The town has already borrowed and spent about $2 million planning the project. It will borrow the remaining $14.2 million in September, and construction could begin by the end of the year.

The project would more than double the size of the current library off Estes Drive, to more than 60,000 square feet.

"The planned expansion will basically keep up with the demand," said Councilman Gene Pease

The council also approved $6.2 million in bonds for sidewalks, streets and park projects. Voters approved a total of $29.4 million in bonds in 2003, but has borrowed only about $9 million of that. Monday's approval will exhaust the voter-approved bonds.

Town Manager Roger Stancil says the town's budget for debt service can accommodate the new borrowing, but operating the larger facility will add about 1.3 cents per $100 of valuation to the tax rate once it opens in 2012, or about $40 on a year on a $300,000 house.

The council also unanimously approved the town's 2010-11 operating budget Monday, keeping the property tax rate at 49.4 cents per $100 assessed value. For the owner of a home valued at $300,000, the Chapel Hill property tax will be $1,482. The total tax bill also depends on the actions of the Board of Orange County Commissioners, which sets the county tax rate, and the special schools tax for Chapel Hill-Carrboro City Schools.

Council members said they will continue to negotiate with Orange County commissioners to increase the county's contribution to the Chapel Hill library, where 40 percent of patrons come from the county but outside Chapel Hill.

UNC economics professor James Wilde pointed out that while the county contributes $250,000 to the library, more than half of that comes from Chapel Hill residents who pay county taxes.

Wilde urged the council to charge non-Chapel Hill patrons an annual fee for using the library but also to move forward with the expansion before that issue is resolved.

"The time is right in terms of interest rates," he said. "The time is right in terms of construction costs."

"It's a great time to build public buildings," agreed Councilman Ed Harrison.

Council members Laurin Easthom and Matt Czajkowski voted against the expansion.

"I think it's fiscally irresponsible in these economic times to move forward," Easthom said.

"We decrease the flexibility in terms of the town's finances at a time when we don't know what's coming," said Czajkowski

Easthom demanded more support from the county before proceeding.

"What we're doing is locking us into this problem that we've had for over 15 years," she said. "I just don't think we're that rich in Chapel Hill to keep on doing this. ... We're going to spend $16 million on a really nice library that's already nice."

Melissa Cain, executive director of the Chapel Hill Public Library Foundation, told the council the library serves as many people as those in college towns Ames, Iowa, and Manhattan, Kan., with half the square footage as those libraries.