Dredging Operations and

Environmental Research

U.S. Army Corps of Engineers

Archived Research Fact Sheets

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Dredged Material Management
Environmental Resource Management
Sediment Dredging Processes
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Focus Area: Dredged Material Management
Focus Area Leader: Tim Welp, Research Hydraulic Engineer, Coastal Hydraulics Laboratory

Title: Adapting Consolidation Modeling to Optimize TLP Project Design and Ecosystem Service Returns

POC: Susan Bailey and Zachary Tyler

Summary: This research task includes bench scale testing and field data collection to improve our understanding of dredged material consolidation behavior after thin layer placement. The RT will result in a better understanding of the physical processes involved in placement, dewatering and settlement of dredged material in wetland environments, examining the effects of vegetation on placement density, and plant transpiration and rooting on consolidation and its dynamics. It will provide more robust application of the PSDDF model to calculate dredged material settlement over time in order to optimize attainment of the design elevation(s) to facilitate maintenance of sustainable wetlands via thin layer placement of dredged material. These improvements will allow USACE planners and other agencies involved in ecosystem restoration to better design wetland creation projects to reach target elevations, resulting in fewer projects that fail as a result of missed target elevations.

Focus Area: Dredged Material Management

Title: Automated Bin Measure Method for Fine-Grained Loads as a Contract Payment Basis

POC: Tim Welp

Summary: This research task is investigating the feasibility of modifying an automated mechanical ullage sensor system (originally designed to measure sand loads) for use in fine-grained material. An automated accurate hopper dredge bin measurement system that can be used as a payment basis in both fine and coarse-grained sediment loads that could be used in lieu of rental contracts will incentivize dredging contractors to maximize production and improve quantification of dredged material being placed to improve dredging contract management efficiency.

Focus Area: Dredged Material Management

Title: Development of an Automated Scow Load Measurement System, Contract Specifications and Engineering Guidance

POC: Jonathan Marshall and Tim Welp

Summary: This DOER research task will provide an improved scow measurement system to allow more accurate quantification of dredged material quantities to optimize project management and regulatory reporting requirements, and incentivize dredging contractor to maximize production.

Focus Area: Dredged Material Management

Title: Innovative Sediment Management Technologies for Channels and Reservoirs

POC: Tim Welp, Joe Gailani, and Paul Schroeder

Summary: Understanding the potential for WID to fluidize sediments and conditions under which these fluidized sediments will move as a density current are key to broader application of WID to maintain navigation channels and maintiain reservoir capacity. If properly applied, WID provides a cost-effecitve method to remove sediments that are notoriously difficult to manage. Demonstration of WID potential will foster the environment for industry/government collaboration to build required WID infrastructure to expand WID application in the United States. Another means to reduce dredging costs is sand trapping; BI technologies provide the opportunity to reduce shoaling by preventing bedload sediment from entering channels and reservoirs at the source, typically creeks, arroyos, and small rivers.

Focus Area: Dredged Material Management

Title: Guidance for Wetland Thin Layer Placement (TLP) of Fine and Course Grained Sediment

POC: Candice Piercy and Tim Welp

Summary: The guidance document provided by this research task will improve the planning, permitting, design, construction, and maintenance of TLP projects to facilitate the acceptance and expansion of TLP in using dredged material from navigation projects beneficially to restore degraded wetlands.

Focus Area: Dredged Material Management

Title: Quantification of DM Layer Thickness over Time as Applied in TLP Wetland Nourishment Projects

POC: Susan Bailey

Summary: This research task includes bench scale testing and field data collection to improve our understanding of dredged material consolidation behavior after thin layer placement. The RT will result in a better understanding of the physical processes involved in placement, dewatering and settlement of dredged material in wetland environments, examining the effects of vegetation on placement density, and plant transpiration and rooting on consolidation and its dynamics. It will provide more robust application of the PSDDF model to calculate dredged material settlement over time in order to optimize attainment of the design elevation(s) to facilitate maintenance of sustainable wetlands via thin layer placement of dredged material. These improvements will allow USACE planners and other agencies involved in ecosystem restoration to better design wetland creation projects to reach target elevations, resulting in fewer projects that fail as a result of missed target elevations.

