New concepts in hydrogeomorphic processes across various scales of space and time

The background, development, and proposed future directions in the emerging discipline of hydrogeomorphology are presented. The need for better understanding of temporal and spatial linkages in hydrogeomorphology is suggested as one of the primary reasons for the internal inaccuracies of many hydrological and sedimentation models, especially because many hydrogeomorphic processes are non steady-state. Examples are presented of the types of temporally and spatially distributed process information that are necessary to evaluate stormflow generation and sediment movement within catchments. Such detailed knowledge of spatial and temporal behaviour is needed to provide management guidelines for sustainable land use activities in catchments. A conceptual model for assessing the effects of land use and other external factors shows that thresholds for natural hydrogeomorphic processes are significantly altered by anthropogenic factors. The need to incorporate spatial and temporal hydrogeomorphic linkages into predictions and models in a relatively simple but meaningful way is stressed; such attempts to date have not focused on internal catchment processes and, thus, are not good analogues for catchment management