Pontcysyllte Aqueduct facts for kids

Kids Encyclopedia Facts

Quick facts for kids Pontcysyllte Aqueduct Traphont Ddŵr Pontcysyllte

Coordinates	52°58′14″N 03°05′16″W / 52.97056°N 3.08778°W / 52.97056; -3.08778
OS grid reference	SJ270420
Carries	Llangollen Canal
Crosses	River Dee
Locale	Froncysyllte, Wrexham, Wales
Maintained by	Glandŵr Cymru – the Canal & River Trust
Heritage status	Grade I listed
Characteristics
Trough construction	Cast iron
Pier construction	Stone
Total length	336 yd (307 m)
Width	12 ft (3.7 m)
Height	126 ft (38 m)
Water depth	5 ft 3 in (1.60 m)
Traversable?	Yes
Towpaths	East side
Number of spans	18
Piers in water	4
History
Designer	Thomas Telford
Construction begin	25 July 1795
Opened	26 November 1805

UNESCO World Heritage Site
Official name	Pontcysyllte Aqueduct and Canal
Criteria	Cultural: i, ii, iv
Inscription	2009 (33rd Session)
Area	105 ha
Buffer zone	4,145 ha

The Pontcysyllte Aqueduct is an amazing bridge that carries a canal, called the Llangollen Canal, high above the River Dee in northeast Wales. It's like a watery road in the sky!

This incredible structure has 18 arches and is made from stone and cast iron. It was built for narrowboats and finished in 1805. It took ten years to design and build.

The aqueduct is about 3.7 meters (12 feet) wide. It is the longest aqueduct in Great Britain. It is also the highest canal aqueduct in the world! A path for walking, called a towpath, runs along one side of the water.

The Pontcysyllte Aqueduct was meant to be a key part of a bigger plan. This plan was for an industrial waterway called the Ellesmere Canal. This canal would have connected the River Severn in Shrewsbury to the Port of Liverpool on the River Mersey. The aqueduct was built to cross a valley where there were lots of valuable minerals.

Not all parts of the canal were finished because there wasn't enough money. Most of the big construction stopped after the aqueduct was completed in 1805. Today, the aqueduct is a very important historical building. It is also part of a UNESCO World Heritage Site.

What's in a Name? Pontcysyllte Explained
Building a Watery Wonder: History of the Aqueduct
How the Aqueduct was Built and is Maintained
A World Heritage Site
Images for kids
See also

What's in a Name? Pontcysyllte Explained

The name Pontcysyllte comes from the Welsh words for "Cysyllte Bridge." Cysyllte was the name of a local area in the old parish of Llangollen. The southern end of the bridge is in this area.

Some people think the name means "bridge of the junction" or "bridge that links." This is because it sounds a bit like the Welsh word for "connections." However, this idea is not correct. The name simply refers to the place it was built.

Building a Watery Wonder: History of the Aqueduct

The aqueduct viewed from the valley below

The Pontcysyllte Aqueduct was designed by two clever engineers, Thomas Telford and William Jessop. They chose a spot near an old road bridge. At first, the plan was to build many locks to lower boats down to an embankment. This embankment would then carry the canal over the River Dee.

But Telford had a better idea! He suggested building one long aqueduct to carry the water straight across the valley. This would allow boats to travel without stopping. Telford was confident because he had already built a similar, but smaller, cast-iron aqueduct. This was the Longdon-on-Tern Aqueduct.

The Pontcysyllte Aqueduct was one of Telford's first big engineering projects. Jessop, who had more experience with canals, oversaw the work. The iron parts were made by William Hazledine in his factories. The whole project took about ten years to plan and build. It cost around £47,000, which was a huge amount of money back then.

The aqueduct officially opened on 26 November 1805. A special plaque was put up to celebrate. It talked about how people from different areas worked together. They wanted to connect England and North Wales using canals. This would help farming and trade.

The bridge is 307 meters (336 yards) long. It is 3.7 meters (12 feet) wide and 1.6 meters (5 feet 3 inches) deep. It has a trough made of cast iron that holds the water. This trough is held up 38 meters (126 feet) above the river by iron arches. These arches rest on 18 hollow stone pillars. Each of the 18 sections is 16 meters (53 feet) wide.

