Hidden waterways help explain the surge in potholes

Yulin L.

Hidden waterways help explain the surge in potholes
City workers fix a large pothole at Fourth Ave and 46th Street. Local hydrology researcher Eymund Diegel says the pothole is likely to return because it sits above a "ghost pond." Photo by Nick Dawson

Potholes are everywhere!

If you feel like the roads are worse than usual, you aren’t alone. According to NYC Open Data, as of April 19, 2026, there have been 38,540 pothole reports across the city, a staggering 176% increase from the 13,916 complaints made during the same period last year. The crisis has become so severe that the Department of Transportation has already launched four "Pothole Blitz" this year. So far, the department has filled more than 102,000 potholes.

In Sunset Park alone, over 346 complaints have been filed since January.

“At the corner of 42nd and 4th Avenue, there have been continual sinkholes for the past 5 years. Every six months, a sinkhole appears. The city comes to fill it, does some repairs and it just comes back,” Jodi Avrigan, a Sunset Park resident, said.

The Department of Transportation attributed this year’s spike in complaints to high-moisture winter weather conditions and the cycle of freezing and thawing conditions. On April 9, after filling the 100,000th pothole, Mayor Mamdani said that for the next step, the Department of Transportation would repave over 1,000 miles of road in the city.

Historically, New York City was not a hotbed for sinkhole activity. However, they have become more frequent in recent years. Several factors, including aging infrastructure and urban development, have contributed to the uptick. Changing weather patterns, such as increased rainfall, lead to the erosion of soil and sediment around underground pipes, weakening the ground and making it more susceptible to sinkhole formation.

Further, heavy rainfall or snowmelt often causes local springs to surge.

According to the 1911 Encyclopedia Britannica, Brooklyn got its name from the Dutch town Breuckelen, which means "marshland." Long before it was an urban hub, the Sunset Park neighborhood was a hardwood forest fed by several natural streams. One of them, Danckaert’s Brook, flows through the area and empties into the Bush Terminal Park lagoon.

These "ghost streams" still make their presence known today. Historically, water pressure from Danckaert’s Brook contributed to the collapse of piers at the Bush Terminal. Buildings that sit close to historic streambeds may experience flooding from rising waters in local springs and streams.

According to Eymund Diegel, a local hydrology researcher who maps hidden waterways in New York City, the mysterious puddles or "upwelling" seen in front of buildings or in backyards after a storm are often the result of this underground history resurfacing.

“An understanding of hydrological history is important because it predicts the future,” Diegel said.

Ghost streams can erode soil under asphalt, causing potholes and other road failures. The city’s storm resiliency planning also relies on understanding historical streams and flooding patterns. The four-mile 4th Avenue corridor project from Park Slope to Sunset Park includes elevating subway vents to match the raised medians as a flooding mitigation consideration.

For those interested in learning more about the city's historical landscape and ecology, several resources are available. The Welikia Project visualizes block-by-block ecosystems and the geologic foundations of the land before it became New York. Residents can look up the historical water life of their own backyards, while NYC H2O offers education programs on the city’s water system and ecology.