A smoldering controversy at Springdale, Washington County, over developments at the gateway of Zion National Park has flared into a confrontation between development and environmental forces that reaches all the way to Congress.

On Thursday, the Springdale Town Council approved a revision in the zoning ordinance that could pave the way toallow construction of a 350-seat IMAX-type theater, parking lot and motel complex at the entrance to Zion.The Town Council has received hundreds of letters opposing the project, said Terri Martin, Utah representative of the National Parks and Conservation Association.

Council members, attempting to deflect the tremendous outpouring of concern over the project, insist that they are basically just updating the zoning ordinance and that nothing official will happen until the project's developer, World Odyssey of Los Altos, Calif., files a formal request for a permit.

"It's really kind of a non-controversy," said council member Steve Sandstrom.But others don't see it that way.

In addition to public fallout over World Odyssey's plans, 19 members of the Interior Committee in the House of Representatives signed a letter opposing the project's location. The signatories include Reps. Morris K. Udall, D-Ariz.; George Miller, D-Calif.; Bruce Vento, D-Minn., and Wayne Owens, D-Utah.

"We are alarmed to learn about the proposal by World Odyssey Inc.," begins the letter. It charges that even with careful architectural design, a development on that scale would unavoidably intrude on the majestic scenery of one of America's most treasured national parks.

It says the signers are willing to purchase the land near the park and urged World Odyssey to find another location.

In fact, so much controversy has attended the project that Springdale Town Council member Dale Gilchrist said a project by another company, to build a water slide nearby, was apparently scrapped because of it. The slide's backers were aware of the "bad vibes" over the World Odyssey proposal, he said.

"There was so much stink raised, they have since pulled out," Gilchrist said.

Kieth Merrill of World Odyssey defended the proposal to build the complex, interviewed in March by the Deseret News. "It's a very good project, it's a very legitimate project, there are none of the behind-doors dealings going on that were insinuated by the National Parks Conservation" group, Merrill said.

Council member Sandstrom, who was appointed to the board a few months ago, wasn't overawed by the 300 or so letters.

"We're looking at 2.3 million-plus (visitors) a year," he said. That's a lot of people, any of whom might have an opinion about it one way or the other.

"In all practicality, a private property owner that owns a piece of property that has been zoned commercial - as this parcel that you're referring to - might very well be able to go in there and build what he wants to anyway, and there's nothing we can do," he said.