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Impact of climatic variations on long-term sustainability of groundwater resources in Nepal

Dr Jared West (SEE), Dr Robert Newton (SEE), Dr Clare Quinn (SEE),

Project partner(s): Dr Moti Rijal (Tribhuvan University, Nepal)

Contact email: j.west@see.leeds.ac.uk

Climate shifts in recent decades have led to drier, warmer winters and shorter, and more intense monsoon rainfall (e.g. Rawat et al, 2011; Singh et al., 2011; Shrestha et al., 2015, see Figure 2) in the Himalayan area including Nepal, parts of India and Tibet (Figure 1). This project will investigate impacts on spring and groundwater resources in Central Nepal (southern side of the Kathmandu valley).  The area is already suffering water shortages due to seasonally low flows in some of the main rivers due to loss of glaciers, which leads to increased reliance on groundwater.  Natural springs and shallow tubewells are the main water resource for this region (Bricker et al., 2014); 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 decreasing flow and many smaller springs 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 deforestation). 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.

Figure 1.  Map of Himalayan region showing atmospheric circulation patterns (Shrestha et al., 2015)

Figure 2: Figure illustrating regional climate change affecting the Hindu Kush area including Nepal, i.e. changes in rainfall pattern and temperature (Singh et al., 2011).

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, you will work with leading scientists at Leeds and Tribhuvan University, Kathmandu, Nepal, to establish whether further decreases in spring and groundwater resources in the region are likely, to predict impacts on the year-round spring and groundwater resources used for agriculture and hydropower generation, and to identity potential mitigation strategies.  You will investigate the nature of groundwater flow pathways in the subsurface, the importance of fractures and rock weathering processes, and groundwater geochemistry and residence time, to try to establish the causes of the recent reductions in spring flows, and attempt to predict whether these will continue into the future.

Figure 3: Engineered structures for enhancing recharge, Nepal (http://www.sikkimsprings.org/ )

According to your particular research interests, the studentship could involve:

  1. Analysis of historical climate and hydrological data to establish key temporal and spatial trends in rainfall, evapotranspiration, and stream flows, 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 groundwater (groundwater age) using geochemical tracers, in order to better understand the resilience of springs etc to times of drought.  This will involve sampling 5 to 10 groundwater spring sites including both ephemeral and perennial springs, in order to investigate seasonal changes. Aspects will include major ions, isotopes of S and O in sulphate and C in bicarbonate which help constrain water source, as well as chlorofluorocarbon/sulphur hexafluoride analysis to constrain groundwater age (Newton and Bottrell, 2007; Bottrell et al., 2000; Baker et al., 2012).

  3. Identification of the nature of the subsurface flow pathways at the spring sites to understand the nature of these flow pathways, and underground storage reservoirs. Geological and topographic data will be used to delineate springsheds (catchment areas) and construct geological models of spring catchments, i.e. representations of the key lithological units and their characteristics, including the nature of flow pathways feeding the springs (e.g. permeable rock matrix / fractures / conduits), and the geological and topographical controls on spring location.  Work 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; Rijal, 2015).

  4. Analysis of predictive scenarios for future regional climate, for their effect on the regional and local water resources. A range of approaches will be investigated including extrapolation of historical trends in regional rainfall and evapotranspiration, and use of International Panel on Climate Change (IPCC) scenario data for the region (e.g. predicted changes in temperature/humidity/rainfall pattern).

  5. Identification of potential societal impacts and mitigation measures.  The feasibility and likely effectiveness of mitigation measures such as engineered artificial / enhanced recharge (e.g. see Figure 3), and social mitigation measures will be investigated (e.g. see Bromley et al, 2005).

Potential for high impact outcome

The proposed research has potential regional impacts for rural farmers, growing small towns, hydropower developers, water, sanitation and hygiene (WASH) program, governmental agencies and policy makers. The research has wider implications for understanding climate change impacts on water resources in monsoonal regions, such as those from changes in rainfall patterns & evapotranspiration; we therefore anticipate the project generating several papers with at least one being suitable for submission to a high impact journal.

