ONE OF OUR FAVORITES among the many ideas and projects that did or didn't materialize as part of Greater Washington's bicentennial program was a plan for a "National Children's Island" on the wasted strip in Kingman Lake between RFK Stadium and the Anacostia River. It wasn't a new idea; for at least 20 years people had been talking about some sort of recreational area there. Then about 11 years ago, landscape architect Lawrence Halprin drew up a proposal for Lady Bird Johnson's beautification committee. He recommended making the lake clean enough to swim in and creating beaches, amusements, picnic areas and facilities for cultural offerings.

Sounded grand. By 1975, that proposal was still around, by then in less ambitious from. Still, architect Richard Dattner, under the administrative direction of Joseph C. Henson, the city's man for special bicentennial projects, had come up with a fine design for a park. It would be planned especially for children, handicapped people of all ages and the elderly.

So how do things stand today? You may have noticed a ominous report in Thursday's District Weekly section of tis newspaper noting that Rep. William H. Natcher's subcommittee had cut all funds sought by the city to continue work on the island. Even worse, the account left an impression that this decision, coupled with another by the subcommittee to shift control of the project to the city's recreation department, might kill the whole thing.

Well, hold the dirges. As many times as we've cited devastating budget cuts perpetrated by Mr. Natcher & Co., these latest moves aren't lethal. At least neither Mr. Henson nor city officials see it that way. Instead, what you have is a bit of a fuss between the many bureaucratic parents of Children's Island over who should be given custody of the project now that the bicentennial's over.

Mr. Henson is executive director of an independent non-profit organization that has been planning the island facilities and soliciting private finacing. He argues strongly that, if the organization is to continue soliciting necessary private support, the project should not be totally taken under the city's wing. He notes that foundations have said that the legal status of their contributions might be jeopardized if they were to make the grants to a city agency. City government officials contend, meanwhile, that the project should be coordinated by the recreation department with other local spending, other programs and the agency's long-commitments.

We rather suspect that the children of the city don't much care how this control is apportioned - and that they might be a bit more interested in whether they will be kids anymore by the time this story ends. Surely, the bureaucrats can find a satisfactory way to mesh a National Children's Island corporation with appropriate oversight by city hall.

As for what to expect on the island itself, officials intend to open one area this fall for arts and crafts programs for designated school groups. Moreover, they're counting on a grand opening next summer of four major play areas, concessions, a cable slide, carrousel, greenhouse, ranger tower, nature sanctuary and much, much more.

We'll see. Certainly Children's Island will need greater help from the private sector as well as continued federal assistance. But for now, it's reassuring to hear that this promising project still lives.