An improvement of only seven percent in the volume of fresh water used suggests that the redesign was probably motivated by increasing the lock size for larger ships and the slight reduction in fresh water was achieved to help sell the design. I'm certain that the seven percent gain will be more than lost by the increase in traffic caused by the larger locks.
I remember reading about all of the technical and logistics challenges when workers were building the Panama canal many years ago. Many lives were lost due to disease at that time. The Panama canal is an engineering accomplishment and I'm glad to see continuous improvements being made.
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