Focus Area: Dredged Material Management

Title: Dredging Portal Web Tools

POC: Linda Lillycrop and Paul Schroder

Summary: Through enhanced analysis and evaluation tools and an integrated web-based portal, this effort will provide improved data access, visualization, and decision support for Corps dredging operations managers, HQ, and R&D, resulting in greater efficiencies across the Navigation business line and increased support for the national marine transportation infrastructure.

Focus Area: Dredged Material Management

Title: Stand-Alone Model Interfaces

POC: Matthew Taylor and Jarrell Smith

Summary: This research task will develop new model interfaces that are user-friendly and that will run on today’s computers. In addition, this project seeks to define sustainable paths forward so as to keep interfaces and tools up to date. These developments will provide districts with easy-to-use interfaces for dredge models.

Focus Area: Dredged Material Management

Title: Evaluation of dredging requirement as a function of channel infill processes

POC: Ashley Frey and Lauren Coe

Summary: This tool will allow for more informed dredging decisions and has the potential for economic benefits as it will allow for more efficient and accurate dredging scheduling that will better coincide with what occurs in the channels and harbors. Finally, the tool will assess the site’s response to periods of high tropical storm activity and rainfall totals to aide in the overall understanding of what factors most impact infilling of channels and harbors.

Focus Area: Dredged Material Management

Focus Area: Risk Management
Focus Area Leader: David Moore, Research Biologist, Environmental Laboratory

Title: Rapid Dredged Material Management Protocol for Amendment Dosage Selection

POC: Carlos Ruiz and Paul Schroeder

Summary: The results of the laboratory studies will be used with modeling to transition laboratory results into predicted field performance considering nature and quality of the amendments to select dosage and placement methods. The prediction of temporal response to amendment addition will address site characteristics, including bioturbation intensity and depth, and sedimentation and resuspension rates, as well as mixing and placement characteristics, including heterogeneity as a function of mixing method and duration, intermixing with sediment bed, thickness of amended layer, and stability.

Focus Area: Risk Management

Title: Quantifying Variability/Uncertainty in Lab Based Bioaccumulation Tests

POC: David Moore

Summary: Improved interpretative guidance better enabling discernment of meaningful differences in bioaccumulation test results will streamline dredged material assessments and reduce unnecessary expenditure of resources when it is not warranted. The proposed work will establish variability inherent to the bioaccumulation test and enable development of improved interpretative guidance that accounts for variability associated with the test so that biologically meaningful differences can be established.

Focus Area: Risk Management

Title: Use of Dredged Material to Facilitate Contaminant Source Control

POC: David Moore

Summary: The goal of this project is to identify the critical biophysical parameters governing the use of clean dredged material to stabilize and isolate contaminant sediment sources and the engineering requirements for successful and cost effective implementation. The application of clean dredged material to contaminated sediment source stabilization/isolation will prevent contaminated sediments from entering USACE managed navigation infrastructure (e.g., channels, turning basins, etc.) potentially yielding significant savings resulting from less costly management requirements. In addition, any reduction in management of contaminated materials in the USACE Operations and Management program will result in reduced long-term environmental liability as a consequence of less material requiring sequestration and management in USACE owned confined disposal facilities (CDFs) and enable a larger percentage of material to be used beneficially.

Focus Area: Risk Management

Title: Proactive Interpretive Guidance to Address Confounding Factors in Dredged Material

POC: Jay Lindsay

Summary: This project will produce guidance that will allow dredge material managers and governing agencies to make informed decisions on species selection based on material parameters that are a best fit for a selection of bioassay species. This informed decision making will allow for more cost effective management of dredge material by reducing the impact of non-contaminant confounding factors.

