8 Jun 2026

Emulation of Peak Storm Surge Across Extended Spatial Domains Using Separable Gaussian Process Techniques

Abstract: Data-driven emulation of peak storm surge has emerged as a popular strategy for overcoming limitations arising from the computational burden of high-fidelity hydrodynamic numerical models used within coastal risk assessment applications. The surrogate models used for this emulation are developed using suites of synthetic storm simulations, and once calibrated, can replace the original high-fidelity model to establish predictions for new storms. These predictions pertain to the geographic domain, and therefore nodal locations, covered by the original high-fidelity simulation suite. This creates a two-dimensional space for the peak surge predictions, with one corresponding to the storm features and the other to the spatial domain. Gaussian Process techniques have emerged as a widely popular surrogate modeling technique for peak surge emulation. In all GP implementations so far, the spatial variability has been incorporated in the analysis through the metamodel output, considering a multi-output GP implementation. This approach fails to explicitly model spatial dependencies for the peak surge. To address this shortcoming, this study examines an alternative implementation that considers spatial and storm feature variability as part of the metamodel input, establishing a surrogate model that simultaneously predicts the peak storm surge across both the spatial domain and the storm features. For computational tractability, a separable covariance function is considered for the GP, establishing separate kernels for the spatial and storm feature spaces. Particularly for the spatial domain, an adaptive covariance tapering formulation, which infuses sparsity in the corresponding covariance matrix, is adopted to support applications with a large number of nodal locations. A simultaneous calibration approach for the hyperparameters of the separate kernels is further proposed to improve emulation accuracy. Comparisons of computational efficiency and accuracy of the alternative GP implementations are established utilizing the Coastal Hazards System–North Atlantic database, with those employing the adaptive covariance tapering formulation evaluated under varying sparsity levels. The case study demonstrates that the simultaneous hyperparameter calibration is beneficial for the separable GP's predictive accuracy, particularly as it relates to the worst-performing nodes in the domain, and that the imposed sparsity level impacts the separable GP's ability to model non-stationary spatial trends in the domain.

5 Jun 2026

Multitemporal Change Detection in the Coastal Zone: Literature Review

Abstract: Beach volume change is a primary metric for quantifying coastal change due to physical and anthropogenic forces. Volumes provide key inputs for the creation and maintenance of regional sediment budgets that inform engineering decisions and ensure the effective management of sediment. This special report provides a comprehensive literature review of the state of the art for developing beach volume change metrics, including methods, software and tools, and common sources of error. The reviewed literature indicates that common proxy-based methods for developing volumes (e.g., shoreline change analysis and beach profile change analysis) are limited in their applicability for study areas with alongshore geomorphic variability. A digital elevation model (DEM) of difference method used with high-resolution (e.g., 1 m DEM) datasets captures volumes over spatially variable geomorphologies more accurately; however, the literature notes limitations related to elevation dataset coverage and geometries used for aggregating volume quantities. Space-time cube methods enable cell-by-cell comparisons of volumes over multiple time periods within defined neighborhoods and provide additional insights, efficiencies, and flexibilities to afore-mentioned methods. A new beach volume framework is required to address limitations related to geomorphic variability, aggregation units, and dataset coverage.

28 May 2026

Encouraging USACE Implementation of Engineering Critical Assessment (ECA): A Pre-ECA Screening Tool and Fracture-Resistance Screening Tool

Abstract: The US Army Corps of Engineers (USACE) manages a large inventory of hydraulic steel structures (HSS). These HSS are aging, and upon inspection, many show signs of damage including large discontinuities in their members, which threaten the HSS operation. Simply repairing every discontinuity will ensure continued HSS operation but may be unnecessarily expensive. Therefore, USACE seeks to balance its constrained budget with safe, reliable HSS operation. One balancing method is the concept of fitness for service. A discontinuity is evaluated using an acceptance criteria based on the principles of structural analysis and fracture mechanics called an engineering condition assessment (ECA) that decides whether it is fit for service. If a discontinuity is fit for service, the HSS will continue regular operations; if it is not fit for service, the discontinuity will be considered a defect and repaired. However, USACE has not widely adopted ECA. Because of resource constraints, engineers often choose to conservatively repair without considering ECA. This study seeks to alleviate the difficulty in committing resources to an ECA in two ways: (1) by providing logical justification for performing an ECA and (2) by reducing the resources necessary for analysis by providing a fracture-resistance screening tool.

27 May 2026

Multi-Temporal Geomorphic Change and Application of the Coastal Engineering Resilience Index Along the Mississippi Mainland Beaches and Dunes

Abstract: This report addresses the Mobile District’s request for a representative resilient beach and dune profile for the Mississippi mainland beach and dune project. The report summarizes a workflow that uses a custom ArcGIS Pro toolbox and 10 lidar datasets spanning a 22-year period of analysis. The workflow involves (1) lidar data compilation; (2) the extraction of geomorphic features, such as shorelines and dune toes and crests, on over 5,800 profiles along the Mississippi mainland coast; (3) the calculation of Coastal Engineering Resilience Index values for each transect for each lidar dataset; (4) selection of representative resilient profiles for various datasets; (5) development of synthetic profiles and Coastal Engineering Resilience Index (CERI) calculations on those profiles; and (6) data delivery and the development of a Web service hosting the project outcomes. The results of these analyses indicate that the protective width (i.e., from the shoreline to the seawall along the coast) is a major contributor to the resilience of a given section of beach. However, the resilience of these estuarine beaches can also be enhanced by increasing protective elevation. Overall, the work demonstrates the value of applying these workflows and toolboxes during the engineering planning and design phase.

