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Dr Joshua Ahmed


Lecturer in Physical Geography

Telephone: +44 (0)20 7882 2753
Room Number: Bancroft Building, Room 2.01


As a fluvial geomorphologist, I get excited about rivers, how they function, and how they respond to changes in external controls – such as climate or land use. I am particularly interested in the morphodynamic evolution of large meandering rivers, such as those occupying the mighty Amazon Basin. I conduct my work using a combination of remote sensing (photographs captured by satellites orbiting the Earth’s atmosphere) and geographic information systems (GIS) to map changes in these exceptionally active river channels. Once these changes have been mapped, I attempt to link these changes to variations in sediment supply or hydrology. My interests also extend to the cause and effect of flooding in both natural and engineered settings and how we as a society may mitigate the impact of events in the latter case. My fascination with the natural world led me to where I am today, and I hope to inspire and instill some of my passion for this wondrous place we inhabit in the students I meet along the way.


I teach on courses spanning the broad area of fluvial geomorphology and physical geography as well as geospatial science. I aim to engage my students by adopting a range of teaching techniques that stray away from the simple ‘relax and take notes’ strategy often associated with university teaching, and try to create an interactive classroom experience in which there is plenty of opportunity for discussion. My broad areas of expertise are in fluvial geomorphology, catchment hydrology, and geospatial science all of which are reflected in my teaching. I aim to integrate cutting-edge research into my course materials so as to demonstrate what scientists are still striving to understand, whilst laying a firm foundation of the basics within each of these fields. My students can expect to be challenged by questions which have plagued, and will continue to plague, scientists’ past and present. They should also expect to be exposed to research techniques currently employed by myself and others who are trying to gain a better understanding of how our planet functions.


  • Green London Induction Project
  • GEG4003 – Geography in the World
  • GEG4004 – Research Methods for Geographers
  • GEG5212 – Environmental Research Methods
  • GEG5213 – Advanced Environmental Research Skills
  • GEG5223 – Geospatial Science
  • GEG5225 - Geomorphology
  • GEG7314 – Flood Risk Management and Modelling (Msc)


Research Interests:

My current research aims to understand the morphodynamic evolution of large meandering river systems in the Amazon Basin. I am attempting to demonstrate the linkage between sediment supplies – of which are highly variable in the Amazon Basin – and the rate of channel evolution across the basin as a whole. My work focuses on the role of point bars in meandering channel evolution and aims to describe the importance of these bedforms in sequestering sediment and accelerating channel change. My work exploits freely available satellite imagery which can be manipulated within a GIS to understand how river channels change through time. Additionally, the use of a morphodynamic meander model is employed to attempt to quantify and demonstrate the processes occurring within the channel with respect sediment supply, point bar growth, and channel change.

Aside from large meandering river changes, I am also interested in understanding channel change on smaller systems such as those in England and Wales. I have been working with colleagues from Cardiff University to monitor changes on a meandering river using aerial photography and a drone coupled to a hydrological record for the river.


  • Constantine, J. A., Dunne, T., Ahmed, J., Legleiter, C., and Lazarus, E. D., 2014, Sediment supply as a driver of river meandering and floodplain evolution in the Amazon Basin, Nature Geoscience, doi:10.1038/ngeo2282
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