Issues in LiDAR DEM based flowpath modelling

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Earth's topography is an important control for many catchment processes because it affects the distribution and flow of water, sediment, nutrients, and contaminants. As such, digital elevation models (DEMs), which convey information about the topography of an area, are widely applied in distributed simulation modelling of hydrological phenomena. Recent advancements in airborne laser scanning (LiDAR) have led to the development of a new generation of fine-resolution DEMs, capable of representing topographic detail at an unprecedented level. These data offer the potential to help model flow-related phenomena more accurately than before. This proposed research will examine the application of LiDAR DEMs to flow modelling. Specifically, two main issues will be examined: 1) the potential for improving the simulation of overland flow pathways in human-modified landscapes offered by these novel data, and 2) the ability of using topographic characteristics derived from fine-resolution DEM data to explain variation in the timing of streamflow in small intermittent headwater channels. The second of these research topics will require the development of extensive monitoring networks using novel sensors for measuring flow duration and timing. These studies will help to better our understanding of the application of these unique DEM data. Also, relatively little is known about the nature of streamflow in intermittent headwater channels, despite the fact that headwater channels are known to play an important role in the delivery of water and other materials to downstream waterways and that recent evidence suggests no-flow periods are becoming increasingly common in headwater catchments, perhaps due to climatic factors. This research will improve our knowledge of and ability to model streamflow timing in headwater channels.