Three Fairfax County athletic groups, tired of playing on scrubby fields or being chased off private property, have engineered the free construction of six new ball fields for the county in Annandale.

The groups, the Fairfax Women's Soccer Association, Northern Virginia Men's Soccer Association and Annandale Little League, are developing three baseball fields and three soccer fields on a 36-acre tract with the help of the Seabees--the U.S. Naval Reserve Mobile Construction Battalion. The county estimates the value of the work being done to build the fields is more than $300,000.

"What's unique about it is the size of the project," said Joe Downs, director of the Fairfax Park Authority. "It's an outstanding example of the kind of thing that can be done when public agencies draw private groups in as copartners."

The new fields are being built off Woodburn Road, on land the park authority leased from the school board. The 36 acres are part of a 42-acre tract bought by the board in the mid-1960s for what was to have been the new Pine Ridge High School. Declining school enrollment later forced the board to abandon plans for the new school.

The Seabees volunteered last spring to do heavy earth-moving work for the fields at the request of women's soccer league official Ruth Walton. She knew that the Seabees frequently repair Little League fields and do work at Boy Scout camps as part of their training exercises.

Lt. Cmdr. Paul Miles of the Seabees 23rd Battalion, based at Fort Belvoir, is overseeing the project. He said the Seabees get many requests from civic groups--many more than they can handle, in fact--but few that give them this good an opportunity to work on skills they'd use in building roads or runways.

"This is one of the normal ways we're able to obtain mobilization training, but the actual number of projects like this where we can use heavy equipment are not too plentiful," Miles said.

A detachment of eight to 10 Seabees will spend one or two weekends a month grading the land and building field drainage. They broke ground on the project in July and expect to be finished by early December.

The athletic groups hope to have the fields in playing condition by next spring, but they have a lot of work ahead of them. They need grass seed for 36 acres, asphalt for the entrance, gravel for a 200-car parking lot, fencing, goal posts, backstops and railroad ties or telephone poles for the fields and parking areas. The groups are planning raffles and other events to raise funds for some of the necessary items and services, but they're working on getting area businesses to donate most of them.

"It's kind of like a big scavenger hunt," said Keith Malos of the men's soccer group. "First, we're going to look at the people we know to see if they're willing to help out. I think there are enough connections out there."

A committee made up of representatives of the three groups has asked several businesses for help already, with some success. Holland Engineering of Alexandria has designed the fields for about $3,000, half the actual estimated cost. A cement company is donating a culvert drain, an oil distributor will supply fuel for the Seabees' heavy equipment at no cost and several large corporations, including Mobil Oil and McDonald's, have agreed to make contributions.

In fact, committee members say, the hard work is behind them. Walton had been laboring to get county approval of the project and its design for three years. For each of the dozen or so meetings she'd had with county officials, she said, there had been four or more meetings with athletic group officials.

Downs said the idea for the project arose as a result of a shortage of fields. Some Little League teams that have played on private property for years are losing their fields to development. The adult soccer assocations say they have to line up behind the kids when the county recreation department makes field assignments, and the fields they do get are often rocky and bare.

In 1980, the park authority leased the Pine Ridge land, intending to build fields there, and then found it did not have the money to do it. Park officials asked the athletic groups for help.

"We started out very naively," Walton said. "We were ready to go out and start fund raising the first day." But they quickly learned they would need a design plan and approvals from the park authority, the school board, the Department of Environmental Management and the Department of Transportation and Highways. Every change in the design required a new round of hearings and approvals.

And they had to find an organization to volunteer to do the heavy earth-moving work. Initially, the Seabees expressed little interest in the project, and the Army Corps of Engineers turned it down. Last spring, Walton gave the Seabees another try, sending them the detailed design plans that won their agreement to build the fields.

"They recognized that this was a good project, and they were going to make a lot of people happy," Walton said.

"We haven't found anybody who didn't think this was a good idea," she said. "It's bringing it to fruition--the nitty-gritty--that's the hard part."