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.

29 Sep 2025

Asset Condition and Probability of Failure Assessment–A Vision for Civil Works: A Document to Guide Collaboration and Innovation for the US Army Corps of Engineers Civil Works Asset Management System

Abstract: The US Army Corps of Engineers (USACE) is rapidly improving its asset management system through a variety of research projects and other work efforts that focus on how risk, condition, and probability of failure are conceived, communicated, and used for decision-making across the agency. As these projects move forward, it is critical that USACE defines a long-term vision for condition and probability of failure assessments across the entire asset management system. This Special Report defines that vision with the goal of achieving consensus and buy-in from a variety of participants that will need to buy-in to achieve success. An additional benefit to identifying an end vision for this work is to identify collaborative opportunities and any gaps that must be addressed to achieve it.

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.

18 Aug 2025

Coupled Modeling to Support Evaluation of Mission-Assurance Risk from Disruption of Water Infrastructure

Abstract: Coupled modeling refers to the combined use of hydraulic models, graphical models, and existing datasets to analyze water distribution networks. Most DoD installations already possess rich planning and asset management datasets that can be leveraged to provide deep in-sights into their water infrastructure; however, installations rarely use them for increasing the resilience of their systems. This study develops strategies for assessing, integrating, and analyzing these sources into a coupled model designed to inform installations’ water-infrastructure resilience planning, wargaming, and project generation. The performance of coupled models was evaluated for accuracy, specificity, interoperability with DoD systems, enterprise applicability, responsiveness to DoD policy, and decision support. The study team encountered a few implementation issues, but none affected the study’s timeline or funding. One issue was that the hydraulic modeling software, Innovyze Infowater, was purchased by AutoDesk, which should be considered for installations evaluating software purchases. Another issue was data accuracy; tests for data validation showed that some data were incorrect. Coupled approaches can help to better identify where these errors may be. Regarding the issue of model interoperability, by default, the models were not fully compatible for the model simulation or for geospatial data, but both were addressed in this study.

1 May 2025

Resilience: Directions for an Uncertain Future Following the COVID-19 Pandemic

Abstract: The concept of resilience is multi-faceted. This commentary builds upon the analytical distinctions of resilience provided by Urquiza et al. (2021, https://doi.org/10.1029/2020EF001508). In response to this article, we emphasize several distinctions between resilience and other systems concepts. These include distinctions between resilience, risk, and vulnerability, the tradeoff between resilience and efficiency, resilience contrasted with robustness, the relationship between resilience and sustainability, and finally methods for building resilience-by-design or resilience-by-intervention. Improving understanding of these concepts will enable planners to select resilience strategies that best support their system goals. We use examples from the 2020–2021 coronavirus pandemic to illustrate the concepts and the juxtapositions between them.

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.

26 Mar 2024

Risk-Based Prioritization of Operational Condition Assessments: Trinity River and Willamette River Case Studies

Abstract: The US Army Corps of Engineers (USACE) operates, maintains, and man-ages over 700 dams and 4,000 miles of levees, providing approximately $257 billion worth of economic benefit to the Nation. USACE employs the Operational Condition Assessment (OCA) process to understand the condition of those assets and allocate resources to minimize risk associated with performance degradation. Understanding risk in flood risk management (FRM) assets requires an understanding of consequence of asset failure from a systemwide FRM watershed perspective and an understanding of likelihood of degradation based on the condition of the low-level components derived from OCA ratings. This research demonstrates a case-study application of a scalable methodology to model the likelihood of a dam performing as expected given the state of its gates and their components. The research team combines this likelihood of degradation with consequences generated by the application of designed simulation experiments with hydrological models to develop risk measures. These risk measures can be developed for all FRM gate assets in order to enable traceable, consistent resource allocation decisions. Two case study applications are provided.

5 Sep 2023

Resilience Modeling for Civil Military Operations with the Framework Incorporating Complex Uncertainty Systems

Abstract: Framework Incorporating Complex Uncertain Systems (FICUS) provides geographic risk analysis capabilities that will dramatically improve military intelligence in locations with the Engineer Research and Development’s (ERDC) demographic and infrastructure models built and calibrated. When completed, FICUS would improve intelligence products by incorporating existing tools from the National Geospatial Intelligence Agency, ERDC, and FICUS prototype models, even in places without demographic or infrastructure capabilities. FICUS would support higher-fidelity intelligence analysis of population, environmental, and infrastructure interaction in areas with Human Infrastructure System Assessment (HISA) and urban security models built and calibrated. This technical report will demonstrate FICUS prototype tools that allow Civil Affairs Soldiers to provide situational awareness information via a browser interface.

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.