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Sinkhole
Lake Evolution and
Effects of Urbanization
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Sinkhole
Lake Evolution
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An estimated 95% of the surface waters in northeastern
Florida are sinkholes (Brainard,
1982; Lane, 1986).
The lakes originate from the direct result of chemical
and/or mechanical processes. The mechanical processes
that result in lake development are: 1) slumping or subsidence
of underlying clastic or carbonate sediments; 2) clustering
of sinkholes; or, 3) a combination of the previous two.
Sinkhole lakes in Florida occur in areas of thin overburden,
typically less than 61 m (100 ft). In areas with an impermeable
confining layer and no breaches, a lake might be a perched
lake (the lake level is held above the groundwater level)
with no communication with subsurface aquifers. Otherwise
a lake will form in conditions where a lack of overburden
or permeable confining layer allows for increased karstification
of the underlying limestone, producing a depression due
to limited fill material.
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The
seismic profiles indicate that sinkhole lakes can be delineated
into a progressive sequence of lake evolution based on
geomorphic types (Kindinger
and others, 1999) (Fig.
13). In central Florida the progression begins with
the subsurface dissolution of the limestone host rock
(Karst Development),
ultimately leading to surface collapse or subsidence.
The depression may be dry or, if a portion is below the
water table, it may contain water. Erosion of sediments
into the depression may cause the sinkhole to become plugged.
Further erosion may eventually bury the sinkhole.
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