After resisting on two previous votes this year, the Senate yesterday pulled the plug on the snail darter, caved in to the House and approved completion of the Tellico Dam.

The Supreme Court had halted work on the nearly completed $100-million-plus Tennessee Valley Authority project on grounds that it would violate the Endangered Species Act by wiping out the snail darter, a tiny fish. Last year Congress created a review board to take another look, but it ruled against the dam not only because of the fish but because it said the project was not economically justified.

Twice this year the House tried to push through legislation to order completion of the dam, and twice the Senate, led by Sen. John Culver (D-Iowa), rejected it. But the Senate apparently tired of the struggle. Yesterday it was told that the snail darter is dying out in the river to be dammed, but has been transplanted and is thriving in other streams. It was also told that if the Senate didn't get out of the way of Tellico the House would scuttle the $10.8 billion energy and water projects appropriations bill to which it was attached and which funds projects in every state.

With that, the Senate voted 48 to 44 to accept House language ordering completion of the dam. Interior Secretary Cecil Andrus has said that he would recommend that President Carter veto the bill if it contained the Tellico provision.