Supervised by Professor Hugh Sinclair, Dr Mikael Attal, Dr Rachel Walcott
Research funded by the Natural Environment Research Council (NERC)
Many of the rivers of the Ganga Plains are prone to abrupt switching of channel courses (avulsion) causing devastating floods over some of the most densely populated regions on the globe. During 2008, a single channel avulsion event resulted in an eastward shift of the River Kosi by 60-100 km, resulting in extensive flooding and devastation to the millions of people living in these areas. Despite this, our understanding of the factors that control the dynamics of these river systems downstream of the mountain front is surprisingly limited.
In order to better understand the controls on the dynamics of rivers draining the Ganga Plains, my PhD aims to understand how the balance between sediment flux, grain size and basin subsidence rate varies across the Himalayan foreland basin. This balance will strongly control the degree to which channels are super elevated or incised relative to their floodplain, and thus their tendency to avulse.
Whilst fieldwork will form a large component of my PhD, I am also undertaking detailed topographic analysis of the Ganga Plains to quantify the spatial differences in channel and floodplain morphology. The main purposes of my fieldwork are to collect detailed grain size data from the modern river bed, and cosmogenic radionuclide samples from which to calculate sediment flux estimates. Given the cosmogenic signal variance measured in previous samples from the Himalayan mountain front, an additional investigation into the robustness of this signal will also be carried out.
Following the 2015 Gorkha earthquake, I have also been involved in a wider European collaboration researching the earth surface response to the earthquake.