What Is A Canal? Dive into these Ancient Engineering Marvels (2024)

Canals are water channels made by humans to create a passage for water or watercraft. They were first built in ancient Persia and China around 500 BC. They are amazing feats of engineering, using locks and bridges to control the flow of water.

The word ‘canal’ can actually mean any tube or channel that transports air, fluid, or food. So your alimentary canal transports food, whilst your ear canal transports sound!

In this case, we’re going to focus on the two types of canals built by humans in the landscape.

Canals were (and are) made to create a passage for boats and ships. Or just water! They can carry goods or passenger crafts.

Some canals are used for irrigation (transporting water). These include aqueducts.

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What is an Aqueduct?

The word ‘aqueduct’ comes from the Latin ‘to lead water.’ It means any structure that transports water from one place to another. This used to mean the part that crossed a valley but now has extended to mean all the surrounding pipes and infrastructure.

Roman engineering genius

Ancient Romans were famous for their aqueducts. Nothing could keep a Roman from a hot bath! The first ever aqueduct was the Aqua Appia, built in 312 BC. This meant most homes in large cities had piped water and a sewage system. An accomplishment not rivaled until the 19th century!

Pontcysyllte Aqueduct

Being a canal boater, I have always wanted to chug across the spectacular Pontycysyllte Aqueduct in Wales. Listed as a World Heritage Site, it involves 11 miles of aqueduct engineering.

Chirk Aqueduct crosses the border between Wales and England. There is a castle, bridges, industrial coal towns, and an artificial waterfall.

Pontycysyllte Aqueduct itself is an 18-pillar majestic row of stone and iron arches. It carries canal boats 126ft (38.4m) high above the fierce River Dee. Its Welsh name means ‘the bridge that connects.’

It is also great fun to pronounce!

All this was designed by top engineers of the Industrial Revolution: Thomas Telford, Williams Jessop, and John Simpson.

Why were aqueducts built?

Aqueducts were built to supply water to towns and cities, usually for drinking water, bathing, and irrigation of crops and gardens.

The actual bridges and arches were made to cross steep valleys where a canal and lock system would have been hard or impossible!

More about locks later…

Waterways – The Other Type of Canal

Waterways are canals made to convey boats and ships, not just water.

I live in a narrowboat on the Grand Union Canal in England. It runs for 137 miles from the River Thames, from London through to Birmingham.

The G.U. was an important route for industrial goods such as coal and steel. Narrowboats traveled back and forth between the two major cities, loading and unloading cargo. At first, boats were horse-drawn. After that, steam-powered, then finally, driven by diesel engines. Which they still are today.

Why were waterways built?

Wherever there was money to be made transporting materials, people, or goods, there was a reason to build a waterway canal. Boats could carry very heavy loads, far more than a horse and cart could. They were slow but steady.

English canals were built in the Industrial Revolution to transport coal, steel, and, later on, goods for the war effort.

China’s Great Canal enabled trade to flourish.

Canals also made communication easier between countries, such as the Suez canal.

What’s different about canal water?

Controlled and still

Canal water is controlled. This means it doesn’t flow how a river does. It is more like a series of long ponds. The water for a canal is pinched from local rivers, however!

Canal water becomes dirty and polluted more easily, as whatever has fallen/been thrown in stays there! Like heavy metals, sewage, dead animals, and shopping trollies. Never drink canal water if you can avoid it.

I do have friends that have experimented with filtering canal water to make it safe, but personally, I wouldn’t risk it!

Locks

We can control canals with locks. Locks (apart from being great places to socialize with other boaters) are how boats can move to higher or lower parts of the canal.

The lock is two lock gates with an area of water between which we can raise or lower. The water between them is called a pound in the U.K.

On the larger shipping canals, the enormous locks are operated by waterway authorities and paid workers. On smaller waterways, you can do it yourself.

Locks are great fun to operate. Here’s how.

• One of your team goes ahead with a windlass. This is like a key that slots onto the end of the gate. You turn the handle, and the gate paddles come up/down. They release streams of water to either fill or empty the lock.
• Depending on whether you are going up or down, another member of your party has either already put the boat in the lock or is now driving it in.
• Quick! Open the lock gate for them!
• Shut the gate and walk to the other end.
• Open/shut the gate paddles or ground paddles at this far end to fill or empty the lock.
• Drive the boat out of the far end.
• The windlass person makes sure all the gate paddles are down and closed. (Otherwise, the lock pound will let all the water out of the top half of the canal. This annoys other boaters. Who are now stranded in an empty channel of sticky mud!)
• Stop to pick up your crewmate with the windlass.
• Chug off!

