As the Colorado River shrinks at the hands of a two-decades-long drought, there’s a lot on the line. The water supply for 40 million people, agriculture, wildlife and hydropower generation are all hanging in the balance as the region grapples with a dwindling river.

The federal agency most involved with the Colorado River and water in the West is the Bureau of Reclamation. The agency’s measurements and actions can lead headlines throughout the region — including the shortage declaration that raised national alarm last August.