CONTRIBUTION OF RELATIVE SEA-LEVEL RISE TO HISTORICAL HURRICANE FLOODING IN NEW YORK CITY

Flooding during hurricanes is a hazard for New York City. Flood height is determined by storm surge characteristics, timing (high or low tide) and relative sea-level (RSL) change. The contribution from these factors is estimated for seven historical hurricanes (1788–2012) that caused flooding in New York City. Measurements from The Battery tide gauge and historical accounts are supplemented with an RSL reconstruction from Barnegat Bay, New Jersey. RSL was reconstructed from foraminifera preserved in salt-marsh sediment that was dated using marker horizons of lead and copper pollution and 137 Cs activity. Between the 1788 hurricane and Hurricane Sandy in 2012, RSL rose by 56 cm, including 15 cm from glacio-isostatic adjustment. Storm surge characteristics and timing with respect to astronomical tides remain the dominant factors in determining flood height. However, RSL rise will raise the base level for flood heights in New York City and exacerbate flooding caused by future hurricanes.