Spon Lane Junction facts for kids
Quick facts for kids Spon Lane Junction |
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Spon Lane top lock, split bridge, and junction, beneath the M5 motorway
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| Specifications | |
| Status | Open |
| Navigation authority | British Waterways |
| History | |
| Date completed | 1772 |
Spon Lane Junction is a special place where two important canals meet. It's the original meeting point of the Wednesbury Old Canal and the Birmingham Canal. You can find it near Oldbury in the West Midlands, England.
Contents
How Did Spon Lane Junction Begin?
Building the First Canals
In 1768, a special law was passed by Parliament. This law allowed the building of the Birmingham Canal all the way to Wolverhampton. It also included a very useful branch canal to the coal mines in Wednesbury. This branch was finished just one year later. It meant that coal could be sent to Birmingham much more cheaply.
Crossing High Ground
Between Birmingham and Wednesbury, there was a high area of land called Smethwick. To get canals over this high ground, engineers built groups of locks. Locks are like water elevators that raise or lower boats. There were six locks at Smethwick and another six at Spon Lane.
Both ends of the canal were at a height of 453 feet (about 138 meters) above sea level. The locks raised the canal by 38 feet (about 11.5 meters) to 491 feet (about 150 meters).
The Main Line Opens
As the main Birmingham Canal continued towards Wolverhampton, it met the Staffordshire and Worcestershire Canal. Spon Lane Junction was created partway down the Spon Lane locks. This part of the canal was 473 feet (about 144 meters) above sea level. The canal stayed at this level all the way to Wolverhampton. There, it dropped through many locks to reach the Staffordshire and Worcestershire Canal. The main canal line officially opened in September 1772.
Changes and Improvements Over Time
Pumping Water for Canals
Getting enough water to the highest parts of the canal was a challenge. In 1778, a special machine called a Boulton and Watt pumping engine was installed at the junction. Its job was to pump water back up the top three locks to the highest point of the canal.
More coal mines opened, meaning more boats used the junction. Also, a new canal, the Birmingham and Fazeley Canal, was being built. This meant even more traffic was expected.
Lowering the Canal Summit
To solve the water problem, the canal company decided to make the highest part of the canal lower. This project started in 1787 and happened in two steps.
First, a new section of canal was dug 12 feet (about 3.7 meters) lower than the original highest point. This meant two locks at each end were no longer needed. This first new section was finished on July 2, 1789.
Then, a second new section was dug another 6 feet (about 1.8 meters) lower. This removed the third lock at each end. The canal had to be closed for 22 days to connect the new sections. But by April 6, 1790, the new, lower canal was open!
Now, Spon Lane Junction was at the top of the three remaining Spon Lane locks. The pumping engine was no longer needed and was removed.
The Unique Split Bridge
The top lock at Spon Lane has a special feature called a split bridge. This bridge has a gap in the middle. It allowed horses pulling boats to cross the canal without having to unhook their towing rope. The example you see there today was rebuilt in 1986.
Telford's New Main Line
Canal traffic kept growing. In 1825, a famous engineer named Thomas Telford was asked to build a new main canal line. Telford's canals were known for being very straight. He used deep cuts and raised banks to make them go in a direct line. His new route made the canal 7.5 miles (about 12 km) shorter!
This new route met the Wednesbury Canal at Pudding Green Junction. The canal was made wider and straighter between there and the bottom of Spon Lane Locks, where Bromford Junction was created.
From Bromford Junction, a huge cutting (a deep ditch) was dug. This created a fourth route to Smethwick Junction. In some places, this cutting was up to 71 feet (about 21.6 meters) deep! It passed under the old main canal line near Spon Lane Junction. Most of this new line was built at the same Birmingham Level. The old canal route, including Spon Lane Junction, was kept open.
Lost Locks
When the top three Spon Lane locks were no longer needed, they were simply filled in with earth. They were briefly uncovered in July 1969 during the building of the M5 motorway. However, they were then destroyed to make way for the new road.
Where is Spon Lane Junction Today?
The junction is on the Wolverhampton Level, which is 473 feet (about 144 meters) above sea level. It's at the top of the three locks that go down to Wednesbury. These locks are now known as the Spon Lane Locks Branch. They are some of the oldest locks in the country that are still mostly original, just as James Brindley built them.
Both the junction and the top lock are now underneath a raised section of the M5 motorway. All three of the locks are special Grade II listed structures. This means they are protected because of their historical importance. From the junction to the top of Smethwick locks, the canal stays level for about 1.6 miles (about 2.6 km).
The Old Main Line canal crosses over the New Main Line on a bridge called the Stewart Aqueduct. This bridge has two curved arches and is made of brick with stone decorations and iron railings. The Old Main Line continues level for about 10 miles (about 16 km) to the top of the Wolverhampton locks. It meets the New Main Line again at Factory Junction after about 4.7 miles (about 7.6 km). The New Main Line to the east of Bromford Junction is also sometimes called the Island Line.