Training

The student will work under the supervision of Dr. Jared West (IAG) and Dr. Robert Newton (ESSI) within the Hydrogeology and Engineering Geology research group, and Dr Clare Quinn (SRI), convenor of the Environment and Development Research Group.  Logistical support will be provided by Dr. Moti Rijal of Tribhuvan University, Kathmandu, Nepal, who has extensive fieldwork experience in the area; CFC and SF6 analysis will be conducted by the British Geological Survey.  This project provides a high level of specialist scientific training in: (i) analysis of hydrological data; (ii) geochemical analysis of waters from spring monitoring sites, including isotopic analysis and groundwater dating approaches; (iii) approaches for prediction of impacts of climate changes and their mitigation, including societal approaches to mitigation. Co-supervision will involve regular Skype meetings with the Nepalese partner, plus two field seasons in Nepal for groundwater sampling set-up and geological and hydrological fieldwork. The student will have access to a broad spectrum of training workshops put on by the Faculty that include an extensive range of training workshops in technical aspects, through to managing your degree, to preparing for your viva (http://www.emeskillstraining.leeds.ac.uk/).

Student profile:

The student should have a degree in geoscience or environmental science with a strong background in a quantitative science and a willingness to undertake fieldwork, and laboratory work in geochemistry.  We expect that the student will need to undertake 2 x 3 week field seasons in Nepal in order to select and characterise sampling sites and oversee data collection; support will be available for year-round sampling via the Nepalese Partner University and their contacts.

References

Baker KM; Bottrell SH; Hatfield D; Mortimer RJG; Newton RJ; Odling NE; Raiswell R (2012) Reactivity of pyrite and organic carbon as electron donors for biogeochemical processes in the fractured Jurassic Lincolnshire limestone aquifer, UK, Chemical Geology, 332-333, pp.26-31. doi: 10.1016/j.chemgeo.2012.07.029Bottrell SH; Moncaster SJ; Tellam JH; Lloyd JW; Fisher QJ;

S.H. BRICKER, S. K. YADAV, A.M. MACDONALD, Y. SATYAL, A. DIXIT AND R. BELL . 2014. Groundwater resilience Nepal: Preliminary findings from a case study in the Middle Hills. British Geological Survey Open Report, OR/14/069. 58pp.

Bromley J (2005) Guidelines for the use of Bayesian networks as a participatory tool for Water Resource Management. Management of the Environment and Resources using Integrated Techniques (MERIT). Centre for Ecology and Hydrology, Wallingford, UK. http://nora.nerc.ac.uk/3300/1/MERITGuidelinesplusApp.pdf

Newton RJ (2000) Controls on bacterial sulphate reduction in a dual porosity aquifer system: the Lincolnshire Limestone aquifer, England, CHEMICAL GEOLOGY, 169, pp.461-470.

Khatiwada KR, Panthi J, Shrestha ML  and Nepal S (2016). Hydro-Climatic Variability in the Karnali River Basin of Nepal Himalaya. Climate 2016, 4, 17; doi:10.3390/cli4020017

Kilner M; West LJ; Murray T (2005) Characterisation of glacial sediments using geophysical methods for groundwater source protection, J APPL GEOPHYS, 57, pp.293-305. doi: 10.1016/j.jappgeo.2005.02.002

Medici G; Boulesteix K; Mountney NP; West LJ; Odling NE (2015) Palaeoenvironment of braided fluvial systems in different tectonic realms of the Triassic Sherwood Sandstone Group, UK, Sedimentary Geology, 329, pp.188-210. doi: 10.1016/j.sedgeo.2015.09.012

Medici G; West LJ; Mountney NP (2016).  Characterizing flow pathways in a sandstone aquifer: tectonic vs sedimentary heterogeneities, Journal of Contaminant Hydrology, in press.

Newton RJ; Bottrell SH (2007) Stable isotopes of carbon and sulphur as indicators of environmental change:, Journal of the Geological Society, 164, pp.691-708. doi: 10.1144/0016-76492006-101

Rawat K.C , P.C. Tiwari  and C. C. Pant  2011. Climate Change accelerating hydrological hazards and risks in Himalaya: A case study through remote sensing and GIS modelling. INTERNATIONAL JOURNAL OF GEOMATICS AND GEOSCIENCES Volume 1, No 4, 2011

Rijal ML. 2015. The importance of springshed approach for the conservation of springs in Nepal Himalaya, Bulletin of Nepal Geological Society,32, 61-64.

Shrestha, AB; Agrawal, NK; Alfthan, B; Bajracharya, SR; Maréchal, J; van Oort, B (eds) (2015) The Himalayan Climate and Water Atlas: Impact of climate change on water resources in five of Asia’s major river basins. ICIMOD, GRID-Arendal and CICERO

Singh, SP; Bassignana-Khadka, I; Karky, BS; Sharma, E (2011) Climate change in the Hindu Kush-Himalayas: The state of current knowledge. Kathmandu: ICIMOD

Related undergraduate subjects:

  • Environmental science
  • Geochemistry
  • Geography
  • Geology
  • Geoscience