• 326 Citations
  • 10 h-Index
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Personal profile


Tim’s research focuses on the geomorphology of rivers and wetlands in dry landscapes. He has worked extensively in the Murray-Darling Basin in Australia, and in Africa (Tshwane-Pienaars River, South Africa; Okavango Delta, Botswana; Nile River, Egypt). His research seeks to understand patterns and processes of fluvial landform change, sediment dynamics, aquatic ecosystem function, and interactions between people and rivers/wetlands in the context of long-term landscape evolution and environmental change. Tim collaborates widely with national and international colleagues, and is a key member of the Wetlands in Drylands Research Network.

Tim is recognised internationally for fluvial geomorphology research and coordination roles in training and capacity building programs for assessment of soil erosion and sediment transport using nuclear techniques, with the International Atomic Energy Agency (IAEA). He is Lead Country Coordinator for the IAEA Regional Cooperative Agreement Project RAS5084 “Assessing and Improving Soil and Water Quality to Minimize Land Degradation and Enhance Crop Productivity Using Nuclear Techniques” from 2018-2021.

Prior to his academic appointment, Tim was a senior environmental scientist at the NSW Office of Environment and Heritage (OEH) where he managed scientific projects and worked with environmental managers to link river and wetland research to decision-making efforts and policies. This work led to publication of the book “Floodplain Wetland Biota in the Murray-Darling Basin: Water and habitat requirements” and continues through co-funded research, engagement and outreach with OEH and the NSW National Parks and Wildlife Service.

Research interests

  • River channel, floodplain and wetland morphodynamics
  • Fluvial responses to environmental variability and climate change
  • Sedimentology, geochronology and palaeoecology
  • Sediment tracing and sediment dynamics in catchments
  • Patterns, rates and hydrogeomorphic controls on aquatic ecosystem metabolism
  • Wetland responses to inundation; water and habitat requirements of freshwater biota
  • Links between fluvial and environmental change and human settlement in ancient civilisations
  • Anthropogenic impacts on environmental systems


Research student supervision

Tim has extensive experience with higher degree research students, having supervised to completion 1 PhD, 7 MRes and 2 Honours students as primary supervisor; and 2 PhD and 3 MRes students as associate supervisor.

Current PhD and MRes candidates:

  • Neda Yousefi (PhD project: Channel bifurcation and (dis)equilibrium conditions in floodplain wetlands)
  • Bradley Graves (PhD project: Channel discontinuity and floodout formation in dryland rivers)
  • Sana Khan (co-supervised PhD project: Analysis of river sensitivity for setting ‘expectations’ of geomorphic adjustment for river management)
  • Carl Helander (MRes project: Sediment flux and filtration by wetlands in inland rivers)
  • Jacob Kiefel (MRes project: Geomorphology and archaeology at Wadi Araba, Egypt)
  • Gareth Evans (co-supervised MRes project: Impacts of vertebrate activity at Peery Lake mound springs)
  • Christoph Langenmaier (MRes project: Predicting global threats to wetlands in drylands)

Community engagement

Research engagement

External positions

Senior Environmental Scientist, Department of Environment Climate Change and Water

20 Aug 200823 Mar 2010

Environmental Scientist, NSW Department of Environment and Climate Change

20 Aug 200719 Aug 2008

Environmental Scientist, Department of Environment and Conservation (DEC)

2 Sep 200630 Sep 2006

Fingerprint Dive into the research topics where Tim Ralph is active. These topic labels come from the works of this person. Together they form a unique fingerprint.

  • 12 Similar Profiles
wetland Earth & Environmental Sciences
floodplain Earth & Environmental Sciences
marsh Earth & Environmental Sciences
avulsion Earth & Environmental Sciences
river Earth & Environmental Sciences
catchment Earth & Environmental Sciences
sediment Earth & Environmental Sciences
habitat Earth & Environmental Sciences

Network Recent external collaboration on country level. Dive into details by clicking on the dots.