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The World’s Most Amazing Canals

Venice – The Most Romantic

Travel by gondola, poled along by a gondolier through the 177 canals of Venice. Many of these started life as natural waterways, as Venice was built on a lagoon. The car-free city has canals that are from 2-5m deep. Gondolas are graceful flat bottomed craft, traditionally black.

Get in there quickly for your romantic date, as Venice is actually sinking! This is due to rising sea levels and structural damage to buildings. Emergency plans by city fathers include rafts of giant flood barriers.

Panama Canal – The Most Expensive Toll

This canal holds the Guinness World Record for the highest toll charge paid to come through it. The cruise ship Coral Princess paid US$226,194.25 for this!

How much you pay depends on the size of your ship.

If it is very small, you only have to pay $500!

Corinth Canal – The Smallest

For its size, the Corinth Canal in Greece is the most expensive waterway in the world. It is only 1km long!

It was the Greek dictator Periander who first had the idea in 612 BC.

This shortcut through the Isthmus of Corinth would avoid ships having to travel the long way. This was a dangerous area of the sea called the Peloponnese.

Greek oracles warned that cutting through the island would bring down the wrath of the God Zeus. Also, the technical challenges of cutting through 78 m of hard rock were daunting.

The Greeks made a second attempt, then the Roman Emperor Nero. The Greeks joined the French to try again in 1830 and 1870. Finally, in 1890, they opened the Corinth Canal with the help of Hungary, England, Greece, and France.

This shortened the trip from Greece to Italy by half. Only 15,000 ships a year use it today, which makes it the most expensive waterway for the amount of use.

China’s Great Canal (Jing-Hang canal) – The Earliest Waterway

Built by King Fuchai to aid trade in the 5th century B.C., this canal is arguably the earliest waterway made to transport boats. It is also the longest, reaching 1,115 miles.

This waterway is the most advanced civil engineering project completed before the Industrial Revolution. It is also a UNESCO World Heritage Site.

The Chinese canals covered 2,000km and covered five of the most important river basins. They aided communication and transported vital goods such as rice and grain.

You can still travel on this waterway today. A testament to the workmanship of these ancient engineers! Yes, it has been renovated three times since the 5th century, and rightly so!

Suez Canal – Biggest Traffic Jam!

This wouldn’t be complete without adding the Suez Canal. This major shipping canal connects shipping routes through Egypt. In 2021 an enormous container ship blocked the entire canal for days. It caused a 72-mile pile-up of waiting ships and cost an estimated $400 million dollars.

Whoops!

How were canals made hundreds of years ago?

Navvies

Manual workers dug out canals by hand. They were called ‘navvies’ in England in the 1700’s. A difficult and dangerous job cutting through deep walls of heavy clay and rock! Teams of men would live in shacks by the side of the canal works.

Cattle

Cows were driven along the clay bed of the canal. This flattened and compressed the clay, smoothing out cracks and air bubbles. The heavy herd of cows did the work much faster (and for less pay!) than the teams of navvies.

How are canals made in modern times?

Surveying

The route of a new canal must be surveyed and researched for geology, land height, water table, hydrology, and much more. This, like a canal boat, can take a very long time! Hydrology is the study of nearby rivers and bodies of water to see how they will feed into the canal.

Excavation with machinery

Nowadays, we use machines such as shovels, diggers, cranes, and dredgers to excavate a canal. Dredgers can be operated from a flat-bottomed barge. They clear debris and mud in watery surroundings.

My son and I have seen dredgers doing maintenance near our home on the Grand Union. It was the best entertainment available during the Covid lockdown! A giant scoop dumps trash and mud into a large pit in a working barge.

Locks are built offsite

We were also privileged to witness new lock gates for our local Leighton Lock coming in by boat. They were made of new oak wood and expected to last a century. The woodwork and iron work done in a specialist carpentry yard.

Facilities

Important services such as sewage points, water points, and rubbish points are installed. Distance markers and signs tell boaters and other canal users where they can fish, picnic, or turn their boats around.

Tunnels!

Where a canal cannot go around an obstruction (such as a hill) or it would take too long to go around it, a tunnel will need to be built.

I was lucky enough to interview Robin Garrett, a civil engineer who worked on the reconstruction of the Blisworth Tunnel. This is the third longest in Britain. It is 2,811 m long and very dark!

Workers often lost their lives in tunnel construction. 50 people died building Standedge Tunnel (the longest in Britain).

Legging

Before engine-powered craft, canal boaters would need to leave their horses on one side of the tunnel or lead them over. Their crewmates would then leg the boat through the tunnel.

This grim job involved lying on the deck and pushing with their feet until they ‘legged’ the boat through the long tunnel.

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What is a canal FAQs