&EPA
US Army Corps
of Engineers
United States
Environmental Protection
Agency
Department of the Army
U.S. Army Corps of Engineers
EPA842-B-92-008
Revised May 2004
Evaluating Environmental
Effects of Dredged Material
Management Alternatives
A Technical Framework
PIPELINE
PLACEMENT
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United States Environmental Protection Agency
Office of Water (4504F)
Department of The Army
U.S. Army Corps of Engineers
EPA842-B-92-008 Revised
May 2004
Evaluating Environmental Effects
Of Dredged Material Management Alternatives
A Technical Framework
Prepared by
DEPARTMENT OF THE ARMY
United States Army Corps of Engineers
Washington, DC
and
United States Environmental Protection Agency
Washington, DC
November 1992
Revised May 2004
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TABLE OF CONTENTS
PREFACE iv
ACRONYMS v
1.0 INTRODUCTION 1
1.1 Purpose 1
1.2 Applicability 1
1.3 Background 2
1.4 Regulatory Overview 3
2.0 OVERVIEW OF DREDGING OPERATIONS AND
DREDGED MATERIAL MANAGEMENT ALTERNATIVES 7
2.1 General 7
2.2 Dredging Process Equipment and Techniques 7
2.3 Transportation of Dredged Material 10
2.4 Placement or Disposal Operations 10
3.0 FRAMEWORK FOR DETERMINING ENVIRONMENTAL
ACCEPTABILITY 15
3.1 Overview 15
3.2 Evaluation of Dredging Project Requirements 15
3.3 Identification of Alternatives 20
3.4 Initial Screening of Alternatives 20
3.5 Detailed Assessment of Alternatives 22
3.6 Alternative Selection 26
4.0 ASSESSMENT OF OPEN-WATER DISPOSAL 27
4.1 Determination of Characteristics of Open-water Sites 27
4.2 Evaluation of Direct Physical Effects and Site Capacity 29
4.3 Evaluation of Contaminant Pathways of Concern 31
4.4 Evaluation of Management Actions and Controls
for Open-water Disposal 33
4.5 Retention of Environmentally Acceptable Open-water Alternatives 35
5.0 ASSESSMENT OF CONFINED (DIKED) DISPOSAL 36
5.1 Determination of Characteristics of Confined Sites 36
5.2 Evaluation of Direct Physical Impacts and Site Capacity 37
5.3 Evaluation of Contaminant Pathways of Concern for CDFs 38
5.4 Evaluation of Management Actions and Contaminant
Control Measures for CDFs 46
5.5 Retention of Environmentally Acceptable Confined Alternatives 52
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6.0 ASSESSMENT OF BENEFICIAL USE ALTERNATIVES 53
6.1 Beneficial Use as an Alternative 53
6.2 Identification of Beneficial Use Needs and Opportunities 54
6.3 Evaluate Physical Suitability of Material 57
6.4 Logistical Considerations for Beneficial Use 58
6.5 Determination of Environmental Suitability 58
6.6 Retention of Environmentally Acceptable Beneficial Use Alternatives 59
7.0 ALTERNATIVE SELECTION 61
7.1 Evaluation of Socioeconomic, Technical, and Other
Applicable Environmental Considerations 61
7.2 Environmental Coordination/Documentation/
Recommended Alternative 63
7.3 Final Decision Document 65
8.0 REFERENCES 66
APPENDIX A: GLOSSARY Al
APPENDIX B: FEDERAL LEGISLATION AND PROGRAMS Bl
LIST OF FIGURES
1-1 Geographical Jurisdictions of the MPRS A and CWA 4
2-1 Commonly Used Dredges 8
2-2 Open-water Placement Operations 11
2-3 Upland, Nearshore, and Island CDFs 13
4-1 Contaminant Pathways for Open-water Disposal 31
5-1 Contaminant Pathways for Upland CDFs 39
5-2 Contaminant Pathways for Nearshore CDFs 40
LIST OF FLOWCHARTS
3-1 Framework for Determining Environmental Acceptability of
Dredged Material Disposal Alternatives 16
3-2 Framework for Testing and Evaluation for Open-water Disposal 17
3-3 Framework for Testing and Evaluation for Confined (Diked) Disposal 18
3-4 Framework for Testing and Evaluation for Beneficial Use Applications 19
B-l NEPA Process for Dredged Material Disposal Projects B2
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PREFACE
The U.S. Army Corps of Engineers (USAGE) and the U.S. Environmental
Protection Agency (USEPA) share the responsibility of regulating dredged material
management activities under the Marine Protection, Research, and Sanctuaries Act
(MPRSA), and the Federal Water Pollution Control Act Amendments of 1972, also called
the Clean Water Act (CWA). Such management activities must also comply with the
applicable requirements of the National Environmental Policy Act (NEPA).
This document provides a consistent technical framework for USAGE and
USEPA personnel to follow in identifying environmentally acceptable alternatives for the
management of dredged material. The framework presented herein is consistent with and
meets the substantive and procedural requirements of NEPA, CWA, and MPRSA and is
applicable to dredged material management alternatives. The technical guidance provided
by other documents such as the MPRSA and CWA testing manuals should be applied
within this framework. Application of this framework will enhance consistency and
coordination in USACE/USEPA decision making in accordance with Federal
environmental statutes regulating dredged material management.
This manual was prepared by a joint USACE/USEPA work group consisting of
the following members: Dr. Michael R. Palermo, Mr. Norman R. Francingues, and Dr.
Thomas Wright, Environmental Laboratory, U.S. Army Engineer Waterways Experiment
Station, Vicksburg, MS; Mr. Jim Reese, U.S. Army Engineer Division, North Pacific,
Portland, OR; Dr. Susan Ivester Rees, U.S. Army Engineer District, Mobile, Mobile, AL;
Mr. David Mathis, Headquarters, U.S. Army Corps of Engineers, Washington, DC; Ms.