21 May 2026

Evaluation of Shore Protection Alternatives at Crescent Beach, Indiana

Abstract: This report documents a numerical modeling investigation of shore protection alternatives at Crescent Beach, Indiana. The integrated flow, wave, sediment transport, and morphology change Coastal Modeling System (CMS) and the long-term shoreline evolution model, GenCade, were applied to evaluate alternatives. Sediment, elevation, and hydrodynamic data were collected nearby to improve model calibration and validation. Eight alternatives were evaluated, with coastal structures in four, beach nourishments in three, and one with both. Structures other than the continuous rubble ridge (Alternative 4) had minimal or negative influences on sediment transport. Stone sizes and costs were estimated for Alternative 4 using StormSim and extremal forcing from the Coastal Hazards System (CHS) Great Lakes Study, but CMS does not predict impacts that justify rubble ridge construction costs. CMS and GenCade were applied to beach nourishments across a range of volume and sediment grain size distributions. Model evaluations indicate that beach nourishment is the most effective shoreline protection technique, using coarse sand mixed with small stones to achieve a median grain size (d50) of 1.80 millimeters successfully extends the beach nourishment lifecycle, and increasing nourishment volume to 87,455 cubic meters to span in front of Mount Baldy substantially increases downdrift benefits.

18 May 2026

Workflow to Build Space-Time Cubes in ArcGIS Pro with High-Resolution Elevation Data

Abstract: This Coastal and Hydraulics Engineering Technical Note (CHETN) presents a workflow to build space-time cubes (STCs) using high-resolution digital elevation models (DEMs). The workflow leverages ArcGIS Pro’s mosaic dataset architecture and multidimensional tools to analyze temporal changes across elevation datasets. This workflow is intended to (1) guide users who may not be familiar with STCs through a step-by-step workflow, (2) share a set of best practices, and (3) highlight considerations when using remotely sensed elevation datasets. This CHETN is a part of a larger effort to develop the next generation of volume change tools for application in the coastal environment.

14 May 2026

Engineering With Nature® Proving Grounds Innovation Handbook

Abstract: The Engineering With Nature® Proving Grounds Innovation Handbook provides a comprehensive framework for integrating innovative natural and nature-based features and sediment management strategies to address climate-driven hazards and increase resilience in coastal and fluvial environments. Developed through collaboration between engineers, scientist, landscape architects, and U.S. Army Corps of Engineers districts and divisions, the EWN Handbook showcases a diverse collection of projects within the four coasts of the United States and offers the wide range of approaches available to achieve multiple benefits (economic, ecological, and social) through the application of traditional engineering with natural infrastructure solutions. The document aims to offer practitioners ideas on how to incorporate EWN concepts and strategies in all phases to build more resilient, multifunctional projects that protect communities and ecosystems against future natural hazards.

13 May 2026

Beach-fx Version 3.0 User’s Manual

Abstract: The need to strengthen the linkages between engineering analyses (project performance and evolution) and planning functions (alternative analysis and economic justification) with respect to coastal storm damage reduction projects within the US Army Corps of Engineers led to the development of the life-cycle simulation model Beach-fx. Beach-fx provides a comprehensive analytical framework for evaluating the physical performance and economic benefits and costs of shore protection projects, particularly beach nourishment along sandy shores. The model has been implemented as an event-based Monte Carlo life-cycle simulation tool that is run on desktop computers. This report describes the components, purpose, and operational function of the Beach-fx graphical user interface, including navigation within the interface and the organization and specification of all model input and output data.

12 May 2026

Barge Arrest System for Dams on Inland Waterways: Design Criteria

Abstract: The US Army Engineer Research and Development Center (ERDC), through the Navigation Systems Research Program, has begun developing a barge arrest system to reduce the damage and recovery costs of allisions (impact events) at US Army Corps of Engineers (USACE) lock and dam (L&D) sites. This development effort addresses a need for a mitigation strategy to address allisions from uncontrolled, breakaway barges following accidents that occur on a relatively frequent basis near USACE L&D sites summarized in the USACE Statement of Need 1974. These allisions have caused millions of dollars in recovery and repair costs to both the L&D structure and to navigation industry property (USACE 2005). In extreme situations, barge impacts to multiple gates have inhibited USACE’s ability to regulate water levels. This Coastal and Hydraulics Engineering Technical Note (CHETN) describes the general problem and findings from an initial design charette conducted with USACE subject matter experts (SMEs) across various technical disciplines. This initial design charette focused on the identification of design criteria for the prototype design and potential case study sites.

4 May 2026

Impact of Vessel Operations on Navigation Channel Stability and the Broader Environment: Insights from a Workshop Held 4–5 September 2024

Abstract: Vessel operations in the US Army Corps of Engineers (USACE) portfolio of waterways create a range of environmental and navigation challenges. This report documents the proceedings of a workshop highlighting research and development (R&D) on vessel-related navigation channel stability and associated environmental impacts. Across 13 workshop presentations, three major themes emerged to guide future USACE R&D efforts: (1) the need for better data and standardized processing routines, (2) the need for a streamlined modeling framework that can simulate all relevant physical processes for vessel operation, and (3) the need for improved internal and external partnerships to better address vessel-related issues. Addressing these critical knowledge gaps will advance engineering practice associated with vessel operations in USACE waterways.