Executive Summary

The “water footprint ” or “embedded water ” of a product is seen as the amount of water consumed during its life cycle (Chapagain and Hoekstra, 2004). As the State of California implements the Low Carbon Fuel Standard (LCFS), a more complete view of environmental and social sustainability demands consideration be given to the effects that various pathways would have on water resources. While the role of biofuels in a climate protection strategy is unclear owing to the global warming consequences of both direct and indirect land-use, water use remains another central issue and could be, in the words of a recent report, the “Achilles heel ” of biofuel production (Keeney, 2006). This study projects the effects on California water resources from some scenarios of in-state feedstock and fuel production. Many analyses of the water implications of bioenergy only take into account consumption by biorefineries. Because the feedstock cultivation phase of the biofuel production process is by far the most water-intensive part of the bioenergy life cycle, our analysis quantifies these consumptions as well. We find that on average over 1500 gallons of water are consumed (i.e. removed from productive use for a given hydrologi