Saying it was "a little painful" as a strong supporter of the environment, Gov. Olene Walker announced Thursday that she opposes the Open Space initiative on the November ballot.

"I have grave concerns," the governor told reporters, warning the $150 million bond proposal could jeopardize Utah's AAA bond rating — the highest possible — and force the state to pay what amounts to property tax to local governments.

While the governor may oppose the measure, a recent Deseret Morning News/KSL-TV poll shows the majority of Utahns support the initiative, which increases sales tax by .05 of a cent, or roughly $14 more a year for a family of four.

Backers of the initiative, sponsored by Utahns for Clean Water, Clean Air & Quality Growth, expressed disappointment in the governor's opposition at their own news conference. Amanda Smith, head of the sponsor group, said the proposal could enhance Walker's own watershed preservation project.

Walker, however, said her qualms about the initiative were not about preservation but rather about funding details.

"The initiative touts open space and other admirable concepts," Walker said, "but do citizens realize that $30 million of the $150 million will be used for such things as convention centers, fairgrounds and local government buildings?"

She questioned, too, why those types of projects should take precedence over protecting the environment. Backers of the initiative included the possibility of funding the local government projects, Walker said, "to make it acceptable to all areas of the state."

The governor said it makes as much sense as having communities across the state pay for the renovations under way at the Capitol.

Smith said she disagreed with each of Walker's doubts about the initiative and attributed many of them to misconceptions about funding.

"We're not sure that Governor Walker understands," Smith said. "We respectfully question her facts."

The $30 million allocated for convention centers and community projects, she said, is not required to be used for recreation centers or city buildings but is simply the maximum amount of funding available to such projects. Cities that apply for community building funds will still have to compete with conservation projects for that $30 million.

"That money is certainly not mandated or earmarked for these things," she said. "Make no mistake, this is a conservation bond."

Former U.S. Sen. Jake Garn backs the bond and weighed in with his opinion after Walker's announcement, saying the community fund is "one of the measure's greatest strengths" because it gives options to cities with varying needs.

Walker also voiced concerns that the initiative may be unconstitutional because it requires the state to reimburse local governments for property tax revenue lost by buying private land for preservation. Such a requirement would not be consistent with a Utah constitutional provision exempting government-owned property from property tax.