1.2 Purpose and Scope

Any of the three habitat types may occur in CDFs in any of the three types of

locations. A particular CDF may evolve through a succession of habitat types

during its life. As sites are filled, aquatic habitat may be replaced by wetland and

then terrestrial habitat. At any point in time, the portions of a single CDF near the

inflow point may exhibit terrestrial habitat characteristics, which may shift to

wetland habitat and then to aquatic habitat near the weir.

CDFs are not solid waste landfills. They are designed and constructed

specifically for disposal of dredged sediment and are designed for the unique

properties of sediments, such as high water content and return flow of excess

water as effluent to surface waters. However, if needed, CDFs can be designed

with control measures, such as liners or surface covers, to provide containment

equivalent to that of an engineered landfill.

1.2 Purpose and Scope

The purpose of the UTM is to provide technical guidance for evaluation,

where appropriate, of potential contaminant migration pathways for proposed

disposal of dredged material in CDFs. Procedures in the UTM will:

1. Determine potential contaminant releases and contaminant-related

environmental effects from CDFs.

2. Determine whether pathway-specific contaminant controls or

management actions are necessary for the proposed CDF to avoid

unacceptable adverse effects outside the site.

This manual is intended as a resource of technical guidance for use by U.S.

Army Corps of Engineers (USACE), Federal, and State regulatory and resource

agencies, dredging permit applicants, and others (e.g., scientists and engineers,

managers, and other involved or concerned individuals). It is intended to facilitate

decision-making with regard to the management of dredged material. Because

this manual is national in scope, the guidance provided is generic and may be

applied within various regulatory settings. Application of this guidance in some

site-specific situations will require best professional judgement, appropriately

documented. Users of the UTM are strongly encouraged to consult with their

appropriate USACE District experts for additional guidance.

1.3 CDF Contaminant Pathways

Contaminant migration pathways (hereinafter referred to as pathways) are

routes by which contaminants or constituents of concern (COCs) associated with

dredged material may move from the dredged material within the site into the

environment outside the site.

The possible pathways from an upland CDF are illustrated in Figure 1-2.

These pathways are:

1-3

Chapter 1

Introduction