University of New South Wales

Ashish Sharma is a Professor of Civil and Environmental Engineering at the University of New South Wales. He is an engineering hydrologist interested in problems involving hydrological uncertainty. Much of his research has focussed on the impact of climate change and variability on hydrological practice, along with applications related to remote sensing, formulating stochastic approaches, developing hydrological models, and the two big hydrology bread-and-butter problems - design flood estimation + water resources management. Most notably, Ashish has developed approaches for correcting systematic biases in model simulations, for generation and downscaling of hydroclimatic variables for impact assessment, and for short-term, seasonal and interannual forecasting using a mix of empirical and dynamical alternatives that facilitate a range of applications in hydrology and other disciplines. Ashish has served as the President of the International Association of Hydrologic Sciences (IAHS) Commission on Statistical Hydrology (ICSH), as a member of the Australian Rainfall and Runoff revision technical committee, as a member of the Australian Research Council College of Experts, and on the editorial board of prominent hydrology journals and conference organising committees. Ashish has graduated over 30 PhDs, many of whom are in reputed positions in academia and industry, and authored over 300 journal articles across all major hydrology and climate journals. More details about Ashish’s research products and software are available at

HS Distinguished Lecture | 01 August (Tue) 08:15 AM – 10:00 AM | Level 3 MR311

The Implications of Global Warming on Dams, Reservoirs, the Probable Maximum Precipitation, and the Probable Maximum Flood

Abstract: While there has been considerable discussion on how warmer temperatures are impacting high precipitation intensities worldwide, design of our critical infrastructure such as dams and nuclear power plants uses upper limits such extremes can assume. Limited guidance on such limits exists, with even lesser guidance on their likely changes that can be expected for these into the future. This presentation summarises the results of a large, industry supported study to assess change in probable maximum precipitation (PMP) and flood (PMF) extremes with expected changes in our climate. The presentation consist of two parts. The first part focusses on the need for better probability models that could be used to produce reliable estimates of the exceedance probabilities for such design extreme events, taking into account the very limited observations that are typically available to specify such models, as well as the fact that future changes are not restricted to event intensities alone, but also to the number of exceedances that are likely to be experienced into the future. The second part revisits existing guidelines for estimating PMPs worldwide, and outlines the nature of changes that are already visible and can be expected between now and the end of the century. It is demonstrated that such changes are going to be fairly consistent across varying climates and topographies, resulting in PMPs (and hence PMFs) that are 33% greater than now. What implications this has on the security and reliability of existing dams, what further implications need to be factored in when water supply reliability is factored in, and how we should approach the design and operation of large water resources infrastructure as we head to an era where temperature (and hydrologic) change will no longer be gradual, are discussed and options presented.