Here's a little more fat for the Ethanol fire:
The water requirements associated with driving on biofuels can be significant. Assuming conservatively a volumetric water to ethanol ratio of 800 (e.g., for irrigated corn ethanol from Nebraska which excludes processing water requirements), and that a car can drive 16 mi on 1 gal of ethanol (or 2/3 of the mileage from gasoline), this represents about 50 gal of water per mile driven (gwpm) (or 0.02 mi per gal of water [mpgw]).
Journal of Environmental Science and Technology, 1 May, 2009 http://pubs.acs.org/doi/full/10.1021/es802162x
RFB