The lengthening of runways at the Charles M. Schulz-Sonoma County Airport has been delayed at least nine months by federal environmental requirements.

The $53.8 million project is the first part of a long-term plan to expand the airport and to offer greater air travel connections.

The immediate plans call for extending the main runway by 885 feet to 6,000 feet and adding 200 feet to the second runway. That work was set to begin this month and wrap up in November next year. The revised timeline now calls for a start date in April and estimated completion by July 2014.

The delay is expected to slow talks with commercial carriers about adding flights at the airport.

Alaska Airlines, now the only airline serving the county, offers five flights a day in and out of the airport. Long term, the expansion would allow up to 21 daily flights.

However, carriers interested in bringing mid-size regional jets to the area, including Delta, US Airways, Frontier and Sky West, are largely holding off on serious discussions until the longer runways are complete, said Jon Stout, airport manager.

"It's disappointing that in effect we're losing a year," said Jonathan Coe, president and chief executive of the Santa Rosa Chamber of Commerce.

The group was one of many in the business community to back the airport expansion as a boon for local industry and selling point for tourism.

In approving the expansion plans in January, county supervisors echoed those points, citing studies that put the value of each additional flight at the airport at $15 million in direct and indirect investment in the local economy.

"The important thing is we get it done, and that's still happening," Coe said. "The sooner the better."

The delay could put in question the extent of federal funding committed to the project, Stout said.

The Federal Aviation Administration is set to pay for about 90 percent of the project, and the county budgeted $26 million in federal money in 2012-2013 for the runway extension.

But with that work now set to begin next year -- in a new fiscal calendar for the federal government -- the budget for the FAA and its allocation for the project is unknown, Stout said.

"Until they see what appropriations are made (by Congress), they won't commit," he said.

County Supervisor Mike McGuire, who represents the airport area, said he was confident the runway funding is secure. The project is a priority for the FAA's Western region, he said.

"I don't know of any concern with the funding," he said.

The additional environmental requirements ordered by federal regulators have helped fuel a more than $10 million cost increase for the runway project since January.

The new requirements include larger habitat offsets for a pair of endangered plant and animal species -- Burke's goldfields, a small wetland flower, and the California tiger salamander. Neither species is known to exist in the 100-acre construction zone, Stout said, but federal regulators have required the county to presume that they do because they are known to exist in the area.

Other federally mandated upgrades around taxiways and the two runways resulted in additional effects on wetlands and more habitat offsets.

Overall, environmental mitigation costs linked to the runway improvements now amount to more than $20 million of the project's $53.8 million cost.

Design, engineering and construction costs are estimated at just less than $28 million.

The county expects to solicit bids after approval of the environmental study now being prepared for the FAA. A 30-day public comment period on the document is expected to begin in August. Final approval by the federal government could come in September.

The overall expansion plan, pegged in January at $84 million, also would add a passenger terminal, control tower, air cargo facility and other improvements. The timing of those upgrades depends on attracting more airlines to the county-owned airport.

You can reach Staff Writer Brett Wilkison at 521-5295 or brett.wilkison@pressdemocrat.com.