The National Park Service has been sued by a non-profit group attempting to block a $150 million high-rise office complex planned along the George Washington Memorial Parkway just south of National Airport.

The development, called Potomac Center, is projected to be almost as large as Crystal City, with a total of 16 high-rise buildings, ranging from 8 to 29 stories, employing more than 22,000 persons and having parking for up to 18,800 cars, according to 1976 Park Service estimates. The developer, though, now is vague on the number of buildings, their height and the number of cars that might be commuting and visiting there.

Potomac Center is planned along the narrow strip of undeveloped land in the Potomac Railroad Yard beside the parkway being leased to Charles Fairchild, the developer, with buildings beginning about 200 feet from the roadway. The major entrance would be directly on the parkway opposite Daingerfield Island and the Washington Sailing Marina.

Fairchild last week submitted plans to the Park Service for an interchange entrance, with a four-lane bridge over the parkway, long sweeping ramps on the river side, and on the west side two two-lane parallel service roads with a total of seven separate auto entrances and exists into Potomac Center.

The Park Service has objected to the parallel roads and the profusion of entrances and exists, and as an alternative is considering long, three-land-wide exists off the parkway - wider than the parkway itself - to stack the heavy auto traffic expected at Potomac Center. Traffic lights would be installed at both ends of the four-lane bridge.

The recently formed Daingerfield Island Protective Society (DIPS) has asked the U.S. District Court here to prevent construction of the bridge interchange. The society claims that the huge development and its car traffic will have a disastrous impact on the parkway and Daingerfield Island.Elimination of the interchange would kill the project because the parkway is planned as the major entrance to the 39-acre site.

The Potomac Center development was made possible by a swap in 1970 in which the Park Service traded access to the scenic parkway opposite Daingerfield Island for 29 acres owned by Fairchild beside Dyke Marsh, a wildlife area along the Potomac south of Alexandria. Fairchild planned to build on the 29 acres first a high-rise complex - blocked by Fairfax County - and then a Palm Beachtype waterfront development, with canals dredged from the marsh and at least 50 houses fronting on the canals.

The swap was favored by a number of Mount Vernon area groups concerned with protecting the marsh, but was strongly opposed by Alexandria civic groups who criticized the Park Service for in effect inviting high-rise development along the parkway near National Airport and turning the scenic memorial drive into "just another freeway."

They also criticized Interior Department officials for concluding the deal in private, without holding any public hearings or meetings on it, and without doing any significant environmental review of the effects such a huge development would have on the federal government's oldest parkway - a review they claimed was required under the then new National Environmental Policy Act.

The five named plaintiffs in the DIPS suit, most of them sailors who use Daingerfield Island because it has the only large public sailing marina on the upper Potomac, contend the Park Service never gave sufficient public or legal notice of the swap in 1970 and that they were unaware of the project until last fall when public hearings were held on long-range plans for Daingerfield. A hearing on their request for an injunction against the bridge-interchange will be heard before U.S. District Court Judge Oliver Gasch June 30 at 2 p.m.

The Park Service contends that it did all that was legally required in 1970, that no public hearings or environmental impact statements were needed then, and that it had the blessing of Congress for the swap.

"That was the public form of the time, the House and Senate interior committees," a Park Service official said this week, although he added "we'd never pull this off today the way we did then." The main Park Service concern at the time was protecting Dyke Marsh and the parkway south of Alexandria from intensive development.

Park Service officials say, however, that while they feel they are now legally obligated to permit Potomac Center access to the parkway under the 1970 agreement, and are working with Fairchild on the bridge interchange, they are seriously considering buying out Fairchild's access rights.

A 1976 Park Service study of the project concluded that Potomac Center will "damage" the parkway and that the impact of its traffic will not be "minimal," as a 1970 Park Service study concluded, but will overwhelm the already near-capacity parkway.

The proposed size and nature of the project have changed dramatically since 1970, based on information Fairchild has given the Park Service. Fairchild said last week no figures that have been used in connection with Potomac Center are correct and insisted the number of buildings, their height, and number of parking spaces still have not been set. Fairchild said Potomac Center would be a "beautiful" complex largely invisible from the parkway through extensive landscaping and having little traffic impact on it because he anticipated most employes would commute by bus or subway if a subway station is built at Potomac Center.

In 1970 when the Park Service approved the swap, parking was to be provided for only 4,000 cars. The 1976 estimate was for 14,500 to 18,800 cars. The 1970 estimate was for 10 to 12 high-rise buildings employing about 10,000 persons. The 1976 estimate was for at least 16 high-rise buildings employing up to 22,800 people.

