Today, Mr. Patterson said, the sub-crypt flooding is way reduced. Why? His theory centers on the rise of Enclave — a 430-unit rental complex that runs the length of West 113th Street between Amsterdam Avenue and Morningside Drive. The dwelling, built from 2014 to 2016, set off protests from opponents who said the 15-story complex obscured street views of the cathedral.
With a rather bemused expression, Mr. Patterson argued that Enclave’s foundation went down far enough to act as a subterranean barrier that diverted many of the underground flow away from the cathedral. “They solved our problem.”
We left his office to take one other have a look at the deep vault. Crucially, Mr. Patterson knew exactly where electricians had recently installed latest light switches, so we had no need for cellphone lights.
The cathedral’s cavernous subbasement consisted of huge rooms, its ceiling perhaps 25 or 30 feet high. It was all poured concrete, and, unlike the crypt above, it was empty, its floor bare. That and its cavern-like size helped to clarify the echoes we heard. With the lights on, the sump pumps looked less spooky, especially when Mr. Patterson began them up manually and the pit water gurgled upward.
We moved into the larger room. The big pit was about eight or nine feet wide, and Mr. Patterson said it served as a gathering point that fed water into the pumps. The encompassing floor, just like the steps, was filled with watery muck. Our shoes made splish-splashy noises.
During our tour, Mr. Patterson kept declaring features of the sub-crypt area that were either old and unused or mysterious in purpose. There have been pipes, stairs and a large shaft that went nowhere — relics from 130 years of constructing and rebuilding.
Now, in passing, he mentioned one other relic.
At the underside of the massive gathering pool, Mr. Patterson said, was a feeder pipe, its source unknown. “It’s one other pipe from nowhere,” he said, his voice reverberating. “Nevertheless it was put there intentionally to get water into that pit.”