Shannon Cunniff, Mr. John Goodin, Mr. Tom Chase, Mr. Mike Kravitz, Mr. Barry
Burgan, and Mr. John Lishman, Headquarters, USEPA, Washington, DC; Dr. Bill Muir,
USEPA, Region III, Philadelphia, PA; Mr. Bob Howard, USEPA, Region IV, Atlanta,
GA; and Mr. John Malek, USEPA, Region X, Seattle, WA. Much of the information in
this manual was taken from various USAGE and USEPA publications, and the
contributions of the original authors are gratefully acknowledged. The manual was
updated in 2004 to reflect the publication of the Inland Testing Manual, the Upland
Testing Manual and other recent references. This work was completed by Trudy J. Estes,
Michael R. Palermo, and Paul R. Schroeder, Environmental Laboratory, Environmental
Research and Development Center Waterways Experiment Station (ERDC WES).
This document should be cited as:
USEP A/US ACE. 2004. "Evaluating Environmental Effects of Dredged Material
Management Alternatives - A Technical Framework," EPA842-B-92-008, U.S.
Environmental Protection Agency and U.S. Army Corps of Engineers,
Washington, D.C.
IV
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ACRONYMS
ADDAMS - Automated Dredging and Disposal Alternatives Management System
ARCS - Assessment and Remediation of Contaminated Sediments
ASTM - American Society for Testing and Materials
CAMP - Comprehensive Analysis of Migration Pathways
CDF - Confined Disposal Facility
CEQ - Council on Environmental Quality
CFR - Code of Federal Regulations
CWA - Clean Water Act
DOTS - Dredging Operations Technical Support
DTPA - Diethylenetriamine-pentaactic Acid
EA - Environmental Assessment
EIS - Environmental Impact Statement
EM - Engineer Manual
ER - Engineer Regulation
ERDC WES - Environmental Research and Development Center Waterways
Experiment Station
FONSI - Finding of No Significant Impact
HELPQ - Hydrologic Evaluation of Leachate Production and Quality
HELP - Hydrologic Evaluation of Landfill Performance
LDC - London Dumping Convention
MEPAS - Multimedia Environmental Pollutant Assessment System
MPRSA - Marine Protection, Research, and Sanctuaries Act
NED - National Economic Development
NEPA - National Environmental Policy Act
PCB - Polychlorinated Biphenyls
PUP - Plant Uptake Program
ROD - Record of Decision
S/S - Solidification/Stabilization
SLRP - Simplified Laboratory Runoff Procedure
SOF - Statement of Findings
USAGE - U.S. Army Corps of Engineers
USEPA - United States Environmental Protection Agency
UV - Ultraviolet light
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1.0 INTRODUCTION
1.1 Purpose
This document is intended to serve as a consistent "roadmap" for U.S. Army
Corps of Engineers (USAGE) and U.S. Environmental Protection Agency (USEPA)
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/USEPA decision making in
accordance with Federal environmental statutes regulating dredged material
management.
1.2 Applicability
The "Technical Framework" was developed to provide a consistent approach to
identifying environmentally acceptable dredged material management alternatives that
meet the substantive and procedural requirements of the National Environmental Policy
Act (NEPA), the Clean Water Act (CWA), and the Marine Protection, Research, and
Sanctuaries Act (MPRSA). This document provides that framework and augments other
technical guidance documents (e.g., the MPRSA and CWA dredged material testing
manuals) for evaluating environmental acceptability. Since this document was first
published in 1992, advances have been made in testing and evaluation procedures, and in
the area of risk assessment. Although the basic framework described in the original
document remains largely unchanged, some new tools are available to facilitate the
recommended evaluations. Additionally, formal risk assessment is emerging as a
commonly used tool for dredged material evaluation in cases where definitive criteria are
not available by which to assess potential environmental impacts. These procedures and
references were included in this 2004 updated version of the Technical Framework.
This document is applicable to proposed actions involving the disposal and
management of dredged material from both the new-work construction and navigation
project maintenance programs of the USAGE as well as proposed dredged material
discharge actions regulated by the USAGE. Further, the document addresses the broad
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range of dredged materials, both clean and contaminated, and the broad array of
management alternatives, confined (diked nearshore or upland) disposal, open-water
(aquatic) disposal, and beneficial use. This document does not present guidance on
evaluation of the No-Action alternative as required for evaluation under NEPA.
Application of this framework will facilitate decision making across the statutory
boundaries of the MPRSA, CWA, and NEPA. The technical framework and guidance
established herein should reduce confusion by both regulators and the regulated
community in all future evaluations.
This framework provides only a general overview of other non-environmental
factors to be considered in decision making. An in-depth discussion of all decision-
making principles regarding selection of a preferred alternative is beyond the scope of
this document. The reader is referred to applicable USAGE regulations (33 Code of
Federal Regulations (CFR) 320-330, 33 CFR 335-338, Engineer Regulation (ER) 1105-2-
100) for further guidance and information on procedures employed by the USAGE in its
required public interest review. However, this document supports the identification,
evaluation, and selection of environmentally acceptable dredged material discharge
alternatives that are fully adaptable and applicable in the broader context of decision
making.
1.3 Background
Several hundred million cubic yards of sediment must be dredged from
waterways and ports each year to improve and maintain the nation's navigation system
and to maintain coastal national defense readiness. Alternatives for the management of
dredged material from these projects must be carefully evaluated from the standpoint of
environmental acceptability, technical feasibility, and economics.
Three management alternatives may be considered for dredged material: open-
water disposal, confined (diked) disposal, and beneficial use.1 Open-water disposal is the
placement of dredged material in rivers, lakes, estuaries, or oceans via pipeline or release
from hopper dredges or barges. Confined disposal is placement of dredged material
within diked nearshore or upland confined disposal facilities via pipeline or other means.
