Sinkholes by Nick Gromicko and Rob London What are Sinkholes? Sinkholes are ground-surface depressions that result when a subterranean void weakens support of the overlying earth. Why are Sinkholes a Concern for Inspectors? They threaten water supplies by draining unfiltered water from streams, lakes and wetlands directly into aquifers. They kill and injure people. A person can