ONE OF THE MORE cumbersome, unnecessary bureaucracies in town is the Supragovernment of the District of Columbia: those congressional committees with control over this city's local affairs. Their authority is not likely to diminish anytime soon, as one subcommittee blatantly demonstrated when it hacked up the city's budget the other day. But the congressional labyrinth through which all District bills must travel is as inefficient as it is unnecessary-and should be changed.

These congressional groups do jobs other people are already doing and waste congressional money and time on excessive staffs. Consider, for example, the House District Committee: Under Rep. Charles C. Diggs Jr. (D-Mich.), who was chairman until this year, the committeehad as many as 52 people attached to it. Since Rep. Ronald V. Dellums (D-Calif.) has become chairman, things are slightly better. The committee has been reduced from 26 House members to 14. But there are still 42 people assigned to the staff.

At least this committee's Senate counterpart was reduced two years ago from a full committee to a subcommittee; and that group is able to do with half as many staff members. It also does other jobs, since officially it is the Senate Governmental Affairs Subcommittee on Governmental Efficiency and the District of Columbia. The House should follow this example and replace its District Committee with a subcommittee that also could handle other urban matters, including costs of public services in various cities, effects of population shifts and federal-state-city responsibilities.

In addition, Congress should consolidate its system for processing the city's budget every year-which now comes under a completely different pair of subcommittees. As it stands, city government agencies first make requests to the mayor; the mayor submits a budget to the council; the council approves a budget; and after vetoes and adjustments in city hall, the budget goes to the White House-and then to Congress. Then it is gone over by the House Appropriations Subcommittee on the District, the full committee, the entire House, a similar string of groups in the Senate and, if necessary, a conference committee before final congressional passage and a presidential signature.

So long as Congress insists on approving every last penny spent by the District, the least it could do is establish a single, House-Senate committee to hold one set of hearings and make decisions. In the long run, of course, Congress could ease its legislative burden considerably by delegating authority over District affairs to a separate body entirely-namely, the local government elected by those whose money is directly involved.