Two major lakes in the Colorado River Basin that operate as one huge reservoir to supply millions of people with water are drying up, scientists have warned. Water levels at Lake Mead and Lake Powell have been steadily declining over the course of a two-decade drought affecting the region. In addition to the extended dry spell hitting the Colorado River Basin, the water supply is suffering a severe ‘structural deficit,’ in which more water is being consumed each year than can be replenished. More than 40 million people and 7,800 square miles of farmland rely on the Colorado River and its tributaries.