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.

10 Jun 2024

Lock and Dam 25, Upper Mississippi River Navigation Study: Ship-Simulation Results

Abstract: The US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory (CHL), used the Ship/Tow Simulator to evaluate navigational conditions for the US Army Corps of Engineers, St. Louis District (MVS), proposed 1,200 feet (ft) lock chamber at Lock and Dam 25 in a tow simulation study. The study considers the impacts to navigation throughout construction sequences of the proposed 1,200 ft lock chamber and the final completed project. Testing occurred at CHL in October–November 2022 with five industry tow pilots. A total of 47 unique test conditions for a total of 187 ship-simulation exercises were evaluated. All final project simulations indicated that the design is feasible. When testing the construction scenarios of the design, it was evident that a tug assist boat would be necessary for entering the 600 ft lock for both approaches. Results found that the intermediate wall construction should begin at the existing structure and progress downstream. Entering the 600 ft lock from the pool side was additionally completed successfully; however, modifications are needed for entering from the tailwater side. Ultimately, the results of this study will aid MVS in the design plan and decision-making regarding the proposed lock.

6 Nov 2023

A Method for Evaluating Automatic Identification System (AIS) Coverage on Select Inland Waterways in 2020 and 2021: Upper Mississippi River, Illinois River, and Ohio River

Abstract: The Automatic Identification System (AIS) shares vessel position information for navigational safety purposes. AIS broadcasts are received by other ships and terrestrial stations; however, in some areas there is no, or low, terrestrial station coverage to receive broadcasts. The US Army Corps of Engineers (USACE) developed an Online Travel Time Atlas (OTTA) to process AIS data and derive a transit count. This study examined OTTA output from 2020 and 2021 to identify areas of high or low AIS coverage along the Upper Mississippi, Illinois, and Ohio Rivers. Segments with a yearly average of two or more transit per day were classified as high coverage, those with less than a yearly average of two transits per day were classified as low coverage. Rivers were segmented using the USACE National Channel Framework reach boundaries. Results based on calculated vessel transits were as follows: Upper Mississippi River: 837.4 miles (98%) had high coverage, with 17.4 miles (2%) of low coverage; Illinois River: 190.5 miles (59%) had high AIS coverage, and 133 miles (41%) had low AIS coverage; Ohio River: 644 miles (66%) had high coverage, and 337 miles (34%) had low coverage. AIS coverage could be improved by raising antennae heights, installing repeater equipment, or adding towers.

15 Sep 2023

Real-Time Forecasting Model Development Work Plan

Abstract: The objective of the Lowermost Mississippi River Management Program is to move the nation toward more holistic management of the lower reaches of the Mississippi River through the development and use of a science-based decision-making framework. There has been substantial investment in the last decade to develop multidimensional numerical models to evaluate the Lowermost Mississippi River (LMMR) hydrodynamics, sediment transport, and salinity dynamics. The focus of this work plan is to leverage the existing scientific knowledge and models to improve holistic management of the LMMR. Specifically, this work plan proposes the development of a real-time forecasting (RTF) system for water, sediment, and selected nutrients in the LMMR. The RTF system will help inform and guide the decision-making process for operating flood-control and sediment-diversion structures. This work plan describes the primary components of the RTF system and their interactions. The work plan includes descriptions of the existing tools and numerical models that could be leveraged to develop this system together with a brief inventory of existing real-time data that could be used to validate the RTF system. A description of the tasks that would be required to develop and set up the RTF system is included together with an associated timeline.

8 Aug 2023

Evaluation of Structural and Operational Alternatives to Optimize the Distribution of Water and Sediment in the Passes of the Mississippi River

Abstract: Mississippi River shoaling and dredging processes in the vicinity of Head of Passes and in Southwest Pass were investigated. Existing rates of deposition and dredging were determined using near-daily eHydro bathymetric surveys, National Dredging Quality Management dredge operating data, and geospatial processing steps developed for this study. These surveys provide a means to characterize the highly dynamic and variable sedimentation patterns observed in the navigation channel. The HEC-6T one-dimensional numerical sedimentation model was used to evaluate possible modifications to the distribution of water and sediment in the Mississippi River near Head of Passes in an attempt to reduce shoaling in the navigation channel. The model was used to evaluate the effects of partial closures of several distributaries downstream from Venice and to evaluate the effects of channel widening and channel deepening adjacent to the Hopper Dredge Disposal Area at Head of Passes. In this study, various structural alternatives were compared to a base test that represented existing conditions. Sedimentation and dredging effects were projected 50 years into the future.

