27 Sep 2021

Atlantic Sturgeon Movements in Relation to a Cutterhead Dredge in the James River, Virginia

Purpose: This technical note describes a field study investigating the movements of federally endangered Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus (ATS), during the summer and fall of 2017 near a cutterhead dredge working in the James River, Virginia, to provide data addressing the concern about the potential impacts of dredging activities (for example, excavation, transit, disposal, sounds, reduced water quality) on the ATS.

21 Sep 2021

Initial Survey of Microplastics in Bottom Sediments from United States Waterways

Abstract: Given the reported extent of microplastics in the aquatic environment, environmentally relevant exposure information for sediments dredged by the US Army Corps of Engineers will lend context to the risks posed by this contaminant during dredging. We measured the occurrence, abundance, and polymer composition of microplastics in sediments collected from nine dredged waterways and two non-dredged reference areas. The number of particles in sediment samples ranged from 162 to 6110 particles/kg dry wt., with a mean of 1636 particles/kg dry wt. Fragments were the most prevalent shape observed among the 11 study sites (100% frequency of occurrence), followed by fibers (81%), spheres (75%), foams (38%) and films (34%). Based on analyses of chemical composition of the particles using Fourier transform infrared spectroscopy, polyethylene:propylene was the most common polymer type observed. Consistent with results presented by other investigators microplastic concentrations and polymer types in bottom sediments in this study were also aligned with the most widely used plastics worldwide.

4 Aug 2021

An Assessment of Long-Term, Multipurpose Ecosystem Functions and Engineering Benefits Derived from Historical Dredged Sediment Beneficial Use Projects

Abstract: The beneficial use of dredged materials improves environmental outcomes while maximizing navigation benefits and minimizing costs, in accordance with the principles of the Engineering With Nature® (EWN) initiative. Yet, few studies document the long-term benefits of innovative dredged material management strategies or conduct comprehensive life-cycle analysis because of a combination of (1) short monitoring time frames and (2) the paucity of constructed projects that have reached ecological maturity. In response, we conducted an ecological functional and engineering benefit assessment of six historic (>40 years old) dredged material–supported habitat improvement projects where initial postconstruction beneficial use monitoring data was available. Conditions at natural reference locations were also documented to facilitate a comparison between natural and engineered landscape features. Results indicate the projects examined provide valuable habitat for a variety of species in addition to yielding a number of engineering (for example, shoreline protection) and other (for example, carbon storage) benefits. Our findings also suggest establishment of ecological success criteria should not overemphasize replicating reference conditions but remain focused on achieving specific ecological functions (that is, habitat and biogeochemical cycling) and engineering benefits (that is, storm surge reduction, navigation channel maintenance) achievable through project design and operational management.

19 Jul 2021

Metrics of Success for Nearshore Nourishment Projects Constructed with Dredged Sediment

Purpose: This Regional Sediment Management Technical Note (RSM TN) provides practical metrics of success for nearshore nourishment projects constructed with dredged sediment. Clearly defined goals and performance metrics for projects will set clear expectations and will lead to long-term project support from local stakeholders and the public.

16 Jun 2021

Field Measurement and Monitoring of Hydrodynamic and Suspended Sediment within the Seven Mile Island Innovation Laboratory, New Jersey

Abstract: The Seven Mile Island Innovation Laboratory (SMIIL) was launched in 2019 to evaluate beneficial use of dredge material management practices in coastal New Jersey. As part of that effort, the Philadelphia District requested that the US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, collect data to characterize the hydrodynamics and turbidity within the central portions of the SMIIL prior to and during dredge material placement. Pre-dredge monitoring found that apart from punctuated wind events, the study area waters were generally calm and clear with small waves, <0.25 m, slow current speeds (~0.1 m/s), low turbidity (~10 ntus), and low suspended sediment concentrations (~10–20 mg/L). In March 2020, 2,475 m3 of dredged sediment was placed on the northern portion of Sturgeon Island within the SMIIL. Turbidity in the waters surrounding the island was monitored to quantify extent of the sediment plume resulting from the placement. Observations found little to no turbidity plume associated with the dredging operations beyond 20 m from the island and that the plume was largely limited to areas near a tidal creek draining the placement area. Additionally, turbidity levels quickly returned to background conditions at times when the dredge was not in operation.

