Topping the list this year is the Colorado River, which is threatened by climate change and outdated water management. Thirty federally-recognized Tribal Nations, seven states, Mexico and 40 million people who rely on the river for drinking water are being impacted by this crisis. Also threatened is vital habitat for wildlife, as the Basin is home to 30 native fish species, two-thirds of which are threatened or endangered, and more than 400 bird species.