Recent Floods a Sign of Things to Come says Professor

Recent Floods a Sign of Things to Come says Professor

University of Waikato Environmental Planning Professor Iain White is an international expert on water management. He says the recent floods in Wellington and Dunedin are a sign of things to come and says that NZ should manage.

1. the international rise in surface water floods and why this is happening in NZ

2. International best practice in managing surface water flooding, from flood resilient buildings to water sensitive design

Professor White says flood risk is shifting from rivers and the sea to urban areas and its time to look at how best to manage urban water the building and community level. He says climate change is making weather events more extreme, and escalating urbanisation is changing catchment behaviour so drains are expected to manage more water than they were designed for. In addition there are more and more surface water flooding events occurring internationally to the extent that it is gone from not even being recognised as a source of flood risk a decade ago to now being the main source of flood risk in many countries. New Zealand can learn from the harsh lessons other countries have had to deal with.

Surface water flooding occurs “through inadequate drainage in the urban area after heavy precipitation. In this case flooding is impossible to defend against with a wall by a river as the problem may not even reach the river.”

Professor White believes there are cost-effective ways to protect smaller settlements which may not warrant a big defence, or houses and streets which are subject to flooding from poor drainage.

Technologies can be fitted to homes and businesses, or temporary barriers can be put up around communities in a reactive fashion in response to weather predictions. The knowledge is there for properties to be kept dry in water up to around a 600mm in depth. This means that all but the worst floods can be managed. It is not a replacement for flood defence, rather a way to protect the areas where flood defences cannot reach or where it is not cost effective to do so.

Some of the ideas to produce flood-proof buildings include installing door and window guards and flood doors to prevent water entering through doors and windows, and installing sump and pump systems in basements in areas where there is surface and ground-water.

“As far as I am aware there is no one else doing this type of research in New Zealand,” says Professor White. “Surface water flooding is an emerging area here and this is a problem we are just starting to grapple with.”

Professor White is giving a lecture in Wellington on the 16 June on managing surface water flooding. He lectures in three papers at the University of Waikato: “Planning for Sustainability”, “Strategic Spatial Planning” and “Planning Theory”. His research focus is in environmental planning, adaptation to climate change and the effective management of water in society.

Professor White has also just finished a large international interdisciplinary project researching the development of flood-resilient buildings – looking at technical and design considerations, the materials involved in creating buildings that will withstand floods and what it might mean for people and planning.

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