No, because the salt water is at sea level and the drinking water is at the level the ships need to rise to via the locks. Water flows out from a lake at 26 met

No, because the salt water is at sea level and the drinking water is at the level the ships need to rise to via the locks. Water flows out from a lake at 26 meters above sea level that is fed by a river that comes from the mountains by gravity. Making the amounts of water that drains out from there move up requires massive amounts of energy. We're not talking a few little pipes here and there. The pumps and energy generation infrastructure project needed to get that done would probably rival or surpass the Panama canal in complexity, scale, and scope. It would be expensive and take a long time to build. Add to that the complexity of doing that while not shutting down the canal for a few years. Basically the amount of water needed for the locks is a function of the amount of tonnage that ships through the canal and the altitude that ships needs to rise to. We're talking about pumping millions of tonnes of water up by 26 meters. Think something in the order of hundreds of gwh per day at least. Of course you could continue to rely on rivers for part of that. But still, it might be doable but it wouldn't be cheap. That and the fact that pumping a lot of salt water would destroy large parts of the ecosystem in Panama is a reason that will likely never happen. The locals might object a bit to that. And they probably also rely on that water for drinking and agriculture.