Climate change means that extreme rainfall events are increasing, causing never-before-seen flooding events in cities like New York. Impermeable urban surfaces like concrete sidewalks, streets or building rooftops prevent rainwater from naturally infiltrating the ground, causing increased surface runoff, overwhelmed sewer systems, flooding and property damage, and pollution in water bodies. Further, many older cities, like NYC, use combined sewer systems where stormwater and sewage share the same pipes. During heavy rainfall, these systems can overflow, resulting in combined sewer overflow, which can lead to contamination of water bodies, increased risk of waterborne diseases, and damage to aquatic ecosystems.
For cities looking for innovative stormwater solutions, green stormwater infrastructure (GSI) has emerged as an important strategy. By absorbing and slowing down stormwater, GSI helps mitigate flooding and relieve pressure on sewer systems, which helps to reduce localized flooding, prevent property damage and enhance resilience against extreme weather events. GSI systems also mimic natural processes to manage stormwater, which helps to reduce pollutants through filtration and infiltration. These processes lead to improved water quality in rivers, lakes and oceans, and enhanced aquatic habitats and biodiversity. The advantages of GSI extend beyond water management, offering creation of urban green spaces, enhanced aesthetic value and recreational opportunities, increased property values, improved air quality and reduced urban heat island effect.
The benefits of GSI are many, however, the pace and cost of implementation have been areas of concern for many communities and implementation has largely been focused on publicly owned properties. A promising solution for addressing these concerns for private properties is to use a pay-for-performance model to deploy GSI. Pay-for-performance delivery models engage delivery partners to deploy GSI at risk, allowing communities to incentivize lower cost and faster timelines, while only paying for completed projects. Since the model emphasizes efficient delivery, pay-for-performance can work particularly well to engage private property owners in GSI implementation. The pay-for-performance model can make an important difference for property owners by allowing project teams to streamline and shorten projects that typically take years to months or even weeks.
In a partnership with the New York City Department of Environmental Protection (DEP), for example, we’ve been able to create a unique partnership through which Arcadis has helped DEP bring stormwater investments to a broad range of properties, like universities, cemeteries, hospitals, and commercial facilities, in ways that enhance the value and resilience of their properties, while helping meet city-wide water quality goals. This kind of program sets a new standard for GSI on private property and marks a pioneering step in urban water management. The DEP program showcases the potential of a pay-for-performance model to address stormwater challenges, improve water quality and enhance urban resilience. For property owners, this initiative offers a more cost- and time-effective solution for managing stormwater, while also reaping the benefits of increased property value and environmental stewardship.
