Signature gatherers are deployed, environmental advocates are engaged and a Web site is under construction. Charles County's southernmost residents are preparing to wage a campaign on several fronts against development on Swan Point and the construction of a wastewater treatment plant.

The project, which the county Planning Commission will consider this month, could add 1,500 homes, a 320-slip marina and a hotel on the peninsula, which is surrounded by Cuckold Creek and the Potomac River.

Residents who oppose the development have formed the Cobb Neck Conservation Alliance to press county officials to first study its effect on roads and Chesapeake Bay tributaries.

"If construction of the large wastewater plant is initiated without a proper impact assessment, the health of Cuckold Creek may be irreparably damaged," Bradford Ross, the alliance's president, wrote in a recent letter to county planning director Roy Hancock.

As development has changed Southern Maryland's landscape, Charles County planners have noticed an increase in public scrutiny of projects. At Swan Point, the attention is particularly intense because of its waterfront location and the number of homes planned.

Villages at Swan Point, which will come before the Planning Commission on June 20, could nearly double the population on the Cobb Neck peninsula.

"We'll be lucky if we can get through all the testimony that night because it has been highly contested," said Steve Andritz, a planner who is assigned to the project.

The developer, Brookfield Homes, has described the golf course community in documents as having "an extensive shoreline protection plan" to create a community "where all residents live in concert with the environment.''

An attorney for the developers did not return phone calls seeking comment Tuesday.

Ross, a developer whose family has owned a historic home across the creek from the planned development for 55 years, is leading the opposition. Cuckold Creek should be plied by kayakers, he said, not 60-foot yachts.

"They are going to ruin the view from my home," said Ross, whose group has collected nearly 1,000 signatures. "I'm not anti-development; I'm pro-clean water."

Before the planning board meets, state environmental officials will gather this week at the invitation of Commissioner Candice Quinn Kelly (R-La Plata) to discuss the plan for a wastewater treatment plant with residents.

Swan Point's wastewater treatment plant has a capacity of 70,000 gallons per day. To accommodate the planned homes, the state has approved a new plant with a 600,000-gallon capacity. The design for the plant is being reviewed by county planners.

"Upgrading that plant is important and necessary,'' Kelly said. But, she asked, "is this the only location? The best location? What went into the decision making?

"My interest is the health and safety of our citizens and the tributaries," she said.

The development's location has also attracted the attention of Clean Water Action, a nonprofit environmental group with 30,000 members in Maryland.

"There are important ecological resources in Charles County that need to be protected,'' said Andrew Fellows, the Chesapeake region program director. "We're concerned that for whatever reason people are rushing toward development."