Floods are inevitable. Flood disasters are not

Friday, 3 February 2023

Rivers bursting their banks, flash floods and more intense cyclones – how climate change is making floods more extreme.

Dr Richard Smith is the director of the Resilience National Science Challenge, a government-funded research programme with a mission to accelerate Aotearoa New Zealand’s resilience to natural hazards.

OPINION: The intense rainfall last Friday resulted in alarming levels of damage, disruption and distress in Tāmaki Makaurau Auckland and surrounding regions.

We have seen what a storm super-charged by climate change can unleash on an under-prepared city.

Those who study natural hazards often say there is no such thing as a “natural” disaster.

Natural hazard events such as floods are inevitable. Whether they create a disaster is dependent on the many decisions we’ve made as a society, long before it started raining.

* Sudden and savage: Auckland's rainfall sets a 'new benchmark'

Post-flood salvage underway at an Auckland business. The country needs to adapt to a new reality that doesn’t have us forever in clean-up mode, writes Richard Smith.

* What now for Auckland? Four ideas for a more climate resilient city

Were people located in harm’s way? Did they have the means to make themselves safer? Did they have the information they needed? Were our response systems ready?

Tāmaki Makaurau Auckland has experienced several damaging storm and flood events in recent years, notably the series of storms that flooded New Lynn in 2017 and the damaging winds in April 2018 that saw 120,000 households lose power.

Friday’s event was unprecedented for Auckland, in terms of rainfall intensity and the widespread impacts.

Yet the lessons from previous events were identified at the time. Were they learned and implemented to increase Auckland’s preparedness and reduce the known risks?

With the seemingly unending rain of Auckland’s summer, the city needs to be thinking of change and investment across multiple fronts to make sure it can cope with the new reality of climate change, writes Richard Smith.

As climate change worsens, we’ll see more of these types of events. We need to invest now in our future resilience to lessen the scale of disruption and make recovery faster.

This means reassessing the systems supporting our cities and towns to understand how we can be better prepared.

This has implications for planning, design, building and engineering, right through to community engagement, emergency management, communications and welfare.

What could a more resilient Aotearoa New Zealand look like? Let’s imagine.

We plan well, so new homes and buildings are out of harm’s way.

We can expect more extreme weather events. Investing in our resilience can lessen the scale of disruption and make recovery faster.

We have developed fair ways of retreating from exposed locations we built in earlier times when the hazards were not considered adequately.

Our urban areas are designed with porous surfaces and green spaces to soak up excess water.

We invest in resilient infrastructure so our transport, water, power and communication networks hold up when extreme weather hits, or can be quickly restored.

People receive timely and meaningful weather warnings, and have the information they need to plan, prepare and respond.

The push to address problems arising from housing developments being built in flood-prone areas doesn’t need to wait for new legislation.

Māori communities are empowered to plan and prepare in accordance with their culture, knowledge and aspirations.

We support the most vulnerable people in our communities, to help them reduce their exposure to dangerous hazards.

Researchers are working together with a wide range of agencies and groups, and delivering knowledge and tools to help realise our aspiration of a resilient Aotearoa New Zealand.

Let’s look at a few specific examples.

A research team led by Dr Sally Potter of GNS Science has conducted research into the most effective ways to communicate hazard warnings.

Dr Richard Smith is the director of the Resilience National Science Challenge.

They found that if agencies include information on the impacts (such as the potential to flood roads or take out power) as well as the weather itself (i.e. rainfall intensity or wind speeds), this can help people relate to and act on the warning.

Much has been said about housing developments being built in flood-prone areas. Research from Dr Judy Lawrence and others has shown that we don’t need to wait for the new Strategic Planning Act and Climate Adaptation Act to address this issue.

Their guidance shows how councils can use existing legislation to control development and avoid further exposure to climate risk.

The infrastructure networks that support our daily lives are interconnected and complex.

Civil engineering researchers at the Universities of Auckland and Canterbury have identified how “loss of service” can occur due to a damaged component, then spread within a network and across into other networks that rely on that service (such as loss of power impacting a wastewater network).

These findings can help improve the resilience of the networks and the communities they service.

When decision-makers adopt solutions that are based on research, we get closer to our goal.

Unless we adapt to our new reality, we will constantly be in clean up and recovery mode. We will fall behind in our ability to maintain liveable cities, towns, and infrastructure.

Last Friday’s event is shaping up to be our costliest flood. Research tells us that for every dollar invested in reducing disaster risk, we save at least $6 on clean up and rebuild costs following a major event.

More importantly, we avoid widespread human suffering that can have ripple effects for decades.

Last weekend demonstrated the power of collective action in responding to crises – neighbours, family, and friends helping each other, and local leaders and volunteers working around the clock to meet their communities’ needs.

We need a similar collective approach in choosing to make resilience and risk reduction a priority, before the next big storm arrives.