Lacustrine Communities are restricted in Tennessee to two natural lakes in the Mississippi Alluvial Plain, Reelfoot Lake and Sunk Lake. The definition of a lacustrine system as used here follows that of the Cowardin System (Cowardin et al. 1979) and is defined as:
In spite having a wealth of TVA "lakes" Tennessee actually only has two types of natural lakes and both are quite rare across the state. The majority of what people call lakes in Tennessee are actually impoundments or reservoirs (e.g. Kentucky Lake, Nickajack Lake) that formed following the damming of rivers by the TVA. Tennessee's natural lakes fall into two groups, earthquake-created lakes and ox-bow lakes. Reelfoot Lake and Sunk Lake were both created by the earthquakes that struck along the New Madrid Fault in 1811-1812. Ox bow lakes are formed when meandering streams, like the Mississippi River, changes course and abandons its former channel. The resulting isolated depressions that become cut off from the newly formed river channel are called ox-bow lakes. They are very frequent in the floodplain of the Mississippi River and the Hatchie River in West Tennessee.
Lacustrine environments are classified primarly following the Cowardin et al. (1979) system, with the exception that Lake Surface is considered separately here. Three categories are recognized for Tennessee: