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CWEST Seminar: Estimating design floods in a warming climate: Gaps, challenges, and the way forward

Wednesday, September 07, 2016, 3:30PM - 4:30PM


Ashish Sharma

University of New South Wales


SEEC room S228

4001 Discovery Drive, Boulder, CO

We have a special hydrology and water resources seminar this afternoon, taking advantage of quick visit by Prof. Ashish Sharma, University of New South Wales, Sydney, Australia


A lot has been said and written about climate change and how it may make floods more frequent and extreme. In this talk I outline what needs to change in a warmer climate for design floods to change, present data based (as opposed to model based) evidence for all the changes till date, and present what I feel is the sensible way design flood estimation should be approached in this new climate we are in. Specifically, I show evidence for clear changes in the spatial and temporal patterns associated with extreme storms, along with an increase in design intensities for shorter duration events. These changes present the clearest evidence till date that design flood magnitudes for urban catchments across the world are increasing, a change that needs to be accepted and factored into our planning guidelines urgently given the implications this has to our existing stormwater infrastructure and society in general.

Some recent publications that will form the basis for much of this talk are:

  • Wasko, C. and A. Sharma (2015). "Steeper temporal distribution of rain intensity at higher temperatures within Australian storms." Nature Geoscience 8(7): 527-529.
  • Wasko, C., A. Sharma and F. Johnson (2015). "Does storm duration modulate the extreme precipitation-temperature scaling relationship?" Geophysical Research Letters 42(20): 8783-8790.
  • Wasko, C., A. Sharma and S. Westra ( 2016). "Reduced spatial extent of extreme storms at higher temperatures." Geophysical Research Letters 43: 4026-4032.
  • Woldemeskel, F. and A. Sharma (2016). "Should flood regimes change in a warming climate? The role of antecedent moisture conditions." Geophysical Research Letters 43. 

More details about me are available at my LinkedIn page or department bio.