Focus Area: Risk Management

Title: Microplastics in Dredged Material

POC: Burton Suedel

Summary: This project will provide a literature review of the available studies to understand the current science on the effects of microplastics in the aquatic environment. The project will assess the presence of microplastics in dredging project sediments and develop techniques to detect and quantify microplastics in sediments so the severity of the problem in existing dredged material can be assessed. Understanding the nature and extent and potential impacts of microplastics in dredged material will allow USACE Districts to apply this knowledge to dredging projects where microplastics are a concern. The USACE dredges approximately 300 million cubic yards of sediment annually so this research has significant potential to be useful to multiple Corps Districts, thereby providing information that can be used as part of ongoing dredging activities.

Focus Area: Risk Management

Title: Streamlining Sediment Bioaccumulation Bioassay Methods and Evaluation Approach

POC: Gui Lotufo

Summary: The goal of this work is to reduce costs associated with sediment bioaccumulation testing on USACE dredging projects by streamlining the list of COC for body burden determination on bioassay organism and follow-up evaluation and by reducing the cost while optimizing bioassay methodology. Specifically, this project will provide an approach for evaluating only those COCs with a potential to result in an undesired impact arising from benthic bioaccumulation. Bioassay methodology will also be improved by proposing new methods efficiently obtain large masses of L. variegatus following whole-sediment exposures.

Focus Area: Risk Management

Title: Sustainability Improvements for the USACE Navigation Mission

POC: Kate Fox-Lent

Summary: This project will undertake a specific exploration of the many formulations and conceptualizations and develop an understanding of how sustainability can be applied to the USACE Navigation mission. The study will be enhanced through a series of case studies that will demonstrate potential sustainability improvements from removing specific inefficiencies or implementing specific improvements. These case studies will include a base case scenario implementing “business as usual” approaches, and also an improved sustainability scenario implementing targeted measures under alternative policies or practice. This will allow side-by-side quantitative comparison of the base case and alternative scenarios in order to inform policy development and decision making.

Focus Area: Risk Management

Title: Innovative Capping for Navigation Channels

POC: Carlos Ruiz and Joe Gailani

Summary: Current capping designs for these high energy sites often require removal of a large depth of sediment to provide for the thickness of an armored cap with many filter layers to preserve the authorized depth of the channel for navigation. A tool to address the effectiveness of a thinner, mobile cap and guidance for design and implementation of these thinner caps will help the public and regulatory agencies maintain their trust in the capping technology resulting in greater acceptance of projects by environmental groups.

Focus Area: Risk Management

Title: Alternative Zooplankton Species for Elutriate Toxicity Tests

POC: Alan Kennedy

Summary: The zooplankton elutriate toxicity tests developed from this research involved acquisition of four marine copepod species and one cladoceran. Selected organisms were shown sensitive to persistent contaminants of concern (e.g., copper) but less confounded by non-persistent contaminant (ammonia) and handling stress relative to development toxicity tests. Further, these organisms were successfully cultured in the laboratory, which is not possible for development tests, making them readily available year round to avoid project delays. The expected results are widespread use of these methods in 103 dredging evaluations and savings to USACE in reduced management costs due to removal overly restrictive Limiting Permissible Concentrations for open water placement operations.

Focus Area: Risk Management

Title: Field Validation of Chronic Sublethal Dredged Material Toxicity Tests

POC: David Moore

Summary: Goal of this project is to more broadly disseminate results of a multiyear field validation study through publication of the study’s findings in the peer reviewed literature.

Focus Area: Risk Management

Title: Development of Rapid Assessment Tools for Sediment Remediation Evaluations-Recovery In Situ

POC: Carlos Ruiz

Summary: As remediation technology implementation keeps running into external disturbances that both impact the design and performance of the remedial action, we need to develop tools/frameworks that can easily evaluate sediment remediation performance subject to those external challenges. The framework to address the effects of lack of complete source removal, temporal impacts to the remedial technology, and other seasonal disturbances will help the public and regulatory agencies maintain their trust in the technology. Therefore, a framework is needed to quantify and aid in the selection and implementation of sediment remediation alternatives.

