Dredged Material Management

Management of sediment produced from dredging navigation channels is becoming more challenging as environmental, economic, and societal drivers evolve. The objectives of this focus area are to develop, validate, and provide technology transfer of innovative numerical models, applications, methodologies, and guidance to promote USACE and dredging stakeholder use for more efficient, environmentally sound, and cost-effective methods of dredging/handling/transport/placement of dredged material. These products address issues that include (but are not limited to) regulatory and habitat aspects concerning dredging processes and dredged material placement, and assessment and optimization of beneficial use of dredged material utilizing EWN and RSM principles. Dredged material management tools, methods, and guidance developed in this focus area will be used to:

• 1) reduce cost and time for regulatory compliance and permit approval,
• 2) improve operations at reduced costs,
• 3) increase dredged material placement options, and
• 4) expand the beneficial uses of dredged material.

Environmental Resource Management

Stewardship of environmental resources is an established priority during the planning, construction, and maintenance of navigation projects. The objective of this Focus Area Research is to develop critically needed, effective protective measures that adequately protect environmental resources, while allowing dredging operations to proceed in an economically feasible manner. An emphasis is placed on quantitative-based research that provides forward-looking solutions to potential project benefits and/or impacts of USACE navigation projects on environmental dynamics, particularly as these projects pertain to Threatened and Endangered Species and sensitive habitats. This research generates end products that identify cost effective engineering and construction alternatives to existing constraints. Given the likelihood that without an expanded pertinent knowledge base dredging costs will continue to escalate, the potential Return on Investment in this research is extremely high.

Risk

The Risk Management focus area supports research and development of innovative, risk-based technology and approaches to improve cost efficiencies and sustainability of dredged material management. Deliverables include models, procedures/guidance, interpretive tools, and new technologies. While the primary emphasis of the focus area is the development of practical, technically defensible, cost-effective tools and technologies, a secondary objective is the proactive identification and assessment of emerging issues potentially affecting risk-based management of dredged material in the future. Work product performance objectives include reductions in operational cost and environmental liability as well as contributions to improved transparency and technical defensibility.

Sediment and Dredging Processes

The objectives of this focus area are to develop accurate methods to measure dredged sediment properties and processes, improved sediment fate models, and guidance for beneficial use. These capabilities are required to support evolving USACE dredged sediment management objectives. The majority of sediment dredged by USACE is a mixture of sand, silt, and clay. The transport dynamics of these mixtures are complex. Inherent uncertainty in measuring and evaluating mixed sediment fate reduces USACE capacity to efficiently manage dredging operations and open water placement. Uncertainties are reduced by accurate methods to measure sediment transport in the field, quantify sediment processes in the laboratory, predict sediment transport using numerical models, and developing guidance based on case studies. These methods permit USACE to reduce uncertainties, thus improving transport evaluations required to:

• 1) demonstrate regulatory compliance,
• 2) beneficially use dredged material,
• 3) support RSM and EWN objectives,
• 4) quantify benefits and risks of alternative dredging methods,
• 5) develop exposure estimates for risk assessment, and
• 6) efficiently certify/manage dredged material placement sites.