Sage argued that stormwater - which involves not just water pipes like freshwater and wastewater, but streams, floodpaths, gutters and parkland - is best left with councils because they are better equipped to do the complicated land use planning that stormwater requires.
Councils better understand the interaction between deliberately flooding parks, using flow paths, and streams as well as stormwater pipes, than an entity whose main focus is drinking water - so the argument goes.
“The lesson from big disasters like Auckland [floods] is in terms of promoting resilience, involving the community in how to plan for a more sustainable city,” Sage said, speaking to the Herald ahead of Cyclone Gabrielle hitting this week.
She said that Auckland Council’s review of the floods needed to look at “how stormwater is managed” and “what happens when you’ve got combined stormwater and sewer systems because that leads to overflow and sewage on beaches”.
“We’ve had massive housing growth in Auckland. We need to make sure we do density well that requires understanding natural drainage patterns, flood paths and how we need to make those systems more resilient,” she said.
Sage said one of the problems was that cities were becoming “hard” with the construction of large roofs, more asphalt and concrete.
“How do we provide the space for water to infiltrate,” Sage said.
She said this would require “more detention bases” or “rainwater basins”.
Sage said that cities had the ability to make better development decisions but they “haven’t always used them well”.
The Greens unsuccessfully tried to have urban tree cover considered in National and Labour’s joint housing legislation that was passed last year to enable more dense development in cities.
Sage said that while greater tree cover would not have prevented Auckland’s flooding they catch rainfall and allow it to infiltrate the ground more easily, slowing flooding.
