A sinkhole is a depression formed as the underlying bedrock is dissolved by groundwater (usually limestone). Sometimes, surface water entering a crevice in the bedrock may be the cause. Thus, sinkholes may form in low-lying areas where water is ponding. A hole will form, at the top of the underground cavern that is dissolved, and the earth above the hole will collapse into the hole.
What’s the Risk?
Sinkholes can be dangerous to the foundations of the building. Sinkholes are conduits for surficial contaminants to reach groundwater. They may cause damages to buried services (water lines and electrical conduits).
How are sinkholes repaired?
A sinkhole is best repaired by excavating to rock then building an aggregate filter in the hole.