Lake Luciana developers are taking steps to sue Napa County over the decision to reject the 18-hole golf course proposed in Pope Valley.

Robert Radovan, the Upvalley developer behind Aetna Springs and Calistoga Ranch, filed a complaint against the county on Friday, alleging the Napa County Board of Supervisors illegally rejected his proposal for a championship golf course in Pope Valley.

The claim lays the groundwork for a lawsuit against the county, according to attorneys for the developers.

“We will be filing in the near future,” said Michael Durkee, the Walnut Creek Lawyer representing Lake Luciana, “probably within the next couple of weeks.”

Napa County Counsel Robert Westmeyer said he was contacted Monday by lawyers for Lake Luciana asking if he would accept service of the lawsuit that afternoon. The move, he said, implies that the lawsuit is more imminent than Durkee suggests.

“I imagine … it will be filed either today or tomorrow,” Westmeyer said. “It’s extremely unlikely that they’re going to be able to allege anything that I believe I can’t defend.”

The debate centers on the 18-hole championship golf course proposed for Pope Valley by Radovan and his partner, William Criswell. The plan — featuring an 18-hole championship golf course, three swimming pools, a lakeside clubhouse and 17 neighboring luxury homes — was rejected by the Napa County Planning Commission in February in a 3-2 vote. Developers appealed the decision to the board of supervisors. The board rejected the proposal in June; with supervisors Diane Dillon, Brad Wagenknecht and Keith Caldwell voting against it.

Following the vote, Durkee delivered a scathing letter to the county alleging bias and violation of procedure. That letter makes up much of the claim filed against the county on Friday.

Durkee alleges that Dillon and Wagenknecht had an inherent bias against Lake Luciana because of their affiliation with the Sierra Club, the organization that formally represented project opponents in the Lake Luciana appeal. He claims that Dillon and Wagenknecht should have disclosed their positions on a Sierra Club legislative committee and recused themselves from the vote.

Both Dillon and Wagenknecht claim that they had only minimal involvement with the Sierra Club. They deny that their affiliation with the club swayed their votes on Lake Luciana.

“I have an impossible time with what they’re accusing me of,” Wageknecht said. “I’ve been on legislative committees … It’s part of the input that I seek before I vote on anything. I try to seek a wide variety of input from the community. It does not affect the outcome of my vote.”

In a separate claim sent to the board on Aug. 20, Durkee said that the board violated the Brown Act by meeting to discuss Lake Luciana out of the public eye.

While the Brown Act is meant to ensure that elected officials do not do the public’s business behind closed doors, Durkee alleges that “certain board members conducted serial meetings in order to develop a collective concurrence” on Lake Luciana.

The letter offers no specifics about the alleged violation, but Durkee on Monday named supervisors Dillon, Caldwell and Wagenknecht as the targets of the accusation.

Dillon said the accusation is “frivolous,” and claims that the lawsuit is a red herring to distract from developers’ unhappiness with the outcome of the vote.

Caldwell maintains that if developers truly believe in their proposal, they should “challenge the county based on the merits of ‘does it or does it not conform with the General Plan,’ not … (make) false accusations.”

Radovan did not return calls for comment.