D.C. Mayor Anthony A. Williams (D) said yesterday that he will retain a professional "mediator" to help resolve disagreements between residents, developers and city government officials over the multimillion-dollar redevelopment plan for Columbia Heights.

"The development has created heated disputes and battles over major projects and these battles are frustrating everyone involved," Williams said. "They create division and send the wrong signal to businesses looking to invest in the District."

The mayor said at a news conference that he will bring in a mediator as soon as possible to "determine the willingness to reach a common ground" on the proposed Columbia Heights development. He also promised to establish a clear public planning process within 30 days and outlined a four-point program for developing city-owned land. He also said he is initiating a new partnership with the federal government to develop the Anacostia waterfront.

"At community meetings across the city, I have listened to citizen concerns and frustrations over a community planning process that is broken," Williams said. "There is a shared concern among neighborhood advocates, developers and the business community that the current planning and development process does not work and must be fixed to bring certainty, openness and fairness to the process."

But even as Williams was announcing his new plan, Columbia Heights residents expressed skepticism about the mayor's strategy and questioned whether it is a legitimate attempt to incorporate the views of residents.

"The problem is that the citizens' input has been disregarded," said Gary Imhoff, a community activist from Columbia Heights. "What assurances do we have" that the community will be involved in the process?

"Some development in the District has not always enhanced the area," said Larry Ellison, another Columbia Heights resident. "I just want to make sure that we have upscale development to rid the area of crime and create jobs for people."

Williams said his plan is "chit-chat" now, but he promised residents that they will be involved in every step of the development process.

D.C. council member Jim Graham (D-Ward 1), who represents Columbia Heights, said he is "hopeful that we can find a new common ground in this controversy."

Williams said he has directed Andrew Altman, director of planning for the District, to begin implementing a plan for city government to work more closely with community leaders, national organizations in urban planning and the federal government.

The Redevelopment Land Agency has given preliminary approval to $149 million worth of development on two city-owned parcels near the Columbia Heights Metro station. But many residents complain that the redevelopment board, a majority of whose members were appointed by Williams, ignored an alternative plan presented by another developer that would have developed twice as much blighted property in the area.

Joseph Horning, president of Horning Bros., one of the developers, said his company "is happy to work with the mayor's office in the new planning process" and looks forward to participating "in a community relations effort."

Horning plans to preserve the lobby of the historic Tivoli Theatre and the facades on 14th Street and Park Road NW. Most of the theater's interior would be gutted for shops adjacent to a new Giant. Horning and a Giant Food Inc. spokesman repeated their opposition yesterday to using a portion of the theater as a performance space, saying there isn't enough room. Graham and many residents insist on a performance space being included.

D.C. Council member Charlene Drew Jarvis (D-Ward 4), who heads the council's Economic Development Committee, cautioned that it wouldn't be "wise" to expect that the mayor's new development assessment process "will lead to overturning the RLA board's decision. Rather, I hope the assessment process will make transparent the variables that the board used in making its decision."