With two major reservoirs on the Colorado River, Lake Powell and Lake Mead, sitting half empty, will a new hydrologic reality be enough to push for big management changes? One conservation group hopes so.

How to solve the problem is a source of political and legal wrangling that’s been going on for years among the seven U.S. states that share the river and Mexico. And it’s exacerbated by climate change: rising temperatures are expected to further shrink runoff in the basin, tightening the belt even more.