Murugesu Sivapalan is an Australian-American engineer and hydrologist of Sri Lankan Tamil origin and a world leader in the area of catchment hydrology. He is currently the Chester and Helen Siess Endowed Professor of Civil and Environmental Engineering, and professor of Geography & Geographic Information Science, at the University of Illinois, Urbana-Champaign. Sivapalan is widely recognized for his fundamental research on scale issues in hydrological modeling, his leadership of global initiatives aimed at hydrologic predictions in ungauged basins, and for his role in launching the new sub-field of socio-hydrology.