10 Things to Know about Green Stormwater Infrastructure

10 Things to Know about Green Stormwater Infrastructure
Mark Maimone and MArISSA BARLETTA
A more sustainable approach to managing urban stormwater is becoming the norm in cities nationwide.

Green infrastructure is a more sustainable approach to managing urban stormwater. It can help you respond to environmental conditions, create cost savings and support resilient communities.

  1. Clean Water Act compliance – Green stormwater infrastructure (GSI) offers a way to achieve Clean Water Act compliance that is comparable in cost to traditional infrastructure, such as storage tanks and tunnels. Its major financial advantage is that it can be implemented in phases and at varying scales, matching expenses to available funding. Additionally, a city will begin reaping benefits of a GSI program immediately, even as the program is incrementally implemented.
  2. Cost-effective partnerships – Fully achieving a large-scale GSI-based program is not typically something that municipalities can implement alone in a cost-effective way. Partnerships between agencies, funders, private developers and industries are critical to leverage resources and bring costs down.
  3. Green regulations – Creating and enforcing regulations for stormwater management onsite—for private development and redevelopment—creates a strong foundation for a city-wide green program.
  4. Stormwater management incentives – Incentivizing stormwater management by redeveloping or retrofitting private properties maximizes cost savings. In regions where a stormwater management fee structure is in place, a stormwater bill credit for property owners who manage runoff could be instituted. Rebates or tax incentives could be considered in areas with no stormwater management fee.
  5. GSI standards – Standardizing designs and processes is critical for cost-effective use of GSI. Creating manuals that include designs and specifications for constructing, inspecting and maintaining GSI will broaden the spectrum of creators and installers of these tools. It will also ensure proper function of the stormwater management practices over the life of the systems.
  6. Social and environmental rewards – Investors in GSI will see significant returns through social and environmental benefits: green job creation, enhanced recreational opportunities, improved community quality of life, reduced effects from excessive heat, improved air quality, energy savings and climate change offsets.
  7. Green planting pros – Maximizing the planting of trees and vegetation will increase the return on investment, providing shade and insulation and reducing cooling and heating costs. Studies indicate that the property value of greened areas increases 5 percent or more—and that people value areas with concentrated vegetation and are more likely to use them for recreation.
  8. A different shade of green management – GSI does not always look green; permeable paving and other onsite stormwater management techniques are also valuable tools in the GSI toolbox.
  9. Flood reduction – GSI can handle 1 to 1.5 inches of rainfall, potentially reducing or eliminating local street flooding for the more frequent, intense storms.
  10. Climate change response and mitigation – GSI can respond to the impacts of climate change, like more frequent and intense storms, by capturing the first 1 to 1.5 inches of rain. GSI can help mitigate climate change by reducing greenhouse gas emissions better than traditional infrastructure--both in the materials used and the fact that no energy is required to pump and treat stormwater.


Marissa Pappas Barletta, CDM Smith planner, has 12 years of experience serving public clients. She specializes in research, planning and implementation coordination and is the author of several publications and presentations on that topic.

Mark Maimone, CDM Smith senior vice president, has over 25 years of experience in water resource planning, groundwater and surface water modeling, and decision support services working for clients both in the United States and abroad. He has worked with the Philadelphia Water Department for 13 years on water supply and CSO planning and is the project manager for their Green City Clean Waters program.

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