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.

1 Sep 2026

Eco-Morphodynamic Dune Response to Beach Nourishment Along the Northern Outer Banks Coast, North Carolina, USA

Abstract: It is recognized that beach nourishment can enhance sediment available for aeolian transport and dune growth in windy coastal settings. Additionally, recently constructed dunes often differ from naturally developed dunes in their plant communities and composition, which can alter the style of dune growth through ecomorphodynamic interactions. However, directly quantifying the influence of beach nourishment and management activities on dune behavior is challenging due to the complexity of coastal sediment-transport dynamics and a lack of field data at appropriate spatio-temporal scales. Here, we assess morphological and ecological changes to three beach-dune systems in Duck, NC, USA at high temporal frequency over one year following a beach nourishment. We found that the average crest and toe elevations of the dunes at all sites increased; however, one of the dunes experienced net volume loss despite the addition of sand to the dune and adjacent beach. Importantly, we found that patterns and magnitudes of local deflation and accretion observed across these sites are correlated to bidirectional, positive feedbacks between vegetation and sedimentation.

31 Aug 2026

Quantifying USACE Reservoir Sedimentation Knowledge Gaps by Expanding the Reservoir Sedimentation Information Portal

Abstract: The Reservoir Sedimentation Information (RSI) Portal provides a database of US Army Corps of Engineers (USACE)–managed reservoir information, including estimates of storage capacity loss. However, the portal lacks critical data regarding acute or localized sedimentation, its impact on reservoir function, and the availability or quality of preimpoundment surveys. This absence of information hampers a manager's ability to project how unplanned changes in sedimentation may impact reservoir capacity. To quantify these challenges, we surveyed 291 of the 445 reservoirs listed in the RSI Portal at the time of this study. Our results showed that 46% reported moderate-to-major sedimentation issues. Furthermore, 77% reported issues with pre-impoundment surveys. This means 224 of the USACE reservoirs surveyed lack sufficient historical data to evaluate the impact of unplanned increases in postconstruction sedimentation. Our assessment also provided a first-order estimate of the number of reservoirs that could benefit from targeted research, such as sub-bottom profiling. Our analyses were hampered by the size and complexity of the dataset, highlighting the critical importance of incorporating these missing datasets directly into the RSI Portal to better manage reservoir resources and safety.

27 Aug 2026

Acoustic Backscatter and Suspended Sediment Data Analysis Tool (ABSSDAT)

Abstract: The Acoustic Backscatter and Suspended Sediment Data Analysis Tool (ABSSDAT), presented by this report, is developed in MATLAB. It streamlines the process of calibration of Acoustic Doppler Current Profilers (ADCPs) and total suspended material (TSM) Data, computation of suspended sediment flux, contour plots, and vector plots. This application was tested with ADCP and TSM Data from the Red River near Overton Lock and Dam in Alexandria, Louisiana. Sediment Flux was calculated with two methods, one with ABSSDAT method and one with the USGS “moving boat” method. The comparison shows that both methods are within less than 5 percent error. The ABSSDAT application was also used to generate contour plots for velocity and TSM for each site along with velocity vector plots for transects. The report also details the manual for the complete usage of the ABSSDAT application.

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.

12 Aug 2026

Lifecycle Analyses of Subaerial Beach Nourishments with Concurrent Nearshore Placement of Dredged Sediment and the Role of Alongshore Transport

Abstract: Beach nourishment has a high cost but offers large economic benefits. Therefore, extending the nourishment lifespan using dredged sediment from navigation channels could have a significant economic impact. This numerical modeling study develops and compares two approaches incorporating nearshore sediment placements into an existing one-dimensional numerical modeling procedure to predict the lifespans of subaerial beach nourishment strategies. Both approaches build directly on the stochastic lifecycle simulation methodology and results used in the Coastal Texas Protection and Restoration Feasibility Study. Simulations for western Galveston Island were modified to include annually recurring nearshore nourishment. Cross-shore beach transects were forced with 50 years of tropical cyclones and nontropical storms in a cross-shore morphological evolution model, and rebuilt when the dune eroded to half of its initial height. One group of simulations applied this previously developed model forcing to cross-shore profiles that were updated with recurring nearshore nourishments. A second group of simulations included a simplified representation of sediment deposition from the along-shore transport gradient created by the nearshore nourishments. In both sets of simulations, a large sediment feature was incrementally constructed at depths between 2.5 and 6 m. Over 30 life cycles, the number of times the beach was rebuilt was tracked for each 50-year simulation. Comparing the number of predicted beach renourishments indicates that this particular nearshore nourishment strategy did not substantially impact the subaerial beach morphology unless alongshore transport gradients were also included. Simulations that did include this alongshore transport gradient predicted 23% longer lifespans. This work was not able to incorporate validation against measured data, but future testing of this approach should be pursued before widespread or high-impact application. Modeling results indicate that along-shore processes are an important part of quantifying the positive impacts of nearshore nourishment.

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.

26 Jun 2026

Water Quality and Sediment Dispersal from Placement of Dredged Material over Former Shell Mining Beds in Mobile Bay, Alabama

Abstract: The US Army Corps of Engineers (USACE) continues to advance regional sediment management practices including Beneficial Use of Dredged Material (BUDM) to reduce dredging costs while improving outcomes for coastal communities and ecosystems. This report describes two field studies conducted to better understand sediment retention and water quality implications associated with in-bay strategic placement of dredged material within former oyster-shell mining areas within Mobile Bay, Alabama. Deployed instrumentation and periodic campaigns of bed and water quality sampling provided data prior to dredged-sediment placement through more than a year after placement. Bed sampling and acoustic sub-bottom profiling indicated that the dredged material deposit was spatially variable in thickness and composition. Placed sediment accumulated quickly, within hours of placement, followed by a 2–4 month period with relatively small adjustments. Beyond 6 months, bed elevation changes became stable at near-background levels. Water quality data indicated that impacts to dissolved oxygen and turbidity associated with the dredged material placement are minor and short-lived. Notably, all water quality parameters remained within the normal range of variability observed within the dynamic Mobile Bay ecosystem. Collectively, these sediment bed and water quality studies support future data driven BUDM decision-making within the Mobile Bay region.

12 Jun 2026

EcoHydraulic Modeling to Inform Sustainable Sediment Management: A Priori Modeling of Reservoir Sediment Release to Estimate Geomorphic and Ecological Response

Abstract: With decreasing storage capacity and increasing operational costs in reservoir management, sediment release is considered a potential alternative to traditional dredging. However, passing sediment through reservoirs may have unexpected effects on downstream river morphology and ecosystem resources. This study uses numerical modeling and a conceptual ecological model to assess the relative effects of sediment load, stream flow magnitude, and grain size distribution in downstream river morphology and aquatic habitat in a case study system of the Big Blue and Kansas Rivers downstream of Tuttle Creek Reservoir, Manhattan, Kansas. The effects of sediment grain size, clearwater flushing rate, and backwater effects from the Kansas River were all found to be relevant in affecting sediment transport and deposition patterns. High-volume water/sediment releases were found to be most effective at emulating historical conditions. Additionally, sediment release was found to increase desirable physical habitat areas that have been lost in the channel. Clearwater flushing further increased the distribution of sediment to support physical habitat creation. These findings can inform sediment release management decisions regarding the timing, duration, and magnitude of sediment releases, particularly in relation to flows at the downstream confluence and for target ecosystem function goals.

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.