Abstract

Understanding the changing behaviour of water and sediment flows from points on a hillslope to a whole 'experimental catchment' is critical to the identification of the hydrogeomorphic effects of specific land-use practices. Such terrain manipulations may be associated with forestry, agricultural, or urban development. This paper utilises a novel modelling technique (that allows the data to indicate the form and complexity of model structure) to characterise rainfall-waterflow and rainfall-sediment flow within a small tropical catchment. This experimental catchment is recovering from the complex patchwork of disturbance associated with the practices of 'selective timber harvesting'. Differences in the dynamic behaviour at scales ranging from 0.1 ha slope plots to the 44.1 ha catchment can be captured by the DBM-modelling undertaken. Explanation of differences in sediment mobilisation with scale change, can be seen to be closely associated with changing waterflow behaviour, in terms of responsiveness and process (i.e., the balance of infiltration-excess and return-flow pathways). These analyses provide: (a) the basis for a conceptual model of the relationship between intra-catchment hydrogeomorphic scales, and (b) a demonstrable linkage between forestry-induced landforms and landscape-scale behaviour.