10 Sep 2026

Evaluating the Impact of Installation of Coastal Structure on Sediment Transport

Abstract: A coastal wave, hydrodynamic and sediment transport model was developed and applied for a small port in an estuarine system. The study focused on evaluating the installation of coastal structures at the modular causeway mooring field of the port, aiming to reduce sedimentation, maximize the usable waterway, and mitigate the potential for impact on the wetland adjacent to the mooring area. The model performance on sediment transport and morphology change was demonstrated by the comparison of survey data and model calculations. The modeled current fields support a plausible sediment source concerning the material accretion and channel infilling in the mooring field. The installation of a solid structure, a riprap or a sheet pile, surrounding the mooring field can act as a sediment barrier in the study area, which can reduce current and erosion in the identified sediment source area behind the mooring field and result in less sediment supply to the mooring field and the channel area over built structures.

27 Aug 2026

A Science Gateway for CSHORE-VEG

Abstract: This Coastal and Hydraulics Engineering Technical Note (CHETN) develops a science gateway for coastal scientists and engineers to evaluate the capacity of coastal and marine wetlands in wave-height reduction using a one-dimensional cross-shore profile model, the CSHORE-VEG (Cross-Shore–Vegetation) model (Chen et al. 2025). This gateway comprises a front-end (i.e., web-based graphical user interface [GUI]) and a backend (i.e., models for wave action and vegetation, linkage between CSHORE and vegetation model, postprocessing for vegetation breakage evaluation, etc.). The GUI, built upon the Jupyter Notebook, streamlines the workflow of model configuration, execution, and output visualization, so that users can quickly make use of CSHORE-VEG, regardless of their prior knowledge of the model. Two examples with laboratory and field wave conditions are provided in this CHETN to guide users through the diverse functionality of this gateway.

25 Aug 2026

Hydrodynamic Mechanisms and Pathways of Potential Navigation Channel Shoaling by Nearby Parallel Islands

Abstract: As the demand for transcontinental commerce has increased over the past century, navigation channels have been maintained at increasingly greater depths to continue access of deep draft vessels to inland ports. Over time, these deep navigation channels require routine dredging to counteract the gradual processes of sedimentary accumulation, known as shoaling, that can enter the channel from terrestrial or oceanic sources through natural (e.g., tides, streamflow, runoff) or anthropogenic (e.g., vessel wake) processes. To limit the cost of moving the dredged material to upland or offshore storage facilities and to prevent long-term sediment loss from the system, the material can instead be reused locally to build marsh or island habitats. While the various environmental impacts of keeping and reusing the material within the sourcing embayment have been investigated at length, the hydrodynamic impacts of large-scale within-embayment placements have previously been understudied, particularly regarding potential changes to navigation channel shoaling. In this work, we use numerical models to investigate how channel-parallel linear island features may modify sediment transport mechanisms and pathways, and discuss long-term shoaling implications. Based on the various tested channel and embayment geometries, taken from nautical charts detailing the evolving topobathymetric history of Lake Calcasieu and the Calcasieu Shipping Channel (Louisiana, USA), linear and near-continuous islands are shown to have the potential to increase sedimentation in the channel by altering both local hydrodynamics around the islands and estuarine-scale tidal dynamics. However, the degree to which the islands are continuous and the dominant forcing factors are shown to limit the increase in shoaling likelihood by island presence.

4 Aug 2026

Modeling Evaluation of a Bird Island Design in Hampton Roads, Virginia

Abstract: This report documents a numerical modeling investigation on the sediment transport and morphology changes surrounding designed marine habitats for seabirds in Hampton Roads, Virginia. It assembles and analyzes historical and newly collected wave and hydrodynamic data from the study area. The datasets are used to calibrate and validate coastal wave, hydrodynamic, and sediment transport models. It describes developments of model alternatives that correspond to different bird island designs. It evaluates current and sediment transport fields and seabed volume changes around the island under a representative normal year (2020) and under a storm simulation condition for a 50 yr return synthetic storm with corresponding sea level rise. Model simulations show weak current and sediment transport fields prior to the island construction. With alternative designs of the island, model results show significant changes in magnitudes and spatial distributions of current and sediment transport rate. Analysis of model bed volume changes demonstrates different erosion and deposition trends under the normal environment and under the storm simulation condition. The island design and configuration, including island orientation, island slopes, and material coverage, respond differently to the impact of physical forcing applied in the modeling.

11 Jun 2026

Simulation of Dredged Material Placement in the San Francisco Bay Using a Multi-Dimensional Hydrodynamics and Sediment Transport Model

Abstract: The US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, has developed an Adaptive Hydraulics (AdH) 2D, hydrodynamic and sediment transport model for San Francisco Bay. This model supports the US Army Corps of Engineers, San Francisco District, in informing navigation and sediment management decisions as part of the Regional Dredged Material Management Plan (RDMMP), which evaluates dredging methods and placement alternatives over a 20-year planning horizon. There is a need to assess the long-term fate of dredged material placed at in-bay sites to better understand associated benefits and potential impacts. This report documents the development, calibration, and validation of the AdH 2D model for conditions in 2022. The model was applied to simulate the multimonth dispersion and transport of dredged material from four sites. Model results demonstrate that sediment transport patterns are influenced by seasonal hydrodynamic forcing and grain-size composition, with coarser material forming stable deposits that persist over time. The findings of this study inform sediment management strategies under the San Francisco Bay RDMMP and support efforts to reduce navigation risks and enhance beneficial use opportunities. The study recommends field data collection to improve sediment characterization at placement sites and strengthen predictive modeling and planning efforts.

