MARTINEZ -- With time running out to stop development of a pristine ridge in the Alhambra hills, the city may foot the bill to find out how much the property is worth.

After years of delay, the City Council in 2011 approved Richfield Investment's plan to build the Alhambra Highlands subdivision of 112 custom homes on 72 acres of a 297-acre parcel near Wildcroft Drive and Alhambra Avenue.

However, the developer agreed to delay grading until April 2014 to give residents who want to protect the property as permanent open space time to raise money to buy it. Richfield president Ricardo Sabella has said he is willing to entertain offers for the property, but he's never disclosed an asking price.

"We've got a limited time frame in which to strike a deal and as with anything, you need to know a price," said Councilman Mark Ross, who serves on the city's Alhambra Highlands Ad Hoc Committee with Councilwoman Lara DeLaney. The pair have been working closely with the Alhambra Hills Open Space Committee, a group of residents trying to preserve the property.

Ross said he plans to confirm that the property is still for sale and to ask the developers to name their price. Ross also has asked the council to put up an estimated $5,000 to $10,000 for an independent property appraisal, "so all parties can agree on the fair market value."

At the Feb. 20 council meeting, Mayor Rob Schroder said he would agree to spend up to $10,000 for an appraisal with the understanding that the city will neither buy the property nor contribute significant funds toward its purchase.

Council members Anamarie Avila Farias and Mike Menesini suggested that Richfield divulge proprietary appraisal information or share the cost of a third-party appraisal.

Potential funding sources include the state and federal government and conservation groups, Ross said. But if the difference between the price Richfield sets and the property's market value is too great, a sale is unlikely, he added.

When the Alhambra Highlands project was first approved in 1990, it included three separate subdivisions with a total of 216 units on 122 acres. It also required three water tanks and the removal of 713 trees.

To protect the Alameda whipsnake, a federally designated threatened species found on the property, the developer submitted a downsized proposal in 2008 that includes 218 acres of whipsnake habitat and 309 additional acres of protected habitat off-site.

Richfield has poured $30 million into the Alhambra Highlands project and planned to spend a total of $114 million, including $35 million for site preparation and infrastructure.

The project includes more than 500 acres of permanent open space. It also calls for the removal of 484 trees, which the developer must replace at a ratio of three trees for every one removed.

Nearby homeowners said the subdivision would cause more landslides and drainage problems. Critics also said construction would displace wildlife, increase noise and damage the roads.

Lisa P. White covers Martinez and Pleasant Hill. Contact her at 925-943-8011. Follow her at Twitter.com/lisa_p_white.