Alluvial rivers migrate laterally and longitudinally and, incident thereto, generate new flood plain lands. Four types of lands are thus formed: sheet accretion, point bar accretion, eddy accretion and back-swamp accretion. The type of flood plain land generated is determined by the nature of the local river migration or movement. Incident to river migration, caving banks are formed, and under certain conditions, the caves can be very sudden, extensive, and dangerous to man, should the area involved be developed or urban. Studies of river migrations and the resulting flood plain lands represent the most generalized aspect of river hydraulics and sedimentation studies. In the present studies, mode of formation is the controlling criterion, and such matters as nature of sediment, types of soil, kind of stratification or other detailed concerns, are of no moment.