Originally Posted by
Jantar
Why would you think the El-Nino would not be helpful for Hydro during this coming summer? All of the published literature tells us that flows tend to increase in the hydro lakes during El-Nino summers and decrease during La-Nina summers. This research goes back to McKerchar and Pearson (1994), McKerchar et al (1998).
El-Nino means stronger westerlies which in turn means wetter in the west and drier in the east, so drought is likely for Hawkes Bay, Central Canterbury, East Otago etc, but higher flows in the Clutha, McKenzie country and Manapouri.
Latest research is showing that the Pacific Decadal Oscillation has a greater effect than El-Nino and that is also positive. There are 2 papers (in press) that will be published later this year that show this stronger relationship.