"For farmers to be sustainable, they must be economically viable, and farmers who rely on off-farm water sources may not be economically viable during drought years," says Bill Liebhardt, director of the UC Davis-based Sustainable Agriculture Research and Education Program. Liebhardt notes that the State Water Project's recent suspension of all water deliveries to agricultural users, and federal agricultural water delivery cuts of up to two-thirds have left many California farmers without options. Sustainable landscaping (drought-tolerant "xeriscapes") will help in urban areas, but it might be necessary to reduce planting in rural areas that don't have enough groundwater, he says. "It's like the energy crisis. You either find new sources of water, or find more effective ways of using what you have. I suspect we'll probably have to consider both in the future."