Effects of Sea Level Rise on Modeled Storm Surge and Current Speeds in New Hampshire Estuaries

Thomas Charles Lippmann, University of New Hampshire, Department of Earth Sciences, Durham, United States, Anna Simpson, Oregon State University, Corvallis, OR, United States, Salme Cook, University of New Hampshire, Durham, NH, United States and Paul H Kirshen, University of Massachusetts Boston, School for the Environment, Boston, MA, United States
Abstract:
The effects of sea level rise on storm surge energy transformation and flood and ebb current magnitudes are examined in two distinctly different New Hampshire estuarine systems using FVCOM. Simulations are computed for 0.01 annual exceedance probability storm surge with and without sea level rise. Results for the Great Bay Estuary show that although the maximum sea surface elevation is much higher during storm events, upstream energy decay is similar (50%) with and without storm surge or sea level rise. Corresponding depth-integrated currents increase by 10-30% with sea level rise, 23-52% with the storm surge, and 32-97% for the combined event. However, results from the Hampton/Seabrook Estuary show that energy loss through the inlet increases from 2-4% for no storm and present day sea level to 30-40% for storm surge with sea level rise, partially mitigating inland inundation. Depth-integrated current magnitudes in Hampton/Seabrook inlet increase by a factor of 4 under sea level rise and storm surge. Model results suggest that sea level rise will have significant impacts on storm surge inundation and current speeds.