New York’s Hudson River stars in Jon Bowermaster’s environmental documentary about America’s “first river.” The Keeper follows patrol boat captain John Lipscomb who has been the eyes and ears of the environmental watchdog group Riverkeeper. Lipscomb’s job entails reporting environmental issues, both natural and, historically, mostly manmade ones. We learn that while the River might look more beautiful and cleaner than it has in many decades, the news isn’t all that great. Polluters like General Electric have terrible track records abusing the waters, and still standing dams disrupt the migration patterns of fish.