Evaluating Environmental Effects Of Dredged Material Management Alternatives

This document is intended to serve as a consistent "roadmap" for U.S. Army Corps of Engineers and U.S. Environmental Protection Agency personnel in evaluating the environmental acceptability of dredged amterial management alternatives. Specifically, its major objectives are to provide: A general technical framwork for evaluating the environmental acceptability of dredged material management, alternatives (open-water disposal, confined (diked) disposal, and beneficial uses). Additional technical guidance to augment present implementation and testing manuals for addressing the environmental acceptability of available management options for the discharge of dredged material in both ope water and confined sites. Enhanced consistency and coordination in USAC/EPA decision making in accordance with Federal environmantl statutes regulating dredged material management.

This Technical Note presents a brief description of a joint U.S. Army Corps of Engineers (USACE) and U.S. Environmental Protection Agency (USEPA) Technical Framework for the identification of environmentally acceptable alternatives for the management of dredged material. This Technical Note replaces the earlier Technical Note EEDPA-06-14, which should be discarded. (MM).

This document is intended to serve as a consistent 'roadmap' for U.S. Army Corps of Engineers (USACE) and U.S. Environmental Protection Agency (EPA) personnel in evaluating the environmental acceptability of dredged material management alternatives. Specifically, its major objectives are to provide: A general technical framework for evaluating the environmental acceptability of dredged material management alternatives (open-water disposal, confined (diked) disposal, and beneficial uses). Additional technical guidance to augment present implementation and testing manuals for addressing the environmental acceptability of available management options for the discharge of dredged material in both open water and confined sites. Enhanced consistency and coordination in USACE/EPA decision making in accordance with Federal environmental statutes regulating dredged material management.

This report is a guidelines manual to assist in selecting disposal alternatives for contaminated dredged material to minimize adverse environmental effects. It is directed to the small percentage of contaminated sediments that are believed to present a high potential for environmental harm, rather than the great majority of dredging projects that involve uncontaminated or slightly contaminated sediments. The contaminants and potentially nuisance substances considered in this report include: mercury, cadmium, lead, zinc, copper, nickel, chromium, arsenic, chlorinated hydrocarbons, petroleum hydrocarbons, iron, manganese, nitrogen, phosphorus, and sulfur. Individual contaminants, and in some cases groups of contaminants that behave similary, are discussed under separate headings. Many of the contaminants respond differently to physical, chemical, and biological conditions at a disposal site. The approach taken in this report is to point out the relative environmental risks of different disposal methods by identifying the possible disposal alternatives and discussing the problems associated with specific contaminants and disposal methods. Certain management practices that may be applicable to some disposal alternatives that will further reduce the environmental risk are also presented.

Contaminated sediment dredged from Black Rock Harbor, Connecticut, was placed in aquatic, upland, and wetland environments as part of the Field Verification Program (FVP), a 6-year joint effort of the U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency (Peddicord 1988). Scientists at the U.S. Army Engineer Waterways Experiment Station (WES) conducted laboratory experiments on the sediment prior to dredging, to evaluate the potential contaminant mobility for each dredged material disposal alternative. In October 1983, WES began evaluating the colonization of plants and animals into the upland and wetland sites and the contaminant mobility of heavy metals. Results of the monitoring conducted between 1983 and 1989 were published in an earlier article (Brandon, Lee, and Simmers 1992). This article examines the colonization and contaminant mobility between 1989 and 1992. It is anticipated that ecosystem development at this site will be evaluated through September 1998.