Elevated drought risk due to multi-decadal climate variability

This study investigates multi-decadal variability of drought risk by analysing the performance of a water storage reservoir in New South Wales, Australia, during different climate epochs defined using the Inter-decadal Pacific Oscillation (IPO) index. The performance of the reservoir is also analysed under three adaptive management techniques and these are compared with the current "reactive" management practices. The results indicate that IPO modulation of both the magnitude and frequency of El Niño/Southern Oscillation (ENSO) events has the effect of reducing and elevating drought risk on multi-decadal timescales. The results also confirm that adaptive reservoir management techniques, based on ENSO forecasts, can improve drought security and become significantly more important during dry climate epochs. These results have marked implications for improving drought security for water storage reservoirs. A possible explanation for the extreme drought in Australia during 2002/2003 is also suggested.