1 Oct 2025

Numerical Storm Surge Modeling and Probabilistic Analysis for Evaluating Proposed New Jersey Back Bays Inlet Closures

Abstract: The US Army Corps of Engineers, Philadelphia District, and the New Jersey Department of Environmental Protection are currently engaged in the New Jersey Back Bays (NJBB) Coastal Storm Risk Management Feasibility Study. The US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, conducted a numerical hydrodynamic modeling and probabilistic hazard analysis study to evaluate the effectiveness of storm surge barriers in reducing water levels in the NJBB. The numerical modeling study included the simulation of water levels and a comparison of water surface elevations and corresponding annual exceedance frequency between existing conditions and six final project alternatives. Results from the hydrodynamic simulations and probabilistic analysis are presented herein.

25 Sep 2025

Evaluation of the Coastal Hazards System (CHS) Probabilistic Framework’s Storm Selection Methods Along the US West Coast

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) evaluates the application of a traditional approach to screening and sampling historical storm events to quantify wave and water-level extremal distributions along the US West Coast, specifically focusing on Washington, Oregon, and California. High-fidelity simulations of storm events enable spatially explicit waves and water-level information in shallow nearshore regions, providing greater context than single-point tide gauges, wave buoys, or hindcast wave nodes in offshore waters. However, the computational expense associated with such simulations necessitates that a select number of events be chosen, ideally representative of the same extreme distribution created by the complete history of storms. Storm selection has previously been shown to be sensitive to the observational record length and the storm sample size but notably also region-specific characteristics such as the common (and uncommon) synoptic weather patterns and the alongshore variability of metocean conditions. The US Army Engineer Research and Development Center (ERDC), Coastal Hazards System (CHS), Stochastic Simulation Technique (SST), which was developed for the quantification of extratropical cyclone (XC) hazards based on extreme value analysis techniques, has previously been used to identify storms for high-fidelity simulations in several regions throughout the United States, including the Great Lakes (Nadal-Caraballo et al. 2012), US mid- and North Atlantic (Nadal-Caraballo et al. 2014; Nadal-Caraballo et al., “North Atlantic Coast,” 2015; Nadal-Caraballo et al., “Statistical Analysis,” 2015), and US South Atlantic (Yawn et al. 2024b) and Gulf of Mexico (Yawn et al. 2024a). However, coastal hazards for the US West Coast and the Pacific Basin are a consequence of multiple compounding oceanographic, meteorologic, and climatic phenomena contributing to waves and water levels with unique characteristics compared to tropical cyclone–dominated coasts. This effort defines total water levels as a combination of still-water levels (SWLs), incident wave runup, and infragravity runup as a proxy for the water elevation experienced at the shoreline during storm events. Dynamic total water levels during extreme events are then separated into individual contributions from oceanic and meteorological phenomena occurring at a variety of timescales, such as seasonal and monthly sea-level anomalies. Results from this analysis highlight future SST developments that will be required as part of a comprehensive CHS-Probabilistic Framework (CHS-PF) for the US West Coast and the Pacific Basin. Specifically, the methodology will need to (1) account for temporal clustering of storm sequences, (2) align with the parameters most relevant to US West Coast coastal storm risk management projects, and (3) develop an approach to create composite storm suites derived from extremes in multiple metocean parameters due to limited overlap between those storms that produce extremes in still water and those storms driving open-coast wave-induced extremes.

2 Sep 2025

Coastal Hazards System–Gulf of Mexico (CHS-GoM)

