Geography of New York Harbor

The system of waterways of the Port of New York and New Jersey forms one of the most intricate natural harbors in the world. Although the overall form of the estuary remains unchanged from the time of Giovanni da Verrazzano's visit in 1524, no part of it remains unaffected by human activity, and some parts, such as Hell Gate and Ellis Island, have been almost completely altered. In the greatest hidden change, the navigational channels have been deepened from the natural 17 feet (5.2 m) depth to 45 feet (14 m), in some places requiring blasting of bedrock.

The harbor lies at the confluence of three major bodies of water. The harbor opens onto the New York Bight (Atlantic Ocean) to the southeast and Long Island Sound to the northeast. Both of these are essentially marine bodies with both tides and saltwater, but the Sound compared to the Atlantic is about 20-30% less saline (as an estuary), and the tide is about 3 hours later with as much as 70% more variation. The Hudson River adds a fresher, non-tidal inflow from the north, although the tide and brackishness extend well up river.

These three combine to generate an extremely complex system of tides and currents throughout the extended hydrologic system from Albany to Montauk Point to the Hudson Canyon region of the New York Bight. The New York Harbor Observing and Prediction System (NYHOPS) utilizes information from sensors, weather forecasts, and environment models to provide real-time forecasts of meteorological and oceanographic conditions in the area.

Since the Ash Wednesday Storm of 1962 beaches along the shores of the East Coast have been regularly replenished with sand pumped in from off-shore.The United States Army Corps of Engineers (USACE) coordinates the projects. In 2016 the USACE and the Port Authority of New York and New Jersey produced a comprehensive restoration plan for the harbour region, which included proposals to mitigate the effects of sea-level rise through projects to restore natural areas.

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