DISTRICT OFFICIALS unveiled their revised plan for a downtown convention center the other day and, as far as we can tell, it is just what the Congress - or should we say Sen. Patrick Leahy (D-Vt.) - ordered. Mayor Walter Washington and his agency directors were sent back to the drawing board about five months ago with instructions to come up with a more prudent plan for the center. Sen. Leahy, chairman of the Senate appropriations subcommittee on the District and the primary opponent of the original plan for the center, argued that the project should be trimmed both in cost and size and that the local business community should pay for a significant portion of the project.

To their credit, city officials have taken Sen. Leahy's direcctive seriously, and without, as far as we can see, subtracting much from the usefulness of the project. About 50,000 square feet have been sliced off of the original design, as have two of the four floors; the price-tag is now just under $99 million, down from an earlier $116 million. The new design is quite compact; its more efficient use of space should mean lower maintenance and utility bills. Despite that trimming, the center is still expected to attract 400,000 conventioneers a year who would not otherwise come to town.

In figuring out financing for the center, the city has come up with what appear to be sound projections. Local business and hotel taxes are expected to bring in about $6 million annually, that money is to be used to pay for the site and the cost of initial expenses for the first five years. The remaining $77 million needed for the center is to be borrowed from the U.S. Treasury, an arrangement that does no harm to the city's future borrowing power. To repay that debt, city officials expect to collect enough tax money from new commercial projects that will be built in town, along with about $12 million a year in taxes from the conventioneers that the center is supposed to attract. Several local and national business representatives have indicated privately to city officials that they intend to start a number of sizeable commercial projects within the next year. So far, their plans are being kept quiet in order not to jeopardize approval of bids on other projects; city officials promise to provide Sen. Leahy with specific commitments when the revised proposal is sent to him in mid-September.

Some opposition to the revised plan has already appeared. But no one has seriously challenged the importance of such a strong stimulus to economic development. City officials have made a prudent and persuasive case that the revised plan for a center can meet Sen. Leahy's requirements and also do good things for the District. At $99 million, it just may be a bargain.