Beneficial use involves the placement or use of dredged material for some
productive purpose. Beneficial use options should be given full and equal consideration
with other alternatives. It is USAGE policy to fully consider all aspects of the dredging
and disposal operations with a view toward maximizing public benefits. Generally,
beneficial use is an adjunct to or involves either open-water or confined placement in
some form, although some beneficial uses involve unconfmed disposal (e.g., wetland
creation, island creation, or beach nourishment). Descriptions of open-water and confined
disposal processes and of the categories of beneficial use are given in Part 2.4 and in
Chapters 4, 5, and 6, respectively.
1 A glossary of terms is presented in Appendix A.
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Potential environmental impacts resulting from dredged material disposal may be
physical, chemical, or biological in nature. Because many of the waterways are located in
industrial and urban areas, sediments often contain contaminants from these sources.
Unless properly managed, dredging and disposal of contaminated sediment can adversely
affect water quality and aquatic or terrestrial organisms. Sound planning, design, and
management of projects are essential if dredged material disposal is to be accomplished
with appropriate environmental protection and in an efficient manner. The selection of a
preferred alternative for dredged material management must be based on a weighing and
balancing of a number of considerations that include environmental acceptability,
technical feasibility, and economics. Although the intended scope of this document is
limited to considerations for determining environmental acceptability, other factors which
must be considered in the decision-making process are also mentioned where appropriate.
1.4 Regulatory Overview
Regulation of dredged material disposal within waters of the United States and
ocean waters is a complex issue and is a shared responsibility of the USEPA and
USAGE. The primary Federal environmental statute governing transportation of dredged
material to the ocean for the purpose of disposal is the MPRSA, also called the Ocean
Dumping Act. The primary Federal environmental statute governing the discharge of
dredged or fill material into waters of the United States (inland of and including the
territorial sea) is the Federal Water Pollution Control Act Amendments of 1972, also
called the CWA. The regulatory path for disposal of dredged material in confined
disposal facilities (CDFs) is not as clear (USAGE 2003). However, both the CWA and
NEPA provide strong mandates for USAGE regulation of placement in CDFs. The
discharge of return flow (effluent and surface runoff) to waters of the United States is
specifically defined as a dredged material discharge under the CWA.
All proposed dredged material disposal activities regulated by the MPRSA and
CWA must also comply with the applicable requirements of NEPA and its implementing
regulations. In addition to MPRSA, CWA, and NEPA, a number of other Federal laws,
Executive orders, etc., must be considered in evaluation of dredging projects. An
overview of MPRSA, CWA, and NEPA is given in the following paragraphs. Additional
discussion of these and other applicable Federal laws is found in Appendix B.
1.4.1 Jurisdiction of MPRSA and CWA
The geographical jurisdictions of the MPRSA and CWA are indicated in Figure
1-1. As shown in Figure 1-1, an overlap of jurisdiction exists within the territorial sea.
The precedence of MPRSA or CWA in the area of the territorial sea is defined in 40 CFR
230.2 (b) and 33 CFR 336.0 (b). Material dredged from waters of the United States and
disposed in the territorial sea is evaluated under MPRSA. In general, dredged material
discharged as fill (e.g., beach nourishment, island creation, or underwater berms) and
placed within the territorial sea is evaluated under the CWA.
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COASTAL
WATERS
INLAND AND
ESTUARINE WATERS
OPEN OCEAN
3 TO I? MIES
AND BEYOND
(CONTIGUOUS X3NE)
'ASELINE TO
3 NAUTICAL
MILfS
(TERRITORIAL
S£A)
CONNECTING
WATERS
TIDAL WETLANDS
BASEUHEOFTHE
TERRITORIAL SEA
TIDAL WETLANDS
MATERIAL
t= PLACED
FOR FILL
INLAND LAKES
AND WATERt
DREDGE
MATERIAL
DISPOSAL
LE DREDGE
MATERIAL
DISPOSAL
Figure 1-1. Geographical Jurisdictions of the MPRSA and CWA
1.4.2 Overview of MPRSA
Section 102 of the MPRSA requires USEPA, in consultation with USAGE, to
develop environmental Criteria2 that must be complied with before any proposed ocean-
disposal activity is allowed to proceed. Section 103 of the MPRSA assigns to the USAGE
the specific responsibility for authorizing the ocean disposal of dredged material. In
evaluating proposed ocean-disposal activities, the USAGE is required to apply the
Criteria developed by USEPA relating to the effects of the proposed disposal activity. In
addition, in reviewing permit applications, the USAGE is also required to consider
navigation, economic, and industrial development, and foreign and domestic commerce,
as well as the availability of alternatives to ocean disposal. USEPA has a major
environmental oversight role in reviewing the USAGE determination of compliance with
the ocean-disposal Criteria relating to the effects of the proposed disposal. If USEPA
determines ocean-disposal Criteria are not met, disposal may not occur without a waiver
For purposes of this report, Criteria (capitalized) refer to criteria developed by the Environmental
Protection Agency under Section 102 of MPRSA relating to the effects of the proposed dumping.
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of the Criteria by USEPA [40 CFR 225.2 (e)]. In addition, USEPA has authority under
Section 102 to designate ocean-disposal sites. The USAGE is required to use such sites
for ocean disposal to the extent feasible. Section 103 does authorize the USAGE, where
use of a USEPA-designated site is not feasible or a site has not been designated by
USEPA, to select ocean-disposal sites for project(s)-specific use. In exercising this
authority, the USAGE utilizes the USEPA site-selection criteria (40 CFR 228), and the
site selection is subject to USEPA review as part of its permit review responsibilities.
1.4.3 Overview of CWA
Section 404 of the CWA requires USEPA, in conjunction with the USAGE, to
promulgate Guidelines3 for the discharge of dredged or fill material to ensure that such
proposed discharge will not result in unacceptable adverse environmental impacts to
waters of the United States. Section 404 assigns to the USAGE the responsibility for
authorizing all such proposed discharges, and requires application of the Guidelines in
assessing the environmental acceptability of the proposed action. Under the Guidelines,
the USAGE is also required to examine practicable alternatives to the proposed
discharge, including alternatives to disposal in waters of the United States and
alternatives with potentially less damaging consequences. The USAGE and USEPA also
have authority under Section 230.80 to identify, in advance, sites that are either suitable
or unsuitable for the discharge of dredged or fill material in waters of the United States.
