California's Delta has a rich agricultural legacy, but farming there can be a risky business. Dozens of farms have been flooded over the past half century as aging levees have collapsed. Now, scientists are encouraging farmers to switch to a new crop. Instead of growing vegetables, they'd grow something that has all but disappeared in the Delta: wetlands.

California's Delta provides drinking water for more than 25 million people and irrigates millions of acres of farmland. But our reliance on the Delta has caused its ecosystem to collapse, harming the fishing industry and putting water supplies at risk. How do we bring it back to health? One group of ecological detectives believes that maps from more than 150 years ago may hold the key.

If you're unfamiliar with where San Francisco Bay's Delta is, or why it's so important to the state, you're not alone. Polls show most Californians have never heard of it. The Delta is where California quenches its thirst. The fate of cities, farmers and even fish depends on it. But the Delta has become ground zero for a decades-long water war. We take a look at the latest efforts to break the deadlock.