SPEAKERS

Understanding the limitations in applying knowledge from geological, pre-European and contemporary epochs for navigating decisions about future flood risk management.


The experiences and knowledge of the past can help us make better decisions about the future. Whether things went well or things went badly the past provides insights about how we might modify our actions and systems to do better in the future. The relevance and applicability of past observations or lessons to a future scenario is related to how similar the environment and context of the past is relative to the future we are predicting. The bigger the difference between the past environment from which we are drawing lessons from and the future we are trying to prepare for, the more difficult it is going to be to usefully apply that knowledge.

Exploring these rather abstract concepts in terms of real world examples I will discuss what we can take from three distinct past epochs in terms of planning and managing future flood risk using examples from Hawkes Bay and the experiences of Cyclone Gabrielle.

Firstly considering the distant past in terms of river and floodplain processes as part of the building blocks of the natural landscape over geological time. Key points that will be reflected on for this epoch will be the different climate, land cover, sea levels and time scales that were evident as well as the lack of interaction with our social systems that did not exist during this time.

The second general period that is considered is the pre-European occupation and use of floodplains. For this I draw on the korero with mana whenua that was shared through the Cyclone Gabrielle review. This includes the seasonal nature of life during this period, with summer dry periods spent in marae and papakāinga by the rivers and coast and wetter winter months spent in the hills. Included in this korero is how and why this has changed and whether we can apply any of these principles to contemporary or future flood risk management.

The third period being discussed is modern contemporary New Zealand which includes the early settlement influences on river management and flood risk practices as well as observations of notable floods as well as seminal publications such as Neil Ericksen’s “Creating Flood Disasters”. Key points being considered are the design philosophies that were evident during this time, the value of assets being on floodplains, not paying attention to past floods and the past declarations of “no one should live in this area”. Examples will be discussed in terms of the Heretaunga stopbank system and development in the Esk and Tangoio valleys.

The various pieces of information that can be gleaned from these three past epochs is then projected forward to thinking about the future direction of flood risk management in New Zealand.