DENVER (AP) – Colorado and the U.S. Bureau of Reclamation are getting closer to finalizing a contract for the state to pay for its share of water from the Animas-La Plata Project and costs for building it.

The half-billion-dollar project, decades in the making, fulfills a settlement of water-rights claims of the Southern Ute and Ute Mountain Ute tribes, but it also will provide water for the state of Colorado and four other entities in Colorado and New Mexico.

Colorado’s Legislature has authorized paying $36 million to the U.S. Bureau of Reclamation for its share of 10,460 acre-feet of water, plus interest on construction costs. But the interest has been building, and the $36 million likely won’t cover everything Colorado owes.

The tribes had proposed that Colorado allow its share of water to revert back to the tribes, which weren’t assessed for construction. The tribes would then sell the water back to the state at what they say would be a much lower price than what the state would pay the bureau.

“When we heard what the state would spend to get water, our first thought was, `Why?”’ said Peter Ortego, general counsel for the Ute Mountain Ute tribe. “We can make it cheaper for the state. Sure, it puts money in our coffers, but it keeps it in Colorado.”

However, after two years of talking with tribal representatives, the Colorado Water Conservation Board has directed its staff to move forward on contract talks with the Bureau of Reclamation, board director Jennifer Gimbel said.

Gimbel said the board took the tribes’ proposal “very seriously.” However some board members questioned whether outside parties would challenge the proposal in court. Though legislators have already approved $36 million for project water, some board members also questioned how willing legislators would be in future years to spend on Animas-La Plata project water.

Gimbel noted the state may still have to talk with the tribes in the future about buying project water, especially if it turns out Colorado is unable to afford its entire share today.

Ryan Christianson of the U.S. Bureau of Reclamation said that following a meeting with state officials last week, he is optimistic a final contract could be reached this year. Another date for negotiations has not yet been set.