YarrowBay, the Kirkland-based developer poised to transform Black Diamond by building 6,050 homes in two urban villages, has won another important court victory.

King County Superior Court Judge Patrick Oishi upheld permits approved by the City Council for The Villages and Lawson Hills developments and affirmed an environmental-impact statement.

Oishi's decision, following an appeals-court ruling that the city didn't follow the wrong process in approving the developments, cleared another legal obstacle in YarrowBay's path.

YarrowBay President Brian Ross said Tuesday he expects to begin construction of roads, off-site road improvements and water and sewer lines next spring, and home building about two years after that.

"Sure, there's always the possibility of further appeal," Ross said, "but frankly I think with the process we've seen, we're very confident in how that will turn out. I don't think it will dissuade us in any way from moving forward and starting construction next spring."

Ross said in a statement that the ruling "is further proof that we have been involved in an open, deliberate approach in partnering with the City of Black Diamond to follow the code every step of the way."

Proponents say the urban villages will bring needed jobs and stores to the financially struggling city of 4,160. Opponents say it would overwhelm Black Diamond and the two-lane roads connecting it to major employment centers.

The Villages and Lawson Hills are projected to bring some 16,000 residents and 1 million square feet of commercial development over 15 to 20 years.

Toward Responsible Development, the group that sued YarrowBay in an attempt to send the urban villages back to the drawing board, hasn't decided whether to appeal Monday's ruling, the group's president, Bob Edelman, said Tuesday.

Edelman said he was "disappointed in the judge. ... Some issues aren't addressed at all in the order. It just leaves you hanging. We think he's erred. We're considering an appeal on this."

Toward Responsible Development still has a suit pending that challenges development agreements that were negotiated after master-plan permits were issued, Edelman said.

Oishi said the city didn't erroneously interpret or apply the law when it approved permits for the developments.

"The Court has not been left with a definite and firm conviction that a mistake has been committed, which is required to grant relief under this standard of review," the judge's order said.

Oishi also said the environmental study contained "a reasonably thorough discussion" of such impacts as traffic congestion and water quality in Lake Sawyer.

Voters last fall elected a city council far more critical of the YarrowBay projects than the previous council, but prior approvals appear to leave the new council limited scope for scaling back the projects.

Keith Ervin: 206-464-2105 or kervin@seattletimes.com