Focus Area: Risk Management

Focus Area: Environmental Resource Management
Focus Area Leader: Todd Swannack, Ph.D., Research Biologist, Environmental Laboratory

Title: Fish entrainment trends during hydraulic dredging in San Francisco Bay

POC: David Smith

Summary: The analysis suggest that we are entraining large numbers of fish and invertebrates which in turn increases probability of entraining federal and state listed species. Reducing overall fish and invertebrate entrainment would also reduce the entrainment of federal and state listed species. Understanding the data we have may help shape effective strategies to reduce entrainment and increase the USACE ability to dredge cost effectively.

Focus Area: Environmental Resource Management

Title: Effects Dredge Activity and Noise on Atlantic Sturgeon Behavior

POC: Matthew Balazik

Summary: There is currently no knowledge of whether or how Atlantic sturgeon modify their behavior due to dredge activities. Time of dredge operations in rivers is already restricted during the spring anadromous fish run and expansion of dredging restrictions specifically for fall run ATS would drastically hinder dredge operations in East Coast rivers. Taking a proactive approach by increasing our knowledge of whether or how dredging modifies ATS behavior will help USACE address concerns from NMFS. This effort will also provide a foundation that can be used for other interactions between dredge activities and aquatic species of concern.

Focus Area: Environmental Resource Management

Title: Characterizing Underwater Sound Risk Due to Dredging

POC: Burton Suedel

Summary: Research on the effects of underwater sound on aquatic life has increased over the last decade, but there are still many unanswered questions, especially with regards to the significance of sound risks due to dredging activities. In particular, the extrapolation of effects on an individual to effects at the population or community level is highly uncertain. In situations when sound alone does not pose unacceptable risk at the population level, these combined with factors such as fishery by-catch, pollution and other stressors may yield adverse effects. It is therefore important to develop a framework whereby the assessment of various sources of underwater sound can be made to improve our ability to manage such stressors. Understanding the effects of underwater sound originating from dredging and other anthropogenic activities will allow for USACE Districts to apply this approach at other dredging sites where underwater sound is a concern. The USACE dredges approximately 300 million cubic yards of sediment annually so the framework developed has significant potential to be used by multiple Corps Districts, thereby providing an approach that can be used as part of ongoing dredging activities. (Image of a backhoe dredge by WODA, 2013).

Focus Area: Environmental Resource Management

Title: Emerging Technologies for Detecting Aquatic Species

POC: Jay Bennett

Summary: ERDC has partnered with an Army military sponsored STTR program to leverage critical funding for this advanced sensor and detection algorithm development and testing effort. A small business technology firm is developing this active acoustic marine life watch system under contract, with technical oversight by ERDC and Jacksonville District Corps of Engineers personnel. The expected result of this effort is a field system that will provide real-time situational awareness of nearby T&E species during dredging and other Corps channel maintenance and enhancement activities (Figure 3).

Focus Area: Environmental Resource Management

Title: Predicting Marsh Response to Dredged Material Placement

POC: Candice Piercy

Summary: Advancing the practice of thin layer placement activities in marshes requires a simple tool that can predict how marsh elevation will respond to the sediment placement so impacts can be better quantified and placement activities can be better designed. The planned updates to MEM will incorporate best current science to provide thin layer placement practitioners a tool to better plan and design marsh thin layer placement projects.

Focus Area: Environmental Resource Management

Title: Implementation Strategies and Effectiveness Evaluation of Turtle Tickler Chains

POC: Tim Welp and Dena Dickerson

Summary: Although a previous study demonstrated the feasibility for deploying the TTC and the underwater performance of the chains during dredging, it did not address the effectiveness of the chains to reduce incidental take of sea turtles. This research task will conduct the coordination between various stakeholders to arrange a TTC demonstration, and evaluations made to determine the effectiveness for the tickler chains to reduce incidental turtle takes. If TTCs are shown to be effective in protecting sea turtles during dredging projects, they may be a more cost-effective protection method than the currently used draghead deflector, and could be used in lieu of the deflectors.

