There’s good news and bad news for the drought-stricken Colorado River system, according to projections just released in a new federal report from the Bureau of Reclamation, manager of dams, powerplants and canals.

The report predicts that Lake Mead — the river system’s largest reservoir, supplying water to millions of people in Nevada, Arizona, California and Mexico — will narrowly escape a shortage declaration next year. But a shortage is looking imminent in 2018, and water experts are growing ever more worried about the river system’s future.