2 Sep 2026

Rapid Approach to Modeling Hyporheic Flow at Instream Geomorphic Features

Purpose: Restoration planning teams need a rapid, repeatable way to identify and quantify hyporheic flows in streams. Current approaches are often only qualitative or require complex models and large datasets that are not practical for rapid analysis. This technical note introduces a simple workflow that couples 2D surface-water models (Hydrologic Engineering Center’s River Analysis System [HEC-RAS]) with 3D groundwater models (Groundwater Modeling System [GMS] and MODFLOW) to quantify hyporheic residence times, flow-path lengths, and exchange rates. The workflow fills a gap between qualitative indicators and data-intensive detailed modeling (e.g., computational fluid dynamics) and provides a rapid screening tool for hyporheic assessment. We demonstrate the workflow with an example application in riffle-pool features on the Concho River, Texas. The workflow provides outputs that can be mapped and tabulated to rank sites, prioritize reaches, and target field data needs in support of restoration planning studies. The outputs provide a consistent basis to compare existing conditions with concept designs that modify channel geometry and define performance measures aligned with project objectives. The scope of this technical note is limited to the hydraulic modeling workflow, and the intended audience is surface-water modelers with a basic understanding of hydrogeologic principles. Field data collection guidance and linking hyporheic flows to ecological indicators are briefly summarized.

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.

20 Apr 2026

New Poe Lock Emergency Closure System Physical Model Study

Abstract: The US Army Corps of Engineers (USACE)–Detroit District (LRE) has begun the process of designing a new emergency bulkhead for Poe Lock in Sault Ste. Marie, Michigan, and has requested assistance from the US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, in determining the hydraulic loads the bulkhead will experience during operation. The US Army Engineer Research and Development Center has constructed a 1:25 scale physical hydraulic model to estimate the hydraulic forces on the bulkhead and pressure on the bulkhead sill during lowering operations. Multiple bulkhead lowering speeds and bulkhead lip designs have been tested over the course of the study. This report provides time histories of the hydraulic loads and bulkhead pressures throughout the bulkhead lowering operations. These results will inform the design of the emergency bulkhead and the size of its operating equipment.

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.

12 Feb 2026

Numerical Study of Submergence-Induced Forces on a Maintenance Bridge

Abstract: The US Army Engineer Research and Development Center–Coastal and Hydraulics Laboratory conducted a numerical study for a proposed maintenance bridge over the Trinity River in downtown Fort Worth, Texas, that will be submerged in flood conditions. The purpose of this study was to determine the hydrodynamic loads on the structure. The study found that, due to a combination of peak velocities and water depth, a return period of 500 yr generates the largest drag forces, while the higher depth and discharge of the standard project flood generate larger lift forces. Two flow structures were observed with shallow submergence: The first resulted in a jet parallel to the deck with a recirculation extending from railing to railing and the second resulted in a plunging jet over the deck with smaller but stronger recirculation. These patterns resulted in significantly different loads on the structure. The study analyzed the bridge’s deck slope to the flow as a possible variable affecting the loads. Observed changes related mostly to the flow pattern predicted for different flow configurations. Finally, it was observed that an open railing provides the best possible conditions in terms of loading; therefore, minimizing the frontal area of the railing is recommended.

5 Nov 2025

Physical Modeling of Filling and Emptying (F&E) Systems of Proposed 1,200 ft Chambers at Locks 22 and 25: Hydraulic Model Investigation

Abstract: The US Army Corps of Engineers (USACE) is considering navigation improvements for several projects to meet predicted increases in tow traffic at the Lock and Dam 22 and Lock and Dam 25 sites in the Mississippi river. Some of these improvements include the addition or replacement of the navigation lock at the site. The following document contains the laboratory model investigations of the lock filling and emptying (F&E) system for additions at the sites. This report provides the results of research testing under the Navigation and Ecosystem Sustainability Program (NESP). The design guidance includes culvert geometry, port size, location, and spacing. Guidance for the lock chamber performance, based on acceptable filling and emptying operations is also included. The results show that the original design is a feasible design based on the hydraulic performance of the system as a result of the experimental tests. Further discussions with the St. Louis District (CEMVS) arrived at a new culvert to port transition design that was more in line with the existing geometry at Lock and Dam 25. The new design and port spacing configuration were agreed by CEMVS and ERDC to not have significant impact on hawser forces or the overall chamber performance.

24 Oct 2025

Hydraulic Evaluation of the Proposed Brandon Road Lock Flushing System

Abstract: The Great Lakes Mississippi River Interbasin Study is a US Army Corps of Engineers effort focused on stopping the migration of aquatic nuisance species (ANS) from the Mississippi River to the Great Lakes. Brandon Road Lock and Dam (BRLD) has been chosen as the location to stop this northward migration. The study described in this report focuses on the performance of a proposed lock flushing system intended to reduce the risk of ANS from passing northward through BRLD. This system is a modification of the existing filling/emptying (F/E) system and must perform as both a lock flushing system and the F/E system. This study focuses on determining the performance of the flushing system and the F/E system to establish flushing and F/E operating parameters for safe lock operation. The results presented include qualitative descriptions and quantitative measurements of the flushing and F/E systems’ hydraulic performance. Finally, this study investigates commercial barge tows entering and exiting the lock chamber to determine the effects such barge tow movement has on both the barge tow and the vessel-generated currents. This report provides recommendations for flushing system and F/E system operation and commercial barge traffic considerations during flushing.

26 Sep 2025

Rapid Assessment Tool for Channel Hydraulics and Floodplain Connectivity

Abstract: This technical note (TN) presents a rapid, nationally applicable web application for analyzing channel hydraulics and floodplain connectivity. The tool uses locally derived relative elevation models (REMs) that allow users to quantify hydraulics, like velocity and shear stress, and floodplain connectivity metrics, like inundation extent and storage volume (Haring and Dougherty, forthcoming).* By delineating cross sections directly from publicly available high-resolution terrain, the tool provides a rapid hydraulic assessment without requiring field survey data and also helps prioritize reaches for more detailed assessments.