Perhaps a power plant, desalination plant and water pumping stations to keep the lakes full?
The easiest and cheapest solution is probably to recycle the water used to run the locks. Or, the entire problem can be avoided by piping saltwater inland to run the locks, with only a minimal contribution from Lake Gatun.
All of that. Nuclear power plant with plenty of back-ups, destination and pump them full again. We provide for ownership again and agreement to maintain, expand, etc
Watch the video. It’s pretty fascinating. It explains how much water it requires to move a ship through the canal and it’s a phenomenal amount that desalination plants are unlikely to be able to supply. One ship passing through the canal uses as much water as 500,000 Panamanians do in a day. Roughly 36 ships use the canal each day during normal times. Also Lake Gatan supplies about half drinking water of Panama as well as water to operate the canal.