Build green infrastructure, not just gray

It remains to be seen if Congress can agree to fix our crumbling roads, bridges and water pipes. But if they do, insist that green infrastructure be part of it: riverside parks that can handle flooding, restored forests to filter our water, and even concrete that can sequester carbon.

Research published in 2017 showed that green infrastructure can be dramatically cheaper to maintain than gray infrastructure. That makes intuitive sense, because forests and fields are living things that grow, while pipes and sidewalks crumble and decay, although in practice, almost all green projects are a blend of green and gray.

When I did a study tour to Curitiba, Brazil in 2004, I learned how they redirected federal dollars intended to wall off the river and instead bought up land along it to divert and slow flood waters. If you wall off the river, you just send a concentrated pulse of water down hill, making it someone else’s problem, like a child pulling up the edges of a table cloth to direct spilled milk toward a sibling. One of their principles was “every river has the right to flood.” So they built lovely parks designed to flood, honoring different ethnic groups that immigrated there. The picture at the top of this post is their Polish Park. They also converted quarries that had become dangerous dumping and drug zones.

Around the same time, communities around Portland, Oregon, were finding it was cheaper to restore the watershed than to build water treatment facilities. Here’s one study.

We also need to design for climate resilience: higher sea levels, extreme weather and warmer temperatures.