3 Mar 2025

Low-Sill Control Structure: Physical Modeling Investigation—Potential Upstream Dike Fields

Abstract: The model investigation reported herein describes the process to analyze the effects of proposed dikes in various locations upstream of the Low-Sill Control Structure (LSCS) using an existing 1:55 Froude-scaled physical model. The purpose of this effort was to utilize the physical model to explore potential configurations of river-training structures in the approach channel that would result in more uniform flow conditions at the structure. This analysis was conducted by constructing dikes out of both sandbags and rock. Each dike configuration was surveyed using lidar and then tested by collecting particle-tracking velocimetry data. A total of nine dike configurations were tested in the physical model, and the resulting flow fields in the approach channel were provided to the US Army Corps of Engineers, Mississippi Valley Division. Most configurations resulted in data that showed improved, straighter flow paths in the approach channel. The results of these tests indicated that an L-head dike configured as the 50 ft stone dike 1-23A provided relatively straight flow conditions approaching the LSCS with relative uniform velocities across the channel.

19 Feb 2025

Lower James River Sediment Transport Modeling: Jordan Point

Abstract: US Army Corps of Engineers–Norfolk District (NAO) requested assistance from the US Army Engineer Research and Development Center (ERDC) to examine currently used placement sites within the James River, Virginia, initiative area, determine potential risk to critical environmental receptors during placement, and predict the life cycle of the placement sites. The focus of the analysis within this work is the Jordan Point placement site. The far-field, fate-transport modeling at Jordan Point shows relatively low maximum values of suspended sediment concentration (less than 40 mg/L) and deposition values (less than 0.2 cm). Material that is placed at Jordan Point appears to quickly disperse through the system, depositing in thin layers at specific areas. The life-cycle analysis performed for the Jordon Point placement site yielded an estimated useable project life of the Jordan Point placement sites of 26 years with an uncertainty of ±4 years. Analysis showed that 97% of the net sediment deposition in the navigation channel in proximity to this site is from the upper James River, 2% is from downstream sources, and 1% is from the two Jordan Point placement sites.

14 Feb 2025

Validating Sediment Budgets Along the North Atlantic Coast Using the Updated Sediment Budget Calculator

Purpose: This Regional Sediment Management (RSM) technical note (TN) outlines two case studies validating the Sediment Budget Calculator (SBC) using accepted values from the literature and published sediment budgets. Initially developed by the US Army Corps of Engineers (USACE) as a web-based tool, the SBC calculates all viable sediment transport rates for an inlet environment given user-defined inputs. The next-generation SBC was converted into Python 3.9 to make it more accessible than the original C++ version. These case studies outline the efficacy of the SBC tool for deriving accurate and reliable sediment budget values. Finally, the TN discusses future SBC improvements and efforts to incorporate SBC results into the Sediment Budget Analysis System (SBAS).

13 Feb 2025

Upper Barataria Basin (UBB) Coastal Storm Risk Management (CSRM) Study : Probabilistic and Numerical Coastal Hazards Modeling

Abstract: This report summarizes the numerical modeling and probabilistic analysis performed by the US Army Engineer Research and Development Center Coastal and Hydraulics Laboratory (CHL) as part of the Upper Barataria Basin (UBB) Coastal Storm Risk Management (CSRM) Study. The intent of this work, performed for the US Army Corps of Engineers (USACE) and St. Paul District, was to evaluate project alternatives to assess flooding risks induced by coastal storms in coastal Louisiana. This study applied the USACE’s Coastal Storm Modeling System for storm surge and wave modeling and Coastal Hazards System–Probabilistic Framework (CHS-PF) to quantify water level and wave hazards, leveraging existing synthetic tropical cyclones (TCs) from the Coastal Hazards System¬–Louisiana (CHS-LA) study for levee recertification. Using a reduced storm suite (RSS) of synthetic TCs from CHS-LA, hydrodynamic model simulations were performed on an updated grid, including five proposed levee systems, to produce storm responses at more than 184,000 mesh node locations and over 21000 special save point locations within the UBB project area. Through the application of the CHS-PF, the joint probability analysis of TC atmospheric-forcing parameters and their associated storm responses were assessed for the estimation of still water level (SWL), significant wave height (Hm0), and wave peak period (Tp) annual exceedance frequencies ranging from 10 to 1 × 10−4 yr−1 to evaluate the impact of the UBB with- and without-project conditions.

12 Feb 2025

Cloud-Based Workflow to Process Regional Topobathymetric Lidar Datasets for Integrated USACE Shoaling Analyses

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) details a methodology to process and format regional topobathymetric datasets for use in the US Army Corps of Engineers (USACE) Corps Shoaling Analysis Tool (CSAT).

