Compare the amount of water they're taking out per day (576,000 gallons) to amount of water that goes over Niagara Falls in a day (about 54,345,600,000 gallons).
In the short term perhaps, but it's not going to take that long to hit 10,000$ worth of energy and again that's just one of many uses of this water which as far as I can tell is uncompensated.
"Not a huge amount of energy", indeed.