An Interior Department official who has played a major role in Southwest water negotiations is stepping down from her position early next week.

Tanya Trujillo, who has served as the assistant secretary for water and science for roughly three years, oversees the U.S. Bureau of Reclamation.

Trujillo had a key role in negotiating plans over use of the Colorado River between Arizona, six other states, the federal government, and Native American tribes.

She said her departure comes at a “normal transition time,” as the Biden administration gears up for a reelection campaign. But it also comes as several areas continue to struggle with finding ways to reduce use of the river’s water.