28 Jan 2025

Montgomery Locks and Dam, Ohio River: Navigation Approach Physical Model

Abstract: A physical model study of the Montgomery Locks and Dam was conducted to optimize the navigation conditions for the new riverside lock and guard wall design developed by the Pittsburgh District. A 1:100 Froude scale physical model was built to evaluate the navigation conditions for tows entering and exiting the locks in the upstream and downstream approaches. Conditions tested were Existing Conditions, Deconstruction Sequences, Construction Sequences, and Proposed Design. Data were also collected for impact analysis on the upstream and downstream riverside guard walls. The final design consisted of an upstream ported guard wall that is 1,000 ft in length and a downstream solid guard wall that is 800 ft in length. The implementation of submerged dikes in the upstream and downstream approaches improve navigation conditions significantly and are an essential part of the final design. Details are shown in Section 3.5 of this report.

7 Jan 2025

Geomorphic Assessment of the St. Francis River Phase II

Abstract: Significant sedimentation issues persist within the St. Francis Basin as a result of extensive drainage alterations. The objective of this study is to characterize the bed and bank sediment throughout the study reach and identify potential sources of sediment contributing to the sanding issues below Holly Island. The sedimentation below Holly Island increases the Memphis District’s maintenance needs in the St. Francis River Basin by requiring millions of dollars for channel cleanout and bank stabilization projects. This effort synthesizes prior geomorphic studies and existing survey data to break the study reach into seven geomorphic reaches of interest. Simultaneously, 151 bed samples and 137 bank samples were collected to characterize the sediments within the study reach to develop a data dictionary for future sediment budget development. Results show the St. Francis River is a poorly sorted, sand-bed river overlain by 10 to 20 feet of silts and clays along the banks. Iron Bridge to Highway U (Reach 1-3) may reach pseudo-stability so long as existing grade-control structures and bank stabilization features remain. Reach 6, between St. Francis and Brown’s Ferry, is evolving with one cutoff forming and one cutoff recently complete. This reach may be a source of sediment to downstream reaches.

11 Dec 2024

Adaptive Hydraulics (AdH) Version 4.7.1 Sediment Transport User’s Manual: A 2D Modeling System Developed by the Coastal and Hydraulics Laboratory

Abstract: Guidelines are presented for using the US Army Corps of Engineers (USACE) Adaptive Hydraulics (AdH) modeling software to model 2D shallow water problems with sediment transport (i.e., AdH linked to the Sediment Transport Library [SEDLIB]). This manual describes the inputs necessary to use the SEDLIB sediment transport library from within AdH, to perform coupled hydrodynamic, sediment, and morphological computations. The SEDLIB sediment transport library is intended to be of general use and, as such, examples are given for basic sediment transport of cohesive, noncohesive, and mixed suspended sediment loads and bedload.

11 Dec 2024

Numerical Modeling of Supercritical Flow in the Los Angeles River: Part II: Existing Conditions Adaptive Hydraulics Numerical Model Study

Abstract: The Los Angeles District of the US Army Corps of Engineers is assisting the City of Los Angeles with restoration efforts on the Los Angeles River. The city wishes to restore portions of the channelized river to a more natural state with riparian green spaces for both wildlife and public recreation usage. The Los Angeles River provides an important role from a flood-control perspective, and functionality needs to be preserved when contemplating system modifications. This report details the development of an Adaptive Hydraulics numerical model capable of modeling this complex system consisting of both subcritical and supercritical flow regimes. The model geometry was developed to represent the existing conditions system for future usage in quantifying the impact associated with proposed restoration alternatives. Due to limited hydraulic data in the study area, an extensive model validation to observed data was not possible. A model was developed and simulated using the most appropriate input parameters. Given the lack of measured data for model validation, an extensive number of sensitivity simulations were completed to identify the most impactful parameters and quantify a reasonable level of confidence in the model results based on the uncertainty in the model inputs.

2 Dec 2024

Establishing a Workflow for Near-Seamless Digital Elevation Model Creation in the Great Lakes for ADCIRC Modeling

Abstract: This report introduces a workflow to create near-seamless, regional digital elevation models (DEMs) for use in coupled Advanced Circulation and Simulating Waves Nearshore modeling. The workflow is based in Esri ArcGIS Pro, leveraging the Mosaic Dataset architecture to organize and mosaic survey data sets into near-seamless DEMs. This workflow includes data collection and preprocessing, creation of source and derived mosaic data sets, manual editing of the data set seamlines, the creation of spatial metadata products, and quality assurance and control measures. These steps were implemented for each Great Lake to provide a high-resolution, near-seamless DEM product for modelers. The workflow may also have utility for other regional-scale investigations.