Twice in the past six weeks the federal Fine Arts Commission has voted against a developer's proposal to build a $100-million condominium, office and commercial complex proposed by Georgetown Harbour Associates for the Georgetown waterfront. The commission does not object to development of the waterfront per se but to the fact that the complex would be located on a flood plain. This is a look at waterfront development in other cities around the rest of the country. America is rediscovering its waterfronts.

Cities and towns on oceans, rivers and lakes throughout the nation are shoring up rundown sections of their waterfronts for recreation, retail trade, restaurants, parks and housing.

In addition to generating thousands of new jobs and millions of dollars in tax revenue, mushrooming waterfront redevelopment projects become, in effect, brand-new neighborhoods, rising phoenix-like from the ashes of industrial and commercial decay.

Though heavily dependent on federal grants during the past decade, these burgeoning "people places" may weather Washington's budget cuts far better than other urban projects. The private sector's role, lured as to sunken treasure with promises of high yields, is inexorably increasing, statistics show.

At the same time, development may take more time because of a growing desire to preserve and incorporate historic structures into such projects and because of greater public participation than ever before in the planning process.

The Rouse Company, one of the nation's leading real estate development firms and developer of Baltimore's Harborplace and Boston's Faneuil Hall Marketplace, currently is participating in waterfront projects in 10 other cities.

In almost every case, said Rouse spokesman Scott Ditch, one of the company's primary jobs is to remove "the barriers between people and the water" -- whether they be ramshackle warehouses, storage lots, or a basic lack of appreciation of the fact that "cities have a jewel in their midst in the form of water. And it has a very humanizing effect on the cities."

Until recently, urban waterfront areas were one of America's most neglected resources," said Ann Creen Cowey of the U.S. Office of Coastal Zone Management. Her office has provided small planning grants to more than 50 cities and towns for waterfront revitalization. "Once thriving, they fell into disuse and disrepair as economic and technological changes occurred."

But the beginning in the early 1960s, she noted, new interest was spawned through federal studies and private initiative. Then, extravaganzas such as Operation Sail during the nation's Bicentennial celebration in 1976 sent public interest soaring.

A look at what some cities are doing:

Baltimore. Harborplace has become the "in" place in downtown Baltimore for residents and visitors. Consisting of two glass-enclosed pavilions on the city's inner harbor, Harborplace boasts restaurants, cafes, markets and specialty shops with harbor views.

Before the city passed its Harbor Renewal Ordinance in 1967, the inner harbor was anything but pretty to look at. But gradually it has undergone a metamorphosis few city officials even dreamed of. In 1977, the city council approved Rouse's plan for Harborplace, and site work began in early 1979. Meanwhile, a new skyscraper, Baltimore's World Trade Center, sprouted on the edge of inner harbor. And pleasure-boat dock space and moorings replaced some of the grimy industrial eyesores.

New York. South Street Seaport, which sits like a diminutive antique along the eastern fringe of a section of downtown Manhattan's glass-and-steel skyscrapers, is on the verge of vast new development that will incorporate the 200-year-old-plus architecture and a small town or "seaport" atmosphere.

After completing a feasibility study, the Rouse Co. has received the green light to invest $69 million in building a commercial-retail complex on an East River pier adjacent to the Fulton Fish Market. Finding a way to save the market, which in its heyday actually sold more meat than fish, was an integral and time-consuming part of Rouse's project. But Rouse and city officials stress that the project could have been possible only with the $20 million Urban Development Action Grant (UDAG) it received to build a new pier.

Boston. This old seaport city is perhaps the "granddaddy" of waterfront redevelopment, with the Faneuil Hall Marketplace widely considered its centerpiece. In 1973, Rouse, together with the architectural firm of Benjamin Thompson & Associates, created a plan to revitalize three antiquated market buildings. Though actually set back from Boston Harbor, the marketplace is closely integrated with the harbor and was considered a linchpin for the establishment of urban parkland and apartments facing the water. Though many shops are not selling as much merchandise as originally envisioned, Faneuil Hall Marketplace now provides some 2,800 jobs, up dramatically from prerenovation levels. Tax revenues from the three buildings now are running at $1.5 million annually compared with less than $100,000 before renovation.

San Francisco. Ghirardelli Square, like Boston's Faneuil Hall, has become a prototype for waterfront revitalization, and renovation there continues. Savannah, Ga.; New Bedford, Mass.; Annapolis; Newport, R.I.; Pittsburgh, Pa.; Norwalk, Conn.; and scores of other cities are doing likewise.

What ultimate effect the proposed federal budget cuts will have on all this is unknown. That it will have some effect is certain. The National Endowment for the Arts, for example, which the Reagan administration wants to slice in half, sponsored studies for waterfront projects in dozens of cities. But private interest is strong, say waterfront experts, and getting stronger all the time.