Research report

How exposed are we to river flooding?

This report is an initial assessment of the exposure of New Zealand to flood inundation. It highlights the need for a more extensive mapping of flood risks to infrastructure and, consequentially, the potential direct and indirect economic loss for flood exposed buildings.

The research builds on and improves national flood mapping carried out by the Parliamentary Commissioner for the Environment in 2015, and provides a comprehensive picture of the impact of coastal and inland flooding on our national infrastructure, including our buildings, roads, railways, airports, electricity transmission lines, water infrastructure and farms.

This maps inland flood risk against infrastructure, and finds, for example, that a staggering $135 billion worth of buildings are potentially exposed. Add to this almost 19,000 kms of roads, 1,500 km of railway tracks, 21,173km of water pipelines, 3,397 km of national grid transmission lines and 20 airports, and you begin to get a sense of the challenges ahead of us. But if we can accurately predict the areas of highest risk, we can better adapt, minimising harm to New Zealand’s population and economy.


National flood risks & climate change