Elyssa De Carli

Leesh

PhD Candidate
Geocoastal Research Group
Rm 358, Madsen Building (F09)
School of Geosciences, University of Sydney
Email:
Blog: http://themightymurray.wordpress.com/

Supervisor
Associate Professor Thomas Hubble, School of Geosciences

Associate Professor
Associate Professor David Airey, School of Civil Engineering

Research

PhD Title: Geologic and Geomorphic Characteristics of Riverbank Failure on the Lower Murray River, South Australia.

The lower Murray River connects the Murray-Darling River Basin to the Southern Ocean and drains 14% of Australia’s landmass. During the Millennium Drought (1997-2011) record low inflows for the Basin were recorded and the lower Murray River received only 19% of its long-term average inflow for 2008-2009, causing the pool-level in the lowermost reaches near Goolwa to fall 1 m below sea level. This event triggered widespread mass failure in the alluvial river banks and ground subsidence in some river-adjacent floodplain deposits between Blanchetown and Lake Alexandrina. Riverbank failures are a common, expected and well-studied phenomenon on a world scale and within Australia’s river systems, however present an apparently new problem for, and significant risk to, private landholders, public infrastructures and river users of The Murray.

This project will investigate known occurrences of riverbank instability along the River Murray downstream of Lock 1. Multibeam bathymetry, aerial photographs and historical surveys and maps will be used to assess whether or not bank instability on the lower Murray is a new phenomenon or if the recent bank failures are examples of a longer-term geomorphic process.

The project will undertake geophysical profiling and collect geological samples to determine spatial distribution of the sediments that form the banks, providing undisturbed material for geotechnical testing. This information will be used to develop an explanatory geological model for the occurrence of bank instability on the lower Murray that will contextualise and enable robust geotechnical modelling of slope failure. Multibeam bathymetric data will be examined using state-of-the-art three-dimensional representation software and these data, as well as geophysical profile data, sediment distribution data and archival aerial photographs will be managed using GIS software. This information will be integrated with slope stability models to develop an enhanced understanding of the bank failure process on the Lower Murray, its geological context, and the potential for reoccurrence which will facilitate the management of this hazard.

Project E.1.8 River Bank Collapse in the Lower Murray River is funded by The Goyder Institute for Water Research and is in collaboration with The University of Adelaide, Prof. David Petley of Durham University, UK and The Department of Environment, Water and Natural Resources (DEWNR).

Publications

Journals

  • Hubble, T., De Carli, E., Penny, D., Petley, D., Clarke, S., Hamilton, R., Gadd, P., Brand, H. (2015) Palaeolake Mannum – The Murray-Darling River’s Holocene Stilling Basin. (Manuscript in preparation).
  • Clarke, S., Hubble, T., Webster, J., Airey, D., De Carli, E., Ferraz, C., Reimer, P., Yu, P., Boyd,, R., Keene, J., Exon, N., James Gardner and Shipboard Party SS12/2008. (2015) Sedimentology and 14C dating of sediment cores taken from submarine landslides on the eastern Australian upper continental slope. (Manuscript in preparation).
  • Hubble, T., Airey, D., Sealey, H., De Carli, E., and Clarke, S. (2013) A little cohesion goes a long way: Estimating appropriate values of additional root cohesion for evaluating slope stability in the Eastern Australian Highlands. Ecological Engineering 61, 621-632.
  • Harris, DL, Webster, JM, De Carli, EV, Vila-Concejo, A. (2011) Geomorphology and morphodynamics of a sand apron, One Tree Reef, Southern Great Barrier Reef. Journal of Coastal Research SI 64, 760-764.
  • De Carli, E.V. (2010) Sediment dynamics on One Tree Reef, Great Barrier Reef Australia. Investigating the controls behind sediment variability and the evolution if the southern sandsheet. B.Sc. (Hons) thesis. School of Geosciences, University of Sydney, Australia.

