The Colorado River runs through seven US states and crosses into Mexico, helping sustain 40 million people living along its banks and far beyond. It’s been dammed 15 times, part of an effort to capture its waters for the people living along its banks. But the Colorado is drying up, and communities along the river will soon face cuts in their allotted shares, part of a complex treaty between Mexico and the US on how to distribute the water. Alisa Reznick, a journalist from Arizona, travels along the river and speaks with the communities, business owners, and everyday people dependent on the flow.