Graduate student seminar: Micro-scale catchment modelling of channel network and drainage features

Erosion in forestry areas is an important aspect of forestry management. Appropriately constructed models can help quantify catchment characteristics and represent topological properties, most of which will guide best management practices for harvesting forests. This seminar presents an analysis of four existing morphologically models for predicting the channel network, in particular relevant drainage features corresponding to forest management, through headwater systems in Lower Cotter Catchment and Kendall State Forest in southeast Australia. This study resulted in the development of a new model that adds a hydrological sub-model to the best performing morphologically based model. The combined model calibrated against ground-based surveys from 15 observation sites in the two study areas.

Major findings include:

  • An explicit definition of the headwater system could enhance the ability to identify drainage features towards BMPs;
  • 1 m resolution LiDAR DEM is necessary but not sufficient to representing discontinuous channel processes in headwater areas;
  • The existing morphological models do not credibly predict the real-world system;
  • Large scale drainage features are more sensitive to morphological factors (elevation, gradient and curvature) than those hydrological factors (rainfall and streamflow); and
  • Integrating hydrological model is necessary to representing existence and location of channel heads, and predicting drainage extension in upland catchment.