Two last-minute amendments to a Senate appropriations bill could create new roadblocks for Indians trying to get water in Arizona and keep their oil in Oklahoma.

One amendment, promoted by Sen. Dennis DeConcini (D-Ariz.), would overturn a decision announced last week by Interior Secretary Cecil D. Andrus for allocating Central Arizona Project water to 12 tribes.

The other, proposed by Sen. Henry Bellmon (R-Okla.), would permit the Army Corps of Engineers to acquire Osage Indian oil and mineral interests underlying several reservoir projects. o

Osage minerals in the northeastern corner of Oklahoma are valued at $1.2 billion and the tribe is not interested in selling its rights. The corp has offered to pay only a fraction of that amount.

The DeConcini and Bellmon amendments are part of a continuing appropriations measure for fiscal 1981 that is scheduled for Senate action this week. The House version does not deal with the two Indian matters.

The Senate bill contained dozens of other provisions for special home-state projects that senators have been unable to obtain through normal authorizing procedures.

The Indian-related amendments, added without hearings or public discussion, drew a critical reaction from Suzan Harjo of the Native American Rights Fund.

She said that adoption of the amendments would result in new and expensive delays in the Indians' efforts to re-establish rights already affirmed by federal courts.

In the Central Arizona Project case, Andrus had just announced terms of a contract to allocate Colorado River water to 12 Arizona tribes.

His decision came after four years of negotiations with the Indians, who had agreed not to file lawsuits if the government would handle their claims in good faith.

DeConcini's amendment forbids the use of federal funds for making any water allocations or signing contracts before next February. This would put the case in the hands of the new Reagan administration, which Arizona farming and development interests hope might reduce the Indians' share of the scarce Colorado water.

Harjo described the retiring Bellmon's amendment as "his goodbye raspberry" to Oklahoma Indians, whose unwillingness to cede valuable oil, gas and mineral rights to the government has slowed reservoir plans.

The legislation would authorize the Army to acquire the Osage rights so that it can move ahead with work on the Skiatook, Candy and Shidler reservoirs.

Candy Reservoir for example, has been stalled by a ruling of the 8th U.S. Circuit Court of Appeals, which said the corps needed a specific congressional authorization to condemn the Osage minerals before it could proceed.

A recent professional study conducted for the Osage Trial Council estimated the market value of oil, gas and minerals under the Skiatook and Candy projects at $1.2 billion.

The corps budgeted $13.2 million to pay the Indians for the right to flood minerals beneath Skiatook. The Osage council, insisting it does not want to sell, says damages there would be $382 million.

Skiatook has been under construction since 1976, even though the government had not cleared up the mineral-rights case. An aide to Bellmon described it as "an oversight."