You don't need to
destroy the water, just get rid of it. A portal or
precipitate breach spell can safely send the water elsewhere for days at a time, a
gate or
reality maelstrom cast at the bottom of a reservoir can get rid of a lot of water in a short time, and so on. If those spells aren't available and you either own the land or can deal with anyone who would object, a bit of work with
move earth can create an artificial river and some more work can create a canal, so one can both move the water produced elsewhere and provide a handy means of transporting whatever is being created with or consumed by the facility.
As far as what can be powered, 600 gallons per round is equivalent to .38 cubic meters per second of water flow, and according to
this link, a hydroelectric dam with that much water flow and at least 6.6 feet of turbine surface can output a maximum of 5 kW of energy, or much more with more space and a bigger turbine. So congratulations, you've basically got a room-sized hydroelectric power plant on your hands and can run anything that said plant's turbines could, which is...pretty much anything you can think of at a Medieval/Renaissance tech level.