Traditional hydrological risk estimation has treated the observations of hydro-climatological extremes as being independent and identically distributed, implying a static climate risk. However, recent research has highlighted the persistence of multi-decadal epochs of distinct climate states across New South Wales (NSW), Australia. Climatological studies have also revealed multi-decadal variability in the magnitude and frequency of El Niño/Southern Oscillation (ENSO) impacts. In this paper, examples of multi-decadal variability are presented with regard to flood and drought risk. The causal mechanisms for the observed variability are then explored. Finally, it is argued that the insights into climate variability provide (a) useful lead time for forecasting seasonal hydrological risk, (b) a strong rationale for a new framework for hydrological design and (c) a strong example of natural climate variability for use in the testing of General Circulation Models of climate change.

Item Type:	Refereed Article
Keywords:	flood, drought, ENSO, rainfall, hydrology, IPO, PDO
Research Division:	Engineering
Research Group:	Environmental Engineering
Research Field:	Environmental Technologies
Objective Division:	Environment
Objective Group:	Land and Water Management
Objective Field:	Land and Water Management of environments not elsewhere classified
Author:	Franks, SW (Professor Stewart Franks)
ID Code:	93392
Year Published:	2004
Web of Science® Times Cited:	15
Deposited By:	Office of the School of Engineering
Deposited On:	2014-07-31
Last Modified:	2014-07-31
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