Issues in LiDAR DEM based flowpath modelling

地球地形是许多集水过程的重要控制因素，因为它影响水、沉积物、营养物质和污染物的分布和流动。因此，表达区域地形信息的数字高程模型(DEM)在水文现象的分布式模拟建模中得到了广泛应用。机载激光扫描(LiDAR)的最新进展导致了新一代高分辨率数字高程模型的发展，能够以前所未有的水平表示地形细节。这些数据为更准确地模拟与流动相关的现象提供了可能。这项拟议的研究将考察LiDAR DEM在流动建模中的应用。具体地说，将考察两个主要问题：1)这些新数据提供的改进人工修改景观中陆面径流路径模拟的潜力；2)使用从高分辨率DEM数据获得的地形特征来解释小型间歇性源头水道中径流时间的变化的能力。这些研究课题中的第二个将需要开发广泛的监测网络，使用新型传感器来测量流量持续时间和计时。这些研究将有助于我们更好地理解这些独特的DEM数据的应用。此外，人们对间歇性源头水道中水流的性质知之甚少，尽管众所周知，源头渠道在向下游水道输送水和其他材料方面发挥着重要作用，而且最近的证据表明，可能是由于气候因素，源头流域的无流期正变得越来越普遍。这项研究将提高我们对水源航道水流计时模型的认识和能力。

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.