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207th Street and 148th Street Transit Yards Site Surveys

New York City<br style='line-height:2px'>New York City Transit

HAKS provided survey services to support a study to mitigate flooding of the 207th Street and 148th Street New York City Transit (NYCT) yards.

The 50-acre 207th Street site is generally bounded by 207th Street and the University Heights Bridge to the south, the Harlem River to the east, West 215th Street to the north and Tenth Avenue to the west. HAKS’ survey division established a horizontal and vertical baseline around the site that was tied to the United States State Plane Coordinate System, Long Island Zone, 1983, and to the North American Vertical Datum 1988. As the entire transit system has been mapped in the NYCT vertical system, equalities to both vertical systems were shown on the plans. Similarly, HAKS performed a topographic survey of the 10-acre 148th Street yard and portal, which was tied to the same horizontal and vertical control. 

The 148th Street Yard survey also included extensive property line tasks. This included a retracement of several parcels, one of which contained a school above the NYCT property. In addition, the survey established the limits of Adam Clayton Boulevard as well as portions under the elevated structure of the Harlem River Drive. Tasks also included identification of easements on the properties. Numerous new permanent easements as well as acquisitions property both at grade and subsurface were prepared as well as drawings and metes and bounds descriptions for the parcels.

For both locations, critical areas prone to flooding were identified. This included a survey of a portion of the tunnel and portal leading out of each yard. Elevations on the perimeter walls and roads for the yards were also obtained. At the 207th Street yard, our survey teams obtained elevation on the visible mud line on the wall in the Harlem River.

Permanent benchmarks established at critical locations can be used to establish elevations of the proposed improvements at the “hot spots” during construction.

In many cases, reflector-free total stations were employed to obtain elevations remotely in inaccessible locations. Where applicable, HAKS employed 3D laser scanning technology to obtain elevations over broad areas.