American Rivers recently released a list of the top 10 most endangered rivers in the U.S. At the top of the list was the Colorado River, which supports more than 36 million people and sustains a variety of uses, from farming to recreation to habitat for endangered wildlife. Due to drought and increasing demand, the river no longer flows to the Sea of Cortez, and its supply is already over allocated. According to American Rivers, climate change is expected to reduce the river’s flow by another 10% to 30% by 2050. Proposed dams and diversions further threaten the river and the supply of those downstream.

In 2011, Yale Environment 360 released a video produced and written by Pete McBride. In the video, McBride follows the Colorado by air and raft, trying to answer his childhood question of how long it took his family’s irrigation water to reach the sea. The video details the many issues facing the Colorado River today.

Watch the full 12 minute video here.

At the end of 2012, the U.S. and Mexico agreed to Minute 319. The agreement’s goal is to ensure that water reaches the river’s delta in Mexico. In the agreement, water is allocated to a variety of uses, of which the environment is a small part. The agreement raises hopes of restoring some of the once-rich delta habitat. For more on these restoration efforts, check out National Geographic’s Colorado River Delta Series.