Green Infrastructure for Stormwater ManagementAs climate change intensifies storms, cities around the world are facing more frequent flooding and water pollution. In urban areas with combined sewer systems, heavy rainfall can overwhelm the pipes, causing sewage to overflow into nearby harbors. A climate solution designed to address this problem is green infrastructure for stormwater management. By using natural systems like plants and soil to absorb rainwater, cities can reduce flooding and improve water quality.
One important Climate solution related to water quality is Green infrastructure for stormwater management. In New York City, heavy rainfall can overwhelm the sewer system, causing combined sewer overflows. When this happens, untreated sewage and stormwater flow directly into waterways like the harbor, polluting the water and harming ecosystems. Climate change is making this problem worse because warmer temperatures increase the intensity of storms and rainfall. Green Infrastructure works by managing rainwater where it falls instead of sending it immediately into underground pipes. According to the (NYC DEP), the city’s Green Infrastructure program is designed to reduce combined sewer overflows (CSOs) by capturing stormwater using natural systems such as bioswales and green roofs. Instead of relying on gray infrastructures like water tanks and tunnels, the city is relying on green infrastructures that invest in nature-based solutions that absorb and filter water. Recent Scientific research shows that green stormwater infrastructure is highly effective at reducing urban flooding and sewer overflow risks. A 2024 study in the (Journal of Hydrology) found that when cities install large amounts of green stormwater systems to control combined sewer overflows, they can significantly reduce runoff. By soaking up and slowing down rainwater before it reaches storm drains, these systems reduce the wear on sewer networks and also lower the risk of flooding and overflow.
Figure 1. A bioswale is a shallow, planted area designed to collect and filter stormwater runoff from streets and parking lots. As shown in the diagram, rainwater flows into the bioswale from nearby pavement (Step 1). The water then slowly seeps into the soil (step 2), where plant roots help remove pollutants and debris. The water continues to filter through layers of sand and gravel until it eventually reaches groundwater. By slowing down and cleaning stormwater before it enters the sewer system, bioswales reduce combined sewer overflows and also lead to the improvement of water quality in the Harbor. Beyond improving water quality, green infrastructure also helps cities adapt to climate change. As global temperatures rise, storms are becoming more intense, increasing flood risk in urban areas. To better understand the climate context, I used En-Roads climate simulator and examined the Population exposed to River Flooding.
Figure 2. En-Roads’ projection of the global population exposed to river flooding.
Under a high- emissions scenario leading to approximately 3.1°C of warming by 2100, the number of people exposed to river flooding increases dramatically over the century. The graph shows that it is rising from roughly 50 million people per year in the early 2000’s to nearly 190 million by 2100. This increase shows how climate change intensifies flood risk. While bioswales alone cannot reduce global temperatures, they directly address the type of flooding risk shown in the model above. As heavy rainfall becomes more intense, urban areas with sewer systems face a higher risk of overflow and contamination. Green infrastructure is able to reduce the volume and the speed at which the runoff enters the storm drains, which would overall lessen flood impacts. This way, bioswales are a strategy that helps protect communities from the flood exposure projected in En-Roads.
The Lawrenceville School already has similar designs, including green spaces and landscaped areas that help absorb rainwater naturally. Unlike the urban areas that have to rely on sewer tunnels, Lawrenceville has more open land, which allows rainwater to soak into the ground more easily. However, Lawrenceville could still benefit from installing some rain gardens or bioswales near parking lots in order to reduce any further runoff.
Local organizations like the Bronx River Alliance explain that green infrastructure systems such as bioswales and rain gardens help slow and filter stormwater, reducing flood risk and improving water quality in urban watersheds (Bronx River Alliance, n.d). Another example from a (Kresge Foundation Article) describes how cities like New Orleans are also investing in rain gardens and bioswales to reduce flood risks in neighborhoods that have faced a lot of environmental hazards. These projects not only help slow and absorb stormwater during heavy rains, but they also help keep several neighborhoods safe. At the same time, implementing green infrastructure requires a long period of planning, funding, and decisions about where investments go and how they can influence which communities.
Works Cited
Shetty, N. H., Hu, R., Mailloux, B. J., Hsueh, D. Y., McGillis, W. R., Wang, M., Chandran, K., & Culligan, P. J. (2019). Studying the effect of bioswales on nutrient pollution in urban combined sewer systems. The Science of the total environment, 665, 944–958. https://doi.org/10.1016/j.scitotenv.2019.02.121
Morby, M. (2025). How bioswales manage stormwater. Retrieved from https://marisamorby.com/bioswales/ (Figure 1)
New York City Department of Environmental Protection. (n.d.). Wastewater treatment system. https://www.nyc.gov/site/dep/water/wastewater-treatment-system.page (NYC DEP)
Kwak, N., Smith, V., & Good, K. D. (2024). Assessing the influence of green stormwater infrastructure implemented for combined sewer overflow control on urban streamflows. Journal of Hydrology, 640, 131670. https://doi.org/10.1016/j.jhydrol.2024.131670 (Journal of Hydrology).
Bronx River Alliance. (n.d.). Green infrastructure. https://bronxriver.org/restoration-access/restoring-the-ecology/green-infrastructure
McLaughlin, K. (2025, July 30). Green infrastructure: Cities turn to nature to solve urban flooding. Kresge Foundation. https://kresge.org/news-views/green-infrastructure-cities-turn-to-nature-to-solve-urban-flooding/
