{"id":15608,"date":"2022-06-03T15:00:00","date_gmt":"2022-06-03T19:00:00","guid":{"rendered":"https:\/\/www.renthop.com\/content-manager\/?p=15608"},"modified":"2022-06-03T15:01:29","modified_gmt":"2022-06-03T19:01:29","slug":"subterranean-network-nyc","status":"publish","type":"post","link":"https:\/\/www.renthop.com\/blog\/subterranean-network-nyc\/","title":{"rendered":"The City Under the City – Subterranean Network Underneath NYC"},"content":{"rendered":"\r\n

Millions of humans (and 600,000 dogs) walk the streets of New York City<\/a> each day, oblivious to the massive subterranean network beneath their feet. This hidden infrastructure moves the city\u2019s electricity, water, internet, wastewater, steam, and natural gas. Private companies and separate agencies control each element of the network. No single map of all of these interconnecting systems exists. Yet street workers will open and repair the streets at least 550 times a day. This is a potentially dangerous situation if workers don’t know what resides below.\u00a0<\/p>\r\n\r\n\r\n\r\n

The city is currently working toward a full map of the underground infrastructure using the Geographic Information System<\/a> (GIS). The GIS is a computer system for organizing information related to the locations on the earth\u2019s surface. New York City already has a base layer map, and various agencies and companies can create layers of data based on that map. There’s already a similar map for above-ground infrastructure<\/a>, and the city\u2019s Open Data Labs also produced a detailed street-related map<\/a>. However, the city likely will not release the subterranean infrastructure version due to security concerns.\u00a0<\/p>\r\n\r\n\r\n\r\n

While we can\u2019t know exactly what\u2019s below us at any given spot in the city, we can explore subterranean New York City from the deepest layer to the concrete and asphalt just below the soles of our shoes.\u00a0<\/p>\r\n\r\n\r\n\r\n

Bedrock<\/h2>\r\n\r\n\r\n\r\n

Deep under NYC lies bedrock, the solid rock below soil and sand that extends inward towards the earth\u2019s core. Between one billion and 300 million years ago, tectonic plates collided, and volcanic ridges erupted, near what would become New York City, forming many of the distinctive rock formations and ridges of Manhattan<\/a> and the Bronx<\/a>. In many areas, this bedrock is visible or very near the surface<\/a>, which is important as modern skyscrapers are anchored to the bedrock, and digging deep for bedrock is difficult and expensive.\u00a0<\/p>\r\n\r\n\r\n\r\n

Between 90,000 and 70,000 years ago the Wisconsin Glacier<\/a> extended south over the city, and as it retreated it left a terminal moraine, a belt of rocks, silt, and debris, over the city, but particularly across Brooklyn<\/a> and Queens<\/a>. Indeed, the boroughs on Long Island would be underwater if not for the sediment left by the glacier, as their bedrock lies below sea level.\u00a0<\/p>\r\n\r\n\r\n\r\n

This may give you high school earth science flashbacks. However, it\u2019s important for engineers to know and track as they build and maintain the city\u2019s subterranean world. Information about both soil types and water levels is planned for the final subterranean infrastructure map.\u00a0<\/p>\r\n\r\n\r\n\r\n

The Water Tunnels and Water System<\/h2>\r\n\r\n\r\n\r\n

The deepest human-made element of the vast infrastructure below the city is the water tunnels. They carry the 981 million gallons of water used every day in New York City from the city\u2019s 2,000 square mile watershed. The tunnels\u2014the first of which was completed in 1917, the second in 1936, and the third of which is nearing completion in 2022\u2014run through the bedrock between 1,110 feet and 520 feet below sea level.<\/p>\r\n

The force of gravity moves water through the tunnels. Pressure from the constant flow creates enough upward pressure to send water up into ducts. They ducts rest 200 feet below the surface, and water then moves through vertical shafts up to 35 feet in diameter. Then, water goes to iron and steel pipes up to 7 feet in diameter that supply water to the service lines that run to individual homes and businesses. The water main sit three feet below the street. The city has almost 7,000 miles of water mains, and they run under nearly every street.\u00a0<\/p>\r\n\r\n\r\n\r\n

Sewer Lines<\/h2>\r\n\r\n\r\n\r\n

Just about 100 feet below New York streets lies 7,000 feet of sewer lines. There are two types of water in NYC sewers: wastewater, consisting of anything that goes down drain the toilet, and stormwater, which is rain and melting snow. About 60% of city sewers are combined sewer systems. The pipes carry both storm and wastewater directly to one of the 95 wastewater treatment plants. The look and structure of sewer pipes aren\u2019t consistent across the system. In 2011, Luis Baerga, a long-serving sewer inspector, told The New York Times<\/em>, \u201cIt depends on how it was built… I remember one time\u2026it looked like a catacomb.\u201d\u00a0<\/a><\/p>\r\n\r\n\r\n\r\n

Learn more:\r\n