21 Sep 2023

Field Demonstration of a Peroxide-Based Algaecide for Harmful Algal Bloom Control in Lake Okeechobee

Abstract: Large-scale cyanobacterial harmful algal blooms (cHABs) in Lake Okeechobee, Florida, and connected waterways routinely impair water resources. This study conducted a field demonstration of a peroxide-based algaecide in 2020 in the Pahokee Marina on Lake Okeechobee to evaluate the algaecide’s suitability for near-future operational implementation. Within minutes of treatment, rapid oxidation of cHAB cells occurred in the form of bleaching and cell lysis. On average, levels in the treatment area decreased by 4 hours after treatment (HAT) and remained low out to 24 HAT: chlorophyll decreased 87%, phycocyanin decreased 85%, total microcystin levels decreased from 50 μg L⁻¹ to 4 μg L⁻¹ at 4 HAT and then increased to 11 μg L⁻¹ by 24 HAT, hydrogen peroxide concentrations averaged 6.1 mg L⁻¹ 0.5 HAT and then dropped below detection limits by 24 HAT, and Microcystis spp. cell densities decreased at 4 HAT in all but four sampling sites. However, inflows of cHAB-infested lake water in some portions of the treatment area resulted in lack of control at these sites. Because of their vulnerability to influxes of cHABs from surrounding nontreated waters via water-exchange processes driven by wind-induced surface currents, future applications must therefore consider treatment area size.

18 Sep 2023

A Resilient Path Forward for the Marine Transportation System: Recommendations for Response and Recovery Operations from the 2017-2019 Hurricane Seasons

Abstract: The Marine Transportation System (MTS), Resilience Integrated Action Team (RIAT), is tasked by the coordinating board of the US Committee on the MTS to serve as a coordinating body to identify the impacts, best practices, and lessons learned by federal agencies involved in the response and recovery of the MTS after hurricane seasons. In response to this request, the RIAT has focused its analysis on the ability of MTS federal agencies to prepare, respond, recover, and adapt to as well as from disruptions. This was accomplished through workshops focused on gathering the collective experiences of emergency response professionals. In 2017, recommendations were gathered based on experiences responding to Hurricanes Harvey, Irma, and Maria. In this report, a similar approach was adopted to gather findings from Hurricanes Florence and Michael in 2018 and Hurricane Dorian in 2019. Utilizing the successes, challenges, and best practices from all six of these storms, the RIAT identified key coordinating bodies and the participants for each and key takeaways relative to the coordination of agencies with respect to the four steps of resilience: prepare, absorb, recover, and adapt.

18 Sep 2023

Accelerated Corrosion of Infrastructural Seven-Strand Cables via Additively Manufactured Corrosion Flow Cells

Purpose: The purpose of this project was to generate an accelerated corrosion methodology capable of producing seven-strand cables with simulated corrosive defects for calibration of nondestructive analysis (NDA) techniques. An additively manufactured accelerated corrosion cell was motivated and designed. Previous attempts at accelerated electrochemical corrosion used a large cable area with a current density that was too low (i.e., 1 A/m²)* to effectuate efficient corrosion. The accelerated corrosion cell presented here takes advantage of the restricted area within the corrosion flow cell to maximize the corrosion rate in a consistent and calibrated manner (i.e., 2,000 A/m²).

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.

13 Sep 2023

Sensitivity of Sediment Transport Analyses in Dam Removal Applications

Abstract: Dam removal has become a widespread river management practice in the US for a variety of goals including ecosystem restoration, removing aging infrastructure, flood risk management, and recreation. The ability to forecast the sediment impacts of dam removal is critical to evaluating different management alternatives that can minimize adverse consequences for ecosystems and human communities. Tullos et al. (2016) identified seven Common Management Concerns (CMCs) associated with dam removal. Four of these CMCs; degree and rate of reservoir sediment erosion, excessive channel incision upstream of reservoirs, downstream sediment aggradation, and elevated downstream turbidity are associated with stored sediment release and changing fluvial hydraulics. There are a range of existing qualitative and quantitative tools developed to infer or quantify geomorphic implications of disturbances like these in river environments (McKay et al. 2019). This study investigated how a one-dimensional (1D) sediment transport model can inform these four CMCs, develop an approach for assessing sediment transport model sensitivity in the context of the Simkins Dam removal, and use sensitivity analyses to identify key uncertainties, which can inform data collection and model building for other dam removal projects. For the selected case study, model outputs including the mean effective invert change (MEIC) and eroded sediment volume from reservoir were highly sensitive to the variation of the reservoir sediment gradation and sorting method selection. These model outputs also showed some sensitivity to the selected transport functions. Erosion method sensitivity using the channel evolution method will vary depending on side slope and channel parameter selection.

