a personal blog

How Do Canal Locks Work?


Grady Hillhouse @ Practical Engineering:

One thing to notice about a lock is that even though boats can move through in both directions, water only moves through in one . The lock always fills from the upper canal and always drains to the lower canal. This is because… gravity. Hopefully that’s obvious. But, it’s important to realize that even though we’re not using pumps, the energy required to raise and lower boats through a lock isn’t necessarily “free”. Each time the lock is operated, you lose a “lockful” of water downstream.

I never thought about water loss from canal system

And sometimes that matters. Canals aren’t full of limitless water, and if there is a lot of traffic or the locks are particularly large, this could mean losing millions of liters of water per day.

What if there was a way to save the water used to fill the lock and reuse it?

On the Panama Canal, the locks use water from Gatun Lake, a critical source of drinking water for the country. During periods of drought, water supply becomes a serious issue. That’s why, when the canal was expanded in 2016, the new locks included water saving basins. Like the locks themselves, these basins are an extremely simple and yet an ingenious way to limit the amount of water lost each time the locks are filled.

Simple yet effective way to save water from loss in canals.