A delicate oasis - and tourists - beneath desert

The overheated wind that blows across this desolate outpost of Chihuahuan Desert dries skin into parchment and leaves nose hairs twitching like brittle tumbleweed.

Descend a few hundred feet underground into the 99 percent humidity of Kartchner Caverns - a seven-acre wonderland of dripping, seeping, and flowing calcite formations - and you metamorphose into human sponge.

The story of how to connect the two fiercely opposing worlds, granting thousands of visitors access to the pristine, subterranean world without destroying it, is a 25-year saga that ends Friday.

By all accounts, Kartchner Caverns State Park, which opens to the public Nov. 12, is a milestone in the development - some say commercialization - of caves. A natural treasure with many rare and some unique structures, Kartchner has learned from the mistakes of other cave developers. From misting humidifiers to low-wattage lights, the site has become a state-of-the-art showroom, uniting the natural world and technology with the goal of preservation and education.

"This is a turning point in the history of developing caves," says Jeanne Gurnee, former president of the National Speleological Society, now a leading developer of caves worldwide. "The reason, simply, is technology.... Everything that the caving community has learned about the preserving and showing of caverns is brought into use here."

Harmony of high tech

Because of this, new visitors here will be exposed to a double marvel. Besides the kaleidoscopic array of first-rank geologic visuals - ranging from six-story, limestone-drip columns to spaghetti-thin "helictites" - that means behind-the-scenes engineering that is designed to provide both comfort and theater without being obtrusive.

Exhibit 1: lighting. For reasons of both heat (which can dry) and light (which can help grow color-destroying algae), cave illumination here is both minimal and intermittent. Controlled by computers, various combinations of diffuse and spotlit halogen lamps highlight different features as groups advance through the cave, turning off behind, and illuminating ahead as if each group bore a miner's helmet with individual light beams.

"We wanted to give the visitor the same feeling that a spelunker has when he first goes into a cave," says Frank Florentine, lighting designer and consultant to the Smithsonian Institution. That means giving the visitor just enough light to see, but "giving the cave enough respect to preserve it for centuries to come."

By lighting specific features in sequence, Kartchner caves not only minimizes damaging light, but also directs attention to specific features that might otherwise go unnoticed. At the close of an hour tour, visitors are treated to a final light performance in the cavern's most spectacular setting, featuring a 58-foot tall column and surrounding coves amid background music.

Exhibit 2: ease of access. A series of sealed doors and chambers provide visitors with a gradual descent on wide, lit paths without stairs for visitors. But more important, they minimize the air exchange between the desert above ground and the cave below ground. (Dry air can ruin the cave: a mere 1 percent drop in humidity could halt the continued formation of stalagmites and stalactites.)

By contrast, an elevator shaft drilled into Carlsbad Caverns when those caves were developed early in the century stunted growth there. Algae from light in Kentucky's Mammoth Caves grew dull-green algae, which discolored features and altered the food chain for microscopic cave organisms. Hundreds of caves world- wide have been similarly diminished by poor planning, experts say.

"Probably the main thing that stands out about the development of Kartchner Caves, is that the discoverers took their time to do things right," says Orian Knox, a cave expert who has been consulted on the development of caves worldwide. "They did environmental studies, geological studies to figure the best way into the cave, and tried to calculate every kind of danger to mitigate it."

A twisted history

The calculations began the day after the cave's discoverers, longtime spelunkers Randy Tufts and Gary Tenen, found the cave after slipping into a sink hole in November 1974. Instead of rushing to authorities with their find, the duo stayed quiet for 14 years. The find was made public only in 1988, after the State of Arizona purchased the property with plans to protect it.

"Our whole purpose since Day 1 has been to protect the cave," says Mr. Tufts. "Historically, caves like this have been vandalized terribly by people who spray paint on walls, break the formations, leave trash. It doesn't take long to destroy a cave. We couldn't bear to see that happen, so we eventually decided the only way to protect it was to develop it."

Eventually, the pair informed the owners of the land, the Kartchner family, of their find. The family then sold the land to the state. Twelve years of negotiating, planning, and building have followed, often amid public criticism for moving slowly.

"There were lots of challenges and some irritation that we were not proceeding apace," says Mr. Tenen. "But whenever we showed people what we had, they agreed we had discovered something monumental. No one wanted to ... screw it up."

Besides the quality of formations (including a 21 foot stalactite the breadth of a soda straw) and the cave's size (one room could host an indoor football game), Kartchner boasts a kind of mud never before seen in a cave, known as nontronite. For several weeks of the year, when cold winter air mixes with warm cave air, a kind of cave cotton - known as nitrocalcite - forms, almost as delicate as the down of a thistle. The formations later melt when summer's first rain storms lower the humidity again.

Such delicate features are the reason so much attention is being paid to lighting, humidity, and ways to keep the cave clean. Drains, for example, will carry daily lint from visitors out of the cave.

"We want this cave to be as pristine, colorful, and alive for our children's grandchildren as we see it today," says Ken Travous, executive director of Arizona State Parks. "This is a tribute to a conservation ethic we didn't know we had until we brought it all together."

(c) Copyright 1999. The Christian Science Publishing Society