My first vivid encounter with the consequences of inadequate water quality occurred during a family vacation to Bangkok, Thailand, when I was just 15 years old. As we embarked on a canal boat ride through the Chao Phraya River, we passed by a village on stilts. To my astonishment, I witnessed residents engaging in daily activities right at the river’s edge—doing laundry, discarding garbage, and even brushing their teeth. It was a stark realization that people actually lived in such conditions, and it struck me that their lives could be vastly improved with access to clean water.
This pivotal experience ignited a passion within me that ultimately led me to pursue a career in Water Resources engineering and research. Today, I am deeply concerned that even in developed countries like the United States, we may not be as far removed from such water quality issues as we would like to believe. Our aging stormwater infrastructure, which has received a dismal D-plus grade from the American Society of Civil Engineers, is no longer adequate to address the challenges posed by today’s stormwater runoff.
Traditional urban drainage systems are designed to whisk away stormwater runoff as quickly and efficiently as possible, out of sight and out of mind. However, this approach fails to consider the significant impacts that even small amounts of runoff can have on our environment and public health. In fact, statistics show that in the New Jersey and New York area, approximately 80% of our day-to-day rainfall events are less than eight tenths of an inch—the equivalent of a couple of tablespoons of water. Yet, this seemingly insignificant amount of rainfall can generate substantial runoff from impervious surfaces, which are ubiquitous in our built environment.
The problem is compounded in cities with combined sewer systems, where stormwater runoff and domestic sewage flow through the same pipes. During heavy rainfall events, the capacity of these combined sewers can be overwhelmed, leading to untreated sewage overflows into nearby waterways. These overflows pose a significant threat to public health, as they contain high levels of pathogens that can cause illness.
The good news is that we have been working diligently on innovative solutions to address these challenges. Stormwater green infrastructure, a suite of natural and engineered systems, offers a promising approach to improving water quality and mitigating the impacts of stormwater runoff. These systems work by promoting natural hydrologic processes, such as soaking up runoff, slowing it down, and making it available to plants for evapotranspiration.
One of the most promising applications of stormwater green infrastructure is on rooftops, which account for a significant portion of impervious surfaces in urban areas. Green roofs, which are essentially vegetated roofs, can eliminate or minimize rooftop runoff by creating a sponge-like layer that absorbs and stores water. This water is then gradually released back into the atmosphere through evapotranspiration, reducing the amount of runoff that enters the sewer system.
Another effective stormwater green infrastructure technology is the bioretention planter. These planters are installed at grade underneath downspouts and collect runoff from rooftops. The water is then slowly released into the surrounding soil, where it is filtered and cleaned before it infiltrates into the groundwater or is discharged into a nearby waterway.
Despite the clear benefits of stormwater green infrastructure, its adoption has been hindered by a number of factors, including perceived risks, resistance to change, and misperceptions about how these systems work. To overcome these barriers, engineers need to work in interdisciplinary teams with experts from other fields, such as plant and soil science, landscape architecture, and urban planning. Public engagement is also crucial, as it fosters understanding and support for green stormwater infrastructure.
It is time for us to demand that development rules catch up to the state of the art. We have the technology to address the challenges posed by stormwater runoff, and it is our responsibility to ensure that our communities have access to clean water. By embracing stormwater green infrastructure, we can protect our waterways, improve public health, and create more sustainable and resilient cities.