3 Jun 2021

Elevation of underlying basement rock, Ogdensburg Harbor, NY

Abstract: Over six linear miles of shallow acoustic reflection geophysical data were collected in an 800 ft by 300 ft survey region at Ogdensburg Harbor, Ogdensburg, NY. To better accommodate modern commercial vessels and expand the harbor’s capacity, the current navigable depth of -19 ft Low Water Depth (LWD) needs to be increased to -28 ft LWD, and an accurate map of the nature of the riverbed material (e.g., unconsolidated sediment, partially indurated glacial till, or bedrock) is required to effectively plan for removal. A total of 28 boreholes were previously collected to map the stratigraphy, and the effort revealed significant spatial variability in unit thickness and elevation between adjacent boreholes. To accurately map this variable stratigraphy, chirp sub-bottom profiles were collected throughout the region, with an average line spacing of 13 ft. These sub-bottom data, validated and augmented by the borehole data, resulted in high-resolution spatial maps of stratigraphic elevation and thickness for the study area. The data will allow for more accurate assessment of the type and extent of different dredging efforts required to achieve a future uniform depth of -28 ft LWD for the navigable region.

21 May 2021

Field Survey to Prioritize Needs for Modernizing Dredged Material Evaluation Guidance

Abstract: This technical note synthesizes and disseminates results of a 2020 survey of USACE dredging program and project managers to identify and prioritize needs related to the modernization and streamlining of the dredged material assessment decision guidance pursuant to Section 404 of the Clean Water Act (CWA) and Section 103 of the Marine Protection Research and Sanctuaries Act (MPRSA). Priorities identified through the survey and subsequent follow-on interviews—together with advances in science and technology—will facilitate development of an electronic decision guidance tool to enable consistent, timely, and cost-effective dredged material management decisions. This tool will also facilitate a standardized database for ready access to historical data.

10 May 2021

Investigation for Shoaling Reduction along the Gulf Intracoastal Waterway (GIWW) at Caney Creek, Sargent, Texas

Purpose: This US Army Corps of Engineers (USACE) Regional Sediment Management (RSM) initiative considered alternatives for shoaling reduction in the Gulf Intracoastal Waterway (GIWW) in the vicinity of Caney Creek near Sargent, TX (Figure 1). Additionally, new beneficial use (BU) sites were considered along degraded islands adjacent to the GIWW with a threefold objective: increase the quality and quantity of habitat, reduce dredging cost via shorter pump distance, and reduce shoaling in the GIWW through East Matagorda Bay.

29 Jan 2021

Environmental Applications of 3D Printing Polymer Composites for Dredging Operations

Abstract: This Dredging Operations Environmental Research (DOER) technical note disseminates novel methods to monitor and reduce contaminant mobility and bioavailability in water, sediments, and soils. These method advancements are enabled by additive manufacturing (i.e., three-dimensional [3D] printing) to deploy and retrieve materials that adsorb contaminants that are traditionally applied as unbound powders. Examples of sorbents added as amendments for remediation of contaminated sediments include activated carbon, biochar, biopolymers, zeolite, and sand caps. Figure 1 provides examples of sorbent and photocatalytic particles successfully compounded and 3D printed using polylactic acid as a binder. Additional adsorptive materials may be applicable and photocatalytic materials (Friedmann et al. 2019) may be applied to degrade contaminants of concern into less hazardous forms. This technical note further describes opportunities for U.S. Army Corps of Engineers (USACE) project managers and the water and sediment resource management community to apply 3D printing of polymers containing adsorptive filler materials as a prototyping tool and as an on-site, on-demand manufacturing capability to remediate and monitor contaminants in the environment. This research was funded by DOER project 19-13, titled “3D Printed Design for Remediation and Monitoring of Dredged Material.”

19 Jan 2021

Incorporating Color Change Propensity into Dredged Material Management to Increase Beneficial Use Opportunities

Dredged materials provide a number of beneficial use opportunities, including beach nourishment, habitat creation and restoration, and other activities. In situ sediment color is important for determining aesthetic and habitat suitability, for beach nourishment, and for other projects. However, dredged materials must meet locally established color compatibility requirements (for example, material cannot be too dark). Often, potential sediment sources are close to meeting specified color thresholds, and previous observations suggest that sediments lighten over time. In response to these observations, this study quantified sediment color change potential in a dredged m material management context. Results indicate that dredged material sediment color responded to changes in secondary color components, sediment mixing, and photolytic bleaching improving the sediment color for beneficial use application. Findings allowed for development of a conceptual color change capacity framework and supported development of tools for resource managers to incorporate color change dynamic into planning and operations activities. The following report provides a framework for determining the color change capacity of dredged materials using (1) a comprehensive laboratory approach and (2) a semiquantitative index based on source material and placement location conditions. These tools allow practitioners to incorporate dredged-material color change into resource management decisions, thus increasing beneficial use opportunities.