Riverine Communities as recognized here following the Cowardin Classification (Cowardin et al. 1979) and include all flowing waters from the mouths of rivers to the springs that serve as their sources and including all first, second, third, and fourth order stream systems. Riverine systems are linear systems. The width along any given stream system spans from shore to shore and includes the intervening stream bottom, stream bed, and aquatic zones. The riverine system is bound on both sides either by the palustrine system or by the upland system. The boundary separating the palustrine and riverine systems is not always sharp. In cases where there are sparsely vegetated shorelines of sand, cobble, or bedrock the riverine system extends to the point along the shoreline where persistent vegetation cover achieves an aerial coverage of 30% or greater. Areas with more than 30% vegetation cover that are still within the flood zone are part of the palustrine system. In some situations the palustrine system extends into the channel of the river. This occurs when there are persistent, emergent wetlands along the shore of the river (rare in Tennessee). Such peristent river marshes are considered part of the palustrine system as is all vegetation shoreward. In such cases, the riverine system is thus limited to the part of the channel that is characterized by submerged, floating, or non-persistent (through winter) emergent vegetation and does not include the persistent, emergent shoreline vegetation.