YANGTZE GEO II

WTZ China YANGTZE GEO II - Landnutzungswandel, Bodenerosion, Massenbewegungen und Stoffeinträge am Yangtze im Bereich der Drei Schluchten

01/06/2012 to 31/05/2015

The Three Gorges Dam (TGD) is among the most prominent human-induced examples for large-scale environmental impacts. Due to the flooding alongside the Yangtze River and its main tributaries, the region is largely characterized by an enormous boost of typical geo-risks such as soil erosion, mass movements, and diffuse matter inputs. Within the immediate reservoir area, the uphill-movement of farmers to the steep sloping uphill sites can result in a high conflict potential between the available and suitable land. Combined with a very steep topography, subtropical monsoon climate, and fragile soils, the population pressure and rapid ecosystem changes till foster the ecological and geological consequences and environmental risks of the TGD.
The subproject ‘Soil Erosion’, situated at the University of Tübingen, aims at a deeper understanding of the mechanisms and control factors of soil erosion by water in highly dynamic mountainous ecosystems. The study site is a small catchment (4.2 km²) close to Badong at the Yangtze River in the western Hubei province. The catchment is characterized by a mountainous relief and a steep sloping complex topography. Land-use is mainly characterized by farming on typically on more or less terraced farmland with contour cultivation. A specific modeling approach by means of monitoring, field investigations, the application of sampling designs, digital soil mapping (DSM), and digital terrain analysis will be developed in order to predict soil loss on the steep sloping land and the subsequent sediment pathways under changing land use and climate. In a second step the soil erosion risk potential will be analyzed for the reservoir area of the TGD towards Chongqing (30,000 km²). Worldwide in mountainous regions, terracing serves as key technology for suitable land management. Terrace maintenance and conditions control their functioning with respect to soil loss and food production. Therefore, new methods to incorporate terracing in soil erosion modeling serve as important tool for environmental and resource planning aiming at suitable land management.