A Role for Geomorphology in Integrated Catchment Management



Catchments (watersheds) are integrated through water movements. Water moves sediments; and the translocation of materials has geomorphic and pedological responses. Fertiliser and pesticide residues and other toxic substances are also transported by water, in solution and attached to sediment particles, affecting various ecological components of catchments. The insertion of pollutants is directly caused by land-use practices. In turn, land uses are influenced by the pedo-geomorphology of the catchments (uplands, valley sides, flood plains and terraces, spurs and hollows, convexities and concavities; position in the upper, middle or lower catchment; and by catenary relationships). Therefore catchment management must deal with interrelationships amongst human activities and various geomorphic elements. Several case study examples from southwestern Australia demonstrate the importance of geomorphology in catchment management. They include: rates of hillslope erosion and translocation of P in micro-catchments within a drainage basin context; stream salinisation; accumulation of heavy metals in stream sediments; geomorphic elements influencing the spread of weeds and the erosion of access tracks; and some relationships between valley-side land uses and stream morphology. The incorporation of these and other issues in a management strategy is then illustrated. Complex skills are involved in producing and implementing a management strategy, including but extending well beyond those of the geomorphologist.