Again, I would say it's not a yes-or-no answer. That's because it depends on the climate situation.
Under the assumptions that were taken of a very dry period--I'm speculating somewhat--some 80% to 90% of that would be represented by that, say, 1%. There would be some additional water required to be diverted, such as groundwater, to prevent it from filling the mines, for example; and some precipitation also occurs, even during dry periods, that would subsequently evaporate, for the most part, as it would normally.