Oral Presentation 9th Australian Stream Management Conference 2018

Understanding the evolution of floodplain channels by avulsion: An investigation on the floodplain of Murray River (#33)

Abdullah Baky 1 , Ian Rutherfurd 1 , Philip Marren
  1. University of Melbourne, Kingsville, VICTORIA, Australia

The evolutionary sequences of avulsion induced floodplain channel include successful entering of floodplain flow to river downvalley. The understanding of evolutionary sequences of such floodplain channel has significant implication on paleo-environment reconstruction, floodplain stratigraphy and overall stream management issues. There are well recognized models of floodplain channel development via avulsion. These models involve downvalley progradation of crevasse-splays and up-valley migration of head-cut across the floodplain. However, the detailed hydraulic and erosion processes that make the floodplain flow entering to river downvalley successful are not quite clear. We hypothesize that a successful flow entry is subjected to establish a direct connection between floodplain-levee channel and the river nearby. This study aims to explore the processes by which floodplain-levee channel connect to its nearby river in Kanyapella, Murray River, Australia. There are abundant floodplain-levee channels of different stages of development, makes this place ideal for this investigation. Geomorphic mapping of these channels and related features along with hydraulic process and field evidence have identified that the connection between floodplain-levee channel and river has certain stages involved: levee hole, levee channel, and then reversing slope of the levee channel. Overall, levee channel connects to the river when the channel will have slope towards the river, resulting a successful entry of floodplain flows.

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