Focus Area: Environmental Resource Management

Focus Area: Sediment Dredging Processes
Focus Area Leader: Joe Gailani, Ph.D., Research Hydraulic Engineer, Coastal Hydraulics Laboratory

Title: Comprehensive Rapid Modeling of Dredged Material Placement and Fate

POC: Joseph Gailani

Summary: The product of this research task will provide a broadly applicable method to evaluate dredging and placement operations within a single user-friendly interface. The model will be able to readily access USACE databases as well as directly generate input required for far-field fate and long-term fate models. District users will no longer require of multiple model interfaces and will not have to post-process data before implementing long-term or far-field models which use dredging model output. Improved physics and process descriptions will improve model accuracy and range of applicability.

Focus Area: Sediment Dredging Processes

Title: Sediment Accretion in Thin Layer Placement (TLP) Marshes

POC: Brandon Boyd

Summary: This project will enhance the understanding of the sustainability of TLP projects as well as identify performance criteria that will be helpful in determining the best practice for beneficial use of dredged material used for TLP. Comparison of the sediment record in TLP and adjacent reference marshes will help determine the trajectory and time line of recovery of natural accretion dynamics to TLP marshes and any alterations in the accretionary process that should be expected temporarily or long-term. Understanding these processes will squarely address gaps in the USACE’s fundamental knowledge of 1) optimizing design of TLP projects 2) how and for how long these beneficial use practices will persist and 3) how TLP site sediment accretion dynamics differs from natural marsh systems.

Focus Area: Sediment Dredging Processes

Title: Acoustic Camera Particle Image Velocimetry (PIV)

POC: Brian McFall and David Young

Summary: This project investigates the use of a 3D acoustic camera to acquire two-dimensional velocity vector fields from PIV analysis. We performed an experiment to quantify the two-dimensional velocity field of a simple laboratory flow using PIV with both 3D acoustic camera images and standard optical camera images, along with ADV transect measurements, to determine whether the acoustic camera PIV results are accurate. The success of this project will lead to an entirely new technique to measure flow velocities in turbid environments in the field, one that yields substantially more information than the technologies currently available (i.e., two-dimensional velocity vector fields) and allows velocity gradient based hydrodynamic signals to be directly estimated.

Focus Area: Sediment Dredging Processes

Title: A New Strategy for Water Quality Monitoring

POC: Burton Suedel

Summary: Alternatives for characterizing turbidity and suspended sediment near-field impacts during dredging operations as currently conducted during compliance monitoring will be improved to more completely understand the potential exposure to sensitive aquatic resources. Unmanned aerial technologies offer a more viable and flexible alternative to conventional platforms such as manned monitoring vessels. This approach will produce evidence-based information about the plumes scale to help engage the process of leveraging better-informed regulations and dredging strategies. Findings of the proposed research will also help direct future dredging assessment and management practices worldwide.

Focus Area: Sediment Dredging Processes

Title: Evaluation of Strategic and Direct Placement to Feed Mudflats and Marshes

POC: Joe Gailani

Summary: Understanding sediment processes after placement of fine grained dredged material on or near mudflats and marshes is key to successful application of these methods for rebuilding valuable habitat and flood protection value provided by these resources. Data are limited on application of dredged FGS to protect and nourish mudflats and marshes. If properly applied, dredged material can provide these benefits with minimal interupption to existing habitat. The lack of data demonstrating the benefits of fine grained dredged material for supporting mudflats and marshes has limited appropriate design and regulatory approval of these projects. Design of new projects presently includes large uncertainties resulting in part from the limited monitoring and analysis of previous projects. Comprehensive data sets from selected ongoing projects for the fate of dredged FGS at direct and strategic placment sites implemented to feed mudflats and marshes will support stakeholder outreach and the regulatory approval processes required to obtain project approval and will improve the design/success of these projects.

