Subway station entrance
Subway sidewalk ventilation detail

In the summer of 2007, heavy rains caused serious flooding problems in many of the subway tunnels that service Manhattan. The Metropolitan Transit Authority (MTA) identified four of the most affected stations and contracted B. Thayer Associates to map the streets above them in three dimensions in an effort to identify possible causes and solutions to this flooding: the 86th Street and 125th Street Stations on the Lexington Avenue line, the Canal Street Station on the Broadway Line, and the Chambers Street Station on the Nassau Street Line. B. Thayer Associates mapped the primary surface hardware associated with the subways using GPS, Total Station, and Differential Leveling Techniques. The B. Thayer Associates team also mapped major grade features to show the general topography from building face to building face. A total of five miles of busy Manhattan streets were mapped and an additional 100 feet of mapping was performed down each intersection of each of the four streets.

Flood Mitigation Survey, Four Subway Stations

Location: New York, NY

Client: New York City Transit