Sinkhole formation is an ongoing hazard for urban karst settings, compromising construction foundations, and accelerating groundwater pollution. In Springfield, Missouri, the uppermost exposed unit is the Burlington limestone, a carbonate bedrock which is susceptible to karst formation, including caves and sinkholes. This study site concerns a detention basin near a major highway interchange, in which a new sinkhole is forming. Electric resistivity, very low-frequency electromagnetics, and dye-tracing surveys were performed at this sinkhole to determine its subsurface extent and any relation to surface features. The low resistivity associated with the sinkhole and thin soil contrasts with the high resistivity of the underlying Burlington limestone. This contrast highlights a curvilinear trough of thicker soil, which correlates with a former intermittent stream and represents a stream channel, which was graded and filled during construction of the highway and basin. The newly formed sinkhole lies entirely within this former stream channel. This relationship between the sinkhole and stream provides useful insights into the effects of urbanization on sinkhole formation. Knowledge of these relationships allows urban managers to better understand the risk this sinkhole poses to major highways and public buildings in the area.
- Received May 29, 2013.
- Revision received April 21, 2014.
- Accepted May 30, 2014.