A Napa judge ruled Tuesday that if a citizen's group can pony up a $180,000 bond, he will temporarily block Wal-Mart from breaking ground on a planned American Canyon Supercenter.

Judge Raymond Guadagni issued a stay blocking two permits that would have allowed construction to begin on the 176,000-square foot Supercenter, but only if opponents can post a bond to cover part of Wal-Mart's losses from having its project delayed.

In his ruling, Guadagni said allowing construction to start before determining whether American Canyon performed sufficient environmental studies is a bad idea.

"A stay is warranted to prevent a certain degree of irreversible momentum, which would be set in place by allowing the site paving and pouring of the pad for this very substantial project to go forward," he wrote. Hearings on whether American Canyon's decision to go forward with the project was proper are slated for June.

Guadagni said his decision was meant to save American Canyon from "a Bakersfield type of dilemma," referring to a 2004 5th District Court of Appeals decision that handed victory to Wal-Mart opposition groups in Bakersfield, but left the city with a partially-finished development facing an uncertain legal future.

The American Canyon City Council approved the design of the Supercenter in October 2004, making Wal-Mart the anchor tenant for the Napa Junction mixed use project, which includes stores, a hotel, apartments and a public park near Highway 29 and Napa Junction Road. City officials hope the project will jump-start commercial activity in the city.

The proposed Wal-Mart sparked heated municipal meetings late last year, with critics of Wal-Mart's business practices trying to stop the city from going forward.

After the city approved the project, American Canyon Community United for Responsible Growth and another group, Citizens Against Poor Planning, filed suit claiming the city disregarded its own ordinances and violated the California Environmental Quality Act by ignoring the economic effect the Supercenter might have.

American Canyon City Attorney William Ross said at an April 28 court hearing the opposition groups were misusing the state's environmental laws to discriminate against Wal-Mart. He was unavailable for comment Tuesday.

Guadagni wrote Tuesday he would hold off on considering the merits of the lawsuits until June, when the two sides are scheduled for a court trial. His ruling represents a two-fold victory for opponents. In April AmCan United and Citizens Against Poor Planning asked to block construction for now and, if that was granted, a reduction of the $3 million bond Wal-Mart attorneys had requested.

"This is a huge victory for us," said Kathleen Shamet, spokeswoman for American Canyon Community United. "...and at least at this point we're not going to have a half-constructed big box."

Shamet declined to say how the group would come up with the money, but the group has a wealthy ally -- Citizens Against Poor Planning is supported by Eric Stille, the president of Nugget Supermarkets, which owns Food 4 Less in Vallejo.

In court papers, Stille said he opposed the Supercenter because he's seen Supercenters cut profits at both upscale Nugget stores and other bargain-basement Food 4 Less stores.

"These formats suffer from loss of market share and inability to compete when a Supercenter enters the surrounding region," Stille wrote.

Lake Street Ventures' Buzz Butler, whose company is developing the rest of the Napa Junction project, said Guadagni's decision makes it too easy for businesses to keep competitors out of the market. Butler is busy finishing other Napa Junction buildings and worries about the stay's effect on his end of the project.

"What it does affect is the leasing of the Main Street retail buildings," he said. "Wal-Mart has such a positive economic effect on the types of retailers we can attract, (the stay) will slow the leasing."

Butler said his company is actively trying to hawk the project to prospective stores, but he may face trouble down the line because some sites have to be pre-leased for him to begin construction, and some potential tenants might be spooked if the anchor is delayed or canceled.

That, said Butler, would be "unfortunate for the community because the whole goal is to create this main street environment with private economic development funds."