Two weeks ago I attended a conference held by a local non-profit organization, Park Pride, focusing on creating greenspaces that capture and store rainwater, act as flood swales and coastal buffers from storms, and meet the challenges presented by climate change of rising seas levels, sporadic weather events, and increasing temperatures. Many of the concepts and case studies presented revolved around huge projects that have huge impacts on the cities in which they were installed. Perhaps more interesting though, and more amazing, was the presentation given by Brad Lancaster. He described how he and a few others in his neighborhood in Tucson, Arizona transformed their community by simply creating small greenspaces in the parkways of their streets.
Lancaster recounted how Tucson drastically changed over the past century, from an area that was supported by the Santa Cruz river to one covered in impervious surfaces that experienced 100-year flood events every ten years. The car-centric development that evolved in America during this time frame drastically changed the local water table and resources available, meaning that water actually has to be transported from resources farther and farther away. “We ignore, deplete, or pollute our local waters — then import ever more distant water,” Lancaster stated, before adding that pumping water in Arizona is the largest expenditure of electricity, “and single source producer of carbon,” in the state.
We ignore, deplete, or pollute our local waters — then import ever more distant water
What Lancaster told us next was truly amazing. He noted that along a stretch of Arizona highway plant life flourished alongside the road, within about 9 meters on either side of the road. These plants of course were supported by the water running off the impervious asphalt, as compared to the more sparse plants further away from the road that only received direct irrigation from rainfall. He ran the numbers and found out that with an average 11 inches of rainwater per year, a single mile on an average street could support 400 native tree and plant species, capturing over one million gallons of rainfall per year. With only a few other members of the neighborhood, Lancaster planted native plants in the parkways of his street and made cuts in the street curbs, at that time an illegal activity, to allow water to flow from the street into the parkways.
The results were astounding. Lancaster and his community, by capturing the runoff stormwater in these small but strategic greenspaces, had planted not just trees, but had essentially planted the rain. The shade provided by the trees decreased peak summer temperatures by 5.5 degrees Celsius (10 degrees Fahrenheit). Edible plants were planted for the community to enjoy. Native species of birds were the first wildlife to return to the neighborhood.
With the success of their initial curb-cutting plain to see, Lancaster and his community pushed to legalize curb-cutting in Tucson and succeeded; now for $45 any homeowner can get a permit to start their own street-side rain garden. More community members jumped at the opportunity and in doing so created small industries for cutting curbs, rain garden design and installation, pruning and chipping for mulch to fertilize the gardens, and even local food production and harvesting! Additionally, All of these benefits are in addition to the decreased water used by residents for irrigating lawns and gardens, ultimately resulting in decreased carbon pollution and energy use.
Lancaster and his community, by capturing the runoff stormwater in these small but strategic greenspaces, had planted not just trees, but had essentially planted the rain.
On top of all of these other incredible benefits, Lancaster showed us how planning stormwater management and roads with “green streets” saves money too. In Portland, Oregon in the early 2000′s, there were plans for a new drainage system in one of the city’s sub-watersheds based on conventional combined stormwater-sewage pipes, with an estimated cost of $144 million. A plan in 2006 for the same area utilized sustainable stormwater controls and green streets, and cost $58 million less than the original plan!
With no negative aspects, why haven’t these green streets been adopted more widely, especially as drought becomes more significant with future climate change? Maybe it’s just because more people don’t know about it yet. Share this so they can!
Image source: Brad Lancaster, “Regenerative Parks and Parkways: Local Harvests and Enhancements in our Community Commons.” 31 March 2014. http://www.slideshare.net/fullscreen/parkpride/regenerative-parks-and-parkways/1