Study area: The Mekong River Basin
The Mekong River Basin is a large international river basin (almost 800,000 km2) and is shared by six countries: China (Yunnan province, Lancang sub-basin), Union of Myanmar, Lao PDR, Kingdom of Thailand, Kingdom of Cambodia and Viet Nam.
More than 70 million inhabitants live in this basin, mainly in rural areas and, consequently, the livelihoods depend to a significant extent on agriculture.
The rapidly growing population (about 2% per year) causes often conflicting demands on the water and land resources, in particular in the lower Mekong River Basin.
Fortunately, the riparian countries recognised the need for a collaborative and integrative water resources management long ago. The Mekong River Commission (focus on lower part of the river basin; established in 1995) can look back on a history of coordinating and planning water resources development of over 50 years in this region.
Recent attempts and developments have been bringing the upper part of the basin closer to the other countries and their regional cooperative development approach.
The water resources availability varies widely in space and time in this river basin due to the monsoon rainfall pattern and the variability in the physiographic characteristics (topography, geology, soils, land use etc.). The total discharge varies significantly with an average of 25,000 m3/s during the rainy season (July-November) and only 2,000 m3/s during the dry season (December-March). The water resources as a whole are not fully developed and to some extent poorly understood (e.g. groundwater resources), but there are several issues related to the water resources such as (Chu Thai Hoanh et al. 2003, IPCC 2007):
- Further development of irrigation connected to further intensification of food production (change of cropping pattern, increased dry-season production, calendar, more harvests per year, increased fish production);
- Floods and flooding with increase damage potential in the last years;
- Reduction of low flows due to (mainly agricultural) water use upstream and consequently increased sea water intrusion in the delta region;
- Hydropower development (proposed or under development) with unequal benefits across the riparian countries and sectors involved;
- Land use changes (e.g. deforestation and maybe local reforestation efforts as adaptation measure; local urbanisation) with impacts on local and regional water cycle dynamics;
- Rapid population growths and economic development impacts water resources quality (surface water and groundwater); and
- Climate change has been evident over past decades and it is likely to cause further shifts in the monsoon weather patterns with increasing floods (more intense rainfalls) and droughts (longer and more severe dry spells), increased number of tropical cyclones, more severe heat waves in particular in larger urban areas, and possible more extensive ENSO phenomena with impacts on the regional climate; on top of that sea levels will rise with significant impacts on coastal regions.
All these issues make the development of well-informed, scientifically sound adaptation measures in the whole river basin essential. Water is key in that respect. The vulnerability to climate change makes this river basin a suitable study area for the post-doctoral programme. Increasing the knowledge base about the interplay of climate change and other changes (with various poorly understood positive and negative feedbacks) in this river basin through well-targeted, interdisciplinary scientific research is essential for future sustainable planning and development of water resources. This needs an integrative water research approach as the adaptation measures cut across all sub-disciplines of watershed sciences including natural sciences, engineering and social sciences. Existing research activities in the area will be the starting point for the programme.