Witold Krajewski, Professor
IIHR-Hydroscience & Engineering
The University of Iowa
Wednesday, September 30, 2009
3:00 pm: Conversation and Cookies in Room 108 Atmospheric Sciences Building
3:30 pm: Seminar in Room 114 Transportation Building
The speaker explores the role of rainfall variability and the associated rainfall estimation uncertainty in the context of flood forecasting. He uses a diagnostic framework of scaling of peak flows with drainage area. It has been know for quite some time that the annual statistics of flood peaks obey power laws with respect to areas. Less known is observational evidence that similar scaling relationships are valid at the event scale. Much of this evidence comes from data analysis of the recent June 2008 floods in Eastern Iowa. Data collected by the USGS from basins with area ranging over four orders of magnitude display strong power laws. This behavior of flood peaks can be explained by the role of the drainage network topology and the associated water transport. The speaker discusses the interplay of rainfall variability and the drainage network topology using the Iowa 2008 floods as an example. He closes with an outline of the implications of the presented framework for real time flood forecasting and for flood frequency prediction under changing climate.
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