This study presents a multi-disciplinary approach for investigating the interactions between groundwater and surface water in the semi-arid Hailiutu catchment in the Erdos Plateau, Northwest China. The study consists of statistical detection of river flow regime shifts at the basin level; multiple in-situ measurements for quantifying groundwater discharges using hydraulic, hydrochemical and temperature methods at a local scale; analysis and simulation of impacts of different land use scenarios on groundwater and surface water interactions at the sub-catchment scale; and the quantification of temporal and spatial groundwater and surface water interactions with hydrochemical tracers and modelling methods at the basin scale.
The study found that the river flow consists of mainly groundwater discharges at all scales. The river flow regime has been intensively altered by human activities, such as the construction of reservoirs, water diversion, groundwater exploitation, and reforestation. Water use by plants and crops consumes majority of the precipitation. Groundwater sustains vegetation growth and feeds river discharges. The water resources and ecosystem management priority should reduce evaporative water uses by promoting dry resistant plant species for vegetating sand dunes and lower irrigation demand crops for socio-economic development. Furthermore, the Hailiutu River catchment must manage the groundwater recharge for water resource conservation and the maintenance of healthy ecosystems.
1.2 Research objectives and approach
1.3 Innovation and challenge
1.4 Thesis outline
2. The flow regime shift in Hailiutu River
2.2 Material and methods
2.3 Results and discussion
3. A multi-method approach to quantify groundwater/surface water interactions
3.2 Material and methods
3.3 Results and discussion
4. Groundwater-surface water interactions under different land use scenarios
4.2 Materials and methods
5. Groundwater and surface water interactions and impacts of human activities in the Hailiutu Catchment, Northwest China
5.2 Materials and methods
6 Conclusions, outlook and future research
6.2 Outlook and future research
IHE Delft PhD programme leads to a deepening of a field of specialisation. PhD fellows do scientific research, often with conclusions that directly influence their region. At IHE Delft, PhD researchers from around the world participate in problem-focused and solution-oriented research on development issues, resulting in an inspiring research environment. PhD fellows work together with other researchers from many countries dealing with topics related to water and the environment.
PhD research is often carried out in the ‘sandwich’ model. Preparation and final reporting – the first and last portion of the programme – are carried out in Delft, while actual research is done in the fellow’s home country, under co-supervision of a local institute. Regular contacts with the promotor are maintained through visits and long-distance communication. This enables researchers to employ solutions directly to problems in their geographical region.
IHE Delft PhD degrees are awarded jointly with a university. The degrees are highly valued and fully recognised in all parts of the world.