BILLINGS, Mont. (AP) – Crow tribal leaders, the state of Montana and the U.S. Department of Interior signed an agreement Friday that aims to resolve longstanding grievances over shortages of water for drinking and crops on the tribe’s arid reservation.

Crow Chairman Cedric Black Eagle said Friday’s signing of the water rights compact assures his people will have clean water for generations.

“Water is life among our people,” Black Eagle said before signing the document during a ceremony in Washington, D.C., that was streamed live online.

As part of the deal, the federal government has committed to spending $461 million on irrigation improvements, industrial and municipal water system upgrades and other projects.

In exchange, the tribe waives any legal claims against the government for being denied adequate water resources in the past. Most of the Crow’s 11,900 enrolled members live on the tribe’s sprawling 2.3 million-acre reservation along the Montana-Wyoming border.

Gov. Brian Schweitzer signed the compact on behalf of the state, and Interior Secretary Ken Salazar signed for the United States.

Salazar said the agreement reflected efforts by the Obama administration to usher in a new era of federal-tribal relations by resolving historic disagreements with individual tribes and their members.

“The existing drinking water system has such significant deficiencies in terms of carrying capacity and water quality that many tribal members at time must haul water,” Salazar said. He added the agreement “places the tribe firmly in control of its natural resources.”

The Crow also gain rights to up to 300,000 acre-feet of water annually from Bighorn Lake, a government-operated reservoir along the Wyoming border, and 500,000 acre-feet annually from the Bighorn River.

One acre-foot is enough to cover 1 acre of land 1 foot deep, or enough to meet the annual needs of about two households.