The proposed development of a spectacular 211-acre waterfront area in St. Mary's County has opponents of the massive waterfront resort/conference center and residential community challenging the county's use of the so-called "floating zone" to approve the site plan.

The use of the controversial zoning category first came under fire in 1983 when the local planning board recommended changing prime farmland on the Patuxent's Myrtle Point zoned R-1 for single homes on one-acre lots to a planned unit development (PDR) with a commercial marina and an average of 2.83 dwelling units per acre.

The decision -- which came after several public hearings and included the most detailed site development plans ever submitted to St. Mary's planners -- nevertheless raised serious questions in opponents' eyes about what they call "spot zoning" in an environmentally fragile area.

A water management and environmental group called the Potomac River Association has been challenging -- so far unsuccessfully -- the county's zoning authority. The group's lawsuit has so far been rejected by both trial and appellate courts, but its members are continuing to press it before the state's highest court.

The proposed community and conference center would include a 300-room hotel, equestrian center, two recreation complexes with a swimming pool, tennis courts, nine-hole golf course and 200-slip marina for visiting and local boat fanciers.

In construction staged over about nine years, 500 residential units would also go in -- clustered town houses making up about 400 of the units along with 100 single-family homes. Between 30 and 40 percent of the homes would likely be vacation or second homes and most would start in the $100,000 price range.

The New York developers behind the project view it as a "lovely, secluded historic village where environmental aspects of the proposals were very, very important." They say there is a critical need for this type of housing for commuters between Baltimore, Washington, Annapolis and Richmond as well as for retired persons.

County economic development coordinator David Morgan says such a complex is long overdue in St. Mary's. At an estimated value in 1982 dollars of $139 million, the finished project could generate in excess of $1.2 million in property taxes alone.

Morgan says the completed resort hotel and conference center would generate a minimum of 300 jobs for county youth who now are often lured to larger cities because of the lack of local employment opportunities.

Opponents of the rezoning of Myrtle Point say county commmissioners failed to show that the original R-1 zoning, in effect for over 30 years, was either a zoning mistake that needed correction or that substantial change in the character of the neighborhood had taken place since the original zoning.

Lawyers for Patuxent River Farms Inc. argue that because the planned unit development zone is in effect a "floating zone" it is not required to abide by the so-called "mistake/change" rule, cited by opponents.

In July 1984, a St. Mary's Circuit Court judge upheld the zoning authority of the county commissioners, and area homeowners and the Potomac River Association have been appealing since.

"We want the county to stop using this 'floating zone' category, which is the equivalent of telling a developer 'do as you damn please,' " said James F. Vance, an attorney for Potomac River Association. This week, Vance also argued the case against Prince George's Bay of Americas Project -- another floating zone development -- before the Court of Special Appeals.

The concept of a floating zone was created to give local governments the option of more creative and flexible development without having to nail down the exact location at the time of a comprehensive rezoning.

The zone in effect "floats" over an entire jurisdiction until an application comes in and the county government decides where to locate it, said James Kenney, the attorney representing Patuxent River Farms Inc. In this case, the applicant requested specific rezoning of the Mrytle Point land, and commissioners approved it with 17 conditions.

Both Montgomery and Prince George's counties have floating zones that have been upheld by the Maryland courts, but this case is St. Mary's first such test.

"We are challenging the whole concept of the floating zone and the way it's working down here," said Jack Witten, head of the Potomac River Association and a property owner in Hollywood, Md., adjacent to the planned resort complex.

"We do not think the county should be able to set aside the comprehensive plan and the zoning maps to make way for the planned unit development."

Perhaps the most controversial aspect of the proposal is the developers' desire to put a 400-slip marina off the project's northwest point where Cuckold, Mill, Hickory Landing and Nats creeks all converge. That request has been scaled back dramatically, and developers will be allowed to build only 40 slips initially. Additional slips -- 40 at a time -- may be built only after local planners do annual water quality and environmental impact studies.

The pier slips will be hooked up to Maryland's first vacuum evacuation sewage disposal system, and any boats owners who fail to comply will be subject to a daily fine of $75.

But Witten remains skeptical of the county's ability to manage such a large project or enforce its own conditions.

But Frank Gerred, director of planning and zoning for St. Mary's, says he has both the authority and the intention to closely monitor every phase of the project.

"The restrictions the county set up for the project were incomplete, too weak and didn't determine the financial strength of the applicant . . . . We didn't want the developer running out of money and leaving the county holding the bag."

Gerred says the use of the floating zone actually requires much more stringent conditions from the developer and is approved only after far more detailed plans than required under other zones are submitted.

The developer will pay for all water and sewer hookups necessary and be required to do an archeological study of the area for early Indian sites and ruins of the colonial Harvey Village settlement before commencing work, Gerred said.

To protect the water system from pollution and sediment buildup, no construction will be allowed within 100 feet of the mean high water line, along with no additional run-off from the project into the Patuxent River. Several holding ponds will be built as part of a strict storm management system ordered by the county, he said.

Planners also had to prove compatibility with the rest of the district before the floating zone could be used for Myrtle Point. But whether they did this sufficiently is also a point being argued in the case.

"We're not anti-development," Witten said. "We told the commissioners that if they were going to take this whole point they should make it a showcase development, enlist the aid of state scenic rivers and coastal management people and try to design a project that would do the least violence to the environmental setting and still permit economic growth."

In 1968 and 1974 Witten headed the effort to keep Stuart Petroleum from building a refinery on Piney Point by putting the issue to a referendum, and also worked to defeat two separate attempts to build a deep-water port at Myrtle Point, so he is no stranger to a fight.

Now he says he just wants to make sure that one of the state's most fertile oyster beds and a breeding ground for osprey is not hurt by development, which he concedes is inevitable.

"I've lived here for eight years. It was zoned rural residential when I moved here and I want it to stay that way," said homeowner Robert Perrygo. He doesn't mind the homes and conference center as much as the marina, which he says is not needed and will pose a threat to oysters, fish and osprey as it is pressured to expand commercial operations.

Several residents, including Jane Sypher, who testified at a public hearing spoke in favor of the proposal, saying it "sure beats" the unplanned, "helter-skelter development" that would follow if the entire point were sold off in individual small lots.

"It sure beats an oil refinery in Piney Point and it sure beats a deep-water port, and we can't increase our economic base unless we bring people into the county," Sypher said.

Patuxent River Farms is the only waterfront project in Maryland for the New York and New Jersey developers behind the complex, Kenney said. The group also has developed the 3,500-home Harmon Cove community on the Hackensack River and Sag Harbour Village.