By Amin Davis
The importance of maintaining and enhancing green infrastructure, or GI, has become a primary area of focus within the Carolinas and nationally as communities seek ways to increase their resiliency against changing weather patterns and more frequent, high-intensity storms. Concurrently rapidly urbanizing regions such as the Research Triangle, NC and Horry County, SC have to address increased development which causes significant increases in stormwater runoff.
What is Green Infrastructure?
GI, including wetlands, use vegetation, soils, and other natural landscape features to manage wet weather impacts, reduce and treat stormwater at its source, and create sustainable and healthy communities (EPA, 2017). The beauty of these nature-based practices is that in addition to providing environmental benefits, they support community resiliency by providing multiple ecosystem services, or community benefits, that can be quantified by economic, public health and social metrics (see Community Benefits of GI table below). Conversely traditional gray infrastructure such as gutters, stormwater pipes and sewer systems are considered single purpose and can cause major water pollution and flooding downstream in our watersheds. Additionally GI can be integrated into nearly every type of land use (residential to commercial) and development density (low to high).
In searching for resources about GI one may find a wide variety of overlapping terminology and frameworks. For the purposes of this article GI is separated into two broad categories: engineered and natural. Engineered GI practices include bioretention cells, constructed wetlands, green roofs, permeable pavements, rain gardens, vegetative swales, rainwater harvesting (rain barrels or cisterns) and rooftop (downspout) disconnection. These practices are designed to reduce stormwater volumes and improve water quality. Natural GI, on which engineered GI practices are based, includes vegetated wetlands, stream buffers and other vegetated or forested areas. The conservation of relatively stable areas of natural GI and the restoration of degraded areas of natural GI is a critical component of maintaining environmental resiliency against more frequent storms, rising seas and shoreline erosion along our Carolina coastlines.
How to Use Green Infrastructure
There are success stories of developers who have been willing to integrate GI into their site development once this alternative was brought to their attention. A leading example of this is the Market at Colonnade Innovative Stormwater Management Plan that was integrated into the site design of a shopping center in Raleigh, NC. This project involved a suite of GI and other stormwater control measures being designed and constructed which led to a 98 percent reduction in stormwater volume and significant reductions in stormwater nutrient concentrations (total nitrogen, phosphorus and suspended solids). This project was used as a model for successfully negotiating the integration of GI into the site design of a proposed multi-hotel development within a wooded site in Cary, NC.
Two key elements for the integration of GI into development plans are: 1.) local stakeholder input advocating for GI at the front end of proposed developments (prior to the completion of preliminary development plans); and 2.) working with local nonprofits and watershed groups to make developers aware of grants and other cost-share funding available to offset the costs of integrating GI into their site plans. Below are some grant programs that provide cost-share funding for engineered GI practice:
- North Carolina Clean Water Management Trust Fund
- Section 319 Grant Program (North Carolina)
- North Carolina Water Resources Development Grant Program
Common Sense Approach
GI is a common-sense solution that should be a primary requirement for all development everywhere, especially in light of increasing development coupled with more frequent, higher-intensity rain events. Local governments should be allowed to require low-impact development (LID) principles, such as the preservation of green spaces and the integration multiple GI practices, for all new development. They should also be allowed to require the integration of GI retrofits for re-development and urban infill projects. Why? Because there’s an abundance of peer-reviewed and anecdotal evidence that clearly demonstrates that GI is really Community Resiliency Infrastructure. Hopefully this message can be delivered to our elected officials and community leaders to a degree that will lead to broad scale changes in development policies that promote GI.
- EPA Green Infrastructure website
- NC Conservation Network’s GSI Wake County Primer
- NCDEQ Stormwater Design Manual
- NC Division of Water Resources
- Options for Greening Raleigh
About the Author
Amin Davis is a volunteer and Outreach Coordinator for the Carolina Wetlands Association. Amin is a Certified Ecologist, Professional Wetland Scientist and is active with several community nonprofit organizations that are based in Southeast Raleigh. He has been employed with the NC Department of Environmental Quality since 2008 and has been employed with the NC Division of Water Resources since 2014. He manages a grant program that provides cost-share funding to local governments and their partners for projects associated with green infrastructure, stream restoration (including dam removals and living shorelines) and water-based recreation.