Innovation in Action!
Kartchner Caverns’ development spanned nearly 11 years, 1988–99, and cost almost $35 million. During that time, we designed innovative ways to allow public access while protecting the cave.
When touring Kartchner Caverns, you appreciate its beauty. But do you wonder what it took to open the cave for public access while keeping its natural beauty intact?
Before entering the cave, you pass through a series of conservation doors which prevent moisture loss from the cave. You receive a mist “shower.” The mist moistens the particles of lint, skin and hair we shed so they fall onto the trail. The trail’s high curbs help contain the particles, allowing us to wash the trails and pump the residue out of the cave. Why do we care? Because particles like lint become food for fungus colonies that can ruin the beauty of the cave.
A major difference between Kartchner Caverns and other show caves is that the lighting is separated into 2 functions: one needed for safety and the other to enjoy the views. As you tour the cave the lights are controlled by the tour guide. This allows us to have less overall illumination, which in turn means fewer problems with algae growth and heat build-up.
Glancing over the side of the trail, you will not see any damage from construction. This is an example of another innovation developed here called “linear construction.” We built several feet of trail, then stood on that to build the next several feet. In that way, we contained human impact to the actual trail itself.
Into the Mountain
The original entrance to the cave, and the one the bats still use, is through the blowhole, a tight fit for the smallest person. Tunnels were the answer to getting visitors into the cave.
The tunnels were a challenge. Mining 1,100 feet of tunnels through highly fractured rock was costly and time-consuming. Depending on the geological conditions, tunneling cost $300 to $3,000 per linear foot and took 2 years to complete. Low-yield dynamite charges were used to lessen vibrations. Plywood and mattress blast barriers protected the cave from shock waves at junctions in the tunnels. Air locks were built in the tunnels, and plastic barriers were erected in the cave to prevent moisture loss. In the last 25 feet before breaking into the cave, miners stopped blasting with dynamite and switched to drills and mechanical splitters.
Construction in the Cavern
The trails in the cave are the result of 7 years of backbreaking work by the Arizona State Parks’ cave development crew. Using electric, pneumatic and hand tools they broke and moved rock, stabilized slopes, built trail bed and retaining walls, laid conduit and pulled miles of wire. They worked in heat and humidity inside dimly lit plastic tents to contain the dust. Surprisingly, there were no serious injuries, only scrapes and bruises.
Wood used in the cave for concrete forms was washed with bleach and coated with polyurethane to seal it against contaminating the cave with sawdust or insects. Concrete reinforcing rebar and remesh were coated with plastic to prevent rust. All construction materials were tested prior to their use to see if they outgassed harmful chemicals or would provide a growth medium for fungus.
Construction Materials: A Surprising List
- 1,461 cubic yards of concrete (Enough to build a walk 3 feet wide, 4 inches thick, 9 miles long. The concrete used in the cave was carried in buckets or wheelbarrows.)
- 41,190 linear feet of lumber (Enough to build a 6,000 square foot house.) How much of this remains in the cave today? None!
- 13.5 miles of conduit
- 107 miles of electrical wire (Enough to stretch to Tucson and back!)
- 512 light bulbs
- 36.5 tons of aluminum oxide, which was used to make trail surfaces slip-resistant.
Funding the Development of the Caverns
You may be surprised to know that very little taxpayer money went into developing the cave and park facilities. Here’s the breakdown on the money:
- 65% Enhancement Fund: User fees paid by people like you to Arizona State Parks
- 17% Arizona Heritage Fund: Arizona State Parks share of Arizona Lottery revenues
- 17% Arizona State Taxpayer dollars: Thank you, Arizona!
- 1% Federal Recreational Trails Program: Thank you, USA!
Kartchner Caverns is a Living Laboratory
Arizona State Parks is committed to the continued study of Kartchner Caverns. We hope to better understand this resource, our impacts on it, and to contribute to the world’s knowledge of caves. We are working with federal agencies such as the USDA Forest Service and National Park Service, state agencies like the Arizona Geological Survey and Department of Water Resources, academic organizations such as the University of Arizona and Arizona-Sonora Desert Museum. Through our partnerships with these groups, we are learning more about the cave environment, geology, hydrology and biology along with ways to improve our monitoring and cave management.
Cave Monitoring: A Full Time Job
From the time Arizona State Parks purchased the property, we have been monitoring the temperature of the air, water and soil, the carbon dioxide (CO2) levels, evaporation rates, humidity and radon levels in the cave. As a result, we have substantial baseline data on cave conditions. We continue that monitoring today. Some changes have been observed in Kartchner Caverns, as well as in local wild caves that we monitor. Since Kartchner Caverns has not been open to the public for many years, it is still too early to determine if changes can be attributed to visitation or natural conditions. Because we are devoted to ensuring the long term health of the caverns, monitoring and studies will continue.
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