Millions of gallons of water used to flow every day from the Rocky Mountains to the Gulf of California. Now, the Colorado River ends at Morelos Dam on the U.S.-Mexico border. Below it, one of North America's largest wetlands is dry.
Karl Flessa, a geoscientist at the University of Arizona, began researching the damage two decades ago. Then he started asking how much water it would take to bring back some of the habitats.
For much of the 20th century, hydroelectric technology led to the construction of giant dams across the American West and around the world. Big hydro projects have a big impact on surrounding ecosystems, Colorado is at the center of a growing move toward hydropower on a smaller scale.
In northern Nevada, a place famous for its wide, open spaces and expansive cattle operations, ranchers are in a bind due to the historic drought.
Much of the state is desert, so when people talk about drought, they're really talking about the snowpack in the Sierra Nevada. It's at barely 20 percent of average.
This is a huge concern for farmers and ranchers like Julie Wolf, because the mountains store the snow that melts and feeds rivers and reservoirs. These bodies of water then allow the desert to bloom with grass and alfalfa for her cattle.