Due to a typographical error, a story in yesterday's editions erroneously stated the estimated cost of the proposed Franklin Delano Roosevelt Memorial. The correct figure is $20 million.

The Fine Arts Commission has given approval to the basic design of a 900-foot granite wall of waterfalls and gardens in West Potomac Park as a memorial to President Franklin Delano Roosevelt.

The memorial, unofficially estimated to cost about $200 million, would curve around the western edge of the Tidal Basin, forcing the closing of almost one mile of West Potomac Park roads. It also would eliminate about 400 parking spaces in West Potomac Park.

The National Park Service, which already has already spent $465,000 in design funds on the project, is preparing an environmental assessment of the impact of the memorial on the Mall area and will hold public hearings on it in June.

The unanimous approval of the Fine Arts Commissions, which gave the memorial its preliminary approval in July, 1975, appears to remove the last major roadblock to creation of a Roosevelt memorial here. But Congress must approve funds for it.

Congress created an FDR Memorial Commission in 1955. But the two designs the commission came up with in the 1960s were killed as monolithic intrusions upon the Mall area.

The first, deemed "instant Stonehenge" by its critics, called fr eight huge concrete slabs in a 27-acre section of West Potomac Park. The second proposal, by architect Marcel Breuer, called for huge granite darts to surround a 32-foot granite cude.

The present design, by California landscape architect Lawrence Halprin, calls for a dark brown roughhewn granite wall, in varying heights up to 14 feet, which will be an almost continuos waterfall for its 900-foot length.

A 150-seat theater, restaurant and audio center are to be built under a mound of earth with a sod roof, according to John Parsons, chief planning coordinator for the Park Service, who is overseeing the design process.

There will be extensive plantings of azaleas, dogwood and rhododendrons and a modest amount of roses . . . about 1,000 bushes,' Parsons said. Previous plans had called for as many as 20,000 rose bushes in honor of Roosvelt, whose name, in Dutch, means "one who lives near the rose fence or field," according to the New Dictionary of American Family Names.

Parsons said the memorial would not intrude on the character of the park area since all that would be seen from the river side are hilly areas of grass, and the Tidal Basin side would be shielded by heavy existing growth of holly and other evergreens.

The wall would generally follow West Basin Drive, which it would eliminate. Fine Arts Commission secretary Charles Atherton said yesterday that the wall itself would be built day that the wall itself would be built on grassy areas alongside the present road, which will require extensive underground pilings since West Potomac Park was a marsh before the area was filled with river dredgings at the turn of the century.

A $125,000 outdoor rest room, built in 1975 by the Park Service beside the Tidal Basin, would be moved to make way for the memorial, according to Parsons. Virtually none of the playing fields, used for soccer, polo and other sports, would be lost.

The closing of West Basin Drive and a small road that connects it with Ohio Drive, which goes along the Potomac River bank, would eliminate about 400 parking spaces. But Parsons said the Park Service is considering building a parking lot in West Potomac Park.