About the Project
"Very large climate shifts have affected the Himalayan area including Nepal, parts of India and Tibet, focussed on drier, warmer winters and shorter, and more intense monsoon rainfall. This project will investigate environmental change impacts on groundwater resources in Central Nepal (southern side of the Kathmandu valley). The area has already suffering water shortages due to low winter base-flows in some of the main rivers due to loss of glaciers, which leads to increased reliance on the base-flow from groundwater. Natural springs of are the main water resource for this region; some of the large springs are also very important for hydropower generation, for both rural communities and for the city of Kathmandu. During recent years, many of these springs (including some of the very large ones) have shown rapidly decreasing flow and others have dried up. Reduction in spring flows is likely to be associated with long-term environmental changes in rainfall, evapotranspiration, and runoff (a result of both anthropogenically-induced changes in the regional climate, and more local factors such as land use change). Predicting whether such trends are likely to continue into the future is very important for water, food and energy resources in the area and more widely in the Himalayan region.
Objectives:
The study area lies in the Lesser Himalaya region of Nepal, which consists of mainly metamorphic rock types of limestone, slate, phyllite, metasandstone, schist and quartzite and some granite intrusions, all of which are often extensively tectonised; spring locations and catchment areas are hence controlled by geological structure and stratigraphy. In this project, the student will work with leading scientists at Leeds and Tribhuvan University, Kathmandu, Nepal, to establish whether further long term changes in groundwater balance in the region are likely, to predict impacts on the perennial spring water resource used for agriculture and hydropower generation, and to identity potential mitigation strategies. The student will investigate the nature of aquifer permeability development, flow mechanism and water residence time, try to establish the causes of the recent reduction in spring flows, and attempt to predict whether these will continue into the future.
According to the student’s particular research interests, the studentship could involve:
1. Analysis of historical climate and hydrological data to establish key temporal and spatial trends in rainfall, ET, streamflows, in order to establish the extent to which the regionally-evident recent climate change is apparent in the local area.
2. Characterising the residence time of the perennial spring aquifers using geochemical tracers, e.g. sampling 5 to 10 groundwater spring sites including both ephemeral and perennial springs , in order to investigate seasonal changes in water source/catchment area and residence time. Aspects may include major ions and isotopes of S and O in sulphate and C in bicarbonate which help constrain water source, as well as stable oxygen isotopes in water, and chlorofluorocarbon/sulphur hexafluoride analysis to constrain groundwater residence times.
3. Identification of aquifer permeability structure at the spring sites to understand storage and transmission properties. Geological and topographic data will be used to delineate spring catchment areas and construct geological models of spring catchments, i.e. representations of the key lithological units and their likely permeability characteristics, including the nature of the permeable pathways developed in the aquifers feeding the springs (e.g. permeable rock matrix / fractures / conduits), and the geological and topographical controls on spring location. This could include outcrop characterisation or geophysical approaches depending on the experience and background of the student (see Kilner et al, 2005; Medici et al, 2015; 2016).
4. Analysis of predictive scenarios for future regional climate for their effect on the regional and local water balance. A range of approaches will be investigated including extrapolation of historical trends in regional rainfall and evapotranspiration, use of IPCC climate change scenario data for the region (predicted changes in ET/rainfall pattern) to predict future resources.
5. Identification of potential societal impacts and mitigation measures. The feasibility and likely effectiveness of mitigation measures such as engineered artificial / enhanced recharge, and social mitigation measures will be investigated."
http://www.nercdtp.leeds.ac.uk/projects/index.php?id=467
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