When people see where the Lost River in southern Indiana becomes "lost," they suddenly realize that they are visiting one of America's natural wonders.
After hiking half a mile across an obliging farmer's cornfields, participants on tours provided by the Lost River Conservation Association descend a steep bank into a dry, rocky riverbed. A little way further up the bed, there is what first appears to be a pool of water.
When they reach the water they find that they are at the point where the river suddenly disappears underground. They hear it gurgling beneath them as it falls into its subterranean channel, in which it will make its mostly secret way for the next eight or so miles, before rising to the surface and becoming a respectable river once again.
The river at that point is shallow and about ten feet wide. It comes up against a small hill and takes a 90-degree turn to the west. But because the base of the hill has several small "swallowholes" into which the river drains, in dry weather the river only goes a few feet farther before it disappears completely into the pebble-strewn sand.
Visit the river after a week of rain, however, and you will see an entirely different watercourse. The river flows on past the point where it once vanished, and swallowholes farther down the riverbed that haven't had a gulp of water in a long while get their chance to chug the flowing water. The more rain that falls, the farther down the riverbed the water will flow, and the more violent the maelstroms over the swallowholes. The huge piles of intertwined tree trunks lying over the larger downstream swallow holes in dry weather are testimony to the hydraulic power of the system when in full flood.
The reason for the river's complex hydrology is the soluble limestone over which it flows. The water has gradually eaten away the stone, opening up holes and underground channels. In upland areas, the same process forms sinkholes, which are depressions where rainwater runs into underground channels. One square mile in the Lost River watershed has 1,022 sinkholes.
The limestone holes don't always swallow the river. Sometimes the pressure of the water underground will send it back to the surface and plumes can be seen in the river where the water is coming out of the channel bedrock.
The water flowing through all these underground channels creates caves. One cave system is known to extend for 18 miles, with still uncharted tunnels yet to explore.
These areas of water flowing over and through soluble bedrock are known as karst terrain, named for a place in the former Yugoslavia that has similar geologic formations. The Lost River system is notable because it has all of the significant features of karst terrain in a small watershed of only about 150 square miles above the "rise" where it becomes a normal surface river again. That allows the leaders of the Lost River Conservation Association tours to show visitors all of the significant features of karst hydrology in a leisurely day's drive.
Another of these features is Wesley Chapel Gulf. A gulf is a place in a karst system where a cave has collapsed, exposing the underground river. At Wesley Chapel, the river shows itself in dry weather as a large green pool, lying under a cave mouth in a cliff. Visit the gulf after a rain, however, and it could be a cauldron of bubbling water, with the river sometimes running a complete circle around raised land in the middle.
The last stop on the tour is the Orangeville Rise, which for many years was thought to be the place where the Lost River returned to the surface. Dye tests showed that its water actually comes from sinkholes to the north and northwest, not the Lost River channel to the west. The "true rise" of the Lost River is on privately owned land a little south of the Orangeville Rise.
The goal of the Lost River Conservation Association is to protect all of the significant features of the system and install facilities to allow people to visit and learn about karst terrain. This could be achieved by various means, such as extending the boundaries of the Hoosier National Forest.
The Sierra Club supports protecting the Lost River system and taking advantage of its unique attributes to attract visitors and assist the local economy. The club included a description of the Lost River system in a national report it published in June, America's Great Outdoors: Sierra Club's Vision for Protecting Our Natural Heritage. Read the report at http://www.sierraclub.org/greatoutdoors/report.asp.
Although Lost River may not have the grandeur of some of our country's more famous natural settings, this little-known wonder of Indiana deserves more recognition and the protection it needs to astonish visitors for generations to come. The Lost River Conservation Association's next scheduled tour is Saturday, Sept. 24. Tours depart at 8 a.m. from the southeast corner of the Orleans town square at the junction of State Routes 37 and 337. They end at about 4:30 p.m. at the rise in Orangeville. For more information, contact Dee Slater at (317) 253-6951.
Copyright © 2007 Hoosier Chapter Sierra Club, all rights reserved.[10/04/05]efp