A Cabinet-level committee yesterday barred the completion of a $116 million Tennessee dam that threatened the existence of the tiny snail darter.

While the endangered three-inch perch emerged victorious in what has been one of the most celebrated environmental battles in recent history, the dam apparently was killed for other reasons.

"Frankly," said Interior Secretary Cecil D. Andrus, "I hate to see the snail darter get the credit for stopping a project that was ill-conceived and uneconomic in the first place."

Andrus met yesterday with Agriculture Secretary Bob Bergland, Army Secretary Clifford Alexander, Charles Schultze of the Council of Economic Advisers. Environmental Protection Agency Administrator Douglas Costle and National Oceanic and Atmospheric Administration head Richard Frank, who all voted against the dam.

The committee was set up by Congress last year to decide whether exemptions to the Endangered Species Act should be granted in cases of irreconcilable conflicts between projects and endangered species. The act previously had barred any project that could extinguish a species.

The Tennessee case prompted an outcry in Congress after the Supreme Court ruled that the dam, although 90 percent completed, could not be used because it would flood the river where the darter lives.

Yesterday, Sen. Howard H. Baker Jr. (R-Tenn.) who cosponsored the bill setting up the committee, said, "If that's all the good the committee process can do, to put us right back where we started from, we might as well save the time and expense. I will introduce legislation to abolish the committee and exempt the Tellico Dam from the provisions of the act."

However, Andrus predicted that the decision would not be overturned, saying that Baker's "... going to need 50 other votes in the Senate and I don't know that that will be the mood of the Congress."

Schultze said he made the motion against the dam because "... it does not pay. The costs clearly outweigh the benefits. It would have cost $35 million to complete it and we would be inundating $40 million worth of land. You would lose important Indian archelogical sites, scenic values and the river in its natural state."

Andrus said, "I see no reason to spend more taxpayers' money when 38,000 acres can be put back into farming and be productive." The dam would have produced electricity and a reservoir for lakeside commercial development.

The dam's builder, the Tennessee Valley Authority (TVA), retreated from a position of strong support last summer and identified several alternatives to the project, including agricultural development around the river. However, TVA's board has yet to take an official position, and eventually Congress would have to deauthorize the dam.

In other action, the Endangered Species Committee yesterday exempted the Grayrocks Dam in Wyoming from the act after its sponsors said they would protect the mating grounds of the world's last whooping cranes.

The dam, part of a $1.6 billion coalfired power plant, will suck water from Nebraska's Platte River where the cranes stop on their annual migrations.

The plant's sponsor, Basin Electric Power Cooperative, agreed to regulate the project's water flow so as not to harm the whoopers, as well as pay $7.5 million to buy land to protect them.

The two cases, Andrus said, indicate that "the Endangered Species Act is working. Since the law passed we've had 5,000 consultations on projects and Tellico was the only one to come to loggerheads."