USEPA is responsible for general environmental oversight under Section 404 and,
pursuant to Section 404(c), retains permit veto authority. In addition, Section 401
provides the States a certification role as to project compliance with applicable State
water quality standards.
1.4.4 Overview of NEPA
Dredged material disposal activities must comply with the applicable NEPA
requirements regarding identification and evaluation of alternatives. The basic NEPA
process discussed in this framework is that specifically associated with the dredging
project (as opposed to other related actions such as ocean-site designation which may
require an entirely separate NEPA process).
Section 102(2) of NEPA requires the examination of reasonable4 alternatives to
the action proposed by the lead agency. The alternatives analyzed in an Environmental
Assessment (EA) or Environmental Impact Statement (EIS) must include not only all
reasonable alternatives but also those that were eliminated from further study (Part
1502.14) by the agency responsible for the final decision. The NEPA document must
rigorously address reasonable alternatives that are beyond the capability of the applicant
3 For purposes of this report, Guidelines (capitalized) refer to the CWA Section 404(b)(l) Guidelines.
4
The terms practicable (CWA), feasible (MPRSA), and reasonable (NEPA) all have specific regulatory
meaning. However, in this document, the term reasonable is used genetically and not in a strict regulatory
sense. Reasonable is herein defined as practical or feasible from the technical and economic standpoint and
using common sense, rather than simply desirable from the standpoint of the project proponent or applicant.
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or project proponent or are beyond the jurisdiction of the lead agency. The Council on
Environmental Quality (CEQ) regulations for implementing the procedural provisions of
NEPA are found at 40 CFR 1500-1508. For USAGE dredging projects, the USAGE is
responsible under NEPA for developing alternatives for the discharge of dredged
material, including all facets of the dredging and discharge operation, including cost,
technical feasibility, and overall environmental protection. The USAGE regulations
provide that the preferred alternative must be the least costly plan that is consistent with
environmental statutes, as set forth in the National Economic Development (NED) Plan
for new work projects (ER 1105-2-100) or as the Federal Standard for required
maintenance dredging of existing projects (33 CFR 335-338). Compliance with the
environmental Criteria of the MPRSA and/or with the CWA Section 404(b)(l)
Guidelines is a controlling factor used by the USAGE in determining the environmental
acceptability of disposal alternatives.
Both the MPRSA and CWA specify similar approaches in evaluating potential
environmental impacts of dredged material discharged in ocean waters or waters of the
United States, respectively. In many regards, these same evaluations provide essential
input in meeting overall NEPA requirements. However, procedural implementation of the
three environmental statutes has evolved more or less separately over time, and
substantial inconsistencies have, in turn, developed particularly in the alternatives
evaluations required by these environmental statutes. For example, while NEPA, CWA,
and MPRSA all require both a detailed evaluation of alternatives to the proposed action
and preparation of appropriate NEPA documentation, present guidance does not provide
clear technical and/or procedural guidance for how such evaluations are to be undertaken.
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2.0 OVERVIEW OF DREDGING
OPERATIONS AND DREDGED MATERIAL
MANAGEMENT ALTERNATIVES
2.1 General
This section of the report is intended to provide a brief introduction and overview
of the dredging process, including types of dredges, transportation systems, and the
placement or disposal practices commonly used in navigation dredging projects.
References throughout this part provide more detailed discussion and explanation of
different kinds of dredges, transport equipment, and disposal practices.
The removal or excavation, transport, and placement of dredged sediments are the
primary components of the "dredging process." In design and implementation of any
dredging project, each part of the dredging process must be closely coordinated to ensure
a successful dredging operation.
The excavation process commonly referred to as "dredging" involves the removal
of sediment in its natural (new-work construction) or recently deposited (maintenance)
condition, either mechanically or hydraulically. After the sediment has been excavated, it
is transported from the dredging site to the placement site or disposal area. This transport
operation, in many cases, is accomplished by the dredge itself or by using additional
equipment such as barges, scows, and pipelines with booster pumps.
Once the dredged material has been collected and transported, the final step in the
dredging process is placement in either open-water, nearshore, or upland locations. The
choice of management alternatives involves a variety of factors related to the dredging
process including environmental acceptability, technical feasibility, and economic
feasibility of the chosen alternative.
2.2 Dredging Process Equipment and Techniques
Compatibility must exist between the dredging equipment and techniques used for
excavation and transport of the material and the management alternatives considered. The
types of equipment and methods used by both the USAGE and private industry vary
considerably throughout the United States. The most commonly used dredges are
illustrated in Figure 2-1. Dredging equipment and dredging operations resist precise
categorization. As a result of specialization and tradition in the industry, numerous
descriptive, often overlapping, terms categorizing dredges have developed. For example,
dredges can be classified according to: the basic means of moving material (mechanical
or hydraulic); the device used for excavating sediments (clamshell, cutterhead, dustpan,
and plain suction); the type of pumping device used (centrifugal, pneumatic, or airlift);
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a. Self-propelled hopper dredge
b. Cutterhead pipeline dredge
c. Clamshell dredge
Figure 2-1. Commonly Used Dredges
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and others. However, for the purposes of this document, dredging is actually
accomplished basically by only two mechanisms:
Hydraulic dredgingRemoval of loosely compacted materials by cutterheads,
dustpans, hoppers, hydraulic pipeline plain suction, and sidecasters, usually
for maintenance dredging projects.
Mechanical dredging-Removal of loose or hard, compacted materials by
clamshell, dipper, or ladder dredges, either for maintenance or new-work
projects.
