Dredging & Marine Construction

GLDT Technical Committee Meets to Discuss Beneficial Use Manual Draft Ahead of Annual Conference

On May 14, the Great Lakes Dredging Team (GLDT) Technical Committee held a meeting to review the 2018-2019 workplan, including discussion of a draft of the Regional Beneficial Use Testing Manual.

Members also gave updates on ongoing beneficial use projects, issues with converting confined disposal facilities (CDFs) into processing and reuse facilities or private contractors taking direct receipt; and exploring a multi-state policy for regulating environmental dredging windows in Lake Michigan.

The meeting was a precursor to the full GLDT 2019 Annual Meeting, June 10 and 11 in Buffalo, New York.

The Great Lakes Dredging Team is a partnership of federal and state agencies created to assure that the dredging of U.S. harbors and channels throughout the Great Lakes, its connecting channels and tributaries is conducted in a timely and cost effective manner, while meeting environmental protection, restoration and enhancement goals.

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Karen Keil of the Corps Buffalo District led the discussion of the Environmental Evaluation and Management of Dredged Material for Beneficial Use: A Regional Manual for the Great Lakes. In March 2019, the GLDT team published this first draft. The development of the manual was funded by the Great Lakes Restoration initiative and the Dredging Operations and Technical Support program of the Engineer Research and Development Center at the U.S. Army Corps of Engineers. In short, the manual was developed to simplify and promote widespread opportunities for beneficial use of dredged material. It was developed on a regional platform to increase collaborative problem-solving and endorse scientific practices for the evaluation of dredged material for any beneficial use.

The manual provides the best available technical guidance on how to evaluate dredged material for beneficial use, not interpret or validate regulatory authority granted to the U.S. Army Corps of Engineers, the U.S. Environmental Protection Agency or Great Lakes state resource agencies.

The manual continues the work done in a series of guidance documents created jointly by the Corps and EPA. The series, “Evaluating Environmental Effects of Dredged Material Management Alternatives — A Technical Framework” (Technical Framework, U.S. EPA/USACE 1992/2004), provides guidance for evaluating and selecting alternatives for the full range of management options: water placement, confined disposal facility (CDF) placement, and beneficial use applications.

The U.S. Army Corps of Engineers also developed the “Regional Beneficial Use Manual” to be consistent with and support the “Technical Framework” by providing detailed procedures for assessing physical and chemical properties that could limit the suitability of dredged material for specific end-use goals or result in unacceptable risks.

The “Evaluation of Dredged Material Proposed for Discharge in Waters of the U.S. — Testing Manual,” commonly referred to as the Inland Testing Manual (ITM, U.S. EPA/USACE 1998a), provides the basis for evaluating environmental compliance for aquatic beneficial uses.

The “Evaluation of Dredged Material Proposed for Disposal at Inland, Nearshore, or Upland Confined Disposal Facilities—Testing Manual,” commonly called the “Upland Testing Manual” (UTM, USACE 2003), provides testing guidance to evaluate potential risks associated with contaminant migration pathways, including groundwater, surface water, volatilization, and plant and animal bioaccumulations.

The Regional Beneficial Use Manual draws from these existing testing manuals to the extent possible for beneficial use assessments to avoid unnecessary additional testing or duplication of testing.

The manual defines eight different categories for beneficial use in the Great Lakes: beach or nearshore placement for shoreline protection or beach nourishment; shallow water placement for wetland or marsh development; unconfined in-water placement (river, lake, and estuary); confined in-water placement for beneficial purpose; upland placement for land development; upland placement for ecological habitat development; upland placement for soil reuse; and island placement. It includes detailed conceptual models for each type of placement option and approaches for testing and evaluating each.

In order to characterize the risks and benefits associated with potential beneficial uses, the GLDT manual provides an overview of approaches and methods for evaluating dredged material.

“Having a holistic and consistent process for evaluating beneficial use alternatives can be difficult. The development of a conceptual site model (CSM) is recommended because it supports the holistic evaluation and communication of project benefits and risks. It is important to note that different alternatives may require different conceptual risk models due to the difference in potential organisms at risk and the prevalent exposure pathways. The development of a conceptual site model is the initial step necessary to determine how dredged material should be evaluated and the information that may be required for the evaluation,” the report said. As an example, the figure on this page represents a generalized conceptual model for dredging operators at beneficial use aquatic placement sites.

The GLDT technical team will continue to review the draft manual for discussions at the upcoming conference, with an expected final report done later this year.

Physical and chemical testing of the sediment is also necessary to provide an initial baseline assessment to determine whether that material is suitable for beneficial use.

Updates and revisions to the Regional Beneficial Use Manual will be made as additional research developments and regulatory updates are completed and practical implementation experience is gained. Users are encouraged to obtain the most recent version of the manual, maintained on the Great Lakes Dredging Team website.