After the aqueduct was finished, the canal was supposed to continue further. However, this part of the plan was cancelled. So, Trevor Basin, just past the aqueduct, became the end of the canal. In 1808, a channel was built to bring water from the River Dee near Llangollen. To make sure there was always enough water, Telford built an artificial waterfall called the Horseshoe Falls.

Later, other smaller canals and railways were built to help local industries. In 1846, the aqueduct became part of the Shropshire Union Railways and Canal Company. This company thought about turning canals into railways. But they decided to keep the canal open because it was still useful.

Plaque commemorating the construction of the Pontcysyllte Aqueduct between 1795 and 1805 by Thomas Telford

Commercial boats used the canal less after a part of it broke in 1936. By 1939, boats had stopped crossing the aqueduct to Llangollen. The canal was officially closed to boats in 1944. In 1945, due to not enough care, the canal banks broke near Llangollen. This caused a train crash, which was very sad.

Even though it was closed to boats, the aqueduct was saved. It was still needed to supply water to other parts of the Shropshire Union Canal. It also supplied drinking water to a reservoir. In 1955, a water board agreed to look after the canal, which secured its future.

In the late 1900s, more people started using the canal for fun. It was renamed the Llangollen Canal. It is now one of the most popular canals for holidays in Britain. People love its aqueducts and beautiful scenery. The Canal & River Trust (known as Glandŵr Cymru in Wales) now looks after the Pontcysyllte Aqueduct. You might even spot otters in the area!

How the Aqueduct was Built and is Maintained

Thomas Telford designed and built the Pontcysyllte aqueduct using the experience he gained from building Longdon-on-Tern Aqueduct on the Shrewsbury Canal

The builders used a special mortar mix. It contained lime, water, and even ox blood! Blood was used in old buildings to help make the mortar stronger. It helped it last longer in freezing and thawing weather.

The iron parts for the water trough were made nearby. They were produced at the Plas Kynaston Foundry. The trough itself was made from cast iron plates. These plates were bolted together. The joints were sealed with Welsh flannel and a mix of white lead and iron particles.

After 25 years, the white lead was replaced with tar. The iron plates are shaped like the stones in a traditional arch. This was a decorative choice, making the iron look like stone.

Special sandstone was found nearby in Cefn Mawr. This stone was used to create many of the shapes needed for the aqueduct. You can still see signs of where the stone was worked today.

The aqueduct has four supporting arches for each section. These are made of cast-iron ribs. Using cast iron in this way made it very strong. It also made the aqueduct look very solid.

The bottom of the canal trough is made of cast plates laid across. The trough is not directly attached to the arches. Instead, special parts on the plates fit over the arches to stop them from moving. The aqueduct was filled with water for six months to make sure it didn't leak.

A cool fact about canal aqueducts is that the weight on them stays almost the same. This is because of Archimedes' principle. When a boat enters the aqueduct, it pushes out an equal weight of water. So, the total weight on the bridge doesn't change much.

The towpath is built above the water level. It rests on cast-iron pillars inside the trough. This design allows water to flow easily under the towpath and around boats. This helps boats move freely. The original wooden towpath was replaced with an iron one in 1831.

Walkers and the horses that once pulled boats are kept safe by railings. But the sides of the trough only rise about 15 centimeters (6 inches) above the water. This is less than the side of an empty narrowboat. So, from a boat, it can feel like you are right on the edge of a huge drop!

Every five years, the ends of the aqueduct are closed. A plug in one of the highest sections is opened to drain the canal water into the River Dee. This allows workers to inspect and maintain the trough. The aqueduct was closed for maintenance in mid-2024. It will close again from January to mid-March 2025 for more work.

A World Heritage Site

The Pontcysyllte Aqueduct and the land around it were first suggested for UNESCO World Heritage Site status in 1999. In 2005, its 200th anniversary, it was put forward as a strong candidate. In 2006, it was announced that a larger area would be nominated. This area included a section of the canal from the aqueduct to Horseshoe Falls. It also included the older Chirk Aqueduct.

Experts from UNESCO visited in October 2008. They checked how the site was managed and its historical importance. On 27 June 2009, the aqueduct was officially added to the World Heritage List. This means it is considered very important for everyone in the world to protect.