Most geographical studies of waterways and boundaries have emphasized the boundary function of waterways, particularly between political entities. Few studies have addressed the problems associated with state ownership of waterbottoms. The important issue in determining ownership is navigability because most states own the waterbottoms of all naturally formed navigable waterways. In recent years, the problem of waterbottom ownership determination has been magnified by accelerating rates of land loss along coastal zones and channel filling within drainage basins. In the state of Louisiana, both of these changes are due, in part, to cultural alterations of sediment- bearing channel flow. This research project will examine the impact of waterway changes on ownership of waterbottoms within south Louisiana waterways. It will test the hypothesis that the state is losing ownership of property through accretion within areas of extensive deposition while it is gaining property through erosion within the coastal zone. The Atchafalaya Basin and the Bayou Lafourche will be compared as extremes of these two processes. Geological, historical, geographical and legal data will be assembled in order to test the hypothesis. This study is unique in that it addresses the ownership of a particular type of property, the waterbottoms of inland and coastal waterways. It blends geomorphological evidence with legal decisions to better understand the relationship between natural and cultural processes which modify waterway boundaries and the legal framework for adjudicating disputes over boundaries. It will have practical applications to boundary determination problems elsewhere, and it will further elucidate the problems which occur when the legal and legislative systems lag behind the actual physical changes to boundaries.