Hydraulic dredges remove and transport sediment in liquid slurry form. They are
usually barge mounted and carry diesel or electric-powered centrifugal pumps with
discharge pipes ranging from 6 to 48 in. in diameter. The pump produces a vacuum on its
intake side, and atmospheric pressure forces water and sediments through the suction
pipe. The slurry is transported by pipeline to a disposal area. Hopper dredges are included
in the category of hydraulic dredges for this report even though the dredged material is
simply pumped into the self-contained hopper on the dredge rather than through a
pipeline. It is often advantageous to overflow hopper dredges to increase the load;
however, this may not always be acceptable due to water quality concerns near the
dredging site.
Mechanical dredges remove bottom sediment through the direct application of
mechanical force to dislodge and excavate the material at almost in situ densities.
Backhoe, bucket (such as clamshell, orange-peel, and dragline), bucket ladder, bucket
wheel, and dipper dredges are types of mechanical dredges. Sediments excavated with a
mechanical dredge are generally placed into a barge or scow for transportation to the
disposal site.
Selection of dredging equipment and method used to perform the dredging will
depend on the following factors:
Physical characteristics of material to be dredged.
Quantities of material to be dredged.
Dredging depth.
Distance to disposal area.
Physical environment of the dredging and disposal areas.
Contamination level of sediments.
Method of di sposal.
Production required.
Type of dredges available.
Cost.
More detailed descriptions of dredging equipment and dredging processes are
available in Engineer Manuals (USAGE 1983 and USAGE in preparation), Houston
(1970), and Turner (1984).
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2.3 Transportation of Dredged Material
Transportation methods generally used to move dredged material include the
following: pipelines, barges or scows, and hopper dredges. Pipeline transport is the
method most commonly associated with cutterhead, dustpan, and other hydraulic
dredges. Dredged material may be directly transported by hydraulic dredges through
pipelines for distances of up to several miles, depending on a number of conditions.
Longer pipeline pumping distances are feasible with the addition of booster pumps, but
the cost of transport greatly increases. Barges and scows, used in conjunction with
mechanical dredges, have been one of the most widely used methods of transporting large
quantities of dredged material over long distances. Hopper dredges are capable of
transporting the material for long distances in a self-contained hopper. Hopper dredges
normally discharge the material from the bottom of the vessel by opening the hopper
doors; however, some hopper dredges are equipped to pump out the material from the
hopper much like a hydraulic pipeline dredge.
2.4 Placement or Disposal Operations
Selection of proper dredging and transport equipment and techniques must be
compatible with disposal site and management requirements. Three major alternatives are
available:
Open-water disposal.
Confined disposal.
Beneficial use.
Each of the major alternatives involves its own set of unique considerations, and selection
of a management alternative should be made based on environmental, technical, and
economic considerations.
2.4.1 Description of Open-Water Disposal
Open-water disposal is the placement of dredged material in rivers, lakes,
estuaries, or oceans via pipeline or release from hopper dredges or barges. Such disposal
may also involve appropriate management actions or controls such as capping. The
potential for environmental impacts is affected by the physical behavior of the open-
water discharge. Physical behavior is dependent on the type of dredging and disposal
operation used, the nature of the material (physical characteristics), and the
hydrodynamics of the disposal site.
Dredged material can be placed in open-water sites using direct pipeline
discharge, direct mechanical placement, or release from hopper dredges or scows. A
conceptual illustration of open-water disposal using the most common placement
techniques is shown in Figure 2-2.
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PIPELINE
PLACEMENT
HOPPER
PLACEMENT
BARGE
PLACEMENT
Figure 2-2. Open-water Placement Operations
Pipeline dredges are commonly used for open-water disposal adjacent to
channels. Material from this dredging operation consists of a slurry with solids
concentration ranging from a few grams per liter to several hundred grams per liter.
Depending on material characteristics, the slurry may contain clay balls, gravel, or coarse
sand material. This coarse material quickly settles to the bottom. The mixture of dredging
site water and finer particles has a higher density than the disposal site water and
therefore can descend to the bottom forming a fluid mud mound. Continuing the
discharge may cause the mound to spread. Some fine material is "stripped" during
descent and is evident as a turbidity plume. Characteristics of the plume are determined
by: discharge rate, characteristics of the slurry (both water and solids), water depth,
currents, meteorological conditions, salinity of receiving water, and discharge
configuration.
The characteristics and operation of hopper dredges result in a mixture of water
and solids stored in the hopper for transport to the disposal site. At the disposal site,
hopper doors in the bottom of the ship's hull are opened, and the entire hopper contents
are emptied in a matter of minutes; the dredge then returns to the dredging site to reload.
This procedure produces a series of discrete discharges at intervals of perhaps one to
several hours. Upon release from the hopper dredge at the disposal site, the dredged
material falls through the water column as a well-defined jet of high-density fluid, which
may contain blocks of solid material. Ambient water is entrained during descent. After it
hits bottom, most of the dredged material comes to rest. Some material enters the
horizontally spreading bottom surge formed by the impact and is carried away from the
impact point until the turbulence of the surge is sufficiently reduced to permit its
deposition.
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Bucket or clamshell dredges remove the sediment being dredged at nearly its in
situ density and place it on a barge or scow for transportation to the disposal area.
Although several barges may be used so that the dredging is essentially continuous,
disposal occurs as a series of discrete discharges. Barges are designed with bottom doors
or with a split-hull, and the contents may be emptied within seconds, essentially as an
instantaneous discharge. Often sediments dredged by clamshell remain in fairly large
consolidated clumps and reach the bottom in this form. Whatever its form, the dredged
material descends rapidly through the water column to the bottom, and only a small
amount of the material remains suspended. Clamshell dredge operations may also be used
for direct material placement adjacent to the area being dredged. In these instances, the
material also falls directly to the bottom as consolidated clumps.
Dredge hoppers and scows are commonly filled past the point of overflow to
increase the load. The gain in hopper or scow load and the characteristics of the
associated overflow are dependent on the characteristics of the material being dredged
and the equipment being used. There is little debate that the load can be increased by
overflow if the material dredged is coarse grained or forms clay balls, as commonly
occurs with new-work dredging. For fine-grained maintenance material, significant
disagreement exists as to whether a load gain can be achieved by overflow.
