Contracts to deliver power from federal dam projects may be signed before the resolution of environmental issues concerning the dams, U.S. District Judge J. Thomas Greene ruled Tuesday afternoon - but there are two catches.

They are that environmental groups were given 24 hours to appeal to the U.S. 10th Circuit Court of Appeals, and that the 15-year contracts must specify that the agreements are not final, pending resolution of the environmentalists' suit against the Western Area Power Administration.They also must say power deliveries may be modified upon the voluntary decision of the U.S. Bureau of Reclamation to change the operation of Glen Canyon Dam and other federal dams after completion of environmental studies that have been under way since 1982.

With this ruling, the focus of litigation shifts from the suit filed in October 1986 by Salt Lake City, Utah Power & Light Co., and more than 150 other cities against WAPA, to a new one filed in December by the National Wildlife Federation, Grand Canyon Trust, America Rivers Inc. and Western River Guide Association.

Plaintiffs in the new suit contend that new power-marketing criteria for Glen Canyon and Flaming Gorge dams could damage the natural habitat downstream.

John C. Keeney Jr., a Washington, D.C., attorney representing the environmentalists, argued that the new suit could be resolved before Oct. 1, the date at which power, under the new contracts, is to begin flowing. He said the groups are ready to go to trial and pledged he will do nothing to delay the action.

Once the contracts are completed, he said, by the time the issues reach the appeals court it could be the third year of using the new criteria. "It's too late to unscramble the eggs" by then, he said - municipalities would have become dependent on the power and could claim they can't cut back.

Under the National Environmental Policy Act, a full environmental review should have been made before the new marketing criteria were adopted in 1984, he said.

"We have what we believe is a fundamental error by the agency (the U.S. Bureau of Reclamation.) They rely on a hydrologic study that is fundamentally wrong."

Keeney said the damage to the environment is continuing, and it's expected to get worse when the new criteria go into effect. The new rules envision greater fluctuations in flows through the dams, and a great volume, which could hurt the river systems even more.

Max C. Vassenelli, representing WAPA, said the earlier suit dragged on for more than two years and was on the verge of settlement when the environmentalists sued, he said.

"But for the filing of the National Wildlife Foundation lawsuit, this case would have been settled, the contracts would have been signed, and we wouldn't be here today," he said.

Also, he said, the settlement makes provision for the contracts to be reopened if necessary because of the new suit.

The natural environment isn't the only public interest, Vassenelli said. Another interest is the millions of people who will receive power under the contracts. Cities and other utilities need to have the contracts so that they can plan for their power usage.