LAS VEGAS (AP) — Conditions on the over-taxed Colorado River have improved dramatically over the past year, but not enough to stave off voluntary cutbacks for some water users in the Southwestern U.S. and Mexico.

A riverboat glides through Lake Mead on the Colorado River at Hoover Dam near Boulder City in this Oct. 14, 2015, file photo. (AP Photo/Jae C. Hong, File)

But the voluntary cutbacks aren’t likely to be noticed by people living in the Las Vegas valley because of conservation efforts driven by the Southern Nevada Water District.

“They’re already leaving water in the lake,” said Patti Aaron, public affairs officer for the Bureau of Reclamation. The 3 percent reduction in Nevada’s allocation through SNWA shouldn’t be noticed, she said.

A federal report released Thursday says the water level in Lake Mead, the biggest reservoir on the river, is expected to be slightly below 1,090 feet above sea level on Jan. 1.

That’s nearly 15 feet higher than projected last year, thanks to a snowy winter. It means river users will avoid tougher mandatory cutbacks.

But it’s low enough for Mexico and the U.S. states of Arizona and Nevada to make voluntary reductions from their share of water, which they agreed to in March.

“Total Colorado River system storage today is 55% of capacity, up from 49% at this time last year,” the report says. That’s after a spring runoff that was 145% of normal in the upper Colorado River basin.

The Colorado River serves 40 million people in Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming as well as Mexico.

Officials are quick to caution: “One year does not end the drought,” Aaron said.