A California company is considering building a large movie theater nearly on the doorstep of Zion National Park, while another company may build a water slide across the street, and environmentalists aren't happy about the plans.

A spokeswoman for World Odyssey Inc. of Los Altos, Calif., said many letters have been written by environmentalists about the project. But she would give no further details.Terri Martin, regional representative of the National Parks and Conservation Association, said a "big screen" IMAX theater, an 80-room hotel, and a 275-space parking lot would be built just outside the park's southern entrance station. The theater would be 50 by 70 feet and would seat 350 people, she said.

The site abuts Zion National Park on two sides, she said. It is "directly across the narrow Virgin River from the park's main `Watchman' campground." She said the decision about whether to allow construction rests with the Springdale Town Council.

"We're not against the project in and of itself, but at this site it's completely inappropriate," Martin said. In fact, conservationists would like to see the site added to the park, she said. The land's private owner would be fully compensated, either in cash or through a trade.

As far as the theater and hotel complex are concerned, she said, "We see a potential for alternative sites in downtown Springdale."

It could be built either on private land or on Bureau of Land Management property the town of Springdale has under lease under a federal act that allows recreation or other public purposes on the land.

"If you combine this project with a shuttle-bus system which took visitors up into the park . . . the project would actually be more lucrative to the community and developer," Martin said. The shuttle would alleviate the park's serious traffic jams.

"We are appalled at this location," Martin said of the proposal to build near the entrance. "Put it somewhere else and we wouldn't have a problem."

The tranquil campground would be forever altered by the proximity of the massive buildings, car traffic and artificial lighting, she said. Presently, campers can look across the Virgin River to an open meadow.

Also, she said, a Springdale official told her that another company is proposing a water slide across the road from the proposed theater site.

She believes the project, sponsored by a Springville company, would be called Zion Park Fun Center.

"People across the United States have shown they're increasingly turned off by strip development and ticky-tacky development in gate communities," Martin said.

As it is today, Springdale is a quiet community, harmonious with the park. Big projects could turn it into one of the national park gateway communities that people are offended by, she said.

"It's very disturbing," she said.

Meanwhile, according to Dixie College, Professor Louise Excell has been awarded a $7,000 grant to fund a lecture series at Springdale and Zion, concerning the environment and development. The grant was awarded by the Utah Endowment for the Humanities.

"Springdale is located at the entrance to Zion National Park in southwestern Utah," Excell said in a Dixie press release.

"It was settled by Mormon pioneers in the 1860s, and its size and character changed little for nearly one hundred years. After such a sleepy existence, Springdale finds itself at a critical juncture; visitation to Zion National Park is soaring and the trend shows no signs of changing.

"Now the small town of some three hundred permanent residents faces increasing pressure to accommodate nearly three million tourists annually."

She said developers are "queuing up to obtain every spare inch of usable space" and that competition for tourist dollars is causing an escalation in garishly bright, large signs.

"Parking is becoming limited and traffic congestion occurs periodically. These rapid changes and prospects of still greater changes have dramatically polarized the community along pro-development and no-growth lines," Excell said.