New York City's Sewer System: A Vital Infrastructure Asset in Need of Modernizahon

By Frank P Orlowski, President Ation Advisory Group | [email protected] |www.ationadvisory.com

As we enter the fourth straight week of heavy weekend rains in New York City, I reflect that New York City is becoming a flood zone. The "once-in-a-century" storms are becoming more common. What used to be a few common flood areas on the FDR Drive, or the West Side Highway are becoming more widespread throughout the city. Scenes such as the one outside my apartment building are becoming more common, where manholes are bursting, and the sewer system is backing up during heavy rains.

Putting aside climate change, why is this happening? Why can't the sewer system of one of the largest cities in the world handle heavy rainstorms and constantly overflow? Given the boom of construction in New York City, why are new and existing buildings having to spend hundreds and sometimes millions of dollars on water remediation because they cannot rely on the New York City Department of Sanitation's sewer system?

To understand the growing problem, one must look at the history of New York City. Unlike many cities, New York, especially Manhattan, was a "planned city." One only must look at the street layout of grids to understand that there was some sort of organized and engineered pattern when designing Manhattan. This also includes never seeing any overhead electric or cable wires or hot water heaters in buildings, as steam is delivered from a central system where both pipes and wires are underground. However, the other underground utility that was planned is the sewer system.

New York City's sewer system is one of the oldest and largest in the world. It was built in the late 19th and early 20th centuries before indoor plumbing and other modern conveniences were widely used. As a result, some of the sewer pipes in New York City are too small to handle the current volume of wastewater (this includes toilets and rainwater).

This can lead to several problems, including sewer backups, flooding, and pollution. Sewer backups can occur when the pipes are clogged with debris or simply overwhelmed by the amount of wastewater flowing through them, which we see more of in New York City. This can cause sewage to back up into homes and businesses. If the pipes cannot handle the volume of wastewater, the excess water overflows into streets, rivers, and streams, as we currently see in Manhattan. This can pollute the water and make it unsafe for fishing and other recreational activities (not to mention the smell!).

Let's examine the root cause of the problem, stemming back from the planning stages of New York. When New York City was built, engineers made choices. The choices for the sewer system centered around cost versus benefit versus planned growth. When the sewer system was first built, there was a choice between using more expensive, durable, thicker pipes or cheaper, less durable, thinner pipes. The city chose to use the cheaper pipes, which has contributed to the problem of bad drainage and flooding.

In addition, New York City, unlike more modern cities, has what's called a Combined Sewer Overflow System (CSO), which means that stormwater runoff and wastewater flow through the same pipes. When it rains heavily, the sewer system can become overwhelmed, causing CSO events. During a CSO event, untreated wastewater is discharged into rivers and streams, as we are observing in the East and Hudson Rivers.

When the city was growing rapidly in the late 19th and early 20th centuries, the engineers were under pressure to build the sewer system quickly and cheaply. Second, they did not anticipate the full extent of the city's growth or the increased demand for water and wastewater services. Third, the technology for designing and building large-scale sewer systems was less advanced at the time. As a result, many of the sewer pipes in New York City are too small to handle the current volume of wastewater. This can lead to several problems, including sewer backups, flooding, and pollution.

The engineers chose to use various pipe sizes, ranging from 6 inches to 12 feet in diameter. The size depended on the specific needs of each area of the city. They used larger pipes in areas with a high population density and demand for wastewater services. For example, they used 12-foot diameter pipes in downtown Manhattan, where the population density was high and many large commercial and industrial buildings were located. The specific pipe sizes that they chose were based on several factors, including the area's estimated population, the type of development (residential, commercial, or industrial), and cost. Since the cost of a 6-inch pipe is almost half as much as a 12-inch pipe, to save money, the engineers went with 6-inch pipes when 12-inch pipes should have been installed. Midtown and uptown residential areas were not developed, and the sewer system implemented needed to be more organized. The 6-inch diameter pipes were meant for single-family homes that lined the Upper East and West Side rather than the large apartment buildings now in place.? The engineers did not anticipate the full extent of the city's growth or the increased demand for water and wastewater services. As a result, many sewer pipes on the Upper East and West Side need to be bigger to handle the current volume of wastewater.

Another crucial economic choice was the type of materials to be used. Brick and stone were the most expensive materials but also the most durable. Iron and steel were less expensive but more susceptible to corrosion, as we can see from watermain breaks in recent times. The engineers decided to use various materials, depending on the specific conditions. They used brick and stone in areas where the sewer pipes would be under heavy load, such as under busy streets. They used iron and steel in areas where the sewer pipes would be under less load, such as in residential areas.

The engineers also had to consider the cost of construction. The sewer system was a complex and ambitious project and was very expensive to build. The city had to borrow money to finance the project, which took many years to complete.

The current sewer system consists of over 7,400 miles of sewer pipes, 135,000 catch basins, and 95 wastewater pumping stations. The system transports over 1.2 billion gallons of wastewater daily to wastewater treatment plants. The wastewater treatment plants remove pollutants before they are discharged into the East River, Hudson River, and New York Bay. However, in times of severe rains wastewater is discharged into these bodies of water.

The New York City Department of Environmental Protection is working to address the problem of sewer pipes that are too small. The department is investing billions of dollars to upgrade the sewer system and build new infrastructure. However, it will take many years to completely replace all of the old sewer pipes in the city.

Upgrading and expanding the sewer system is a very expensive proposition. It is estimated that it would cost hundreds of billions of dollars to completely replace all of the old sewer pipes in New York City.

There needs to be more political will to invest in the sewer system, which currently does not exist. This is due in part to the fact that the sewer system is out of sight and out of mind for most people. It is also since the benefits of investing in the sewer system take time to be obvious. Time shall tell if and when the situation becomes glaringly obvious!