In this talk Simon will discuss the potential for airborne Light Detection and Ranging (LiDAR) to help improve our understanding of the topographic limits of gully and channel formation.
Gully erosion is a widespread issue across all inhabited continents, with many costly environmental ramifications. Over recent decades analysis of gully head topographic position has become ubiquitous among methods to understand the phenomena. The widely accepted theoretical basis for this analysis relates the topographic position of gully heads to catchment area and local slope at the gully head. Early published work relied on extensive fieldwork to gather topographic information required for the analysis. However, high-resolution terrain data is becoming increasingly available in many countries through advances in airborne lidar capability. This new source of data provides an opportunity to investigate the topographic threshold of gully and channel initiation across many environments without the need for extensive fieldwork campaigns.
Recent analyses have begun moving toward a unified model of gully head topographic thresholds. These studies incorporate data on ground cover and local climate to help explain some of the observed variation in gully head position between different environments. Given this new direction, and the increasing availability of airborne lidar data, now is the right time to establish an objective programmatic method to exploit the troves of new data and enable global comparisons of gully head topographic thresholds.
About the speaker
Simon Walker is a current PhD candidate at the ANU Fenner School of Environment and Society. His research is centered on understanding processes that drive gully erosion and sediment delivery to the Great Barrier Reef (GBR) lagoon.
Simon’s educational background is in Earth science and natural hazards with a specific focus on the application of remote sensing and spatial analysis for understanding Earth systems. He has worked as a spatial analysis research assistant at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and also a program officer (science) for the Australian Flood Risk Information Project at Geoscience Australia (GA).