SALT LAKE CITY — Plans for the Utah Performing Arts Center are moving forward as a one-man show.

And that has city leaders worried.

"We're doing this alone," Salt Lake City Councilman Luke Garrott said during a council work session Tuesday. "I think that's a really big risk."

City officials say they're optimistic Salt Lake County will partner in the $110 million performing arts center. But until a deal is done, city leaders can't count on that support.

They also can't wait.

In December, the City Council voted to issue up to $18 million in bonds to design a performing arts center capable of hosting first-run touring Broadway shows. On Tuesday, $15 million of those funds were committed to Garfield Traub Swisher, the Illinois-based firm selected in October 2009 to develop the theater.

The City Council, acting as the Salt Lake City Redevelopment Agency's Board of Directors, voted unanimously Tuesday to approve a development agreement with Garfield Traub Swisher, allowing the company to proceed with the one-year design process.

The city's financing plan for the performing arts center calls for the county to cover 20 percent of the project's cost — roughly $22 million. If the county opts not to participate, the theater could be scaled back, city officials said.

That's the part that bothers Garrott. Practice and performance space for community use are crucial in making sure the theater helps and not harms local arts groups, he said.

"The risk (building the theater without county participation) is huge because we may end up with a theater just for touring Broadway," Garrott said. "The community benefit of that is much more limited."

Councilman Carlton Christensen said moving forward without the county is risky but necessary.

"For me, making the decision to move forward with this was the best thing for Salt Lake City," Christensen said. "Do I think Salt Lake County ought to be a part of that? I do. But I can't make them do it."

City officials have an alternate financing plan in place in the event the county chooses to pass on a partnership. A decision by the Salt Lake County Council could come as soon as next month, officials said.

"Until we see a vote of the County Council, it's not something we're going to depend on," Salt Lake City Mayor Ralph Becker said. "We're going to continue along parallel tracks (with separate financing plans)."

Fundraising and the sale of naming rights also could make up some of the funding gap that would be created by the loss of county support, city officials said.

Garfield Traub Swisher estimates the theater would attract 123,000 new visitors to Salt Lake City each year, meeting the pent-up demand for first-run touring Broadway productions in Utah. Currently, space and scheduling limitations prevent Salt Lake City from attracting such shows until their seventh, eighth or ninth runs.

In 2008, Becker announced plans to build the Utah Performing Arts Center at approximately 135 S. Main, just south of the City Creek development.