Abstract: The US Army Corps of Engineers completed the South Atlantic Coastal Study (SACS) to quantify storm surge and wave hazards, expanding the Coastal Hazards System (CHS) to the South Atlantic Division (SAD) domain. The goal of CHS-SACS was to quantify coastal storm hazards for present conditions and future mean sea level fluctuation scenarios to reduce flooding risk and increase resiliency in coastal environments. CHS-SACS was completed for three regions within the SAD domain, and this report focuses on the Gulf of Mexico (CHS-GoM). This study applied the CHS’ Probabilistic Framework with Joint Probability Method Augmented by Metamodeling Prediction (JPM-AMP) to perform a probabilistic coastal hazard analysis (PCHA) of tropical cyclone (TC) and extratropical cyclone (XC) responses, including new atmospheric and hydrodynamic numerical model simulations of synthetic TCs and historical XCs. This report documents the CHS probabilistic framework for the CHS-GoM region by executing the JPM-AMP, and comprising storm climate characterization, storm sampling, storm recurrence rate estimation, marginal distributions, correlation and dependence structures of TC atmospheric-forcing parameters, development of augmented storm suites, and assignment of discrete storm weights to the synthetic TCs. Coastal hazards were quantified for annual exceedance frequencies over the range of 10 yr−1 to 10−4 yr−1.

28 Aug 2025

South Atlantic Coastal Study (SACS) Calibration and Validation of the Coastal Storm Modeling System (CSTORM) for Water Levels and Waves Part 3. Gulf of Mexico Domain

Abstract: The US Army Corps of Engineers, South Atlantic Division, is currently engaged in the South Atlantic Coastal Study. One of the phases of this study is focused on conducting coastal storm modeling for the eastern and central Gulf of Mexico coastline of the United States. This technical report details the development of input for the Coastal Storm Modeling System (CSTORM) suite of models (WAVEWATCH III, ADCIRC, and STWAVE) for this project and presents the efforts made to calibrate model setups and validate results for eight historical tropical storm events impacting the study area.

28 Aug 2025

South Atlantic Coastal Study (SACS) Calibration and Validation of the Coastal Storm Modeling System (CSTORM-MS) for Water Levels and Waves: Part 2. South Atlantic Coast Domain

Abstract: The US Army Corps of Engineers, South Atlantic Division, is currently engaged in the South Atlantic Coastal Study. One of the phases of this study is focused on conducting coastal storm modeling for the southern Atlantic coastline of the United States. This technical report details the development of input for the Coastal Storm Modeling System suite of models (WAVEWATCH III, ADCIRC, and STWAVE) for this project and presents the efforts made to calibrate model setups and validate results for seven historical tropical storm events impacting the study area.

28 Aug 2025

South Atlantic Coastal Study (SACS) Calibration and Validation of the Coastal Storm Modeling System (CSTORM-MS) for Water Levels and Waves: Part 1: Puerto Rico / US Virgin Island Domain

Abstract: The US Army Corps of Engineers, South Atlantic Division, is currently engaged in the South Atlantic Coastal Study. One of the phases of this study is focused on conducting coastal storm modeling for the Puerto Rico and US Virgin Islands. This technical report details the development of input for the Coastal Storm Modeling System suite of models (WAVEWATCH III, ADCIRC, and STWAVE) for this project and presents the efforts made to calibrate model setups and validate results for four historical tropical storm events impacting the study area.

11 Sep 2024

Coastal Hazards System–South Atlantic (CHS-SA)

Abstract: The US Army Corps of Engineers completed the South Atlantic Coastal Study (SACS) to quantify storm surge and wave hazards, allowing for the expansion of the Coastal Hazards System (CHS) to the South Atlantic Division (SAD) domain. The goal of CHS-SACS was to quantify storm hazards for present conditions and future sea level rise scenarios to reduce flooding risk and increase resiliency in coastal environments. CHS-SACS was completed for three regions within the SAD domain, and this report focuses on the South Atlantic (CHS-SA). This study applied the CHS’ Probabilistic Framework with Joint Probability Method Augmented by Metamodeling Prediction (JPM-AMP) to perform a probabilistic coastal hazard analysis (PCHA) of tropical cyclone (TC) and extratropical cyclone (XC) responses, leveraging new atmospheric and hydrodynamic numerical model simulations of synthetic TCs and historical XCs. This report documents the CHS probabilistic framework to perform the PCHA for CHS-SA by executing the JPM-AMP, including storm climate characterization, storm sampling, storm recurrence rate estimation, marginal distributions, correlation and dependence structures of TC atmospheric-forcing parameters, development of augmented storm suites, and assignment of discrete storm weights to the synthetic TCs. Coastal hazards were estimated for annual exceedance frequencies over the range of 10 yr−1 to 10−4 yr−1.