Environmental considerations of overflow may be related to aesthetics, potential effects
of water-column turbidity, potential effects of deposition of solids, or potential effects of
sediment-associated contaminants (Palermo and Randall 1990).
Open-water disposal sites can be either predominantly nondispersive or
predominantly dispersive. At predominantly nondispersive sites, most of the material is
intended to remain on the bottom following placement and may be placed to form
mounds. At predominantly dispersive sites, material may be dispersed either during
placement or eroded from the bottom over time and transported away from the disposal
site by currents and/or wave action. However, both predominantly dispersive and
predominantly nondispersive sites can be managed in a number of ways to achieve
environmental objectives or reduce potential operational conflicts. Additional discussion
of open-water disposal processes is found in Chapter 4.
2.4.2 Description of Confined Disposal
Confined disposal is placement of dredged material within diked nearshore or
upland confined disposal facilities5 (CDFs) via pipeline or other means. The term CDF is
used in this document in its broadest sense. CDFs may be constructed as upland sites,
nearshore sites with one or more sides in water (sometimes called intertidal sites), or as
island containment areas as shown in Figure 2-3.
5 The terms "confined disposal facility," "confined disposal area," "confined disposal site," "diked disposal
site," and "containment area" all appear in the literature and refer to an engineered structure for
containment of dredged material. The confinement dikes or structures in a CDF enclose the disposal area
above any adjacent water surface, isolating the dredged material from adjacent waters during placement. In
this document, confined disposal does not refer to subaqueous capping or contained aquatic disposal (see
Chapter 4).
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Framework for Dredged Material Management
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UPLAND
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Framework for Dredged Material Management
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2.4.3 Categories of Beneficial Use
Beneficial use includes a wide variety of options, which utilize the material for
some productive purpose. Dredged material is a manageable, valuable soil resource, with
beneficial uses of such importance that they should be incorporated into project plans and
goals at the project's inception to the maximum extent possible.
Ten broad categories of beneficial uses have been identified, based on the
functional use of the dredged material or site. They are:
Habitat restoration/enhancement (wetland, upland, island, and aquatic sites
including use by waterfowl and other birds).
Beach nourishment.
Aquaculture.
Parks and recreation (commercial and noncommercial).
Agriculture, forestry, and horticulture.
Strip mine reclamation and landfill cover for solid waste management.
Shoreline stabilization and erosion control (fills, artificial reefs, submerged
berms, etc.).
Construction and industrial use (including port development, airports, urban,
and residential).
Material transfer (fill, dikes, levees, parking lots, and roads).
Multiple purpose.
Opportunities for beneficial use applications under each of these categories are
discussed in Chapter 6. Detailed guidelines for various beneficial use applications are
given in Engineer Manuals (USAGE 1983, 1986 and in preparation). Additional
information and case studies on beneficial use are available at the following website,
which is a collaborative effort between USAGE and USEPA:
http://www.wes.army.mil/el/dots/budm/budm.html
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Framework for Dredged Material Management
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3.0 FRAMEWORK FOR DETERMINING
ENVIRONMENTAL ACCEPTABILITY
3.1 Overview
This framework for determining environmentally acceptable placement
alternatives for dredged material can be applied nationwide and is relatively general, but
comprehensive. This framework addresses a wide range of dredged material
characteristics, dredging techniques, and management alternatives. Because this
framework provides national guidance, flexibility is necessary. It should be used as a
technical guide to evaluate the commonly important factors to be considered in managing
dredged material in an environmentally acceptable manner.
The overall technical framework for developing environmentally acceptable
alternatives for the discharge of dredged material is illustrated in Flowchart 3-1. As
indicated in the flowchart, the framework determines the environmental acceptability of
any of several alternatives considered. The framework presented is consistent with and
incorporates the evaluations conducted under NEPA, CWA, and MPRSA and consists of
the following broad steps, as illustrated in Flowchart 3-1:
Evaluation of dredging proj ect requirements.
Identification of alternatives.
Initial screening of alternatives.
Detailed assessment of alternatives.
Alternative selection.
The framework logic is discussed in detail in the following paragraphs. The
respective paragraph numbers are referenced as appropriate in the blocks of Flowchart
3-1. Additional portions of the framework pertaining to the detailed assessments of open-
water disposal, confined disposal, and beneficial use alternatives are illustrated in
Flowcharts 3-2, 3-3, and 3-4 and are described in Chapters 4, 5, and 6, respectively.
3.2 Evaluation of Dredging Project Requirements
3.2.1 Dredging Needs
The need for dredging and the requirements for disposal must be established.
Information gathered at this stage would include the dredging location(s), required
volumes to be dredged, etc. Within the context of NEPA, the initial impact assessment
for dredging projects relates to the purpose and need for the proposed action in the case
of new work or continued viability (purpose, need, and effect of new information on
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Framework for Dredged Material Management
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EVALUATE DREDONO AND DISPOSAL NEEDS
NEPA/
CWA/MPRSA
ALTERNATIVES
ANALYSIS
ADEQUATE
PRO
ACTION
SIGNIFICANT
EIS/SEIS
REQUIRED
COORDINATION WITH
AGENCIES ANCVOR
AFFECTED PUBLICS
POTENTIAL
ALTERNATIVES
AND NO ACTION
PERFORM MITIAL SCREENMQ OF ALL POTENTIAL DISPOSAL
ALTERNATIVES USMQ AVALABLE M FORMATION
EUMNATE
UNREASONABLE
ALTERNATIVES
ALTERNATIVES
REASONABLE
RETAIN REASONABLE ALTERNATIVES
(3.5.1)
EMSTMO
DATA ADEQUATE
AND TIMELY
7
CONDUCT INITIAL EVALUATION OF SEDMENTS TO BE DREDGED
PERFORM APPROPRIATE ASSESSMENTS FOR
REASONABLE ALTERNATIVES!
