A study of spatially-distributed sediment supply, delivery and management in the Xihanshui River Basin, Gansu Province, China

The Soil and Water Conservation Project in the Xihanshui River Basin started in the late 1980s, and climatology, hydrology and sediment yield data from 1983 to 2005 have been collected for this thesis research, in order to be able to identify the trends in climate, and the effect of their interacting outcomes with the Soil and Water Conservation Project. Three scenario years based on the rainfall data were identified, to be used in SEDNET modelling; a dry year (1997), a wet year (1984), and an average year (2000). The four main sediment production processes: hillslope erosion, bank erosion, gully erosion and mass movement are discussed, as well as the floodplain deposition. All of these are the prerequisites for defining the element (subcatchment) sediment budgets in order to run SEDNET. SEDNET has also been used to examine alternative practices for targeting soil conservation initiatives, and a variety of tests is undertaken to assess the optimal strategy for selecting subcatchments for treating hillslope erosion, gully erosion and bank erosion in order to reduce sediment supply and yield. The progress of soil and water conservation in the Xihanshui River Basin since the 1980s has had a significant beneficial impact in lowering rates of sediment production and sediment yield. The use of a spatially-distributed modelling strategy allows identification of the relative effects of land cover changes and climate as controls of sediment yield, and provides a framework for guiding the implementation of conservation policy. There are some limitations to the SEDNET methodology, such as its steady state assumption, the lack of flexibility in its hydrological routines, and the lack of sub-models for some processes; however, this detailed application shows its considerable potential in sediment modelling for a large catchment.EThOS - Electronic Theses Online ServiceGBUnited Kingdo