Parameterization of Coastal Wetlands and Their Role in Back Bay Hydrodynamics

This paper will provide an evaluation of the role of coastal wetlands in flood risk mediation by performing hydrodynamic modeling of storm surge in back bays that include various configurations of wetland features. Wetland parameters varied in the research study include the elevation, shape, volume, and vegetation type (represented by the Manning’s friction coefficient) to identify the role of wetlands in reducing back bay flooding.   This information can be used to determine best future management practices for dredged material placement that will serve to maintain and restore wetlands in light of environmental pressures such as climate change, subsidence, storm-induced erosion, boat wakes, and other factors influencing coastal wetland dynamics.

Following Hurricane Sandy in 2012, the United States (U.S.) Congress authorized the large scale North Atlantic Coast Comprehensive Study (NACCS) to address the present and future flood risk to this region. Part of that study was an in-depth numerical modeling and statistical analysis using the ADvanced CIRCulation (ADCIRC) and STeady-state spectral WAVE (STWAVE) models and the Joint Probability with Optimal Sampling (JPM-OS) statistical technique. Following the NACCS, the New Jersey back bays were identified as a high-risk area requiring further in-depth analysis of the effectiveness of surge barriers and coastal wetlands to reduce water levels in the back bays during storms. This paper will discuss the analysis of a set of coastal wetland configurations in the New Jersey back bay region simulated with a set of 10 synthetic storm suite selected from the NACCS study.   Analysis of maximum surge envelopes, water level time series, and characteristics of tropical storm forcing conditions were used to evaluate and compare the effectiveness of the wetland configurations.