Ultimately, the outcome of what happens to Waimea Valley will come down to its fair market value.

What that value is right now is unclear. But there is no shortage of speculation.

Guesses range from below the $5.1 million assessment that went into effect when the city condemned the property in 2001 to more than the $18.2 million figure given a year later by an appraiser who was hired by New York investor Christian Wolffer, who holds the land's title.

The debate over the land's value comes after the Honolulu City Council voted 9-0 on Wednesday to kill a proposal to divide the valley between the city, which has possession of the valley, and Wolffer.

A court will decide the matter unless Wolffer and Mayor Mufi Hannemann can negotiate an agreement on a market value before court proceedings start in February.

"The most the court can come in with is $18 million," said attorney James Case, who represents the Stewards of Waimea, the group that's worked for years to save the valley from development. "Because that's what the land owner's appraiser says it's worth and the jury can't go above what the landowner himself says."

But Wolffer's attorney, William McCorriston, doesn't see it that way.

"The $18 million is just for the land," McCorriston said. "There's also an appraisal for the plants, there's an appraisal for the infrastructure, there's an appraisal for lost business opportunities."

The final tally could easily top $20 million, he said.

Steven Chee, a partner with Lesher Chee Stadlbauer real estate appraisers and consultants, said the process of fixing value would be difficult because the valley's cultural and archaeological uniqueness makes it difficult to find another piece of property to compare it with.

Speaking in general terms, Chee said, an appraiser would begin to calculate the valley's value by trying to determine the property's maximum productive capability, or "highest and best use."

Chee said the uniqueness of the valley could explain in part the disparity between the $5.1 million city assessment and the $18.2 million figure from Wolffer's appraiser.

"Or maybe the two experts just approached the problem differently," Chee said.

Reach Will Hoover at whoover@honoluluadvertiser.com.