30 Aug 2022

Screening Dredged Material to Meet Placement Requirements

Abstract: Certain types of dredging projects require screening of the dredged material (DM) to achieve the project’s DM placement requirement(s). Screening in the context of this report will be defined as the separation of an oversized fraction of the DM from the remaining fraction to meet project-specific placement compliance criteria (or criterion). Examples of DM placement requirements include aspects such as removing Munitions and Explosives of Concern (MEC) to address safety concerns and extracting over-sized material for beneficial use of DM (e.g., gravel and debris from sand to meet beach nourishment placement standards). Welp et al. (2008) provide detailed guidance for personnel involved in dredging projects with sediment containing MEC. The purpose of this document is to not only update the previous MEC-centric guidance with newly developed or identified technology but to also expand upon screening aspects to provide guidance for personnel involved in dredging projects that require removal of an oversized fraction for screening purposes other than just MEC removal.

12 Aug 2022

Swan Island: Monitoring and Adaptive Management Plan

Abstract: Swan Island is a 10.12 ha island located in the Maryland waters of the Chesapeake Bay. Because of its value as a natural wave break for the town of Ewell on nearby Smith Island, as well as the ongoing erosion and subsidence of the island, in 2019 US Army Corps of Engineers (USACE)–Baltimore District placed 45,873 m³ of dredged sediment and planted 200,000 marsh plants. This restoration provided an opportunity to quantify the engineering (that is, resilience) and ecological performance of the island, postplacement. The lack of quantitative data on the performance of natural features such as islands has led to perceived uncertainties that are often cited as barriers to implementation. To address these data gaps, a multidisciplinary collaboration of five government entities identified project objectives and monitoring parameters through a series of mediated workshops and then developed a conceptual model to articulate those parameters and the linkages between them. This monitoring and adaptive management plan (MAMP) documents those monitoring parameters and procedures and can serve as an example for other scales, regions, and research questions. Documenting research and monitoring efforts may help to foster widespread acceptance of nature-based solutions such as islands.

11 Aug 2022

Environmental Evaluation and Management of Dredged Material for Beneficial Use: A Regional Beneficial Use Testing Manual for the Great Lakes

Abstract: The Environmental Evaluation and Management of Dredged Material for Beneficial Use: A Regional Beneficial Use Testing Manual for the Great Lakes (a.k.a. Great Lakes Beneficial Use Testing Manual) is a resource document providing technical guidance for evaluating the suitability of dredged sediment for beneficial use in aquatic and terrestrial environments in the Great Lakes region. The procedures in this manual are based on the Environmental Laboratory extensive research, working with US Army Corps of Engineers (USACE) Great Lakes districts, state resource agencies, and local stakeholders seeking to develop dredged material beneficial use alternatives consistent with regional needs and goals. This manual is the first guidance document developed by USACE for evaluating the environmental suitability of dredged material specifically for beneficial use placements. It provides a tiered framework for evaluating the environmental suitability of aquatic and upland beneficial uses consistent with the Inland Testing Manual and the Upland Testing Manual. This manual is intended to serve as a regional platform to increase collaborative problem-solving and endorse a common understanding of the scientific and institutional practices for evaluating dredged material for any beneficial use. Dredged sediment may be managed as a valuable resource, with great potential to create economic, environmental, and social benefits.

4 Aug 2022

Supporting Bank and Near-bank Stabilization and Habitat Using Dredged Sediment: Documenting Best Practices

