Figure 1. Model bathymetry. (a) Lower Hudson River and New York Harbor in outer grid; the full grid extends north to the tidal limit of the Hudson and includes regions to the east (Western Long Island Sound) and west (Newark Bay, Arthur Kill). Distance from The Battery (km) are marked in red. (b) Zoom on center of nest grid at Verrazano Narrows for base case. Gray lines mark every fifth grid cell, and A-A' marks the cross-section in the lower panel. (c) Center of nest grid for barrier cases. (d) Cross section at location of barriers, with bathymetry for base case (blue markers) and barrier case (red markers). From Ralston (2022), “Impacts of Storm Surge Barriers on Drag, Mixing, and Exchange Flow in a Partially Mixed Estuary, J. Geophys. Res., 127, e2021JC018246. https://doi.org/10.1029/2021JC018246
Tuesday, January 24, 2023 from 10:30AM - 12:00PM EST via Webinar
Presented by: Dr. David Ralston, Woods Hole Oceanographic Institution
Storm surge barriers are increasingly being considered as flood mitigation strategies for coastal cities around the world. In New York Harbor and the surrounding region, storm surge barriers are among the options being considered by the Army Corps of Engineers (ACE) under the New Jersey Harbor and Tributaries Coastal Storm Risk Management Feasibility Study (HATS). Dr. Ralston discussed his independent research and findings on the potential impacts of a storm surge barrier located in the Verrazzano Narrows section of Upper Bay, New York Harbor (Figure 1). While a single barrier in the Verrazano Narrows is not a scenario being considered under the HATS, the ACE study does include a barrier in the Verrazano Narrows as a component evaluated under alternative 3a. Dr. Ralston’s work provides important projections of how barrier infrastructure can influence tidal currents and estuarine conditions. Dr. Ralston found that changes in flow through and around the barrier structures are expected to reduce the tidal amplitude and cause changes in tidal water levels, currents, and the distributions of salinity and sediment in the Estuary. His research builds on a 2019 study by Dr. Orton and Dr. Ralston on how barriers may affect flow and transport processes in the estuary. In his current study, Dr. Ralston developed a higher resolution numerical model to better represent flow near barriers and applied the model to evaluate potential impacts on the physical conditions and sediment transport processes in the Estuary. These findings provide important insights into expected changes that should be confirmed in future modeling studies and thoroughly evaluated under the HATS.