WATER

Lake Powell recently dropped to a historic low, slashing hydropower and the flow of water downstream. As drought deepens, groups are pushing to drain the lake entirely to reveal its long-submerged rock arches and spires and allow wildlife along the Colorado River to recover.

The 27-year-long drought in the Southwestern U.S. — the longest dry period in the last 1,200 years — is taking a serious toll on the flow of the Colorado River. Climate change is shrinking the snowpack in Colorado’s Rocky Mountains, the source of roughly 80 percent of the river’s annual flow, and higher temperatures are melting the snowpack earlier in the year, which saps runoff in late summer and fall.…