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Before and After: Franklin Extensometer

Detailed Description

Before and after imagery of the original Franklin Extensometer. The original Franklin extensometer measured aquifer compaction near the groundwater pumping center at Franklin, Virginia from 1979 to 1995.

Aquifer compaction is caused by groundwater overuse, and this compaction in turn leads to land subsidence. However, a reduction in groundwater use can lead to the aquifer recovering and the land surface regaining some of its lost elevaiton.

At some point between 1995 and 2015, groundwater withdrawals slowed in the Franklin area and the aquifer recovered to such an extent that it caused uplift that bent the steel extensometer rod and tipped the weighted fulcrum arm out of alignment.


Public Domain.