PROVIDENCE — WaterFire fans can finally stop holding their breath.

At a news conference yesterday, WaterFire organizers said the popular display would return for at least 11 full lightings this year, with the first set for Saturday, May 26, cosponsored by Brown University and Bank of America. Three partial lightings were also announced, including one on Monday, May 21, and another on Wednesday, May 23. Both will be held in the Waterplace basin.

Facing an audience that included Mayor David N. Cicilline and Lt. Gov. Elizabeth Roberts, WaterFire creator Barnaby Evans predicted that several more dates would be added over the next few months, bringing the total of full lightings to about 15.

“It should be an average year for us,” he said.

Evans added that popular WaterFire spinoffs such as the Verizon Jazz Stage and the Sovereign Ballroom also would return this year. (According to the WaterFire Web site, www.waterfire.com, the ballroom will resume in conjunction with the May 26 lighting. The jazz stage, meanwhile, will debut June 1.)

At the same time, Evans noted that while WaterFire remains one of Rhode Island’s more popular attractions, it continues to face a number of major economic and logistical challenges. One is the cost of staging the event, which can run as high as $100,000 for a full lighting of all 100 braziers.

“When you come to a WaterFire and everything is working the way it’s supposed to — the boats sliding through the river, the fires burning, the people wandering around enjoying the evening — it’s easy to forget how complicated it all is,” Evans said. “It may look easy, but it isn’t.”

In particular, Evans said that weaker-than-expected corporate support had caused WaterFire to delay announcing dates for its 2007 season. “Normally, we like to post a schedule by the end of April,” he said. “This year, for some reason, we had trouble getting commitments from some of our sponsors.”

Another concern is the gradual silting-up of the city’s rivers. Although sections of the Providence River and its two feeders, the Moshassuck and the Woonasquatucket, were dredged as recently as 1998, Evans said the build-up of sand and sediment in the rivers is becoming a problem once more. And with the rivers blocked, WaterFire crews can’t perform routine maintenance or keep the event’s bonfires burning.

“Right now, it’s possible to work around it,” Evans said. “But the more it builds up, the more of a problem it is.”

In an effort to solve such problems, Evans has been working with WaterFire’s board of directors on plans aimed at ensuring the event’s long-term survival. Among the possibilities: creating an endowment that would help cover yearly maintenance, insurance and other costs and asking businesses that directly benefit from WaterFire lightings, such as hotels, bars and restaurants, to pay a larger share of WaterFire’s budget.

Another potential solution — boosting the number of donations from individuals attending WaterFire lightings — has been tried before, though so far with limited success.

“In a sense, we’re victims of our own success,” Evans said. “By the time we actually do a lighting, everything’s already paid for. There’s this illusion that it all just happens.”

Still, Evans said he was pleased with the level of support for this year’s WaterFire season — its 12th as a regular summertime event. He said WaterFire had already raised 80 percent of its 2007 budget, which he estimated would reach about $1.75 million by the end of the year.

He also pointed to the list of sponsors who had signed on for the 2007 season, including corporate heavyweights such as Dunkin’ Donuts, Amica Insurance and GTECH and nonprofit institutions such the Rhode Island Foundation and the Champlin Foundations.

Asked if he had any surprises in store, Evans mentioned several possibilities. One was extending WaterFire’s reach farther down the Providence River, toward the city’s fast-developing Old Harbor area. Another was adding more performance-style events along the Providence riverwalk.

“If I say anymore, it won’t be a surprise,” Evans said.

bvansicl@projo.com