Masters Thesis Abstract: Andrew Welsh
Delineating debris-flow hazards on alluvial fans in the Coromandel and Kaimai regions, New Zealand, using GIS
Debris-flows pose serious hazards to communities in mountainous regions of the world and are often responsible for loss of life and damages to infrastructure. Characterised by high flow velocity, large impact forces and long runout, debris-flows have potential discharges several times greater than clear water flood discharges and possess much greater erosive and destructive potential. In combination with poor temporal predictability, they present a significant hazard to settlements, transport routes and other infrastructure located on fans. Thus, it is important that areas vulnerable to debris-flows are identified in order to aid decisions on appropriate land-uses for alluvial fans.
The intention of the research is to develop a methodology for delineating debris-flow prone fans using information from the Coromandel and Kaimai regions. Key objectives of the research are as follows:
- To generate useful definitions and distinctions between debris-flows, debris-floods and flood hazards
- Identify through extensive review of literature, the morphological catchment parameters associated with each of these hazards
- Use GIS techniques, aerial photograph analysis and field inspection of suitable sites, to delineate the extent of the above hazards on the depositional fans of catchments in the Coromandel and Kaimai regions
- Produce indicative debris-flow hazard maps of the Coromandel and Kaimai regions.
This research aims to supply useful technology for CDEM groups in regional hazard assessment through provision of new insight into the evaluation of debris-flow and debris-flood hazards and greater appreciation of the extent and severity of such hazards in the Coromandel and Kaimai regions .