Canals and Locks

This weekend I found myself reading about canals. This happened because I am moving to a place which has ‘Canal’ in its name. I did not pay much attention to it at first. I have seen many Canals in my lifetime.

But, this one was different. I noticed something peculiar when researching the area on YouTube. I found this video and it made me realize how big it actually is.

It then dawned on me that the canals I had seen so far were all irrigation canals. These irrigation canals were much narrower than the Europakanal. The water from these Canals was used for irrigating the fields.

The Europakanal, on the other hand is used for transportation, and it is huge. As I was reading up more about this Canal, I learned something interesting: Locks.

I might have read the concepts about Locks before at school but possibly never paid enough attention to enjoy the engineering behind it. This time I watched a few videos clearing those concepts and admiring the engineering.

Read along to know more about this particular canal and locks. There are very good resources on internet. I will only point to those resources wherever possible instead of trying to explain it myself.

Rhine-Main-Danube Canal (Am Europakanal)

This Canal connects two rivers: the Rhine and the Danube.

Rhine river is a major European river starting from Swiss in the South, travels 525 kms and flows into the North sea to the north of Germany. The red mark on the map shows the river.

Danube river which is shown in blue starts from Black forest in Germany and ends into the Black Sea near Romania. This is the second longest river in Europe. This river is 2857 kms. For comparison, Ganges is 2525 kms long.

The Canal connects these two rivers and allows a continuous 3500 kms of navigable water route from North sea to Black sea. But for this canal, the maritime detour would have been very long.

The canal connects the largest tributary of Rhine river, called Main river, marked in Magenta. The closest point is at Bamberg and Kelheim. The canal is 171 kms between these two points. These two circles represents the two points on the map.

What is fascination beyond being able to build a long canal was the practical problem that comes along with it.

First the two rivers are not at the same height. The Danube river is 108m above Main river.

Second the terrain between the two rivers is not flat. There is an ascent of 175m and a descent of 68m.

This brings to the practical problem: How to hold water at higher elevation while allowing ships to pass through? We need locks.

Locks

The task of going up and down with water brings a very practical problem. Water naturally flows downhill, so keeping it at higher elevation is a challenge.

One can solve the problem using dams or other storage structures to hold the water. But, that wont solve the purpose of maritime. The ships or the boats need to pass through the canal if the canal has to be useful for navigation.

That’s where the Locks come into play. The locks are cleverly designed chambers with gates which allow ships and boat to pass through, but prevent water from flowing out!

Along with this feat it performs another important task. That is to elevate the boats up to the next level.

The Maritime vessels are great on flat waters but have a tough time going up and down a hill. That’s why in the above figure you can see that there are sections which are level and there are places where there is a sudden change in height.

The vessels cross this level change using locks. The vessels enters the lock chambers and water is filled or emptied to moved the vessel up or down to the next level. Whats more incredible is that such a complicated task of locking in the water, allowing the vessels to pass and lifting the vessel happens with a simple cleverly designed human operated low tech mechanism.

Look at this video to understand how locks work.

It is indeed possible to automate these simple mechanisms. But it is interesting to note that, even without automation, the whole process can be done by just a few people safely. The mechanism has a self protection mechanism against accidently opening both the doors which can completely drain the water from higher level. The water pressure allows only one door to be opened at a time.

Free Energy?

The question which arises now is whether the energy to lift the ship to the next level is free energy? Of course, people aren’t using any cranes to lift the ship here.

The answer is No. Every time the Lock is operated some water flows from the higher elevation to lower elevation. This results a loss in potential energy.

To ensure continued operation, the water has to be pumped back to the top. Otherwise, there should be an unlimited supply of water at the top via a water source.

So, either the solar energy has to evaporate the water and puts the water back to the top or electrical energy in a pump does this this work.

Some other intersting Lock videos

The Europakanal has 16 locks – 11 uphill and 5 downhill. Similar to these there are few other interesting locks in the world. I list two such systems here.

Caen Hill Locks:

Panama Canal

Conclusion

I spent a day learning about locks and canals. This blogs attempts to capture that information.

It is interesting to learn how canals can drastically reduce travel time. It plays very important economic role.

Although constructing a canal is a challenge of its own but without Locks these canals will be useless. Locks are amazing engineering feat.

The design of the locks avoids any accidental incorrect operation. It is easy to operate it manually. Most importantly it keeps the water locked in even when it allows an entire vessel to pass through its gates.

I hope you enjoy this article as much as I did.