Flash flooding is a powerful reminder that public infrastructure is vulnerable under extreme pressure. In late September, when seven inches of rain fell in New York City within less than 24 hours on the evening of September 28 and early morning of September 29, this fragility was on full display. Tunnel traffic, subway cars, passenger rail, and air travel all ground to a halt as the city’s streets became fast-moving rivers. 

I experienced marginal effects from the flooding firsthand. I was in town for a convention at a conference center in Lincoln Harbor, on the west side of the Hudson River. A group of conferees crossed the river by water taxi for drinks. On our way back in the wee hours of the morning, we spent nearly three hours in traffic—and much more in fare—for what would normally be a 15-minute ride through the Lincoln Tunnel. These inconveniences were trivial in comparison to the devastating floods in apartments and schools. Even though the recent floods did not exact a death toll, they signaled what some community leaders cite as citywide unpreparedness for flooding. And officials are already worried about more rain to come. 

Conversations about where, when, and how public infrastructure fails are necessary. But we can more productively frame them when we zoom out and provide a full portrait: of failures, yes, but also everyday, mundane successes across the sweep of a city’s history. Almost all human settlements demonstrate infrastructure resilience and examining our largest and tallest cities clarifies the scale of their functionality. A city like New York provides a case study like no other.

With over 7.8 million residents, New York is the most populous city in the US, over twice as large as the city in second place, Los Angeles. The city’s current form represents layers upon layers of human history. Early settlements by the Algonquian and Lenape peoples in the fifteenth and sixteenth centuries made fishing and trading outposts along the islands and waterways of what would become New York. These settlements expanded as French, Dutch, and English explorers, at the behest of royal European powers, built settlements, ports, wharves, and drydocks along the East River in particular. 

After American Independence and throughout the 1800s, New York’s waterborne passenger and trade traffic ballooned. It was shaped by natural factors, including the initial depth of the Hudson River, and human design, most notably the city’s connection to the Great Lakes, etched into the earth with the completion of the Erie Canal in 1825. These features made its ports the premier commercial gateway for a region and, indeed, a country undergoing industrial transformations with global reach. With the invention of steamships, the dissemination of manufacturing, waves of mass immigration, and the consolidation of various boroughs into the City of New York in 1898, it had become the largest city in the US—an “urban colossus” that appeared to herald the future.

These patterns of growth only persisted in the early twentieth century. Immigration continued apace, but so did migration within the US. Indeed, the Great Migration, in which six million African Americans uprooted themselves from the South and traveled north, transformed New York into the largest urban African-American community in the country, setting the stage for the explosion of artistic and creative life known as the Harlem Renaissance in the 1920s and ’30s.

By 1920, as the city swelled with newcomers, New York—long the largest city in the country—became the largest city in the world and held this title well into the midcentury. The city’s built environment was not 3-D printed, but accumulated over centuries, decade by decade, project by project. Its shape reflects the city’s greatest aspirations, and its starkest failures, all etched into concrete. Public infrastructure is effectively a palimpsest, layered artifact of iterative efforts across history. Though its failures are traumatic and highly publicized, public infrastructure yields consistent, invisible results. 

Today, and every day, New York City’s wastewater treatment facilities act as organs that process 1.3 billion gallons of storm and wastewater, removing sewage, sludge, and other solids before aerating, disinfecting, and recycling the water into the harbor. Each day this process yields 60 truckloads of biosolids, some of which are sold to contractors, who use it as the basis of dense and nutrient-rich soil supplements. To wit, new and innovative programs like a citywide composting program promise to transform food scraps from rat feasts into an asset capable of fertilizing farms and even generating gasses to heat homes. In the 1850s, Baron von Haussmann, the architect who designed much of modern Paris, described the earliest versions of treatment systems as ”underground galleries, organs” where hidden systems would “maintain public health without troubling the good order of the city and without spoiling its exterior beauty.” That a city of 8.5 million can metabolize its shit with routinized ease, even transforming smelly waste into significant assets, would strike Haussmann—and should strike us—as an astounding fact. 

Often parallel to the sluices and tunnels that channel the city’s waste, 6,300 miles of streets and avenues and 800 tunnels and bridges—regulated by just under 1 million street signs, 315,000 street lights, and 13,250 signal stoplights—structure patterns of exchange, movement, and everyday life in the country’s largest city. Strutting atop the city’s 12,000 miles of sidewalk, this year’s industry experts predict the city will host 61 million tourists—a major upswing from pandemic lows. Some of those tourists drive into the city. Every day, nearly 4.5 million vehicles weave in and out of traffic in New York. When drivers hear a signature metallic clunk, it’s likely because they drove over one of the city’s 350,000 manholes, access points to the pipes beneath. Those who don’t drive might be among the 2.4 million or 1.2 million daily riders on the subway and bus systems, respectively. 

I think it is safe to say that sheer quantities of matter and throngs of people that course in and out of the city are enough to inspire, at scale, silent awe. 

City infrastructure, in New York and quite possibly every human city, is far from perfect. Unfortunately, communities where infrastructure is the weakest within the US are more often than not non-white and poor communities. The building blocks of infrastructure for everything from drinking water, power plants, broadband, and rail, to roads, bridges, and highways are under greater stress in poorer and non-white communities. Cumulatively, this means that the adverse effects of poor infrastructure are concentrated among the poorest Americans. The concentration of failure in public infrastructure has been on public display in Flint, Michigan since its water system broke down in 2014. These effects range from damage and wear to cars accrued on pothole-riddled roads, health risks downstream from malfunctioning water systems, and, indeed, flooding, which forces transit to halt and can cause financial and personal stress for those personally affected. Addressing disparities in the effects of infrastructure failure is a task that should be high on the priority list of every local elected official. We know how to build resilient infrastructure. 

This is especially true when it comes to flooding, a trend that climate scientists suggest will only increase in frequency over the years to come. This is true for all sorts of cities, ranging from global hubs like New York to regional coastal destinations like Charleston. Theirs is—at minimum—a two-sided challenge. First, there is a pressing need and concern to prepare for increasingly common weather events, from multi-inch rains to the remnants of Atlantic hurricanes. And second, the management of a public who is deeply concerned—and rightly so—about its future place in the city. Ideally, that place sits above the city’s expanding floodplain. 

Public infrastructure is not perfect. But if we wish to understand the significance of when and how it fails, and what we can do about it, we should begin with recognizing its overwhelming functionality. Problems arise—of course they do. But cities represent winning track records of creative solutions to collective problems. If it were not so, half of the world wouldn’t live in them.