Mitigating Flood Impacts With Resiliency Parks

Southwest Park, which opened last fall, can manage 200,000 gallons of stormwater runoff.

Southwest Park, which opened last fall, can manage 200,000 gallons of stormwater runoff. City of Hoboken


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How a New Jersey city is combating flood risks with comprehensive parks planning

Southwest Park, a 1-acre parcel of land in Hoboken, New Jersey, boasts shade trees, lighted pathways, restrooms, a dog run, a pop-up market zone and a small performance space with multi-level seating—typical amenities for what is meant to be an urban oasis. But the park also contains rain gardens, porous surfaces and an underground network of pipes and tanks that can collect and divert up to 200,000 gallons of stormwater, preventing flooding of the surrounding businesses and residences.

The park, which opened last September, is one of three resiliency projects underway in Hoboken—spaces designed to provide greenery and refuge in a historically industrial city filled with residents who for years lobbied for parks. The spaces are also designed to mitigate flooding by diverting stormwater runoff away from Hoboken’s century-old combined sewer system, a long-standing problem that proved particularly difficult during Hurricane Irene in 2011 and Hurricane Sandy in 2012.

“Residents really favored the acquisition of a park or open space, and in such a flood-prone neighborhood, they wanted to install green infrastructure. The community was really the driving force, but we also experienced heavy flooding through Hurricane Irene and then Sandy,” said Stephen Marks, business administrator for the city of Hoboken. “Those were transformative moments for the city.”

The dog run at Southwest Park (courtesy city of Hoboken)

Work on the park began with the acquisition of a vacant parking lot. Much of the impervious concrete surface there was excavated to make way for installation of large perforated pipes nestled within levels of porous crushed stone, providing what Marks called “layers of stormwater management.” The underground infrastructure—including pumps that direct water to the Hudson River during heavy storms and a sensor system that monitors tanks in real-time—works in conjunction with projects on the surface, such as rain gardens and cisterns that help filter and slow the deluge of water during heavy rainstorms.

“The rain gardens act as more of a means of conveyance than actual retention. They’re more filtration,” said Caleb Stratton, the city’s chief resilience officer. “It’s not traditional green infrastructure, in that it’s all married with corresponding infrastructure underground.”

Thus far, the park’s infrastructure has been tested by extreme rainfall three times, most recently in August, during the heaviest storm the city had seen in two years. Each time, the stormwater mitigation system performed as intended.

"Although Hoboken experienced rainfall flooding, the flood waters receded immediately after the storm because of two wet weather pumps and rainwater storage at Southwest Park,” the city said in a statement after the August storm. “The rainwater storage tank under the park filled up today, and is now emptying out before the next intense rain event. Without the wet weather pumps and rainwater storage at Southwest Park, Hoboken could have experienced significantly worse flooding conditions, which could have lasted much longer."

City officials hope to expand Southwest Park and have other resiliency projects in the works, including a large park in the northwestern part of the city that’s expected to have 1 million gallons of underground stormwater storage and the capacity to store 750,000 gallons at the surface level. A third, developer-led municipal park project with 470,000 gallons of storage is currently under construction as well.

Collectively, the projects reflect the city’s dedication to holistic development, Stratton said.

“The reason we like to use the word resiliency goes back to Hurricane Irene and Sandy. We’re not designing infrastructure under the premise of business as usual,” he said. “We’re not going to look at projects like, ‘This is just a park’ or ‘This is just stormwater management.’ Resiliency means we have to adapt our thinking.”

The concept can be useful everywhere, even in places that face challenges other than flooding, said Jennifer Gonzalez, Hoboken’s chief sustainability officer and director of environmental services.

“The sheer concept of always looking at capital projects to have as many benefits for quality of life, and also looking at them from a lens of physical and social resiliency—that’s a replicable concept anywhere,” she said. “It may look totally differently in a place where your risks are droughts and earthquakes, but the concepts we’re doing here can be used across the country.”

Kate Elizabeth Queram is a Staff Correspondent for Government Executive’s Route Fifty and is based in Washington, D.C.

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