I don't know why you think that. It makes no sense. The viaduct comes from far far north away of the central valley. That water would otherwise not even ever fl

I don't know why you think that. It makes no sense. The viaduct comes from far far north away of the central valley. That water would otherwise not even ever flow through the central valley. Naturally this area doesn't really retain most of its water. It just goes right into the ocean. The central valley lake naturally appears and disappears through no fault of humanity.