|Photograph from Northeast Iowa RC&D website: http://northeastiowarcd.org|
Sinkholes commonly form when the earth beneath the surface erodes away forming a gap that the surface can slowly recede or quickly collapse into. Because they are an easy path for water to drain from the surface, the Iowa Department of Natural Resources maps sinkholes in Iowa to protect groundwater from high levels of manure contamination, investigate how chemical runoff can affect ground water, and to better understand the geology of Iowa.
The layers are available in the DNR GIS Library if you want to examine them yourself (Potential Karst, Current and Historic Sinkhole Points, Current Sinkhole Polygons.)
Is your home near a sinkhole?