7 Apr 2025

Review of Mississippi River Sediment-Sampling Protocols

Abstract: The Mississippi River sediment data protocols located in the US Army Corps of Engineer (USACE), St Louis, Memphis, Vicksburg, and New Orleans Districts, were reviewed and evaluated. The review included both USACE and US Geological Survey (USGS) sampling sites. The purpose of this review was to evaluate the reported historical sediment data and to provide guidance for moving forward with an accurate and consistent sediment data collection program. The review was focused on the reliability of the reported historical data and its usefulness for use in sedimentation studies related to long-term aggradation, degradation, and dredging. Recommendations to implement effective sediment data collection, laboratory analyses, and reporting were provided.

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).

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).

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 Jul 2024

Mississippi River AdH Model Modification and Evaluation, Thebes, Illinois, to Birds Point, Missouri, Reach

Abstract: A calibrated hydrodynamic and sediment transport model of the Upper Mississippi River, from Thebes, Illinois, to Birds Point, Missouri, was created to investigate hydraulics and sediment transport in the river channel and across the Dogtooth Island Peninsula (DIP) as the result of the Len Small levee breach. A hydrodynamic model was developed for the reach and calibrated to stage and breach outflow discharge data for the floods of 2011, 2015–2016, and 2017. The hydrodynamic model was used to investigate breach outflow discharges and shear stress distribution over the DIP. Soil and geologic maps were investigated to determine soil parameters and the long-term stability of soil formations on the DIP. The Upper Mississippi River sediment transport model was built upon the hydrodynamic model and soil mapping efforts. The sediment transport model was calibrated to the 2015 and 2017 flood events. Calibration data were limited to changes in elevation, which were then areally averaged, computed from comprehensive channel surveys and lidar data for the DIP. This model provides a solid foundation for comparing alternative measures to minimize further erosion of the DIP and for analyzing the risk of a channel cutoff occurring.

6 May 2024

Monitoring Geomorphology to Inform Ecological Outcomes Downstream of Reservoirs Affected by Sediment Release

Abstract: Increasingly, reservoir managers are seeking techniques that improve sediment management while considering long-term sedimentation and reduced operational flexibility. These techniques, often termed sustainable sediment management, involve passing sediment through reservoirs and into downstream rivers. Conceptually, restoring sediment continuity can benefit ecosystem function by increasing floodplain connectivity, contributing to the heterogeneity of channel geomorphology, and supporting the continuity of nutrient cycling. However, when a change is made to operations, geomorphic changes may need to be monitored to document benefits and mitigate any unexpected effects of the change. This investigation develops a geomorphic monitoring plan for downstream reaches affected by sediment-release operations at reservoirs. The monitoring objectives are aligned with potential geomorphic change caused by changes to sediment supply and the associated effects on river function. A tiered approach is presented to explain the quality of information that can be assessed from increasing levels of data collection. A general conceptual model is described in which geomorphic data may be linked to physical habitat conditions and, therefore, ecological processes. The geomorphic monitoring plan for the Tuttle Creek Reservoir water injection dredging (WID) pilot project is presented as a case study. This technical note establishes a general framework for monitoring the design for sustainable sediment management in different ecological and geomorphic contexts.

8 Apr 2024

Coastal Modeling System User’s Manual

Abstract: The Coastal Modeling System (CMS) is a suite of coupled 2D numerical models for simulating nearshore waves, currents, water levels, sediment transport, morphology change, and salinity and temperature. Developed by the Coastal Inlets Research Program of the US Army Corps of Engineers, the CMS provides coastal engineers and scientists a PC-based, easy-to-use, accurate, and efficient tool for understanding of coastal processes and for designing and managing of coastal inlets research, navigation projects, and sediment exchange between inlets and adjacent beaches. The present technical report acts as a user guide for the CMS, which contains comprehensive information on model theory, model setup, and model features. The detailed descriptions include creation of a new project, configuration of model grid, various types of boundary conditions, representation of coastal structures, numerical methods, and coupled simulations of waves, hydrodynamics, and sediment transport. Pre- and postmodel data processing and CMS modeling procedures are also described through operation within a graphic user interface—the Surface Water Modeling System.

4 Apr 2024

Use of Sediment Tracers to Evaluate Sediment Plume at Beaufort Inlet and Adjacent Beaches, North Carolina

Abstract: This report documents a numerical modeling investigation on the transport of sediment material placed on designated disposal sites adjacent to Beaufort Inlet, North Carolina. Historical and newly collected wave and hydrodynamic data around the inlet are assembled and analyzed. The data sets are used to calibrate and validate a coastal wave, hydrodynamic and sediment transport model, the Coastal Modeling System. Model alternatives are developed corresponding to different material placement sites. Sediment transport and sediment plume distribution are evaluated within and around the immediate vicinity of the Beaufort Inlet estuarine system for a representative summer and winter month. Results of model simulations show that high flows occur along navigation channels and low flows occur outside the inlet in open ocean area. Sand materials placed in nearshore sites tend to be trapped in and move along navigation channels entering the inlet. In offshore placement sites the sediment plume shows slow spreading and no significant sand migration from its release locations. Simulations for the summer and winter month present similar distribution patterns of sediments originating from placement sites.

21 Mar 2024

A Beneficial Placement Decision Support Framework for Wetlands: Case Study for Mobile Harbor, USA

Abstract: The US Army Corps of Engineers, in the responsibility of maintaining navigational infrastructure, has a unique opportunity to improve coastal wetland resiliency and conserve coastal natural infrastructure through the beneficial use of dredged material for wetland restoration. Opportunities are widespread, and tools such as biophysical models can aid coastal managers in assessing habitat vulnerability and planning restoration. In this study, the Marsh Equilibrium Model was utilized in concert with observed data to predict future conditions and evaluate potential effects of beneficial use of dredged material to restore marshes in Mobile Harbor, Alabama. A range of site conditions and two restoration strategies were considered, and the subsequent impact to dredged material management area volumes evaluated. Results showed that wetland restoration via the thin-layer placement of dredged material can restore marsh elevation to combat sea level rise and conserve fill capacity at dredged material management areas. This approach is demonstrated for adoption nationwide by coastal managers.