Abstract: In-water beneficial use of dredged sediment provides the US Army Corps of Engineers (USACE) the opportunity to increase beneficial use while controlling costs. Beneficial use projects in riverine environments include bank and near-bank placement, where sediments can protect against bank erosion and support habitat diversity. While bank and near-bank placement of navigation dredged sediment to support river-bank stabilization and habitat is currently practiced, documented examples are sparse. Documenting successful projects can support advancing the practice across USACE. In addition, documentation identifies data gaps required to develop engineering and ecosystem restoration guidance using navigation-dredged sediment. This report documents five USACE and international case studies that successfully applied these practices: Ephemeral Island Creation on the Upper Mississippi River; Gravel Island Creation on the Danube River; Gravel Bar Creation on the Tombigbee River; Wetland Habitat Restoration on the Sacramento-San Joaquin River Delta; and Island and Wetland Creation on the Lower Columbia River Estuary. Increased bank and near-bank placement can have multiple benefits, including reduced dredge volumes that would otherwise increase as banks erode, improved sustainable dredged sediment management strategies, expanded ecosystem restoration opportunities, and improved flood risk management. Data collected from site monitoring can be applied to support development of USACE engineering and ecosystem restoration guidance.

29 Jul 2022

Investigation of Sources of Sediment Associated with Deposition in the Calcasieu Ship Channel

Abstract: The Calcasieu Ship Channel (CSC) is a deep-draft federal channel located in southwest Louisiana. It is the channelized lowermost segment of the Calcasieu River, connecting Lake Charles to the Gulf of Mexico. With support from the Regional Sediment Management Program, the US Army Corps of Engineers, New Orleans District, requested that the US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, perform an investigation of the potential sources of sediment associated with dredging in the CSC. A previous study had quantified sediment from known sources, indicating that the known sediment sources contribute approximately only 21% of the volume that is regularly dredged from the channel. This technical report details the results of the current study, which employed multiple methods, including numerical analysis, to identify potential additional sources of sediment by first examining the available literature and the modeled energetics and flow pathways, and then estimating the quantities of sediment associated with these identified sources that may be contributing to the shoaling of the CSC. The results of these efforts were used to update the original sediment budget with estimates of the contributions from two additional sources: the erosion of interior wetlands and coastally derived sediments.

29 Jul 2022

Using Geophysical and Erosion Properties to Identify Potential Beneficial Use Applications for Atlantic Intracoastal Waterway Sediments

Abstract: In an effort to identify alternative and beneficial use placement strategies for dredged sediments from the Atlantic Intracoastal Waterway (AIWW), the US Army Corps of Engineers, Savannah District (SAS), and the US Army Engineer Research and Development Center (ERDC) performed a series of physical property tests of 34 core borings from the SAS AIWW. Physical property testing found that 14 of the borings were non-cohesive sandy materials that may be suitable for potential beach renourishment or berm construction. The remaining 20 borings had mud contents sufficient enough to result in cohesive behavior. A subset of six of these materials from across the geographic region were further evaluated to characterize their erosion behavior. Following a self-weight consolidation period of 30 days, erosion testing showed that the tested cohesive sediments had critical shear stress values that ranged from 1.7 Pa to 2.9 Pa, suggesting that these sediments would likely be resistant to erosion in most wetland environments after placement. Additionally, the cohesive sediments were found to produce gravel-sized mud clasts. These clasts could account for 20% or more of the eroded mass and significantly reduce the amount of silts and clays incorporated in suspended plumes during and immediately following placement.

29 Jul 2022

Sediment Provenance Studies of the Calcasieu Ship Channel, Louisiana

Abstract: To maintain the navigability of the Calcasieu Ship Channel (CSC), the US Army Corps of Engineers annually dredges millions of cubic yards of sediment from the inland channel. To assess sources of channel shoaling, a previous study examined river and bankline erosion as inputs. Results from that study accounted for approximately 20% of dredged volumes. Through the support of the Regional Sediment Management Program, a follow-up investigation reviewed prior sediment budgets, identified potential missing sediment sources, modeled potential sediment pathways, and utilized geochemical fingerprinting to discern primary shoaling sources to the channel. The missing sediment sources from the original budget include coastally derived sediment from the Gulf of Mexico and terrestrially derived sediment from Lake Calcasieu and surrounding wetlands. Results from geochemical fingerprinting of various potential sediment sources indicate the Calcasieu River and the Gulf of Mexico are primary contributors of sediment to the CSC, and sediments sourced from bankline erosion, Lake Calcasieu bed, and interior wetlands are secondary in nature. These results suggest that engineering solutions to control shoaling in the CSC should be focused on sources originating from the Gulf of Mexico and river headwaters as opposed to Lake Calcasieu, channel banklines, and surrounding wetlands

