This earnest documentary by Grant Aaker and Josh Wallaert, best suited to schoolkids, relates the parched history of the Columbia River Basin. It will come as news to few that the region's original Native American inhabitants were displaced by federal irrigation projects to benefit agriculture. Then the white pioneer farms got Hanford as a neighbor during World War II; thus the A-bomb that fell on Nagasaki. Since then, the ongoing federal cleanup of the nuclear waste site has given Benton County the third-highest per capita income in the state. Meanwhile, Columbia River dams have virtually eradicated the greatest salmon run on the planet. Arid Lands dutifully relates the historical record without making it terribly vivid. Indians, farmers, scientists, and other talking heads all speak their mind. All viewpoints are fairly represented in a bland, reasonable chorus. If there are villains lurking behind this dramatic re-engineering of the parched landscape, as in Chinatown, Arid Lands isn't conducting that kind of investigation. Rather, the film stretches yellow police tape around the crime scene, snaps a few photos, and shakes its head at the tragedy.