Green infrastructure: a solution to storm water management and urban resilience?

On January 15, Dr. Tara Kulkarni of Norwich University gave a talk titled “Urban Resilience – What’s the Role of Water Infrastructure?” – it was the first lecture of Northeastern University’s Spring 2019 “Contemporary Issues in Security and Resilience Studies” speaker series. (Video of the lecture can be found at the bottom of this article)

Dr. Kulkarni is an Associate Professor of Civil & Environmental Engineering and the Director of the Center for Global Resilience and Security (CGRS) at Norwich University. She has prior professional experience as the sustainability manager at a consulting firm, and as a state regulator of industrial wastewater, hazardous waste, and petroleum cleanup.

The urban landscape as it currently exists cannot optimally manage the effects of heavy rain and storms. The abundance of impervious surfaces in urban areas affects the local hydrology, reducing infiltration and groundwater recharge, and increasing dirtied runoff into surrounding bodies of water. In many cities, particularly in the U.S. Northeast, antiquated combined sewer systems collect all household and industrial wastewater and storm water in one pipe, funneling it all to a treatment facility. However, during severe rain events, high volumes of water inevitably overwhelm the system, creating a serious health hazard when the sewers overflow into public waterways. The changing climate will only exacerbate existing problems: climate reports predict that rainfall will only get heavier in New England. In addition, the American Society of Civil Engineers (ASCE) has given the infrastructure of the United States a grade of “D+”. While it is a dismal rating, there are creative ways to simultaneously improve both infrastructure and urban resilience.

One of the proposed solutions to mitigate storm water problems is green storm water infrastructure. Traditional “grey” storm water infrastructure consists of gutters, drains, pipes and collection systems, that are intended to move the water away from urban areas; green storm water infrastructure, on the other hand, treats the water in place. It incorporates greened areas into the city, and ensures rain absorption by the soil, where it is stored and filtered instead of becoming runoff, contaminating waterways with debris. Bioswales, rain gardens, green roofs, permeable pavement, rain collection systems and street trees are all examples of green infrastructure. Dr. Kulkarni shared her belief that “co-benefits” are what truly make green storm water infrastructure worth the investment – they are not necessarily directly related to the management of storm water, but are the positive side-effects of the system. Co-benefits include the potential insulating benefits of green roofs, the recreational opportunities of new green spaces, or drinking water supplied by rainwater collection systems. Additionally, green spaces inevitably increase the aesthetic value of the city, filter the air, capture carbon dioxide, stabilize the surrounding temperature, and provide habitat for wildlife, like pollinators. 

A street-side rain garden collects water to be filtered by garden plants preventing runoff (Courtesy: EPA)

Green infrastructure has a direct relationship to resilience, which Scott, et al. (2012) defines as: “…the ability to gracefully degrade and subsequently recover from a potentially catastrophic disturbance that is internal or external in origin.”* Dr. Kulkarni suggests that resilience could be measured by comparison to the 100 recognized resilient cities in the United States. These cities exemplify the principles of resilience by surviving and thriving. One way to quantify the resilience of a city is through the City Resilience Index, an assessment tool developed by Arup, a global engineering and design consulting firm. Using 52 indicators and a 156-question questionnaire, a municipality can complete the assessment online to evaluate the city against 12 resilience goals, or indices, to help guide resilience decisions. There seem to be infinite factors to consider: potential shocks, stresses, necessary actions, partners, timeframes, funding, and more. Thus, Dr. Kulkarni questions whether there needs to be a redefinition of resilience, or metamorphosis of the outlook on resilience as a whole. Perhaps, she argues, we need to ask how our relationship to design makes it resilient, not just discuss the “how-to” of building resilience. The first step to resilience infrastructure, she believes, is developing care for and understanding of the structures that surround us: infrastructure will become more resilient when we each care about its longevity. By having conversations about the impact of our actions, we can effectively combine infrastructure-building and community-building under the umbrella of resilience.

It is crucial that development does not happen blindly, but is instead done consciously, prioritizing the needs of the community and actively involving its members in a conversation, starting from the planning stage of any project. The city of Boulder, Colorado is an example of a city that voluntarily raised taxes to acquire communal green space for recreation. It is time for more cities to follow their example – local, tangible actions are what will collectively improve a community’s resilience. In Vermont, where Dr. Kulkarni first found inspiration for her research in green infrastructure, hazard mitigation responses are implemented at the town-level. While they are much larger than Vermont towns, cities can nonetheless take this small-scale approach to implementation because they are comprised of neighborhoods and communities that might be willing to partake in the decision-making processes to find solutions that would best serve their needs. Grassroots city volunteer programs, such as Resilient City Builders in Norfolk, Virginia, enable residents to contribute to the resilience of their community. In New York City, MillionTreesNYC uses volunteer power to expand its urban forest. Here in the City of Boston, Speak for the Trees is working to increase the quantity and health of public street trees by conducting a tree survey, while building a community around the city’s trees. Also, green workforce training is becoming increasingly popular due to the demand for workers that need to be trained to work on new green technologies. Thus, successful resilience improvement projects should realize that community identity and cohesion is an essential step in implementing resilient solutions.

One of the best ways to engage communities is to use visual arts and storytelling to communicate problems and proposed solutions. In this respect, data visualization can serve as an effective tool, empowering members of the community to find the solutions that fit into their neighborhood, leading to more equitable cities. This strategy was implemented in New Orleans, where mapping food deserts resulted in the planting of community gardens in areas that were farthest from supermarkets and did not have access to fresh food. Local governments can facilitate and contribute to resilience building by simply recognizing the interconnection of urban systems. This knowledge could be used in action plan development, and partnership formation, whether with academia, nonprofits, or local businesses. The city of Berkeley eloquently encapsulates this ideology: “Be connected. Be prepared. Be Berkeley”. 

While community organizing to build resilience seems to promise inevitable success, there are still significant challenges in its implementation. Senior officials and experts may avoid taking risks using promising new technology to avoid damaging their reputations. Growing electronic databases might increase a city’s vulnerability to cyber security threats. Additionally, there is the financial obstacle: while everyone agrees that resilience is important, there is still a lot to be done to ensure that local governments and private investors see such investments as long-term savings rather than additional spending. Dr. Kulkarni assures us that once we start asking the right questions, municipalities will be enabled to build sustainability and resilience into the urban fabric by incorporating green infrastructure while completing the necessary infrastructure upgrades. New infrastructure will be most effective if it is a combination of grey and green; and while grey is already common, incorporating green structures will not only reduce the amount of bulky, brute-force construction, it will beautify and benefit the whole community.

*Note on the definition of resilience
Dr. Kulkarni stated in her lecture that she preferred this definition of resilience, which is originally found in the following paper:
Scott, C.A., Bailey, C.J., Marra, R.P., Woods, G.J., Ormerod, K. J., Lansey, K. (2012). Scenario Planning to Address Critical Uncertainties for Robust and Resilient Water–Wastewater Infrastructures under Conditions of Water Scarcity and Rapid Development. Water, 4(4), 848-868. doi:10.3390/w4040848

For the full schedule of the Spring 2019 Speaker Series, visit the official event website by clicking here