The projected traffic impact on the parkway in 1970 was seen as "minimal" by the Park Service partly because it assumed a large freeway running through the railroad yards, the once-proposed Northeast Freeway, would be built and connect to Potomac Center - although the road was even then considered dead by local officials. The freeway has since been erased from all long-range highway plans.

Following the 1976 review of the project and its impact on the parkway, a number of Park Service officials began having second thoughts about it and began discussing buying out Fairchild's access rights to the parkway.

"In the public interest, the only realistic course on action would be to retain Dyke Marsh and seek to negotiate a monetary settlement" with Fairchild, National Capital Parks director Jack Fish wrote in a Park Service memorandum last year, made available under a Freedom of Information Act request.

Congress would have to approve and fund any purchase of Fairchild's easement onto the parkway. A spokesman for Rep. Herbert Harris (D-Va.), whose district includes Alexandria, said this week Harris "has reservations about the project and its environmental impact" and last week had asked city officials their position on Potomac Center. The city has taken no position, however, because Fairchild has submitted no over-all plans for Potomac Center. While a site plan for one building was approved, the permit for that has since expired, City Manager Douglas Harmon said earlier this week.

Two appraisals of the cost of buying out Fairchild's access rights to the parkway have been made by the Park Service, a November 1976 estimate of $581,000 and a subsequent estimate apparently in excess of $1 million, the amount Metro recently had to pay by court decree to the Richmond, Fredericksburg and Potomac Railroad for a right-of-way through the Potomac Yard land Fairchild is leasing for Potomac Center.

Fairchild would not say whether he shared in that payment but the award was high because the property, once land-locked and largely undevelopable, is more valuable since the Park Service granted access to the parkway.

Environmentalists have claimed that the Interior Department could have avoided the whole issue and possibly saved itself a lot of money by simply buying or condemning the 29 marshy acres owned by Fairchild. Fairfax County had issued a building permit for a proposed waterfront development there, but environmental groups claimed the land was mostly undevelopable because it would require dredging of marshland and permission from the U.S. Army Corps of Engineers and Interior itself.

Nationally known conservationist Michael Frome, writing on behalf of the Northern Virginia Conservation Council to Park Service Director William J. Whalen six months ago, called the "Fairchild land giveway . . . one of the most shameful betrayals of public trust in the history of the National Park Service and the Department of Interior."

The conservation council considers "bizarre," wrote Frome, Interior's contention that Interior need not comply with the National Environmental Policy Act of 1969 because the department had not established departmental guidelines on the act until Sept. 27, 1971. The NEPA law went into effect Jan. 1, 1970. The Dyke Marsh land swamp agreement was signed June 5, 1970. The DIPS suit argues Interior should have completed with NEPA.

Frome also accused former Secretary of Interior Stewart Udall of conflict of interest in the land swap, because Udall, a lawyer, now represents Fairchild and the Potomac Center. As Interior Secretary, Udall took an active part in opposing Fairchild's development of Dyke Marsh in 1965 and was secretary during two years of negotiation over the land exchange, until he resigned in early 1969 when Richard Nixon became President.

Udall said last week he had not taken an active role in the land swap itself and saw no conflict of interest in now representing Fairchild. The U.S. Code prohibits a former government official from representing anyone on a contract "or either particular matter . . . in which he participated personally and substantially as an officer or employe . . . of the U.S. government."

Udall said one reason he agreed to represent Fairchild was his (Udall's) interest in seeing development occur along Metrorail lines, "something everyone should be working for as a means of reducing car use."

Ironically, a Metro stop at the Potomac Center is in doubt because Metro insists that if one is built Fairchild must build it - such a station could cost anywhere from $8 million to more than $20 million, according to Metro officials - and Fairchild said last week he thinks Metro and the city of Alexandria should build the station.

"Metro designed the line for one. It's just a question of who's going to pay for it," Fairchild said. "It's a matter of negotiation."

Without a Metro subway stop Potomac Center would be largely dependent on automobile commuting for the variously estimated 10,000 to 22,800 employes who night work there. The number of Metro buses using the parkway will drop significantly when the subway line is extended beyond National Airport in 1980 and buses are routed into outlying stations.

A 1975 Alexandria study, by the citizen Potential Growth Committee, urged the city not to approve any rezoning of Potomac Center land without a Metro station.

Fairchild said this week, however, that he may not seek to rezone any of the land since it is now zoned industrial and he can put office and commercial buildings on it "any time I want," although not the high-rise residential buildings he originally had planned. Residential units are porhibited in an industrial zone. While Alexandria's planning commission must review site plans for buildings, "all they can say," says Fairchild, "is put in a few more trees."