11 Jun 2026

The Bird Islands Ecosystem Design Using Boussinesq Modeling—Barren Island, Mid-Chesapeake Bay

Purpose: The US Army Corps of Engineers (USACE) Baltimore District is currently engaged in an ecosystem restoration within the Chesapeake Bay, Maryland. Specifically, two islands, Barren Island and James Island, are to undergo restoration using dredged materials and creation of berms and breakwaters to offer a level of protection to the island from wave and surge during storm events. This report focuses on the design of bird habitat development on the Tarbay side of the detached breakwaters in the Barren Island design. During the ongoing Preconstruction, Engineering, and Design (PED) phase of the project, it was determined that terraced islands would be created on the leeside of the detached breakwater system for bird habitat development. Coastal storm inundation and wave loading from Coastal Storm Modeling System (CSTORM-MS) coupled surge and wave modeling system were quantified in a previous effort. These results are used as input to local high-fidelity phase-resolved wave modeling to quantify the hydrodynamics on the island. The terraced structure will include berms. Berm and breakwater stone stability was quantified using Ahrens (1989) reef equations. This report discusses potential erosion and additional structure configurations. Additional offshore reef-type breakwaters were considered to protect the bird islands from waves propagating from the east to the west toward the Tarbay side of the island.

26 Mar 2026

Development of a Three-Dimensional (3D) Hydrodynamic, Salinity, and Sediment Transport Model of the San Francisco Bay

Abstract: The US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory (ERDC-CHL), has developed the multimodule Adaptive Hydraulics (AdH) model for San Francisco Bay, incorporating hydrodynamics, salinity, and sediment transport. This model supports the US Army Corps of Engineers San Francisco District in navigation and sediment management, particularly for the development of a Regional Dredged Material Management Plan to assess dredging methods and placement alternatives. San Francisco Bay is a dynamic estuary shaped by strong tidal currents, seasonal freshwater inflows, and complex sediment transport. As a key hub for international maritime trade, its federal navigation channels require regular maintenance dredging. Dredged sediment plays a crucial role in sustaining mudflats, tidal marshes, and intertidal habitats that mitigate coastal flooding and provide ecological benefits. This report documents the development, application, and validation of the AdH-3D model for 2022, demonstrating its ability to reproduce observed hydrodynamic, salinity, and sediment conditions. It details the model setup, boundary conditions, and validation, ensuring its reliability for informing sediment management and navigation planning. The model serves as a valuable tool for evaluating long-term sediment fate and optimizing regional dredging strategies.

18 Feb 2026

Mesh Convergence Study of Adaptive Hydraulics (AdH) Version 5.9

Abstract: This report details performance and convergence tests of the Adaptive Hydraulics (AdH) v5.9 software suite on the Engineer Research and Development Center ONYX Cray X40/50 supercomputer. In particular, the performance of a recently developed monolithic model coupling AdH framework between the Richards equation for variable groundwater and surface water flows or for overland sloped conditions is studied. The effort is part of a quality assurance test of a recently restructured version of AdH. The report also includes a scalability analysis of AdH on a Cray system.

10 Dec 2025

Evaluation of Vegetated Shoreline Capacity Using CSHORE-VEG

Abstract: A versatile vegetation module has been implemented into the Cross-Shore model (CSHORE) to evaluate the capacity of coastal and marine wetlands with respect to wave-height attenuation and wave-runup reduction. This extended model, Cross-Shore-Vegetation (CSHORE-VEG), is capable of simulating the effects of rigid and flexible vegetation with spatially varying biomechanical properties. To accurately estimate the vegetation-induced energy dissipation rate, a drag coefficient formula that is independent of the vegetation flexibility was developed based on field data collected in salt marshes in Terrebonne Bay, Louisiana, during a tropical storm. This universal drag coefficient formula along with other existing drag coefficient formulas have been implemented into CSHORE-VEG to meet different needs. CSHORE-VEG has been validated against four independent datasets involving different vegetation properties for wave attenuation and mean water level change. After achieving good agreement in model-data comparisons, CSHORE-VEG was employed to quantify the capacity of two representative salt marshes composed of Spartina alterniflora and Elymus athericus for wave attenuation. As a result, two ineffective vegetated shoreline scenarios were identified. Furthermore, a procedure for determining the percentage of broken vegetation stems and modeling the corresponding wave-height reduction was applied to evaluate the wave-height reduction under realistic field conditions.

3 Sep 2025

Hydrodynamics in the Morganza Floodway and Atchafalaya Basin, Report 5: Phase 5

Abstract: The Morganza Floodway and Atchafalaya Basin, located in Louisiana west of the Mississippi River, were evaluated using a 2D Adaptive Hydraulics model. Prior to this study, Phase 1 and 2 model studies showed that the Morganza Floodway may not be able to pass the Project Design Flood discharge of 600,000 cubic feet per second due to levee overtopping. Phase 3 and 4 model studies help to further the understanding of how flood waters propagate throughout the floodway as well examined alternatives to increase the discharge capacity of the floodway. Phase 5 furthered the work completed in Phases 3 and 4 by exploring more alternatives to aid the Morganza Floodway in passing the Project Design Flood.