Projects 2011 2021

Research Outputs 2002 2019

Application of feature selection methods and machine learning algorithms for saltmarsh biomass estimation using Worldview-2 imagery

Rasel, S. M. M., Chang, H. C., Ralph, T. J., Saintilan, N. & Diti, I. J., 11 Jun 2019, In : Geocarto International. 25 p.

Research output: Contribution to journalArticleResearchpeer-review


Dust: a potential nutrient source to the large semi-arid wetland, the Okavango Delta

Humphries, M. S., Benitez-Nelson, C. R., Bizimis, M., Ralph, T. J., Larkin, Z. T. & McCarthy, T. S., 31 Jul 2019, (Submitted) In : Earth Surface Processes and Landforms.

Research output: Contribution to journalArticleResearchpeer-review

Southern Africa

Influence of historical inundation frequency on soil microbes (Cyanobacteria, Proteobacteria, Actinobacteria) in semi-arid floodplain wetlands

Kobayashi, T., Ralph, T. J., Sharma, P. & Mitrovic, S. M., 31 May 2019, In : Marine and Freshwater Research.

Research output: Contribution to journalArticleResearchpeer-review

soil microorganisms

Macro-charcoal accumulation in floodplain wetlands: problems and prospects for reconstruction of fire regimes and environmental conditions

Graves, B. P., Ralph, T. J., Hesse, P. P., Westaway, K. E., Kobayashi, T., Gadd, P. S. & Mazumder, D., 24 Oct 2019, In : PLoS ONE. 14, 10, p. 1-33 33 p., e0224011.

Research output: Contribution to journalArticleResearchpeer-review

Open Access
fire regime

Product vs. process? The role of geomorphology in wetland characterization

Lisenby, P. E., Tooth, S. & Ralph, T. J., 1 May 2019, In : Science of the Total Environment. 663, p. 980-991 12 p.

Research output: Contribution to journalArticleResearchpeer-review



2017 BHERT Award for Outstanding Collaboration for National (non-economic) Benefit

Lesley Hughes (Recipient), Michelle Leishman (Recipient), Leigh Staas (Recipient), Rachael Gallagher (Recipient), Nola Hancock (Recipient), Linda Beaumont (Recipient), Victoria Graham (Recipient), Timothy Ralph (Recipient), Hsing-Chung Chang (Recipient), Kerrie Tomkins (Recipient), Emilie-Jane Ens (Recipient) & Melanie Bishop (Recipient), 2017

Prize: Honorary award

Faculty of Science and Engineering Award for Excellence in Research

Michelle Leishman (Recipient), Lesley Hughes (Recipient), Victoria Graham (Recipient), Linda Beaumont (Recipient), Melanie Bishop (Recipient), Rachael Gallagher (Recipient), Nola Hancock (Recipient), Kerrie Tomkins (Recipient), Hsing-Chung Chang (Recipient), Emilie-Jane Ens (Recipient), Leigh Staas (Recipient) & Timothy Ralph (Recipient), 24 Nov 2017



Fellow of The Royal Geographical Society

Timothy Ralph (Recipient), Jul 2018

Prize: Other distinction

Activities 2018 2018

  • 1 Invited talk

Communicating geomorphology (or not)

Tim Ralph (Speaker)
11 Sep 2018

Activity: Talk or presentationInvited talk

Press / Media

Sharing expertise with regional neighbours

Timothy Ralph


1 media contribution

Press/Media: Expert Comment

Project focuses on improving soil and water quality in Asia Pacific countries

Timothy Ralph


1 item of media coverage

Press/Media: Public Engagement Activities

Preventing soil erosion with nuclear know-how

Timothy Ralph


1 item of media coverage

Press/Media: Expert Comment

Embracing change: Dr Tim Ralph on conservation

Timothy Ralph


1 media contribution

Press/Media: Public Engagement Activities