Perhaps you can't destroy it, but I'll bet it can be rendered unfit for human use. If all the water that ever existed on the planet is still here, is it distributed the same? As my ponds evaporate, their water vapor falls somewhere as rain, so perhaps someone somewhere benefits from my lower water levels. Unfortunately, although that water still exists, it is no longer usable to me, as it is now too far away to do me any good. Therein lies the rub, especially in a drought year. The water is still here, planet-wise, but it's moved...
And until we get enough rain to replenish our groundwater, our local supply will continue to diminish.
