Operational Coastal Flooding Early Warning System for Metropolitan New York and Long Island

Introduction

Significant portions of the coastal margins of New York City, Long Island and northern New Jersey are particularly prone to serious flooding due to the low topography and gentle slopes of the surrounding coastal plain. The shape and orientation of Long Island Sound makes it a natural funnel for northeast winds to blow into and pile up water in the western Sound during major storm events. Such set ups then propagate into New York Harbor through the East River. Northeast winds over the coastal Atlantic Ocean also raise sea level against the south coast of Long Island due to the Ekman effect (Coriolis force), further driving storm waters into New York Harbor.

LIDAR image of business district of Manhattan showing seawall locations and elevations. The imager is flying above the Hudson River, looking east.

The New York Metropolitan region could, in principle, be protected against future flooding catastrophies by constructing three large storm surge barriers, strategically located at The Narrows, the eastern end of the East River near Whitestone, and at Perth Amboy, Staten Island. Normally open, at the onset of a major hurricane or nor'easter event, the barriers would be closed against the sea for a limited period of time (up to two days) to prevent ocean surges from entering the Harbor and causing wide-spread damage.