Focus Area: Sediment Dredging Processes

Title: Development of a Dredged Material Color Change Propensity Index to Promote Beneficial Use

POC: Jacob Berkowitz

Summary: Development of a standardized protocol for evaluating dredged sediments considered for beneficial use placement will encourage further usage of sediments associated with navigation dredging efforts. Additionally, our approach will provide a template to develop predictive capabilities regarding the capacity of dredges sediments to change color following placement.

Focus Area: Sediment Dredging Processes

Title: Physical Properties and Settling Velocities of Eroded Aggregates

POC: David Perkey

Summary: Recent flume studies conducted at CHL, investigating the erosion processes involving cohesive (mud) and heterogeneous (mud and sand) sediments, have observed that erosion frequently occurs as aggregates of sediment, as opposed to discrete particles. The larger size of aggregated particles can have settling velocities several orders of magnitude greater than disaggregated sediment, and thus reduce their transport time within the water column. The aggregation of sediment may also significantly impact the mode of transport of material (i.e. bedload vs suspended load). By measuring and parameterizing these aggregate erosion properties and processes new algorithms can be developed that will allow for the improvement of current cohesive sediment transport models.

Focus Area: Sediment Dredging Processes

Title: Durability of Bed Aggregates

POC: Jacob Berkowitz

Summary: DOER is engaged in improving the understanding of fine-sediment transport processes to better anticipate the outcomes of innovative techniques for sustainably handling dredged material. Laboratory experiments will define hydrodynamic and sediment property controls on aggregate durability and fine sediment transport modes. This research will be transferred into practice through 1) technical reports and technical notes that will communcate general concepts and field-applicable understanding and 2) computational algorithms that can be applied to evaluate strategic placement design alternatives.

Focus Area: Sediment Dredging Processes

Title: Technology for Measuring Thin Sedimentation

POC: Matthew Taylor and Anthony Priestas

Summary: This RT will develop methods and data collection protocols to quantify small-scale, dredge-induced bed elevation change in sensitive habitats where small amounts of sedimentation/erosion must be quantified to identify risk. These methods will help address questions concerning topics such as the impacts of dredging operations on downstream or nearby ecosystems; as well as the effectiveness and fate of dredge material placed in a region for beneficial use. The data from fine scale bed elevation monitoring will be used to validate models for far-field sedimentation, which presently remain un-validated due to the lack of data collection methods.

Focus Area: Sediment Dredging Processes

Title: Sand Enhancement from the Dredging Process

POC: Tim Welp

Summary: Understanding the losses of fine material during the initial dredging and placement process provides an opportunity to better utilize currently unacceptable sediment from navigation channels while not negatively impacting the environmental functionality of beaches. This opportunity will also reduce the need for expansion of Offshore Dredge Material Disposal Sites (ODMDS) and upland Dredge Material Management Areas (DMMA’s) or Confined Disposal Facilities (CDF’s). Furthermore, it will save O&M dollars by opening up placement areas close to shore. Results of this initiative are not only important to Regional Sediment Management (RSM) goals and basic principles of retaining sand to the littoral zone but also rely on the sorting of sediment during dredging and the natural sorting of sediment once placed to match background conditions that are key principles of Engineering With Nature (EWN) and strategic placement.

Focus Area: Sediment Dredging Processes

Title: Physical Model of Flow Field around a Draghead

POC: Brian McFall and Duncan Bryant

Summary: Coastal USACE Districts currently work with regulatory agencies to determine hopper monitoring techniques and entrainment risk, but there are extremely limited published data on the hydraulic flow field around hopper dragheads. This study is conducting a scaled physical model of a draghead to quantify flow field around a draghead. The collected from this model can be used to validate numerical hydraulic and entrainment models.

Focus Area: Sediment Dredging Processes

Last updated on 7/24/2020.