Improving flood predictions

Barnaby Pace has been exploring regional hazard management.

It is expected that climate change will increase the likelihood of heavy rainfall events, because warmer air carries more water. The Ministry for the Environment is already starting to predict the effects of climate change on potential flood heights. More flooding will have greater capacity to damage housing, infrastructure and farmland.

Barnaby Pace, with Nicholas Whittaker from Victoria University of Wellington, has developed a flood modelling tool which takes climate change variables into consideration. They used the flooding of the Waikato River in and around Hamilton in 1998 as a case study. Using data from that 1998 flood event, they predict that climate change could cause:

  • a 0.656m increase in peak flood height (or more, if a storm were to occur when the river was already running high after previous rainfalls)
  • an 8% increase in average river level due to increasing standard rainfall events

Barnaby hopes that this tool will help identify potential future flood zones and plan accordingly. Hamilton City Council has already used the model to determine river levels in recent storm events, and to check that further damage would not occur after a water mains failure when a riverbank collapsed.

April 2018

Image credit: Phillip Capper, used under Creative Commons licence CC BY 2.0