7 Aug 2023

Acoustic Doppler Current Profiler Study of Water and Sediment Movement through a Deep Scour Hole in the Lower Mississippi River

Abstract: A series of acoustic Doppler current profiler (ADCP) transects were collected through a deep scour hole at the bend near River Mile 60 on the Lower Mississippi River. The measurements were collected during both a low and a high flow. The ADCP results show a 3D flow field through the deep bend. The backscatter intensity of the ADCP measurements indicates the majority of the sediment remains close to the inside of the bed and high in the water column, with minimal concentrations at the bottom of the bend. These findings have implications for numerical sediment transport models, which tend to deposit material at the bottom of deep scour holes like the one in this study

25 May 2023

Automatic Identification System (AIS) Data Case Study: Identifying Unofficial Mooring Areas along the Upper Mississippi River

Purpose: This Dredging Operations and Technical Support (DOTS) program technical note presents the results of a study undertaken at the request of staff from the US Army Corps of Engineers (USACE) Rock Island District (MVR) as part of a larger effort examining the potential creation of seven new permanent mooring cells along the Upper Mississippi River in proximity to lock and dam (LD) locations selected by MVR. MVR staff were interested in evaluating vessel traffic and identifying unofficial mooring areas (i.e., waiting areas) in the vicinity of LD7, LD10, LD11, LD14, LD15, LD20, and LD22; they were also interested in travel times from those unofficial mooring areas to the destination lock. The search distance for unofficial mooring areas was limited to 20 miles from the lock, or the distance to the next closest lock if less than 20 miles, in the appropriate direction (i.e., upstream or downstream), as specified by MVR staff.

31 Aug 2022

Sediment Supply from Bank Caving on the Lower Mississippi River, 1765 to Present

Abstract: Bank caving rates and associated total sediment supply were calculated along the Lower Mississippi River from Cairo, IL, to Baton Rouge, LA, using historical maps between 1765 and 1992. Comparison of these maps reveals that the added sediment loads from bank erosion have greatly declined through time. In the pre-1960s period, erosion rates generally ranged from approximately 300 million cubic yards (MCY) to 400 MCY, with the 1880–1930s period having the highest erosion rates of approximately 600 MCY. By the 1990s, the sediment supply from bank erosion was essentially eliminated, with significant erosion being observed at only a few locations, totaling approximately 40 MCY/year. This equates to approximately a 90% reduction in the amount of total sediment being supplied to the channel system from bank erosion.

19 Aug 2022

The Old River, Mississippi River, Atchafalaya River, and Red River (OMAR) Technical Assessment

NOTE: The Old River, Mississippi River, Atchafalaya River, and Red River (OMAR) Technical Assessment is a 9-volume series of reports that was produced under the direction of the Mississippi River Geomorphology & Potamology Program. An abstract from the main report, Volume 1, is listed below, along with the individual volume titles and links to the relevant reports. ABSTRACT: This is the main report of Old River, Mississippi River, Atchafalaya River, and Red River (OMAR) Technical Assessment. The primary objective of the OMAR Technical Assessment was to conduct a comprehensive evaluation that aimed to understand the impacts of former and potential changes to the system in the vicinity of the Old River Control Complex (ORCC) over time, the water and sediment delivery regime at the ORCC, and the effects to the river system surrounding the ORCC. Scenarios evaluated in this technical assessment were designed to investigate potential system responses to a wide range of possible operational alternatives and identify knowledge gaps in current understanding of system behavior. This report summarizes and synthesizes the individual reports detailing the investigations into specific aspects of the ORCC and the surrounding region.

20 May 2022

Low-Sill Control Structure Gate Load Study

Abstract: The effort performed here describes the process to determine the gate lifting loads at the Low-Sill Control Structure. To measure the gate loads, a 1:55 Froude-scaled model of the Low-Sill Control Structure was tested. Load cells were placed on 3 of the 11 gates. Tests evaluated the gate loads for various hydraulic heads across the structure. A total of 109 tests were conducted for 14 flows with each flow having two gate settings provided by the United States Army Corps of Engineers, New Orleans District. The load data illustrated the potential for higher gate lifting loads (GLL) to occur at the mid-range gate opening (Go) for Gates 3 and 6. While for Gate 10, the highest GLL (452 kips, maximum load in testing) was at a Go = 4.2 ft. Conversely, for the low-flow bays, the highest load occurred at Go = 24.86 ft.