Technical Reports

  • Hubble, T., De Carli, E. (2015) Mechanisms and Processes of the Millennium Drought River Bank Failures – Lower Murray River, South Australia. Goyder Institute for Water Research Technical Report Series No. 15/X, Adelaide, South Australia. (Manuscript under review)
  • Jaksa, M.B., Hubble, T.C.T., Kuo, Y.L., De Carli, E. and Liang, C. (2013) Goyder Institute Research Project: E.1.8 Riverbank Collapse in the Lower River Murray – Literature Review and Knowledge Gap Analysis, Goyder Institute for Water Research Technical Report Series No. 13/15, Adelaide, South Australia.

Conference Proceedings

  • De Carli, E. (2014) Geomorphic and hydraulic controls on large-scale riverbank failure on a mixed bedrock-alluvial river system, the River Murray, South Australia: a bathymetric analysis. Presented at the 2014 AGU Fall Meeting, San Francisco, California, 15-19 Dec 2014.
  • De Carli, E. Geologic and Geomorphic Characteristics of Riverbank Failure on the Lower Murray River, South Australia. Presented at The 7th Annual Stream Management Conference, Townsville, Australia 27-30 July 2014.
  • De Carli, E., & Hubble, T. (2014). Morphological Characteristics of Riverbank Failure on the Lower
    River Murray, South Australia. In G. Vietz, I. D. Rutherfurd & R. Hughes (editors). Paper presented at the 7th Australian Stream Management Conference, Townsville, Queensland.
  • Hubble, T., De Carli, E., Clarke, S., Penny, D., Hamilton, R., Petley, D., Gadd, P. (2014) The Lower Murray River’s Mannum Muds: A Holocene Age Lacustrine Deposit in a Bedrock Gorge. Abstract EP13A-3496 presented at 2014 AGU Fall Meeting, San Francisco, California, 15-19 Dec 2014.
  • Hubble, T., De Carli, E., & Airey, D. (2014). Geomechanical modelling of the Murray’s Millennium Drought river bank failures: a case of the unexpected consequences of slow drawdown, soft bank materials and anthropogenic change. In G. Vietz, I. D. Rutherfurd & R. Hughes (editors). Paper presented at the 7th Australian Stream Management Conference Townsville, Queensland.
  • Hubble, T., De Carli, E., Airey, D., and Scientific Parties MV Breakfree 2012-2013. The characteristics of rotational slumps and subaqueous translational slab slides of the Lower Murray River, South Australia: do they have any implications for the weal layer hypothesis? Abstract EGU2014-4824 presented at European Geosciences Union General Assembly 2014, Vienna, Austria, 27 April – 2 May 2014.
  • De Carli, E.V., Hubble, T.C.T., Jaksa, M., Clarke, S.L., Airey, D.W., O’Toole, J., and Carpenter, G. and Scientific Parties MV Breakfree 2012/2013. (2014) Riverbank Collapse on the lower Murray River: recent phenomenon or long-term geomorphic process? Abstract 1380 presented at 2014 Ocean Sciences Meeting, Honolulu, Hawaii, 23-28 Feb 2014.
  • De Carli, E.V., Hubble, T.C.T., Jaksa, M., Clarke, S.L., Airey, D.W., O’Toole, J., and Carpenter, G. and Scientific Parties MV Breakfree 2012/2013. (2013) Riverbank Collapse on the lower Murray River: recent phenomenon or long-term geomorphic process? Abstract NH13A-1595 presented at 2013 AGU Fall Meeting, San Francisco, California, 9-13 Dec 2013.
  • Clarke, S.L., Hubble, T.C.T., Webster, J., Airey, D., De Carli, E., Ferraz, C., Reimer, P.J., Boyd, R., and Keene, J. (2013) A sedimentologic and 14C dating study of five eastern Australian upper continental slope submarine landslides. Abstract OS11D-1672 presented at 2013 AGU Fall Meeting, San Francisco, California, 9-13 Dec 2013.
  • Fletcher, M., Hubble, T., Clarke, S., Airey, D., Webster, J., Yu, P., and E. De Carli (2013) Submarine landslide morphology of box slides present in the continental slope offshore Fraser Island, Queensland, Australia. Abstract 2.3.3 presented at 2013 Geosciences Conference, University of Canterbury, Christchurch, New Zealand 24-27 Nov.