Here's an idea, charge 5x the amount for water for farms than we do residential, (or any industrial/commercial purpose) and if you pollute the water ways you pay 3x the cost to fix it, and if it isn't fixable you pay some really exorbitant (might as well go out of business fee).

Sure prices will go up on goods from those water ways, but maybe they won't..maybe they'll do better more environmental farming to preserve water, like vertical farming.