Current and future flood risk under climate change in New Paltz, New York

Downtown New Paltz, New York

photo by Daniel Case, CC BY-SA 3.0

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New Paltz report cover


Inland floods are some of the most devastating natural disasters and are expected to worsen under climate change due to the intensification of extreme precipitation. In this study, present and future flood risk in New Paltz, NY, is examined through changes in the 1-in-100 year and 1-in-500 year flood events. Future rainfall and streamflow are estimated for two time periods, 2041-2060 and 2071-2090 representing the mid and late 21st century, respectively, using a regional climate model and river-reach scale hydrologic model.

The output of these simulations show that the historical 100-year rainfall event is 1.5x and 4x as likely in 2041-2060 and 2071-2090, respectively. The historical 100-year streamflow event is 2x and 3.7x as likely in 2041-2060 and 2071-2090, respectively. Greater changes in frequency were calculated for the 500-year rainfall and streamflow events.

Using these estimates as inputs into a flood model reveal significant increases in flood risk across New Paltz. The total inundated area for the 100-year event within the flood model domain increases by 7% and 20% by mid and late 21st century, respectively. The number of buildings inundated by the 100-year event increases by 12% and 34% by the mid and late 21st century, respectively. These metrics also increase in the future periods for the 500-year event but the changes are smaller in magnitude.

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