About a year ago, I got a letter from a reader about an underground river hidden somewhere in Morningside Heights:

Years ago, I lived at [removed]. My father swore there was a stream running under a lot of the buildings there.

I’m endlessly fascinated by Manhattan’s underground rivers. Once an island covered in streams, brooks, rivers, swamps, and marshes, many of these waterways have managed to cut through landfill and building foundations to continue to follow beneath the city to this day. Last week, I finally found myself in the area, and stopped by the building to investigate.

According to the letter:

In the basement where we lived, there was a room to the right as you got off the elevator.

It was pretty large and had at one time been used for storage.

On the left as you entered the room was a large wooden trap door built into the floor. There was always the sound of rushing water from under it and once when I had a chance, I saw my father lift it. There was gushing water behind it.

I pulled up the trap door, and while there wasn’t a gushing river…

…I could definitely see a small stream flowing very quickly through a missing chunk of the foundation. It was hard to photograph, but those little bits you can see were zipping along as water flowed through.

That water would be underground here makes sense. The area used to have have a number of waterways, as seen on the 1865 Viele Map below. In fact, up until the early 1900s, two nearby springs, the Tiemann fountain and Indian Spring, provided drinking water for locals. From Springs and Wells of Manhattan and the Bronx, by way of Watercourses: the Tiemann drinking fountain was “one stop that nearly every driver of the old Broadway stages and trolleys might be counted upon to make several times during the day.”

But to those more familiar with building foundations, what exactly is going on here? What would be the purpose of having a trap door here? Could this have been filled in to close up the waterflow, only to have the stream erode its way right through again?

Will definitely have to check it out after a heavy rainfall.

-SCOUT

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