Channel head location and characteristics using digital elevation models

The drainage network is the conduit through which much surface water and sediment are routed within a catchment. In a catchment, the position of where hillslopes begin and channels end has long been considered the position of transition between diffusive processes upslope and the more incisive fluvial processes downslope. Consequently, understanding channel head location is an important issue in understanding catchment hydrology and geomorphology. This study examines channel head position and characteristics in a catchment in Arnhem Land, Northern Territory, Australia. In this study the position of channel heads was mapped within the catchment and plotted on a reliable digital elevation model of the catchment. It was found that the majority of channel heads have relatively small source areas and that graphical catchment descriptors, such as the area-slope relationship and cumulative area distribution, can provide reliable measures of the field position of the heads of first-order streams and the transition from hillslope to channel. The area-slope relationship and cumulative area distribution are also shown to be good tools for determining digital elevation model grid size which can capture hillslope detail and the transition from hillslope to channel. Copyright (c) 2005 John Wiley & Sons, Ltd.