The future of a planned UA science center in the Tucson’s downtown Rio Nuevo district hangs in the balance as an estimate released last week put the cost of its construction at $175 million.

The figure is almost twice the amount of an initial estimate for the center and half the cost of the recently axed Rainbow Bridge project.

Tucson City Manager Mike Hein and Councilwoman Nina Trasoff said they were surprised by how high the estimate turned out to be.

Alexis Faust, executive director at the Flandrau Science Center, helped create the center’s plan, which now calls for 150,000 square feet of floor space.

“”I’m actually pretty surprised it wasn’t higher,”” Faust said, citing a meteoric rise in the cost of construction materials and labor.

UA budget director Dick Roberts, who was not as enthusiastic about the estimate, said he is still optimistic. But he said the new estimate doesn’t reflect the same construction plan as when an analysis was first conducted. The new estimate is for a large-scale center located on the west side of Interstate 10 in downtown Tucson, while initial plans were for a smaller center located on the east side of the freeway, Roberts said.

Roberts said administrators will decide how to approach the center after they hear the results of an economic analysis by a private company that will show its moneymaking potential.

After seeing those results, the UA will subtract the cost of operation and find out how much of the construction it can pay for.

The rest is up to the city, Roberts said.

Tucson has a tax increment financing district plan in place for Rio Nuevo and will ultimately decide how much money goes where.

A tax increment financing district is an arrangement with the state in which the state sets a benchmark for any tax money from that specific land.

Under the arrangement, the city can collect any of the excess – money beyond the benchmark – that may come from Rio Nuevo.

Hein said the projected earnings from Rio Nuevo under those conditions would probably reach about $500 million in today’s dollars by the end of its 22-year span.

Once the center is completed, Hein said he would like it to be a “”regional, if not national or international, draw for visitors.””

The city of Tucson has many projects vying for that $500 million, though, and Roberts said the UA might end up scaling back its plans for the center in order to find an agreeable solution.

Trasoff said she knows money from the city “”certainly wouldn’t be near”” the $175 million total price tag, but she is still committed to making the center a reality.

Greg Shelko, director of the Rio Nuevo project, said he is fairly confident the city and the university will find a way to make the center work without scaling it back too much.

Though the center has gone through many different designs, including one that had it suspended from the Rainbow Bridge over I-10, Shelko said he is optimistic about its future.

“”No matter what package you put it in, it’s going to be a world-class facility,”” Shelko said.

Once the Rio Nuevo science center is finished, Faust said the funding for its daily operation will come entirely from money that currently funds Flandrau.

When Flandrau’s operations move downtown, the Department of Campus and Facilities Planning will decide what to do with the buildings left on campus.