Round Spring, Missouri
January 23, 2014
Photographer: Tommy Hornbeck
Summary Author: Tommy Hornbeck
Shown above is Round Spring, Missouri, about 12 mi (19 km) north of the town of Eminence. The inset illustrates its nearly perfectly round shape. It's a collapsed cave chamber some 55 ft (17 m) deep; the spring water rises until it exits through a natural tunnel to join the Current River a few hundred yards downstream. Every ten years or so the water enters the spring faster than the tunnel is able to drain. As a result the chamber fills and finally overflows at its lowest point. The average daily flow is around 26 million gallons, but varies widely from 6.5 million gallons per day to a record 239 million gallons.
Much of the state of Missouri is karst landscape, formed from the dissolution of rock such as dolomite, limestone and gypsum, and characterized by sinkholes, caves and underground drainage systems. Most surface karst features, Round Spring for example, result from processes associated with the collapse of underlying caves. Photo taken on September 17, 2013.