LANGLEY — The Langley City Council unanimously rejected the plan for Langley Passage, a proposed 20-home subdivision on the northeast end of town, and rebuked the city’s planning director for his “clearly erroneous” environmental review of the project.

The two back-to-back rejections at Monday night’s council meeting left opponents to the new neighborhood jubilant. The Langley Critical Area Alliance, a group made up of homeowners and others who live on Edgecliff Drive near the project site, and the Whidbey Environmental Action Network, had warned that stormwater and subsurface seepage from the development would worsen landslides along the nearby bluff overlooking Saratoga Passage.

“We’re delighted,” said Robin Adams of the Langley Critical Area Alliance.

“I think they made the right decision. There is clearly something wrong here,” he added. “I’m impressed that everybody got their minds around what is highly voluminous and technical stuff.”

Langley Passage has been working its way through the city review process since February 2006. Earlier this year, in August, the city’s Planning Advisory Board recommended the controversial project be denied by the council.

The alliance, WEAN, and Whidbey Neighborhood Partners, the developers of Langley Passage, then filed appeals to the board’s recommendations.

On a 4-0 vote Monday, council members rejected the environmental review of the project, led by Langley Planning Director Larry Cort, and said an environmental impact statement should be prepared on the proposed development.

An environmental impact statement, or EIS, is an exhaustive and often expensive study that examines possible problems that development projects may pose on water, air, wildlife and other resources.

The council also rejected the preliminary plan on a 4-0 vote.

Council members said there were still questions about how much water would flow from the site after the 8.52 acre property is developed. More scientific studies and analysis are needed, they said.

“I still have qualms and worries that more still has to be done before the project can move forward,” said Councilwoman Rene Neff.

Councilman Robert Gilman said dueling scientific opinions on the impact of water flows from the Langley Passage property – there are three, with the developer’s experts and the city-hired peer reviewer in agreement on one side, and opponent’s expert on the other – meant that more study was needed.

“My core concerns are the basic documents are contradictory,” Gilman said.

Critics of the project have repeatedly raised concerns that water runoff from the property will worsen landslides along Saratoga Passage, where many opponents to the project have homes. Scientists who have studied the geology in the area have indicated the potential for underground flows to move north toward the bluff from Langley Passage, but experts also agree that the main cause of landslides comes from wave action along the bottom of the bluff, which is underwater during high tides.

Gary Roth, the local builder leading the project for Langley Neighborhood Partners, declined to comment on the decisions, but added that the developers may have something to say near the end of the 21-day period for an appeal.

The next avenue for any appeal, however, is a lawsuit in superior court.

That said, the council’s work on Langley Passage is not yet finished.

The council must adopt “findings of fact” that spell out the city’s reasons for rejecting the project, and after that happens, the clock will start ticking on the deadline for the filing of any court challenge.

Council members were warned by their legal counsel at the close of Monday’s meeting not to talk about the decision until the council has approved its findings at a later session.