By The Hon. Eugenie Sage, Green MP, and environment and local government spokesperson
Recent intense severe weather events in Northland, Auckland, Coromandel, Nelson, Buller, the East Coast/Tairāwhiti, and Hawke’s Bay have highlighted the need to improve resilience, and rethink how we can better provide for community safety and wellbeing.
Climate change has worsened weather events and their impacts. We know that the frequency and intensity of severe weather events will increase, and that we need to adapt in a way that is fair, just, and inclusive.
Cyclones Hale and Gabrielle, as well as other storms, have had huge social, cultural, economic and environmental impacts. Flood flows and forestry slash have made homes uninhabitable, taken out bridges and roads, compromised electrical substations and city water supplies, pockmarked hills with slips, made roads impassable, and blanketed land important for food production with silt. Climate change is having real impacts on individuals, communities and our country right now. The recent storms have highlighted the vulnerability of our settlement patterns, roading, transport, energy, water supply, wastewater and other systems.
Adapting to a changing climate, and improving the resilience of people and places, requires a greater focus on, and understanding of, the importance of our most essential infrastructure – nature. Human life and wellbeing relies on clean air to breathe, clean water to drink, and healthy soils and sunshine to grow the food we eat. We are nothing without the ecosystem services that nature provides for free.
Nature-based solutions are a cost-effective method of building resilience, retaining beauty and natural landscape features, and providing habitat to support native plants and wildlife, while conserving water and moderating flood flows.
Urban and agricultural development, farming and river engineering have all reduced the physical area of river flood plains, reducing their ability to contain large floods and also recharge aquifers in areas such as Hawke’s Bay and Canterbury. Ensuring rivers and streams have room to move over their flood plains, and avoiding intensive development on those flood plains, works with nature rather than against it to reduce future flood impacts.
Wetlands are sponges in the landscape, soaking up run-off and rain, and filtering water. They provide habitat for native plants and wildlife. Yet, since 1840, we have destroyed more than 90 per cent of the extent of natural wetlands, and their capacity to absorb and filter run-off. Implementing Forest & Bird’s goal of doubling the extent of our wetlands by 2050 will reduce flooding and improve water quality, while increasing wildlife habitat.
Waiatarua wetland, in the Auckland suburb of St Johns, is a large urban wetland restoration project. Each year, it prevents an estimated 130 tonnes of sediment and contaminants from entering the Waitemāta Harbour because it filters stormwater run-off through bunds and sediment traps, before it flows into the Ōrākei Basin and harbour. During the Auckland Anniversary weekend storm, Waiatarua wetland, and the swales and constructed wetland at nearby Stonefields, became large watery expanses. By storing large volumes of water, these wetlands helped reduce peak flows, avoided overloading the stormwater network and prevented flooding.
We need to create space for water beyond pipes. The ‘sponge city’ concept, where green spaces, wetlands, permeable pavements, rain gardens, planted swales and streams collect water to prevent flooding, was promoted by Chinese researchers more than 20 years ago. Singapore receives intense rain, and flooding was common in the 1960s and 1970s. Since then, establishing a network of urban ponds, streams and green spaces has reduced the frequency of flooding.
Making our cities and towns more ‘spongy’ is cost‑effective green infrastructure with additional benefits for biodiversity and livability. It involves more permeable surfaces instead of concrete and asphalt, more urban vegetation and green roofs, and more unbuilt green spaces that can act as overland flow paths and retention basins for stormwater. Streams are given room to move, instead of piping them underground.
Christchurch City Council has constructed several new wetland areas in the south-west of the city to act as storage basins in large rain events. They capture sediment-laden run‑off from the hills, filter stormwater and improve the quality of water flowing into rivers. These new wetlands, in areas where water once ponded on farmland, have helped reduce the flooding risk to homes and roads beside the Ōpāwaho Heathcote River. Thousands of native plants are attracting birds and other wildlife, and the wetlands are popular for walking, cycling, and enjoying nature.
Similarly on the coast, restoring coastal estuaries and wetlands can help buffer roads and homes against rising seas and coastal erosion, while protecting mangroves helps reduce wave intensity.
Urban trees are also valuable green infrastructure that deserve greater recognition and protection. The shade and evapotranspiration that mature trees provide cools surface temperatures and reduces the urban heat island effect. Urban trees protect people from exposure to high levels of ultraviolet radiation. They sequester carbon, buffer noise and wind, and help reduce air pollution, benefiting human health. And, of course, mature urban trees intercept rain, which helps reduce the volume and intensity of surface water run-off entering stormwater systems.
Vitally, this requires trees to be protected on private land. In Auckland, only 15 per cent of trees on private land are protected, yet they make up two-thirds of the city’s entire urban forest.
Hard infrastructure that uses concrete, steel and similar materials obviously has a role, but we would benefit from a fundamental shift in the design ethos to work with nature rather than always imposing on it. This would increase the livability of cities and towns, increase climate resilience and be cost effective. This change requires engineers to work with ecologists, hydrologists, botanists, coastal scientists, landscape architects, and holders of mātauranga Māori to understand natural processes and patterns, what is happening in a landscape, and cultural connections with land and water before starting any design work.
Climate change needs to be a central focus in the planning, design, development and building of all infrastructure. We need to ensure that buildings and their surroundings are designed, constructed, renovated, and repurposed to better provide for people’s wellbeing and mitigate climate change. The way we design and grow the places where we live, work, and play – and our transport, energy and telecommunications networks – will affect our exposure and vulnerability, and our ability to cope with the impacts of climate change. Climate-resilient infrastructure will help reduce direct losses and reduce the costs of disruption caused by severe weather events – intense drought and fire, rising seas and floods.
Nature-based solutions are part of Aotearoa New Zealand’s first National Adaptation Plan (NAP), which was released in August 2022. It brings together the government’s current efforts to build climate resilience and sets out a future work program, including the government’s priorities over the next six years. Minister for Climate Change the Hon. James Shaw says the actions in the plan, ‘are intended to drive a significant, long-term shift in our policies and institutional frameworks. They will ensure climate-resilient development in the right places and better support communities in considering a range of adaptation options’.
Chapter four of the NAP deals with adaptation options, including managed retreat. One of the NAP objectives is to ‘Support working with nature to build resilience’, with a critical action being to ‘prioritise nature-based solutions in our planning and regulatory systems to address the climate and biodiversity crisis together’. This can include restoring and protecting ecosystems, identifying sites that can be a buffer against climate risks and supporting communities in understanding nature-based solutions as a choice for adaptation. The Department of Conservation and the Ministry for the Environment are tasked with developing a framework for nature-based solutions, and prioritising these in planning and regulations for both carbon removal and climate change adaptation.
The Ministry of Transport is the lead agency for Action 8.7 in the NAP to ‘embed nature-based solutions as part of the response to reducing transport emissions and improving climate adaptation and biodiversity outcomes’.
The absence of any substantive reference to nature-based solutions in the Te Waihanga (the New Zealand Infrastructure Commission) Infrastructure Strategy for the next 30 years is disappointing and a major gap, though the strategy does talk about considering and prioritising non-built options when choosing how to address infrastructure challenges, such as using variable pricing to spread demand between peak and off-peak periods.
The NAP tasks Te Waihanga with scoping a resilience standard or code for infrastructure, and its potential costs and benefits, and whether such a standard would encourage risk reduction and resilience planning in new and existing assets. Any sensible scoping exercise should include nature-based solutions to encourage their use and recognise all the additional benefits they provide.