Trends in Extreme Rainfall Events in Tasmania, Australia

Speaker: Ataur Rahman

Affiliation: University of Western Sydney

Time: Monday 16/03/2015 from 15:00 to 16:00

Venue: Access Grid UWS. Presented from Penrith (Y239), accessible from Parramatta (EB.1.32) and Campbelltown (26.1.50).

Abstract: Climate change will affect various aspects of hydrological cycle such as rainfall. A change in rainfall will affect flood magnitude and frequency in future which will affect the design and operation of hydraulic structures. In this paper, trends in sub-hourly, sub-daily, and daily extreme rainfall events from 18 rainfall stations located in Tasmania, Australia are examined. Two non-parametric tests (Mann-Kendall and Spearman’s Rho) are applied to detect trends at 10%, 5%, and 1% significance levels. Sub-hourly (6, 12, 18, and 30 minutes) annual maximum rainfall events have been found to experience statistically significant upward trends at 10% level of significance. However, sub-daily durations (1 hour, 3 and 12 hours) exhibit decreasing trends and no trends exists for longer duration rainfall events (e.g. 24 and 72 hours). Some of the durations (e.g. 6 minutes and 6 hours) show similar results (with upward trends) for both the tests. For 12, 18, 60 minutes and 3 hours durations both the tests show similar downward trends. This finding has important implication for Tasmania in the design of urban infrastructure where shorter duration rainfall events are more relevant for smaller urban catchments such as parking lots, roof catchments and smaller sub-divisions.

Biography: Assoc Professor Ataur Rahman has over 20 years experiences in water industries, research and universities in Australia and South-east Asia. He obtained his PhD degree in Hydrology from Monash University in Australia. His research interest includes flood hydrology, urban hydrology and environmental risk assessment. He received ‘The G. N. Alexander Medal’ from the Institution of Engineers Australia in 2002. He has published over 230 research papers, reports and book chapters in water and environmental engineering field. He is acting as Project 5 Leader (Regional flood methods) in the forthcoming revised version of Australian Rainfall and Runoff (ARR). He is serving in the editorial board of Australian Journal of Water Resources and international journal Water.