As the climate changes, and worries about water increase, more and more cities are taking another look at their water management policies.  You may have heard of green roofs and maybe even rain gardens, but it's going to take more than a rooftop garden to mitigate the issues facing many cities when it comes to the water supply.  Urban planners and city leaders are working together to develop strategies to create sustainable water management plans as part of the larger goals to become "green cities."

 Chicago, Illinois may have cornered the market on public relations when it comes to self-promotion of its green credentials, and for the most part, the City That Works can be proud of its progress in saving its own battered environment.  Chicago is leading the US in green roofs in terms of total area, and has a goal of 6,000 rooftop gardens.  How did Chicago do this?  Easy.  Give ‘em grants and tax credits.    It is working so well that the program is being expanded in to a "Cool Roofs Grants Program" to help homeowners and businesses change rooftops to high-albedo surfaces (which reflects the sun's heat rather than absorbing it to create that ever-so-pleasant "urban heat island effect").

Mayor Daley's next target is the alley.  Chicago has nearly 1900 miles of alleyways, or 3500 acres of impermeable concrete that not only compacts soils, but also causes large amount of stormwater runoff during those summertime thunderstorms that frequent the Midwestern US.

Chicago has a long history of stormwater issues and monumental efforts to deal with wastewater overflow.  Back in the day, Chicago used to dump its waste right into Lake Michigan, until the water became polluted. 

Then Chicago built the Sanitary and Ship Canal, which actually reversed the flow of the Chicago River.  That helped for a while, but when it rained, things backed up and again ended up in the Great Lake.  So then Chicago built huge underground tunnels in order to store the extra stormwater until it could be processed later.

But guess what, processing storm water costs money, and a lot of it.  So, what would be a simple solution to Chicago's problem?  Reduce the amount of storm water that reaches the sewers. 

And that's where green alleys come in.  The idea is to construct alleyways with permeable paving materials, so that storm water can pass through the previously unpassable materials and down into the water table.  When storm water filters through soil, it is cleaned naturally (for the most part), which reduces the city's need for water treatment.  And it recharges the groundwater supply.

Chicago put a green roof on its City Hall, and also built a green-roofed Chicago Center for Green Technology, the first platinum-certified LEED municipal building in the United States.  So, many would say that Chicago is definitely leading the pack in the New Urbanism movement, and they would be right - mostly.  Truth be told, there are lots of cities around the world going "green."

Back in the early 1990's, a city in Brazil called Curitiba became the poster child for New Urbanism before New Urbanism became a movement.  Simply put, New Urbanism is a movement to build and develop sustainably.  Among Curitiba's innovations was diverting storm water to small ponds in public spaces like parks, to alleviate pressure on its sewers while still creating livable green space for its inhabitants.

Despite Curitiba's example, few cities jumped at the chance to redesign themselves as a green city.  That's where climate change comes in, with a dash of increased energy costs.  Now, more and more cities are waking up to their ill-planned pasts. 

Not surprisingly, it was the European cities facing water scarcity that took the lead in sustainable urban planning.  London has planned the "East London Green Grid" to include sustainable water management and reclaiming former industrial wasteland as riverside green space, which not only makes the East Side liveable, but also protects the Thames.  Barcelona, Spain has its "Local Agenda 21" which among other things encourages urban gardens, rainwater collection, and cutting back on water usage in general.

Agenda 21 is bigger than just Barcelona.  The idea of Agenda 21 started after the 1992 Rio Summit, and more than 6,000 cities worldwide have signed on as part of a larger movement to transform urban spaces into sustainable cities.

European cities may seem to have taken the lead in sustainable urban planning, but don't count the rest of the world out.  Syndey, Australia is building a "Green Square" to test out new ways of saving water and the environment.  Even China is building a whole "eco-city".  Dongtan, China will feature such innovations as a natural wall insulation that filters wastewater.  In a country that is expected to build hundreds of new cities to accommodate its billion-plus citizens, Dongtan will prove a useful case study and testing ground in planned sustainable urban architecture.

But let's return to the United States.  The US as a whole has not exactly been a leader in combating climate change.   Sure, the West Coast became know for its "treehugger" cities:  San Francisco, Portland, Seattle. But what is happening outside of those cities and Chicago?  Well, when other cities started noticing the public benefits from green urban planning, more city planners started looking for ways to make their own cities more sustainable.  Cities like Denver, Washington DC, New York City and Austin are taking on Chicago for title of "Who is the greenest of them all."

Some examples of changes being made in water management practices include NYC's PlaNYC, a set of 127 initiatives including one of which is to plant one million trees in the next ten years.  Trees not only absorb carbon dioxide, but also help break up compacted city soils to help water infiltrate through to the subsoils.  NYC is also starting to encourage rooftop gardens with tax abatements.  Honolulu, Hawaii is also supporting green roof and storm water cachement projects.  Even Washington, D.C. "suburbs" like Annapolis, Maryland has built 70 bio-retention areas to divert water from flowing directly into the polluted Chesapeake Bay.

Even smaller US cities are doing their part to go green.  Carmel, Indiana has re-designed its roads to include 40 roundabouts, replacing intersections with traffic signals.  Idling cars at stop lights can be a large source of carbon emissions, so a roundabout not only improves the flow of traffic, but also provides space for trees and other native plants that can serve as bio-retention gardens and carbon sinks.  Scranton, Pennsylvania has hired a professional city forester, part of an urban forestry program to give trees away to every school kid and teach them how to care for trees. 

Of course, what is good for one city may not be good for another in terms of urban design, but it is becoming very clear that water is a resource that requires better management.  A typical large city allows only 15 percent of all rainfall to permeate its concrete jungle, with the remaining water flushed into the toilet, literally.  Some cities are taking the lead, showing us that we can do better.

Worth checking out:

Mayors Climate Protection Center
New Urbanism
Smart Growth

Related Reading:
Defining the 'Green' House: Some Basic Traits to Know
Smart Urban Transportation: Transforming Existing Systems
 
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www.leopardo.com