Did you know that nearly every city in the U.S. is built on top of an aging and inadequate wastewater infrastructure system? When these systems fail, and all too often they do, untreated sewage and polluted stormwater gets dumped into our favorite waterways.

Chicago Rain GardenFortunately, many cities are now looking beyond what is referred to as "gray infrastructure" to find green solutions to this problem. Green infrastructure offers environmentally friendly ways to control combined sewer overflows (CSOs) and stormwater discharges.This approach integrates soil and vegetation into city planning and architectural design by making plants a major component of a community's wastewater infrastructure system.

Using vegetation (trees, shrubs, flowers and grasses) to manage rain where it falls keeps rain water from picking up nasty pollutants (like oil, salt, dirt and trash). Otherwise these unfiltered pollutants would just run off of paved surfaces and into storm sewers - then eventually into rivers and coastal waters.

This sounds like common sense, but green infrastructure also makes economic sense. You see, less water in our sewer system equals less pollution discharged from CSOs or separate stormwater sewers. That, in turn, equals lower treatment costs at wastewater treatment plants.

Rivers aren't just the only things that are saved by green infrastructure. Here are some prime examples of other "savings" cities are achieving from implementing green designs:

- Saving Money for a Rainy Day in Portland, Oregon: An $8 million subsidized downspout disconnection program has saved a whopping $250 million in infrastructure improvements by keeping 1 billion gallons of rain water annually out of the city's combined sewer system - just by letting rainwater soak into the ground instead.

- Saving Salmon in Seattle: The city's Street Edge Alternative (SEA) pilot project has retained 99 percent of the rain that has fallen during the last five years, thus preventing harmful discharges into sensitive waters that are critical salmon habitat.

- Saving Energy in Chicago: Temperatures above the City Hall's green roof average 10-15°F cooler than nearby black tar roofs (with the difference being as much as 50°F in August). The associated energy savings for the building are estimated to be $3,600 annually - and that's just one building!

Keeping sewage out of our favorite rivers, saving salmon and reducing energy costs are just the tip of the iceberg when it comes to the benefits of green infrastructure design. Rain gardens, green roofs and just having more plants in our cityscapes - period - also helps take pollutants like carbon dioxide out of the air we breathe, offsets urban "heat island" effects, and even reduces the threat of global warming.

And lets be honest - having more tress, flowers and plants in our cities is way more pleasing to the eye than being surrounded by a concrete jungle.

Implementing green design is a good idea, but to make it a reality requires bold leadership from city officials and public investment. That's where we as concerned citizens come in. It's time for us to get active by demanding green infrastructure in our own cities and towns. At every opportunity we must step up the pressure on our elected officials and planners to create incentives for builders to go green.

You can learn more about the variety of green innovations from my new report: Rooftops to Rivers: Green Strategies for Controlling Stormwater and Combined Sewer Overflows available at: http://www.nrdc.org/water/pollution/rooftops/contents.asp.