Petter Nyman
Forests and Water Research Group
Department of Forest and Ecosystem Science
The University of Melbourne
Level 1, 221 Bouverie St, Parkville
VIC, 3010, Australia
Email: p.nyman@pgrad.unimelb.edu.au
Degree
PhD
Thesis title
Modelling the initiation and magnitude of runoff generated debris flows in catchments burnt by wildfire
Supervisors
Dr Patrick Lane
Dr Gary Sheridan
Dr Leon Bren
Project Outline
Wildfire is linked to significant changes in hydrological and geomorphic processes in forested catchments. While it is generally accepted that wildfire increases the susceptibility of hillslopes to erosion, the observed response is highly dependent on intrinsic catchment characteristics and the timing, magnitude and sequence of rainfall events during the recovery to pre-fire conditions. The combination of steep, severely burnt slopes and high intensity rainfall can result in extreme erosion events typically associated with flash floods and runoff-generated debris flows. A large number of these high magnitude events have occurred in Victorian catchments following wildfires in recent years.
The aim of this project is to identify and model the key hydrological processes involved in debris flow initiation and quantify the relevant parameters during the recovery of the catchment to pre-fire conditions. The research will address the following questions:
- How much sediment is generated from debris flows and where is it sourced from?
- What are the critical thresholds for debris flow initiation after wildfire?
- What are the dominant processes and how can these be modelled?
- How will temporal changes in key parameters influence the likelihood of debris flow occurrence during the recovery of the catchment to pre-fire conditions?
While the study has applications in predicting impacts and managing risk to water resources it will also generate new knowledge relating to the role of wildfire on landscape processes and geomorphology in south-east Australian catchments.
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