What is a fluvial levee?

Abstract

Fluvial levees are elevated partitions between channels and floodplains. Because of their character and position, levees may provide critical controls on, and insights into, geomorphic processes that determine the distribution of water and sediment within river systems. Few studies have analysed the character, distribution, sedimentology and processes that form levees in modern depositional environments. Characterisation of levee deposits from the Mississippi River continues to form the basis for most levee interpretations from the rock record. This discussion paper assesses the reliability of interpretations of levee deposits in numerous examples from the rock record, and their associated inferences for river style. This uncertainty reflects the lack of definitive sedimentological attributes for levee deposits, their limited preservation potential, and the fact that levee identification in the rock record is inhibited by the reliance on geometric descriptors or indirect associations between channel and floodplain facies. Given these concerns, it is suggested that geomorphologists and sedimentologists need to recognise the limitations of our present knowledge of levees, and work towards a more systematic understanding of these significant fluvial landforms in the full spectrum of modern (and ancient) river settings.