About 40 protesters jeered Mayor Anthony A. Williams yesterday in Meridian Hill Park over a city panel's development plan for Columbia Heights.

"Explain yourself, Mayor!" they shouted, along with "We deserve better!" during what was supposed to have been a friendly meet-the-neighborhood event in the park on 16th Street NW.

The previously scheduled Ward 1 picnic--one of a series organized by Williams's supporters in each ward--happened to fall three days after the Redevelopment Land Agency gave preliminary approval to $149 million worth of development on two city-owned parcels near the new Columbia Heights Metro station. The station will open Saturday.

The plans call for building a Giant supermarket; restoring the facade and lobby of the historic Tivoli Theater while gutting the auditorium for two floors of shops; erecting a retail-entertainment complex with stores, an ice rink, an amusement park and movie theaters; and building town houses.

Many residents believe the five-member panel--a majority of whom were appointed by Williams (D)--ignored months of community meetings that called for a more comprehensive alternative plan proposed by a developer that was rejected. That plan would have developed twice as much blighted property in the area and reused the Tivoli as a performance space.

More politically damaging to Williams, perhaps, than the noisy but peaceful demonstrators were the comments of some of the mayor's strongest supporters in the ward, who said they felt bitterly let down.

"I think he made a grave political error," said Joan Gordon, who was on the committee that drafted Williams to run for mayor and who helped organize the picnic. "He and the RLA should have known through his political apparatus what some of his strongest supporters felt."

Saying it was hard to smile at the picnic, Gordon continued: "More than disappointed, we just think it's wrong. . . . The mayor damn well better have known what was happening and how it was playing out."

Asked if she still supported Williams, she replied: "My support is less strong, let's say that."

The picnic also attracted about 100 people who were Williams's fans or expressed no opinion as they enjoyed free food. Williams, dressed in shorts, shirt and a baseball cap, avoided lengthy debate with the protesters, who were kept back by U.S. Park Police.

Answering the taunts of "explain yourself," he said simply, "I appointed the board, the board expedited its vote, and I stand behind the decision of the board."

Speaking to reporters, Williams added, "This [project] is a good thing. This is a community that has wanted development for a long time. We're moving this on a fast track."

The proposed development has ignited strong passions on all sides because it represents the most significant project east of Rock Creek Park in decades, and it could go a long way toward repairing the commercial heart of Columbia Heights, along 14th Street NW, which has never recovered from the 1968 riots after the assassination of Martin Luther King Jr., when nearly 300 stores were burned or looted.

"The mayor talked about neighborhood development when he was a candidate," said Dorothy Brizill, one of the organizers of the protest. "But he doesn't get it."

Brizill said the Columbia Heights project amounted to a closely watched test of the administration's ability to renew struggling sections of the city. Williams failed the test, Brizill said.

But not everyone is so disheartened.

"Thank you for the RLA decision," said Advisory Neighborhood Commissioner Lawrence Guyot, pumping the mayor's hand. Guyot said the decision reflected the wishes of many residents.

And when the decision was announced last week, resident Sabrina Kenney said that at last neighborhood young people would have activities to attend and adults would have more services at hand.

"It's not fair we have to catch the bus to Greenbelt or Georgetown," she said. "We deserve better."

CAPTION: About 40 protesters at Meridian Hill Park show their disapproval of a $149 million redevelopment plan.