20 Jul 2022

Impacts of Granular Activated Carbon (GAC) on Erosion Behavior of Muddy Sediment

Abstract: Recent policy changes regarding the placement of dredged material have encouraged the USACE to increase its beneficial use (BU) of the sediments dredged from the nation’s navigation channels. A good portion of this material is fine grained (<63 mm), which traditionally has limited use in BU applications, in part due to its dispersive nature. A need exists to evaluate the potential of stabilizing and using fine-grained sediment (FGS) in BU projects. Previous studies have shown the addition of granular sand to FGS reduces the mobility of the bed. The potential of using Granular Activated Carbon (GAC), an amendment commonly used in environmental capping involving FGS, as a similar bed stabilizing material was explored in this study. A series of laboratory erosion tests using Sedflume were performed on FGS-GAC mixtures that ranged from 5% to 20% GAC by mass. Results suggested that GAC content ≤10% had no influence on the stability of the bed while GAC content ≥15% appeared to reduce both critical shear stress (τcr) and erosion rate (n). However, when compared to control cores, those without GAC, clear evidence of bed stabilization of FGS from the addition of GAC was not observed.

11 Jul 2022

USACE Navigation Sediment Placement: An RSM Program Database (1998 – 2019)

Abstract: This US Army Corps of Engineers, Regional Sediment Management, technical note describes a geodatabase of federal coastal and inland navigation projects developed to determine the extent to which RSM goals have been implemented across the USACE at the project and district levels. The effort 1) quantified the volume of sediment dredged from federal navigation channels by both contract and USACE-owned dredges and 2) identified the placement type and whether sediment was placed beneficially. The majority of the dredging data used to populate the geodatabase were based on the USACE Dredging Information System DIS database, but when available, the geodatabase was expanded to include more detailed USACE district-specific data that were not included in the DIS database. Two datasets were developed in this study: the National Dataset and the District-Specific and Quality-Checked Dataset. The National Dataset is based on statistics extracted from the combined DIS Contract and Government Plant data. This database is a largely unedited database that combined two available USACE datasets. Due to varying degrees of data completeness in these two datasets, this study undertook a data refinement process to improve the information. This was done through interviews with the districts, literature search, and the inclusion of additional district-specific data provided by individual districts that often represent more detailed information on dredging activities. The District-Specific and Quality-Checked Database represents a customized database generated by this study. An interactive web-based tool was developed that accesses both datasets and displays them on a national map that can be viewed at the district or project scale

11 Jul 2022

National Sediment Placement Data Viewer Users Guide

Purpose: This US Army Corps of Engineers (USACE) Regional Sediment Management (RSM) technical note serves as a user’s guide for the RSM National Sediment Placement Data Viewer. This application was created utilizing over 20 yr* of detailed and verified USACE dredging data, giving users an interactive web-based tool that takes these datasets and displays them on a national map, viewable at the district or project scale. The Data Viewer will quantify the total cubic yards dredged, disposed, and/or beneficially used based on the user selected parameters. Detailed information on the datasets utilized and the verification processes followed to create this application can be found in ERDC/TN RSM-22-4, USACE Navigation Sediment Placement: An RSM Program Database (1998 – 2019) (Elko et al. 2022). This technical note attempts to define each of the inputs/outputs given from the Data Viewer and then provide a step-by-step example of utilizing the Data Viewer, accessed here: https://www.arcgis.com/apps/MapSeries/index.html?appid=0ea8fc0a956f46068428c862e7497233