Climate change has profoundly impacted cities worldwide in recent years and nowhere is this more evident than in Boston and New York City. Heavy rainfalls, rising sea levels, and unpredictable weather patterns have turned these two major U.S. cities into battlegrounds for flood management. Climate change is messing with city sewers in NYC and Boston, pushing both cities to overhaul their old infrastructure. Their responses, however, have taken different paths, offering valuable insights into urban resilience and adaptation.

The Sewer Crisis Unfolds: Two Cities Underwater

In July 2023, Boston received 3.07 inches of rain in just one day, overwhelming its sewer systems. The sewage overflow into Boston Harbor triggered a public health warning. It was part of the second-rainiest summer in the city’s history.

A few months later, on a single day in September, New York City received 8.65 inches of rain, the highest September rainfall since Hurricane Donna in 1960. Low-lying neighbourhoods flooded, and nearly half of the city’s subway lines were suspended as water-filled underground stations.

Both events highlighted the growing vulnerability of East Coast cities to extreme weather. But climate change isn’t the only factor. Outdated infrastructure, particularly combined sewer systems that manage stormwater and sewage in the same pipes, worsens the problem.

When these systems reach capacity, they overflow, sending untreated sewage into waterways and city streets. This mix of rainwater and raw sewage poses public health risks and violates the Clean Water Act.

Consent Decrees: Legal Mandates for Flood Management

Because of these violations, both cities operate under consent decrees with the U.S. Environmental Protection Agency (EPA). These legally binding agreements require Boston and NYC to address the combined sewer overflow (CSO) issues. Failure to comply could result in hefty fines and further legal action.

John Sullivan, the chief engineer at the Boston Water and Sewer Commission, shared that 90% of the nation’s sewer systems are under consent decrees. “A consent decree outlines how many years you have to get this problem fixed,” said Sullivan. Though the timeline can be long, cities must take action to meet legal requirements.

Also Read: Historic Rainfall Cause Severe Floods In North Carolina

Boston’s Strategy: Separating Sewers

Boston’s approach focuses on separating its combined sewer system. This involves creating separate pipes for stormwater and sewage, preventing them from mixing during floods. This process began well before the current flood crisis. In response to a 1987 court order, the Massachusetts Water Resources Authority initiated nine sewer separation projects between 2000 and 2015. Only about 10% of Boston’s 1,538 miles of sewer pipes remain combined today.

Critical points of Boston’s sewer separation plan include:

• Priority Areas: Projects focus on areas where human contact with contaminated water is most likely, such as public beaches.
• Costly Projects: In 2021, the cost averaged $340,000 per acre, totalling over $30 million for 88 acres of work.
• Future Plans: The city has earmarked 230 acres in East Boston and 400 acres in South Boston for separation projects between 2024 and 2029.

However, space constraints in Boston’s dense urban areas pose challenges. Underground infrastructure already includes gas, electricity, and telephone lines, making it difficult to install new sewer pipes.

Also Read: How Sorghum is Leading the Way in Reducing Nitrogen Loss and Greenhouse Gases

New York City’s Strategy: Cloudburst and Green Infrastructure

In contrast, New York City’s response to climate change is messing with city sewers by relying on green infrastructure rather than separating its sewers. Given that 60% of its 7,400 miles of sewer lines are combined, fully modernising the system would cost an estimated $100 billion. Instead, the city has developed the Cloudburst plan in partnership with Copenhagen, Denmark.

The Cloudburst plan employs a combination of grey and green infrastructure to manage stormwater:

• Gray Infrastructure: Underground storage tanks capture excess rainwater during storms.
• Green Infrastructure: Rain gardens and porous concrete in streets help capture and divert stormwater. For example, sunken basketball courts at public housing developments store rainwater during heavy downpours.

In 2023, NYC invested $84 million into Cloudburst infrastructure at eight public housing sites. Another $390 million was allocated for four neighbourhoods in the Bronx, Brooklyn, and Queens, chosen based on their flooding history and socio-economic vulnerability.

Alexx Caceres, who manages East New York Farms, praised the new infrastructure’s provision of time for the sewer system to drain excess water. Other initiatives across Staten Island and the Bronx have focused on restoring natural drainage corridors.

Also Read: Is The US Census Ready To Tackle Climate-Driven Population Displacement?

The Science Behind the Solutions

While climate change is messing with city sewers in NYC, both cities are taking distinctly different approaches. Boston’s focus on sewer separation is rooted in a need for robust, large-scale infrastructure to handle increased rainfalls and rising sea levels.

• Sea Level Rise: Boston’s coast is particularly vulnerable, with sea levels rising 3x faster than the national average. During high tide events, Boston’s outfalls (pipes that discharge excess sewage) can become submerged, slowing the draining process and exacerbating flooding.
• Heavy Rainfall: Due to the changing climate, the Northeast is seeing more frequent and intense storms. In Boston, storms can drop up to six inches of rain. Sewer separation ensures that stormwater can be quickly diverted out of the city.

Meanwhile, New York’s strategy leverages the benefits of green infrastructure:

• Stormwater Management: Green infrastructure helps to absorb and slow down rainwater, easing the burden on the city’s combined sewers. These measures are also more space-efficient in NYC’s densely populated boroughs.
• Cloudburst Success: By focusing on neighbourhoods vulnerable to flooding and social inequalities, New York is addressing not just the physical damage caused by storms but also the disproportionate impacts on low-income communities.

The Cost of Adaptation

Both cities need more financial help to modernise their infrastructure. Boston’s sewer separation projects are expensive, and finding space for new pipes in already crowded streets is difficult. Meanwhile, New York’s Cloudburst plan also comes with a high price tag, and scaling the program to cover more of the city will require substantial investment.

Other cities across the U.S. are grappling with similar issues. However, they often have fewer resources than Boston and New York to tackle these challenges. According to Joseph Kane, a fellow at the Brookings Institution, cities and states bear 90% of the cost of public water infrastructure.

Although federal programs such as the Clean Water State Revolving Fund and the 2021 bipartisan infrastructure law provide some financial assistance, they do not cover the full scope of needs.

Stormwater Fees: A Solution?

Cities are increasingly turning to stormwater fees to raise funds. Property owners are charged based on the number of impervious surfaces, like parking lots or rooftops, contributing to stormwater runoff. Boston recently implemented a fee for properties with more than 400 sq. ft. of impervious area.

• Benefits of Fees: Stormwater fees ensure that property owners contribute to the costs of maintaining and improving the city’s flood management infrastructure.
• Debates: There’s ongoing debate over how high these fees should be and whether they are an equitable solution. New York has yet to adopt such fees, although discussions are continuing.

The Road Ahead: Is It Enough?

Climate change is messing with city sewers in NYC and Boston, and both cities have taken meaningful steps to address this issue. However, the road to fully climate-proofing sewer systems is long and expensive. Boston’s separation strategy and New York’s Cloudburst plan have benefits and challenges. Their success will depend on continued investment and adaptation.

As cities across the U.S. face similar climate-related infrastructure issues, Boston and New York’s experiences offer valuable lessons. Urban resilience will require a blend of innovation, funding, and collaboration across sectors, whether through investing in green infrastructure or retrofitting existing systems.

Also Read: Has Extreme Weather Made Voters in US Care More About Climate Change?