporates a public footbridge. The footbridge crosses the conventional lock, the slipway and the barrage, which comprises three vertical steel sluice gates suspended from the footbridge structure. These gates weigh 32 tons each and are 66 feet in width and 12 feet in depth. The lock permits passage of vessels up to 250 feet long by 26 feet 8 inches wide.
The water level above Richmond lock is maintained at, at least 1.72 m above ODN (i.e. it is tidal but the weir prevents it from falling below this level). The three miles between Teddington and Richmond are only truly tidal for about 2 hours before and 2 hours after high tide. High tide at Richmond is about 1 hour after high water at London Bridge with low tide being between 3 and 3½ hours after low water at London Bridge.
Originally there was a penny toll to use the footbridge. The toll booth with its “Silent Reversible Patented 1887” turnstile is still in position on the Surrey side of the footbridge.
A petition was raised in 1913 to get the toll abolished but it wasn’t finally removed until 1938. Then there were cheers and celebrations in St Margarets because now they had a free short cut to Richmond on their doorstep. There were similar celebrations in Isleworth as well. They were cheering because they didn’t have a free short cut to Richmond on their doorstep.
– from Martyn Day
Credits: Richmond Lock footbridge is by Jacqueline Banerjee. Richmond Lock by Mark Percy