[pietjepuk88]

See https://news.ycombinator.com/item?id=38255225 for a back-of-the-envelope calculation of why it's intractable to pump the water back.

And see https://news.ycombinator.com/item?id=38256185 for why the water saving basins are not as great as you would think (at least for the new locks). For the old locks, adding them would probably just add too much too the leveling time. And the construction would take those locks out of operation for at least a couple months, and they just cannot afford that.

In the Netherlands there are locks with pumps for directly leveling, reducing/preventing salt intrusion, or "evening out" the loss of water with a separate pumping station (look up Krammersluizen and Kreekraksluizen). But we're talking a meter or 2 water level difference, not a whopping 26 meters. And those locks are generally not as big, and even then we tend to get rid of those systems where we can (Krammersluizen) as it's just too expensive to operate and maintain.

[happytiger]

Extremely informative. Thank you very much for taking the time to educate me. I deeply appreciate it.

[pietjepuk88]

Locks are fun! (Can you tell I'm Dutch? ;) )

[cozzyd]

Now I finally understand the origin of the GIL.