The states that rely on the Colorado River, which is shrinking because of climate change and overuse, are rushing to agree on a long-term deal to share the dwindling resource by the end of the year. They worry that a change in administrations after the election could set back talks.

Negotiators are seeking an agreement that would prepare for extraordinary cuts in the amount of river water that can be tapped. The Colorado provides drinking water to 40 million people in seven states, 30 tribes and Mexico, as well as irrigation for some of America’s most productive farmland.

But the amount of water flowing in the Colorado has declined over time as rising temperatures reduce the snowpack that feeds the river.

“How do we live with the river that we have, not the river that we hope and dream for?” said Becky Mitchell, the lead negotiator for the state of Colorado.

The rules that govern the distribution of Colorado River water expire at the end of 2026. Negotiators are trying to reach a deal quickly, in case the White House changes hands. It’s not the prospect of a Republican administration that is particularly concerning, negotiators said, but rather a change in personnel and the time required to build new relationships between state and federal officials.