Alexandria and the federal government have tentatively agreed on a plan that would end an eight-year quarrel over who owns the city's valuable Potomac waterfront.

The compromise plan, to be given a public hearing May 14, would restrict building heights and preserve as open space almost 30 of the 39.5 disputed acres of waterfront between the Woodrow Wilson Bridge and the Potomac Electric Power Co. plant south of National Airport.

The proposal was praised yesterday by city and National Park Service officials and by the Northern Virginia Conservation Council. The council initiated a 1973 lawsuit over the city's ownership of the riverfront.

The council suit, followed by another filed by the Justice Department, halted construction of four 20-story condominiums at the edge of the Old Town historic district and has subsequently stalled all other development along the city's waterfront.

If Alexandria and the park service adopt the plan in June, it would serve as the basis for settling the lawsuit against the city and a dozen major property owners. The suit claims the waterfront is part of the District of Columbia, which owns the river up to its highwater mark, and thus is under the federal government's control.

Former Alexandria City Council member Ellen Pickering, president of the conservation council, said the latest plan "preserves the edge of the river for the public, with parkland or activities the public can participate in. And that's just great."

Park service regional director Manus (Jack) Fish called the plan "a balanced resolution which will pave the way for a revitalized waterfront."

Alexandria City Manager Douglas Herman called it "a reasonable, practical plan that should satisfy most people, groups and interests. It doesn't spell out everything, but then it shouldn't."

The plan leaves unresolved, said Herman, the questions of who will own and maintain the public land -- the park service or the city -- and exactly how much development will be allowed on the major private tracts of land along the river. They are 15 acres near the Alexandria Ramada Inn and 3.5 acres at a former Pepco substation beside the Old Town Yacht Basin.

The city wants to own all public lands along the waterfront and the park service apparently has offered no objection in the compromise plan.

The proposal would limit building heights along the waterfront to 30 and 50 feet, except north of Pendleton Street where 77-foot-high buildings would be permitted, if located one-to-three blocks from the river. The park service, which last summer sought a 45-foot-height limit in many areas, now has agreed to the 50 feet proposed by the city.

Only one area is still in dispute, near the Ramada Inn, where the park service wants a 30-foot limit and the city wants 50 feet.

While the exact amount of open space would be determined in settling, the lawsuit with landowners, both the city and park service agree that "open space" would include marinas, outdoor restaurants and cafes, seafood and farmers' markets, even a public auditorium, as well as parkland.