ASSESS
CONFINED
DISPOSAL
ALTERNATIVES
(SEE FLOWCHART 3-3)
ASSESS
OPEN-WATER
DISPOSAL
ALTERNATIVES
(SEE FLOWCHART 3-2)
ASSESS
BENEFICIAL
USES
ALTERNATIVES
(SEE FLOWCHART 34)
RETAIN ENVIRONMENTALLY
ACCEPTABLE ALTERNATIVES
EVALUATE SOCIOECOMOMIC, TECHNICAL, MANAGEMENT, AND
OTHER ENVIRONMENTAL CONSIDERATIONS
SELECTION Of PREFERRED ALTERNATIVE
NOTICE OFAVALABtlTY
OF DRAFT EIS/SEIS
AND 103/404
COORDMATION
PUBLIC NOTICE OF
EA/DRAFT FONSI
OR/AND 103/404
COORDINATION
SELECT RECOMMENDED
ALTERNATIVE
HTIATE40I
WQ CERTIFICATION
MITIATE40I
WQ CERTIFICATION
COORDNATE
30-90 DAYS
FtUL EIS/SEIS AND
103/404 EVALUATION
AND 401 CERTIFICATION
AND OTHER
PROJECT COMPLIANCE
WITH NEPA AND ALL
APPLICABLE ENVIRONMENTAL
LAWS AND REGULATIONS
ROD AND
PUBLIC NOTICE
EVALUATION OF
DREDGING
PROJECT
REQUIREMENTS
IDENTIFICATION
OF
ALTERNATIVES
INITIAL
SCREENING
OF
ALTERNATIVES
DETAILED
ASSESSMENT
OF
ALTERNATIVES
ALTERNATIVE
SELECTION
X IF AT ANY TIME H THE EA PROCESS. THE
FEDERAL ACTION IS REASSESSED AS BENG
SIGNIFICANT, EJS SCOPNO IS MTIATEO.
EA . ENVIRONMENTAL ASSESSMENT
EIS/SEIS . ENVIRONMENTAL IMPACT STATEMENT/SUPPLEMENT
FONSI -FINDING OF NO SIGNIFICANT MPACT
ROD - RECORD OF DECISION
SOF . STATEMENT OF FNDNOS
Flowchart 3-1. Framework for Determining Environmental Acceptability of
Dredged Material Disposal Alternatives
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Framework for Dredged Material Management
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ENTER FROM FLOWCHART 3-1 TO EVALUATE
OPEN-WATER DISPOSAL
DETERMINE CHARACTERISTICS OF POTENTIAL SITES
1
SI
ADEC
1
* I
f
,(4.2.3)
16 ^^^ NO
JUATE "^ »
7 ^^^^
| YES
EVALUATE DIRECT PHYSICAL IMPACTS AND SITE CAPACITY |
EVALUATE
MANAGEMENT OPTIONS
SUBMERGED DISCHARGE
OPERATIONAL MODIFICATION
LATERAL CONTAINMENT
THIN LAYER DISPOSAL
OTHERS
(4.4)
^ ^""^ MANAGEMENT
W ^^^ EFFECTIVE
[YES
(4.2)
(3.5.3)
EVALUATE CONTAMINANT PATHWAYS OF CONCERN
(4'3'
T (4.3.1
EVALUATE
WATER-COLUMN
IMPACTS
(4.3.2)
and
/or
APPLY 103/404
TESTING AND
ASSESSMENT
PROCEDURES
'
EVALUATE CONTROL MEASURES FOR
PATHWAYS OF CONCERN
|4'4)
WATER-COLUMN CONTROLS
SUBMERGED
DISCHARGE
OPERATIONAL
MODIFICATION
TREATMENT
OTHERS
BENTHIC CONTROLS
CAPPING
CONTAINED
AQUATIC DISPOSAL
OTHERS
RETAIN
ENVIRONMENTALLY
ACCEPTABLE
ALTERNATIVES
(4.5)
RETURN TO FLOWCHART 3-1
(3.5.6)
Flowchart 3-2. Framework for Testing and Evaluation
for Open-water Disposal
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Framework for Dredged Material Management
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ENTER FROM FLOWCHART 3-1 TO EVALUATE
CONFINED DISPOSAL
DETERMINE CHARACTERISTICS OF ALL POTENTIAL
CONFINED SITES
(5.1)
EVALUATE DIRECT PHYSICAL IMPACTS AND
SITE CAPACITY
(5.2)
(5.2.4)
EVALUATE
MANAGEMENT OPTIONS
OPERATIONAL
MODIFICATIONS
DEWATERING
SITE MANAGEMENT
OTHERS
(3.5.3)
MATERIAL
y (5.3.4)
EVALUATE 1 AND
EFFLUENT 1
QUALITY 1
MOOIREO 1
ELUTRIATE 1
TESTING 1
/BIOASSAY 1
y
t
EFFLUENT
CONTROLS
TREATMENT
OPERATIONAL
MODIFICATIONS
OTHERS
T
T (5.3.5)
EVALUATE
SURFACE
RUNOFF
f
SURFACE
RUNOFF
TESTING
BIOASSAY
Y
t
EVALUATE CONTAMINANT PATHWAYS OF CONCERN || >3'°'
/OR
SURFACE
RUNOFF CONTROLS
PONDING
TREATMENT
OTHERS
T
T (5.3.6)
EVALUATE 1 .....
