New York City Plans To Boost Resilience Against Floods

Linda Poon describes New York City’s efforts to plan for a more resilient future in the face of recurring floods. “[Hurricane Ida in 2021] and the ones before it, including a cloudburst downpour during Tropical Storm Elsa in July, have forced New York to take a hard look at becoming a ‘spongier’ city — one that combines nature-based green infrastructure like street-side rain gardens with gray infrastructure like storm drains to divert or absorb water and prevent catastrophic flooding.”

“A recent Arup report comparing the ‘sponginess’ of seven global cities ranked New York in the middle of the pack, after Auckland and Nairobi, and tied with Mumbai and Singapore. The researchers combined satellite imagery showing land use in the 58 square miles of each city’s main urban center with data from a global soil permeability analysis, and applied machine learning to determine their ability to manage sudden soakings.” According to the report, “Some 39% of the city is considered green spaces, leaving a bit less than two-thirds of the urban environment covered in impermeable surfaces.”

The article describes the challenges faced by the city in flood-proofing many of its neighborhoods and the limited potential for overhauling the city’s massive system of stormwater infrastructure. “In the more immediate term, the city is moving ahead with green infrastructure projects that can mitigate the most destructive kinds of flooding and help the city live with water from intense downpours.” Poon writes, “New York’s green infrastructure program was first laid out in 2010, and the city has since poured $1 billion into it. It’s become one of the nation’s largest, with more than 11,000 projects across all five boroughs that are either completed or under construction.”