I was feeling a little over the top at the Cities Alive Conference, so as chair of the October 19 session on urban agriculture, I opened the event as a wedding ceremony.[rssbreak]
“Dearly beloved,” I intoned, and proceeded to join together sustainable urban design and food production.
I made a big miscalculation about the couple, who are really just newly-mets. The fact is, almost no one is growing food on rooftops in Toronto, as FoodShare’s Debbie Field points out later in the session. Skyward agriculture hasn’t risen to top of mind yet for green roof visionaries.
But you can see why I got excited.
The session just before mine is led off by California “starchitect” Paul Kephart from the firm Rana Creek Habitat Restoration and Living Architecture. He tells those gathered in the Sheraton conference room that finding natural ways to manage rainwater flow in an oceanside but water-deprived city like San Francisco has to become a crucial function of buildings.
“Lift up the park and put a structure under it” is his concept. Roofing becomes the first, not the afterthought, of green builders. His prize work atop a Frisco train terminal is a gigantic wetland that, as in nature, performs a variety of cleansing functions, starting with exhaust fumes that bubble up from the street to be purified by plants and sunlight.
All the rain that falls on the building, as well as all the water raised up from the air conditioners, is cleaned. Water from the roof handles all the building’s non-drinking-water functions, from toilets to floor-washing, which used to consume drinking water piped in from miles away.
Nigel Dunnett, director of the Green Roof Centre in Sheffield, England, shows off the world’s first nature reserve in a city, which offers the same range of and protection to biodiversity as in a countryside park.
From Chicago comes Jeffrey Bruce, designer of the largest green roof in the world, the monumental 24.5 acre Millennium Park atop a car park and train station. There’s nothing flat about this space, which incorporates a dozen features, from skating rink, outdoor theatre and café to open meadow and wetland.
For those who worry about the economics of job-generating green infrastructure projects, Bruce does some quick calculations on the return to the city government and private donors on the $475 million Millennium investment.
It’s a top Chicago attraction that gets as many as 4 million visitors a year. Those who pay to park their cars below repay the city bond taken out to finance the greenery, while nearby residents in the hottest real estate zone in North America repay city coffers through residential taxes.
The city also rents the entire roof out for corporate special events for $800,000 a day. The green dividends from on high also include relieving sewers of 59 million litres of stormwater, and 1,000 tons’ worth of evaporative cooling spread over the downtown on summer days.
Make no small plans, says Bruce, quoting historic Chicago architect Daniel Burnham.
Meanwhile, participants in the urban agriculture session I chair are trying to avoid the temptation to make big plans before the smallish details on the basics have been mastered. It turns out that not all building walls can bear the extra load of soil on roofs, especially the box stores thrown up for the lowest price to move discounted goods.
There are also security and safety issues with having so many people on roofs, issues that planners are still wrestling with.
You also need to know the particulars of the climate you’re dealing with, says Daniel Roehr of University of British Columbia’s Greenskins Lab. Tokyo and Hong Kong have enough rain during the growing season to feed food gardens, but Vancouver doesn’t. Crops also matter. Medicinal plants grow well on roofs, but many conventional crops find the weather up top too volatile, he says.
We need to design new structures that are “congenial to and interactive with food production,” says Mark Gorgolewski of Ryerson U, one of the organizers of the popular Carrot City exhibit now touring the world. Designing buildings with an eye to reusing washwater for irrigation and reusing composted food scraps and humanure for soil fertility are examples of such adaptations.
Veteran landscaper George Irwin, head of Green Living Technologies in Rochester, New York, learned about the food angle when his children planted seeds inside see-through walls he used as energy-saving exteriors for main walls. The seeds took, and his new career in “green walls and vertical agriculture” was born.
“Why bring the food to the city when you can bring the entire farm?” asks Irwin with a zesty personal style that’s always looking up. No marriage yet between urban ag and the new city design, but my inner matchmaker tells me the second date won’t be long in coming.
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