FALLBROOK —— County parks and recreation officials said Thursday that the county has agreed to pay $3.2 million for the first piece of land in what will eventually become a sprawling preserve along the San Luis Rey River.

The 116-acre parcel, commonly referred to as the "model airplane site" for the remote-controlled aircraft hobbyists who meet there, is just south of Highway 76, about a mile west of Olive Hill Road.

San Diego County's chief of parks and recreation development, Matt Bohan, called the purchase "a very exciting first step" for the park concept, which is in the early stages of environmental review.

"Like any property acquisition, public or private, until the final papers close, something can always come up," Bohan said of the transaction, which will be finalized during a December 6 meeting of the Board of Supervisors. "But both parties are moving forward, and we don't anticipate any problems."

The seller, San Luis Rey Downs Enterprises, did not return phone calls seeking a comment Thursday.

When completed, the preserve will run parallel to Highway 76, from Interstate 15 to East Vista Way —— a 1,500-acre monster with a continuous trail from end to end, trail heads, equestrian staging areas, ball fields and picnic areas, along with hundreds of acres of preserved habitat.

Combined with a donation of 83 acres last year from the Rincon San Luiseno band of Mission Indians, this week's buy brings to roughly 200 acres that the county owns for the river park. With a goal of 1,500, the Parks and Recreation Department now owns about 13 percent of the land it needs to establish the park.

The 116 acres bought this week is not just any piece of land, Bohan said. The site has been promoted by the park's planners as an ideal place for an "active recreation node," where ball fields and picnic areas would provide much needed recreation space for the community of Bonsall.

"It definitely has active recreation potential," he said, adding that the exact plans for what will be built at the site will not be finalized for several years. "At the time when we're ready to move forward with development, we'll be back out in the community, getting input … on what their top priorities are there."

Vivian Collins, vice president of Bonsall Valley Little League, said Thursday that 12 teams and about 160 children in her league shared one baseball field at Bonsall Elementary School last season.

"We need space," Collins said, adding that Proposition C, the recently passed bond measure to improve facilities at the elementary school, may jeopardize the league's access to their only field. "My understanding is that they are eventually going to build new classrooms on the playground, and we're going to lose our ball field."

During an intensive planning phase that began in 2004, Collins was approached by county parks planners about Bonsall Valley Little League being provided space at the model airplane site, an idea that now appears close to happening.

"We're really looking forward to it —— it's a great opportunity for us," she said. "If we could acquire more fields, we could get bigger. We'd like to grow."

Supervisor Bill Horn, a longtime proponent of building a park along the San Luis Rey, said Thursday that he is proud of the fast pace with which plans for the preserve have materialized.

"I think we're on our way, finally. It's going to take a while to acquire all that property, but I think this is a really good purchase," said Horn, adding that he expects that the park "is going to be a tremendous legacy for the future —— we're preserving the last freshwater river in San Diego County.

"North County doesn't want a lot of growth," Horn continued. "They have to take some, but this sets aside a large number of acres, and assures the public that we're going to preserve the environment and still look to the widening of Highway 76."

County officials have said that they expect the land acquisition phase to drag on for several years, in part because the county will only acquire land for the park from willing sellers, and in part because the widening of Highway 76 —— a main source of acreage —— is still years away from starting.

For every foot that the road widening project encroaches on the nearby river's habitat, a corresponding amount of land must be purchased and turned over to the county to become part of the river park.

Transportation planners aren't exactly sure how many acres the Highway 76 project will consume, Bohan said, but he added that it will likely add several hundred acres to the park.

The $3.2 million purchase approved this week was made from a $5 million grant that the Board of Supervisors set aside for the river park in July. Bohan said his department will continue to seek property to buy while the 18-month environmental review process continues, after which the Board of Supervisors will review the proposal in its entirety.

Contact staff writer Tom Pfingsten at (760) 731-5799 or tpfingsten@nctimes.com.