To view a set of images from Lisa's study of the Central Valley's water, click here for a slide show. California's Central Valley is home to some of the most fertile farmland in the world. In 1901, USDA engineer Elwood Mead predicted it would be "the Egypt of the Western Hemisphere." But this rich land faces an intrinsic natural obstacle: it has little surface water and receives virtually no rain. Some areas get an average of just seven inches each year, on par with the Gobi Desert.

Industrious people have found ways to overcome the land's dry character, by pumping water from aquifers, diverting it from rivers, and, in the past half-century, funneling it from hundreds of miles away. The result of those efforts is an unrivaled agricultural empire.

In 2007, the eight counties comprising the Valley's southern half turned out $22.7 billion in agricultural products—by value, eight percent of the United States' total. And yet that success comes with its own challenge, which is that the water supply has no guarantee.

Indeed, due to circumstances including climate change, population growth, and environmental degradation, recently the water has begun to run out.

In 2009, I began looking at what this means for the region. In a feature for the latest McSweeney's, I explored the impacts on local communities, particularly the town of Firebaugh. (You can read that article here.)

In an ongoing photo series, I'm examining how the coming and going of water manifests in the landscape. This slide show is a first view of that work.