Nature-based solutions for flood mitigation

By Laura Kvigstad, Auckland Council reporter. Public Interest Journalism funded through NZ On Air.

Auckland Council has been urged to change its approach to planning for the effects of climate change.

At a Planning, Environment and Parks committee on May 4, Forest and Bird freshwater representative Tom Kay advocated for a nature-based planning approach.

“Having big stop banks with concrete walls puts communities at risk behind those stop banks or next to those streams,” he said.

“We know that giving rivers more space means more space for habitat, lower flood waters and communities at lower risk of flooding.”

Kay said reports going back to 1988 suggested deforestation and wetland draining had intensified flooding events.

“We have lost 90 percent of our wetlands across the country – we have done the same thing to forests. Forests, like wetlands, absorb rainfall and slow down water in the landscape.

“International studies show that allowing a river to self-adjust is cheaper and more effective than active interventions that force a river into a particular place.” Cr John Watson said the cost of land was a major barrier to nature-based solutions.

“North Shore City Council, and some of the old borough councils, had that kind of green infrastructure because, in some respects, it was not worthwhile building on that land,” Watson said.

“What would you advise Auckland Council do in terms of that green infrastructure acquisition in light of very high land prices?”

Kay acknowledged the difficult economic and cultural situation in Auckland Council.

“Private property rights and inflated land values make this kind of thing very difficult for councils that have historically had relatively low rates and, therefore, limited funds,” Kay said.

“You should be looking to central government for support in your flood protection infrastructure so you can do things differently over a longer period.”

Kay said Wellington City Council had spent $100 million to acquire properties in a flood-prone area because the cost of a flood would be over $1 billion.

“There will be situations where the cost benefit would probably work for Auckland Council.”