A proposed plan for future use of Alexandria's waterfront met with a mixed reception last week at a public hearing, with many residents criticizing the plan because its controls on future development are too loose and business groups criticizing it because the controls are too tight.

The plan, a joint 18-month effort of the city and the National Park Service, would designate almost three-fourths of the 39.5 acres of disputed riverside land as a new open-space zone.

Park Service and Alexandria officials are expected to approve the plan or a modified version of it in early June, shortly after the May 29 deadline for additional public comment.

Even after a waterfront use plan has been approved, however, no development can take place until the question of who owns the waterfront land is settled. Still unresolved is a 1973 federal suit claiming that much of the waterfront is federal land.

Many of the more than 60 speakers at the hearing, which drew about 400 people, said they thought the open space and recreation zone proposed in the plan is a "misnomer" because it would still permit construction of buildings to be used for recreational purposes such as restaurants, museums and bicycle rental shops.

Timothy Elliott, chairman of the ciy's park and recreation commission, said the plan should specify "just how much open space will be truly open space" -- a position taken by the League of Women Voters and more than a dozen other speakers.

Elliott said his commission also found the proposed height limits "bordering on the ludicrous" because they would permit construction of several 50-foot-high buildings in the midst of proposed 30-foot zones.

Five-story buildings would "create almost a solid wall of buildings" blocking the city from the main part of the waterfront between Queen and Wilkes streets, Elliott said.

The present building height limit is 50 feet within the historic district south of Queen Street and 150 feet on industrially zoned land north of Queen. The city-Park Service plan proposes a 30-foot height limit along most of the water's edge and a 50-foot limit elsewhere south of pendleton Street. Buildings up to 77 feet would be permitted north of Pendletown and west of Lee Street.

Under the proposed plan, the city would rezone the 39.5 acres between the Pepco power plant and the Woodrow Wilson Bridge to comprise 27.9 acres (71 percent) open space, 6.6 acres of mixed-use office, residential and commercial space, and five acres of space used only for businesses dependent on water.

Responding to criticism about the open space zone, Ric Davidge, the Interior Department official who cochaired the hearing with Alexandria Mayor Charles E. Beatley Jr., assured the crowd: "I've asked that the legal definitions of open space . . . be put into the plan."

Davidge, deputy assistant secretary for fish, wildlife and parks, also said he was asking Interior lawyers to review the controversial flood plain issue. Virtually the entire 39.5-acre plot is within a flood plan "and has been flooded 16 times in the past 32 years," said Frederick Tilp, author of a recent book on the Potomac River, who said he opposes any additional construction along the river's edge.

The city-Park Service plan proposes several options for eventual ownership of the waterfront: making the waterfront a federal park to be maintained by the Park Service, which is opposed by the city and considered unlikely; joint federal, city and private ownership, with controls on private use; and city-private ownership.

City-private ownership could mean less public open space than envisioned in the proposed plan, since it would allow large portions of several properties to be privately owned. However, this is subject to the outcome of the federal suit, or settlement of the suit, since the federal government claims to own most of that land.

Lloyd Gerber, president of the Robinson Warehouse Terminal Co., a Washington Post subsidiary which owns two newsprint warehouses on the waterfront, said the city-Park Service plan is an attempt ""to resolve a sticky problem, but what we have is the city settling with the Park Service at the expense of the rest of the defendants" in the suit.

Under the plan, both warehouse properties, now zoned industrial, would become open-space land if Robinson stopped using them for the water-related purposes of receiving newsprint from cargo ships.