PhD Research Project:
Scholarship and Funding Agency:
Swiss Government Excellence Scholarship funded by the Federal Commission for Scholarships (FCS)
Understanding of the seasonal snow and glacier meltwater influence on streamflow
Summary of the Project:
Glacier-fed rivers are the primary sources of fresh water for millions of people downstream in the Himalayas. Climate-change induced seasonal snow and glacier melt may have tremendous impacts on streamflow in such basins under the changing climate. Such impacts may be combined with anthropogenic interventions (e.g. hydropower) and land use changes. Not only are water resources likely to be significantly impacted but also natural hazards, notably glacial lake outburst floods or GLOFs. As a result, it is crucial to understand how snow and glacier melt during both the monsoon and non-monsoon seasons influences river discharge and its variation. Therefore, this project has following two specific research questions to answer,
Can the anatomical analysis of tree rings be used to reconstruct combined records of changing water supply and flood frequency in the Himalayan river basins?
2. What's the spatio-temporal extent of changing flood frequency and water supply?
To answer these two research questions, three specific methodologies are being used; (1) standard dendrochronology procedures for anatomical analysis of tree rings based upon measuring the annual and intra-annual (e.g. of earlywood and latewood) ring-widths, blue intensity from scanned images of tree cores to develop ring-width time-series; (2) application of statistical techniques including detrending to standardize the resulting time-series and to develop ring-width chronology and finally to reconstruct paleohydrology (e.g. of streamflow); (3) quantitative wood anatomy method for analysing xylem structures to detect damages in tracheid due to extreme events such as floods, landslides, earthquakes etc. A graphical representation of the methodology involved in this project is as follows;
Figure: Steps involved in sample pre-processing; starting from tree-coring (a), followed by gluing, mounting and drying them in room temperature (b), sanding selected samples (c), slicing remaining samples using a core-microtome (d), and scanning all samples using a prototype machine called “Skippy” (e) to produce digital images (f).
This research will provide scientific evidence to understand the evolution of streamflow, changing frequency and magnitude of extreme flood events in the Himalayan headwater catchments over a longer-time period in the past. The key findings will then be shared with local government officials to develop strategies for water resource management and flood risk mitigation.
PhD thesis is in progress and will be available soon.....