28 May 2024

Statistical Analysis of Storm Surge and Seiche Hazards for Lake Erie

Abstract: Storm surge and seiche events are generally forced by severe storms, initially resulting in a wind-driven super elevation of water level on one or more sides of a lake (surge) followed by a rebound and periodic oscillation of water levels between opposing sides of the lake (seiche). These events have caused flooding along Lake Erie and significant damages to coastal communities and infrastructure. This study builds upon statistical analysis methods initially developed for the 2012 federal interagency Great Lakes Coastal Flood Study. Using the Coastal Hazards System's stochastic Storm Simulation (StormSim) suite of tools, including the Probabilistic Simulation Technique (PST), and regional frequency model, historical extreme events were assessed in a local frequency analysis and a regional frequency analysis to quantify the annual exceedance frequency (AEF) of WLD events specific to Lake Erie. The objective of this study was to quantify AEFs of storm surge and seiche hazards to provide a better understanding of these events to aid flood mitigation and risk reduction for lakeside properties.

8 Dec 2022

Coastal Hazards System–Puerto Rico and US Virgin Islands (CHS-PR)

Abstract: The South Atlantic Coastal Study (SACS) was completed by the US Army Corps of Engineers to quantify storm surge and wave hazards allowing for the expansion of the Coastal Hazards System (CHS) to the South Atlantic Division (SAD) domain. The goal of the CHS-SACS was to quantify coastal storm hazards for present conditions and future sea level rise (SLR) scenarios to aid in reducing flooding risk and increasing resiliency in coastal environments. CHS-SACS was completed for three regions within the SAD domain, and this report focuses on the Coastal Hazards System–Puerto Rico and US Virgin Islands (CHS-PR). This study applied the CHS Probabilistic Coastal Hazard Analysis (PCHA) framework for quantifying tropical cyclone (TC) responses, leveraging new atmospheric and hydrodynamic numerical model simulations of synthetic TCs developed explicitly for the CHS-PR region. This report focuses on documenting the PCHA conducted for CHS-PR, including the characterization of storm climate, storm sampling, storm recurrence rate estimation, marginal distributions, correlation and dependence structure of TC atmospheric-forcing parameters, development of augmented storm suites, and assignment of discrete storm weights to the synthetic TCs. As part of CHS-PR, coastal hazards were estimated for annual exceedance frequencies over the range of 10 yr⁻¹ to 10⁻⁴ yr⁻¹.

31 Aug 2022

Coastal Hazards System–Louisiana (CHS-LA)

Abstract: The US Army Engineer Research and Development Center (ERDC), Coastal and Hydraulics Laboratory (CHL) expanded the Coastal Hazards System (CHS) to quantify storm surge and wave hazards for coastal Louisiana. The CHS Louisiana (CHS-LA) coastal study was sponsored by the Louisiana Coastal Protection and Restoration Authority (CPRA) and the New Orleans District (MVN), US Army Corps of Engineers (USACE) to support Louisiana’s critical coastal infrastructure and to ensure the effectiveness of coastal storm risk management projects. The CHS-LA applied the CHS Probabilistic Coastal Hazard Analysis (PCHA) framework to quantify tropical cyclone (TC) responses, leveraging new atmospheric and hydrodynamic numerical model simulations of synthetic TCs developed explicitly for the Louisiana region. This report focuses on documenting the PCHA conducted for the CHS-LA, including details related to the characterization of storm climate, storm sampling, storm recurrence rate estimation, marginal distributions, correlation and dependence structure of TC atmospheric-forcing parameters, development of augmented storm suites, and assignment of discrete storm weights to the synthetic TCs. As part of CHS-LA, coastal hazards were estimated within the study area for annual exceedance frequencies (AEFs) over the range of 10 yr-1 to 1×10-4 yr-1.