TUSKAHOMA, Okla. >> Sardis Lake, a reservoir in southeastern Oklahoma young enough to have drowned saplings still poking through its surface and old enough to have become a renowned bass fishery, is not wanting for suitors.

Oklahoma City and fast-growing suburbs like Edmond want to see the water flowing through their shower heads someday. So do the water masters of Tarrant County, Texas, 200 miles to the south, who are looking to supply new subdivisions around Fort Worth and are suing for access.

Now another rival has arrived: the Choctaw and Chickasaw tribes, which were exiled to southeastern Oklahoma 175 years ago and given land in the area.

Gregory Pyle, chief of the Choctaw nation, said his tribe would sue to win some of the water if necessary. “All this water was controlled originally by the Indian tribes in this area,” Pyle said. “It is all Choctaw and Chickasaw water.”

The tribes want the state to recognize them as joint owners. The issue has been increasingly on the minds of city planners in fast-developing cities as they contemplate the prospect of tapping other existing water sources.

By midcentury, water is expected to loom as large as oil in the economic and political life of the country, as parties race to lock up supplies. As droughts exacerbated by climate change and by population growth expand in the Great Plains and the Southwest, Indian water rights loom as a largely unsettled — and unsettling — factor that could affect the price and availability of water to millions of homes and businesses.

“There are huge and vested rights to water that are unquantified,” said Taiawagi Helton, an expert on Indian law and water law at the University of Oklahoma College of Law and a member of the Cherokee tribe.

Turning theoretical rights into what is widely termed “wet water” under the terms of long-ago court rulings can take decades. Each case involves other local water users, the state government, the Interior Department, the local congressional delegation and the federal court system.

A 103-year-old Supreme Court decision effectively put tribes in Western states at the head of the line in times of water shortage, or if a water basin is oversubscribed. But Interior Department officials want to be certain there are no big losers when a tribe’s rights are recognized.

If the Choctaw and Chickasaw were to gain water rights under that old court ruling, legal experts say, it could prompt a new push for similar rights across Oklahoma, which has 39 federally recognized tribes. It could also encourage more tribes in the West to start claiming their reserved rights.

Despite the age of the Supreme Court ruling, known as the Winters doctrine, efforts to quantify tribes’ water rights proceeded at a crawl until the 1980s and 1990s. Since then, about three dozen Indian claims have been tabulated, mostly though drawn-out settlements. Today the Interior Department is presiding over water negotiations with 18 tribes.

A push by the department and by senators in Arizona, Montana and New Mexico resolved four claims at the end of last year. Yet unlike tribes whose rights were signed into law recently, the Choctaw and Chickasaw no longer have reservations, which raises the question of whether water claims must be tied to a specific land grant. The tribes’ land was parceled out to tribal members more than 110 years ago.

Still, “the water was never taken away,” said Stephen Greetham, the lawyer for the Chickasaw nation.

When the Choctaw and Chickasaw did have reservations, their land covered virtually all of southeastern Oklahoma and was watered by the Kiamichi River, whose tributary, Jackfork Creek, was impounded by the Sardis Dam in 1982. The tribes’ goals are to have some ownership and control over the water, to keep as much water as possible in the lake and to enhance southeastern Oklahoma’s recreational industry.

And, assuming the water is valuable, they want to share in the profits from selling or leasing it.

That prospect is unsettling for places that could face water shortages, like Oklahoma City and suburbs like Edmond, whose City Council has already voted to issue $102.5 million in bonds to help bring Sardis Lake water 110 miles north, to the taps of new homes. It is even more unsettling in the Southwest, where irrigated agriculture and industries consume most of the available water.

Daniel McCool, director of the environmental studies program at the University of Utah, cautioned that the more broadly tribes seek to assert their rights, the greater the risk that the federal courts — the Supreme Court in particular — will trim or even eviscerate earlier rulings establishing Indian rights. “It’s case law, and case law can be changed,” McCool said.

The political pushback against Indian rights could come from other local users who fear for their livelihoods, said Chris Kenney, a former federal water rights negotiator now living in Oklahoma.

“You’ve got local people who have used water for many, many years,” Kenney said. “ In many cases they are at enormous risk.”

A settlement just approved by Congress and signed by President Barack Obama granted water from a Colorado River tributary to the Navajo tribe. Two New Mexico towns, Bloomfield and Aztec, are suing to overturn it.

Interior Department officials suggest that the Navajo case is an exception. Negotiated settlements are far more advantageous to both tribes and existing users than litigation, they said in an e-mail response to a query.Other claims are waiting in the wings. A California tribe, the Chemehuevi, whose reservation was partly inundated in the 1930s when Parker Dam was constructed and Lake Havasu was created in one of the hottest parts of the Mojave Desert, has the right to some Colorado River water. It uses less than a fifth of that annually.

But an effort by the tribe 15 years ago to get federal approval to sell some of the excess met with objections from water users in the area and died for lack of federal support. Now the Chemehuevi would like to lease some water to the Barona Band of Mission Indians in the San Diego area, their lawyer, Lester Marston, said.

Marston said he wanted to avoid a cumbersome settlement process, however, and Interior Department officials have not warmed to his shortcut. In a statement, department officials said they preferred settlements because they involved the consent of a large number of water users and “benefit the community.”

Also in California, the Tule River Tribe is trying to get rights to water from the South Fork of the Tule River. Kenney, who is advising the tribe, said the effort was stalled, but would continue.

The Apache in Oklahoma have gone to federal court, so far unsuccessfully, seeking to sell or lease water to the Tarrant County water agency in Texas. And the largest Oklahoma tribe, the Cherokee, has received mixed signals from federal courts as to its rights concerning the Illinois River. A leading Oklahoma water official said in an interview that he wanted to negotiate with the Choctaw and Chickasaw. “Certainly we’re not foreign to the concept of sitting around the table and working things out with tribes and these tribes in particular,” said the official, J.D. Strong, executive director of the Oklahoma Water Resources Board, the state’s primary water agency. “It will happen if the leadership of this state wants to do that.”

So far two Oklahoma governors — Brad Henry, a Democrat who left office in January, and his successor, Mary Fallin, a Republican — have not opened formal negotiations with the tribes over Sardis Lake. Alex Weintz, a spokesman for Fallin, said in an e-mail that the governor was awaiting a report being prepared by the state water agency before deciding on her approach.

Pyle, the Choctaw chief, said he worried most about preserving the economic viability of southeastern Oklahoma for recreation. “When water goes from a region, so goes your economy,” he said.

He said that before water leaves the area, there should be a complete study of local needs and local capacity.

“I want to make sure for history going forward that we have enough water here,” he said.

© 2011 The New York Times Company