HRFIDSS Flood scenarios

Sea level rise scenarios range from 0 to 6 feet above the base mean sea level of 1983-2001, a standard sea level used by the National Oceanic and Atmospheric Administration (NOAA). These sea level rise estimates are based on projections from the 2011-2014 ClimAID report. Projections for the year 2100 range from 1.25 to 6.25 feet near New York City.

Users can also choose from a wide range of possible storm scenarios that could strike the region. Scenarios range from common storms like the 5-year return period (20% chance of annual occurrence ), to the less common 1000-year (.1% chance of annual occurrence). Community resilience and vulnerability can be evaluated by looking at the locations of critical infrastructure such as transportation and emergency services, natural features such as forests and wildlife, social vulnerability, and estimated damage.

The Hudson River Flood Impact Decision Support System flood maps are unique in that they determine risk based on dynamic water flow modelling that accounts for tides, storm surges, sea level rise, and tributary freshwater inputs to the Hudson. This means that the flood scenarios capture the effects of rainfall to the extent possible, which can be particularly significant in the upper parts of the Hudson, just below the Troy dam. However, it is important to note that tributary floodplains are not included in the modelling and mapping – the flood maps show only the Hudson River’s floodplain. The model used here is the same one used for the New York Harbor Observing and Prediction System (NYHOPS;