12 Sep 2023

The Use of Native Vegetation for Structural Stability in Dredged Material Placement Areas: A Case Study of Beneficial Use Site 4A, Chocolate Bayou, Brazoria County, Texas

PURPOSE: This technical note is the third in a series about using native plant communities to enhance dredge material placement areas (DMPAs), confined disposal facilities (CDFs), and projects where dredged sediments are used for various engineering purposes. DMPAs and CDFs occur in numerous locations spanning different geographic locations nationwide. Oftentimes, these containment dikes are constructed using earthen materials. The materials are either barged in from an off-site location or obtained on-site from new or virgin materials, consisting of heavy clay particles and sediments removed from the nearby channel. In the Gulf Coast region of the United States, new or virgin materials are obtained during channel deepening activities using mechanical or hydraulic dredging methods. Examples of these dredging methods include hopper dredge, pipeline dredge, and excavator or bucket dredge. When materials are considered suitable for beneficial use purposes, and following environmental compliance, the materials are often used to construct containment dikes in DMPAs and CDFs. The project site used in this study—Beneficial Use Site 4A (BUS 4A)—used dredged material during its construction and has periodically received dredged material to maintain its target elevation of 2 ft (0.67 m) above the mean lower low water; hence, this site presents an opportunity for use as a demonstration study. Project goals include (1) demonstrating the use of native plant communities to provide structural stability, (2) introducing targeted vegetation establishment on DMPAs and CDFs as a management strategy to improve engineering and environmental outcomes, and (3) providing technology transfer to the U.S. Army Corps of Engineers (USACE) districts through hands-on planting techniques and installation of natural material (in this demonstration, coir logs).

11 Sep 2023

The Use of Native Vegetation and Natural Materials in Shoreline Stabilization: A Case Study of Bubble Gum Beach, Rehoboth Beach, Delaware

PURPOSE: This technical note is the fourth in a series about using native plant communities to achieve engineering and ecological purposes such as shoreline stabilization, structural enhancements, habitat creation, and ecosystem development. In this series, we demonstrate the utility of natural materials (specifically, native vegetation, oyster reefs, and coir logs) in living shoreline projects. Plant species and plant communities play critical roles in wave attenuation and sediment accretion in coastal areas. The application of vegetation in the coastal areas, especially on the East and Gulf Coasts, has focused heavily on the creation of living shorelines—serving both environmental and engineering purposes. This technical note documents the workshop conducted by the US Army Engineering Research and Development Center (ERDC) and hosted by the US Army Corps of Engineers’ (USACE) Philadelphia District (NAP) and Center for the Inland Bays. The goals of this technical note are (1) to demonstrate the application of native plant communities, oyster shells, and coir (coconut) materials and their installation techniques along shorelines to the engineering community; (2) to demonstrate how targeted vegetation establishment can facilitate ecosystem development along shorelines to improve engineering and environmental outcomes; and (3) to provide native vegetation installation techniques for living shorelines projects’ purposes.

11 Sep 2023

Selection of a Time Series of Beneficial Use Wetland Creation Sites in the Sabine National Wildlife Refuge for Use in Restoration Trajectory Development

PURPOSE: The development of regional restoration trajectories of marsh creation and nourishment projects is key to improved design, management, and implementation of adaptive management principles. Synthesizing information from multiple marsh creation projects constructed at various times but with consistent site characteristics and borrow material sources, helps elucidate restoration success in a specific region. Specifically, this technical note (TN) documents the process of determining a suitable study area, construction methods, and the current state of establishing sites in the Louisiana Gulf Coast that could be used for restoration trajectory development. This investigation compiled information from the construction phases, Landset 8 satellite imagery, and the most recent digital elevation model (DEM) to investigate elevation and vegetation establishment within these sites.

5 Sep 2023

Resilience Modeling for Civil Military Operations with the Framework Incorporating Complex Uncertainty Systems

Abstract: Framework Incorporating Complex Uncertain Systems (FICUS) provides geographic risk analysis capabilities that will dramatically improve military intelligence in locations with the Engineer Research and Development’s (ERDC) demographic and infrastructure models built and calibrated. When completed, FICUS would improve intelligence products by incorporating existing tools from the National Geospatial Intelligence Agency, ERDC, and FICUS prototype models, even in places without demographic or infrastructure capabilities. FICUS would support higher-fidelity intelligence analysis of population, environmental, and infrastructure interaction in areas with Human Infrastructure System Assessment (HISA) and urban security models built and calibrated. This technical report will demonstrate FICUS prototype tools that allow Civil Affairs Soldiers to provide situational awareness information via a browser interface.

5 Sep 2023

Proceedings from the US Army Corps of Engineers (USACE) 2021 Beneficial Use of Dredged Material Virtual Workshop

Abstract: On 13–15 July 2021, 58 representatives from Headquarters, US Army Corps of Engineers (USACE), 2 USACE Divisions, 14 USACE districts, and US Army Engineer Research and Development Center’s (ERDC) Environmental (EL) and Coastal Hydraulics (CHL) Laboratories came together and participated in a virtual workshop on the beneficial use (BU) of dredged material. The overall goal was to organize the BU community across USACE and develop a path forward to increase BU practices. Talks and discussions focused on the current status of BU across USACE, including success stories on innovative BU projects, challenges related to regulatory issues, state and federal policies, technical logistics, and stakeholder engagement, as well opportunities for expanding current practices to include more regular and innovative applications. The workshop was cohosted by Dr. Amanda Tritinger (CHL) and Dr. Kelsey Fall (CHL) on behalf of the Engineering With Nature®, Coastal Inlets Research Program, Dredging Operations and Environmental Research, and Regional Sediment Management research programs. The workshop concluded by introducing and awarding the first annual Timothy L. Welp Award for Advancing Beneficial Use of Dredged Sediments to recognize teams (with members across and outside of USACE) that have advanced progress on BU through collaboration, partnering, and innovation.