Flood mitigation schemes: are they working in flood-prone areas?

Economic losses from flooding are substantial in New Zealand and are projected to increase. Floods have caused almost $300 million in damages since only 2014 (not including the New Year floods of 2017/18), with particularly disruptive impacts on homes and farming.

The most common method of managing flood risk in New Zealand is through flood mitigation schemes, in which flood-related infrastructure is funded via targeted property rates and government budget. However, many of these schemes were implemented last century, with mounting evidence that land use and population changes render them insufficient for future risk. There is also a surprising lack of research on these schemes.

This research explores several important and new research questions related to flood mitigation schemes. We have explored whether or not all flood-prone settlements have schemes in place – and have catalogued and mapped flood mitigation scheme locations using regional council data. Additionally, we are investigating whether flood mitigation scheme funding is adequate, by analysing data on flood damage claims and property rates. We will use this information to identify possible improvements in the system.

We also aim to understand whether flood mitigation schemes are sufficient to protect exposed communities from increased flooding due to climate change. Economic modelling is helping us to investigate the costs and benefits of flood mitigation schemes, comparing flood risk management in areas with mitigation schemes to areas without such schemes.

This project in the media:
Improving flood management BuildNZ
Treading water LGNZ Magazine
No time to delay on adapting to climate change Nelson Mail
NZ needs to do more before we get caught out by climate change NZ Herald