New NRDC Report Shows Music City and Motor City Are "Emerald Cities" Investing in Green Infrastructure

My colleagues in the NRDC Water Program have been talking a lot this week about our new report, Rooftops to Rivers II, which shows how communities across the country are using green infrastructure techniques to stop water pollution.  That’s because the report provides such a fantastic resource for communities across the country who are looking for information on these innovative techniques.  It provides case studies for 14 cities that all can be considered green infrastructure leaders, using a six-point “Emerald City Scale” to identify which key strategies each city is using to become cleaner and greener. 

Two of the communities profiled in the report, Nashville and the Rouge River watershed (which includes Detroit), are showing the rest of the country how green infrastructure can be used to solve a city’s unique water management problems.

In Nashville, last year’s catastrophic flooding led the city to focus on green infrastructure techniques, which can help prevent flooding by catching and stopping rain where it falls.  Nashville recognized that this aspect of green infrastructure was a huge benefit that could help mitigate the city’s risk of floods in the future. 

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  • Nashville green roof -- photo courtesy RD Herbert

Thanks to its commitment to this approach, Nashville achieved a score of 3 on the Emerald City Scale with the following strategies:

  1. Nashville adopted a Green Infrastructure Master Plan in 2009 to guide the city’s progress.  The plan identifies green infrastructure practices for use in the 12.3-square-mile downtown area and analyzes the benefits that implementation of those practices could have.
  2. The city provides guidance and assistance to help people use green infrastructure at their own properties.  It maintains a website with information about rain gardens and rain barrels, and the city has conducted a green street demonstration project to show Nashville residents all the benefits that green infrastructure can provide.
  3. Nashville also has a dedicated funding source for green infrastructure: its stormwater user fee, which is based on the amount of impervious surface area on each user’s property.

The Detroit-area communities of the Rouge River watershed have also begun to use green infrastructure as a solution to their own local problem: combined sewer overflows, which occur when rainwater mixes with raw sewage in outdated sewer pipes, spilling untreated into waterways.  The Detroit area has been spending millions of dollars on conventional infrastructure solutions like pipes and tunnels, but they’ve switched tactics to focus more on green infrastructure because it can save the city money.

As a result, the Rouge River watershed achieved a 1 on the Emerald City Scale thanks to its guidance and demonstration projects, including rain gardens, rain barrels, downspout disconnect programs, constructed wetlands, and “grow zones” along streams.  Detroit has also been removing structures from vacant lots, taking them off the sewer system, and replacing them with porous land covers.  These projects are increasing the visibility of green infrastructure in the region.

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  • Greening of Detroit tree planting (Oct. 20, 2007) -- photo by Santa Fabio

However, both the Music City and the Motor City could do more to improve their Emerald City standings.  Neither community has adopted a requirement for newly developed and redeveloped properties to use green infrastructure to reduce runoff, as cities like Philadelphia and Milwaukee have done.  Neither requires the use of green infrastructure to reduce runoff from existing impervious areas.  And neither provides strong incentives for individuals and businesses to install green infrastructure on their properties.  Adopting these strategies would really help move the ball forward in both cities.

Still, the steps that Nashville and the Rouge River watershed communities have taken are a strong start.  These cities’ experiences are proof that green infrastructure works.  We hope that they inspire communities around the country to follow suit and invest in these green technologies.