Certainly the additional set of parallel locks opened in recent years would only serve to hasten the speed with which they are dumping the fresh water into the oceans on each side.
Seems to me that if you forced the locks to be used in sync so that as the water was being lowered in the exiting lane, its water was being used to raise the ships in the entering lane. This is such an absurdly simple idea, that there must be a reason it is not happening. Does anyone know what the water isn't shared between the 2 lanes at each level? Is it something with different mass between the ships means the amount of water is not always equal?
- On the new locks they recycle ~60% of the water used already, it's a smart system.
- Another commenter pointed out that they have to allow fresh water through the lock system to prevent salt water contamination of the lakes.
I guess a reason they haven't retro-fitted (yet) the 60% water saving mechanism to the older locks is the scale of the engineering efford involved, plus they can charge people $4.5 million to jump the queue ;)
I think the main reason is that the (big!) ships just don't have room to pass each other anywhere other than on Gatun lake. They can't pass in the Gaillard cut, and not really in the approach harbors either. So it's one way traffic basically.
Also, anything taking the old locks out of operation for a few weeks/months is basically a no-go. That's just too costly.
As a side note, do keep in mind that water is already "saved" a little by going up in a convoy. With the three lock chambers, you get to reuse the same water three times. Not exactly true of course because convoys start and end, but you get the idea.
In the new locks they pump the water between tanks and the locks. The problem is the water has to be fresh water because to get to the other side you have to traverse this massive fresh water lake. There's always going to be some release of fresh water to keep the lake from becoming brackish.
The water from the "down" ship can be used to raise the "up" ship... until it's at the same level as the down ship. Then you're stuck [Edit: unless you have] either water coming from the elevation of the top of the locks, or pumps.
