Professor Sivapalan has made significant theoretical breakthroughs towards predictions of ungauged catchments - without calibration, which is the current standard. He enjoys a worldwide reputation for his work on the effects of spatial heterogeneity and scale in hydrologic modelling. With sustained support from state water agencies and mining companies, he has exploited these breakthroughs in developing his large catchment model (LASCAM), for prediction of floods, sediments, nutrients and salinity, for sustainably managing catchments - the first such model developed in Australia. His achievements have propelled him to the top of his profession in Australia and internationally, to being one of only 120 scientists worldwide so far inducted into the International Water Academy in Oslo.