Another warm, arid winter could leave Colorado River reservoirs nearly dry.

That is one of the projections a group of Colorado River experts released Monday, building on a previous report released last September assessing the future of the waterway’s federally managed dams under different hydrological scenarios. The new report forecasted the impacts of another dry winter and a wetter one, which it found would not provide enough water to extricate the basin from the depths of a climate change-fueled drought.

“Both scenarios demonstrate the need to adopt significant additional measures to permanently decrease consumptive uses across the entire Basin,” the authors wrote.

The Colorado River and its tributaries serve 40 million people across seven Western states, 30 tribal nations and Mexico. In the U.S., the Colorado River Basin is split into an upper basin containing Colorado, New Mexico, Utah and Wyoming, and a lower basin comprising Arizona, California and Nevada. Water use in the basins, between 11 and 13 million acre feet recently, has consistently outstripped what nature provides, leading to some reductions in usage but an imminent need for much steeper cuts.

But the new report finds the supply-and-demand imbalance is likely to persist under a range of weather and usage scenarios.