The National Capital Planning Commission gave its approval yesterday to the construction design of the planned Georgetown waterfront park, part of which could be started as early as next month.

John G. Parsons, the National Park Service's associate regional director here, said the initial walkways, grassy areas and a promenade along the Potomac River would be built between 31st Street and Wisconsin Avenue NW, immediately to the west of the Washington Harbour condominium and commercial complex that is slated for completion later this year.

But Parsons said that before the park construction can start, the District government still has to give the Park Service nine acres of land it owns on the Potomac shoreline from 31st Street to Key Bridge and the park design must be approved by city historic preservation officials. The formal transfer of the land, promised last fall by Mayor Marion Barry, has been delayed by technical requirements for surveying the land and the City Council has yet to approve it.

While approving the design for the narrow waterfront park, which eventually will extend from Rock Creek to just west of Key Bridge, the planning commission also adopted plans for extending the C&O Canal National Historic Park west from the waterfront park along the river to Foundry Branch near Foxhall Road. The parkland would include walkways, lawns, park benches, bike trails, boat docks and fountains, but no areas for more active recreation.

"We're not going to overprogram the park with riverfests and things like that," Parsons said.

Despite the commission's approval of the general design for the park, thorny questions remain unresolved on the development of the waterfront. The commission deleted, pending further study, a part of the plan that calls for docking the USS Williamsburg, a one-time presidential yacht, on the waterfront near Key Bridge and turning it into a restaurant.

Meanwhile, a lawsuit is still pending that contests the Park Service decision lifting a 20-foot height restriction for buildings on land between 30th Street and Rock Creek and permitting construction of a luxury hotel next to the Washington Harbour project.

Some Georgetown activists have protested the plans by the owners of Clyde's restaurant in Georgetown for creation of the 480-to-500-seat Williamsburg restaurant and also disputed plans for a large parking garage within the park to serve the restaurant.

"We do not see that as a facility enhancing a national park," Ann Satterthwaite, a long-time opponent of Georgetown waterfront development, told the commission.

John Laytham, one of Clyde's owners, said he and his partners are willing to spend $3 million to build a 350-to-400-space underground garage near the Williamsburg. But he said they object to a Park Service plan calling for five feet of dirt on top of the entire two-acre garage, a proposal he said would help balloon the cost to $12 million.

"What really adds to the cost is the weight of the earth and the problems with the water table," he said. As an alternative, he said the garage could be built away from where the Park Service wants to plant large trees.

Sarah Campbell, a public works official, said negotiations over the lease of the property are continuing and that two private foundations have expressed interest in operating the garage, with the profits helping finance construction of the park.