GROUNDWATER! ,;
LEACHATE I
y
LEACHATE 1
TESTING 1
1
^^<»X*APPLIC
<^ STAND
T (5.3.7) T (5.3.7)
EVALUATE II AN[J
UPTAKE (I
^^
PLANT 1
BIOASSAY 1
EVALUATE
ANIMAL
UPTAKE
T
ANIMAL
BIOASSAY
T T
NO
EVALUATE CONTROL MEASURES FOR II '
CONTAMINANT PATHWAYS OF CONCERN ||
1
t
LEACHATE
CONTROLS
COVERS
LINERS
TREATMENT
OTHERS
T
5.4)
t t
PLANT UPTAKE
CONTROLS
COVERS
SELECTIVE
VEGETATION
OTHERS
ANIMAL UPTAKE
CONTROLS
COVERS
OTHERS
T T
^^"CONTROLS^-^.^ NO /
, f [
^^^^^ 7 ^^^^^^ \
r ELIMINATE
CONFINED
^ ALTERNATIVES
^^^^SS^^E^SSP
AND
)
T (5.3.8
EVALUATE
VOLATILE
RELEASES
^^
EMISSIONS 1
TESTING 1
y
t
VOLATILIZATION
CONTROLS
COVERS
VEGETATION
TREATMENT
OTHERS
T
}
f RETAIN ^
fc I ENVIRONMENTALLY Yl
ACCEPTABLE
ALTERNATIVES
RETURN TO FLOWCHART 3-1
(3.5.6)
Flowchart 3-3. Framework for Testing and Evaluation
for Confined (Diked) Disposal
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Framework for Dredged Material Management
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ENTER FROM FLOWCHART 3-1 TO EVALUATE
BENEFICIAL USE
I DETERMINE BENEFICIAL USE NEEDS AND/OR OPPORTUNITIES || (6'2)
I
EVALUATE PHYSICAL SUITABILITY OF MATERIAL
FOR PROPOSED USES
(6.3)
EVALUATE LOGISTICAL
AND MANAGEMENT REQUIREMENTS
(6.4)
t
EVALUATE
ENVIRONMENTAL
SUITABILITY
(3.5.3)
(6.5)
ALTERNATIVE
SUITABLE
9
ELIMINATE
UNSUITABLE
ALTERNATIVES
RETAIN
ENVIRONMENTALLY
ACCEPTABLE
ALTERNATIVES
RETURN TO FLOWCHART 3-1
(3.5.6)
Flowchart 3-4. Framework for Testing and Evaluation
for Beneficial Use Applications
environmental acceptability of the proposal) in the case of existing projects. In contrast,
the needs and determinations under CWA or MPRSA are specifically concerned with a
justification of the need for dredged material disposal in waters of the United States or
ocean waters, respectively. Both types of determinations are addressed in the detailed
evaluation of alternatives in the NEPA document and may also be addressed in the
project's purpose and need statement, compliance with environmental statutes, and other
sections of the NEPA document where appropriate. In identifying reasonable alternatives
to pursue, environmental impact, cost, and agency policy/regulation, among other factors,
may be considered.
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Framework for Dredged Material Management
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3.2.2 Determination of Availability of Alternatives and Coverage in Existing
NEPA Document
A review of the project requirements in terms of all reasonable alternatives and
the adequate coverage of these alternatives in the existing NEPA document should be
made. Supplemental NEPA documentation is required when significant changes are made
in the proposed alternative, or when significant new circumstances or information
relevant to environmental concerns and bearing on the proposed action or its impacts
exist (40 CFR 1502.9 (c)). In particular, CWA/MPRSA alternatives analyses should be
reviewed for adequacy. Evaluations conducted for purposes of MPRSA or CWA
compliance indicating potential environmental impacts not previously considered in the
selection of an alternative may trigger the need for a supplemental EA or EIS to ensure
NEPA compliance.
3.3 Identification of Alternatives
Under the NEPA process, the potential environmental impacts of the discharge of
dredged material including confined (diked), open water (CWA and/or MPRSA sites),
and beneficial uses, must be considered, taking into consideration the nature and needs of
the dredging projects and the material to be dredged. The NEPA scoping process
encourages the identification of all potential alternatives for dredged material
management. Proposed alternatives may consist of any combination of options as
warranted by local conditions. Beneficial use of dredged material should be fully
considered to ensure that benefits are maximized.
When a large number of potential alternatives exist, a reasonable number of
examples covering the full spectrum of alternatives must be analyzed and compared in
the NEPA document (40 CFR 1502.9(c)). The NEPA document must rigorously address
reasonable alternatives that are beyond the capability of the applicant or project
proponent or are beyond the jurisdiction of the lead agency. Under CEQ regulations, the
No-Action (no dredging or continuation of an existing practice) alternative must also be
included and retained throughout the NEPA process as a basis for impact comparison.
Subsequent evaluations in the framework determine the reasonableness of alternatives
identified at this level.
3.4 Initial Screening of Alternatives
An initial screening is undertaken to eliminate from further consideration those
management alternatives that clearly are not reasonable for the specific project.
Reasonable alternatives include those that are practical or feasible from the
environmental, technical, and economic standpoint (40 CFR 1502.9 (c)), and use
common sense, rather than being simply desirable from the standpoint of the project
proponent or applicant. The screening should utilize all available information and should
consider factors such as environmental concerns (e.g., endangered species), cost,
technical feasibility (e.g., site availability and site characteristics that may be
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Framework for Dredged Material Management
May 2004
incompatible with dredged sediment volume or characteristics or available dredging
plant), and legal considerations.
All potential alternatives are evaluated with respect to the availability of the
required site(s) and the likelihood that the site can be used. If there are no existing sites
available, then a determination is made as to whether a site(s) can be designated and/or
selected after taking into consideration the reasonableness of doing so for the project in
question. For example, the time frame for designating an ocean site under MPRSA or
selecting a CWA open-water site would have to be factored into this determination. In
those cases where site designation by USEPA under Section 102 of MPRSA is required,
the NEPA process for site designation and for the dredging project may be performed
jointly or concurrently.
Consideration must also be given to design limitations of the project, climatic
conditions, dredging equipment availability, physical and chemical aspects of the
material to be dredged, local interests, public concerns, and known environmental and
economic constraints. Maintenance history of the project in question or projects in the
general area and the experience and knowledge of the public and resource agencies
provide a basis for the screening process.
3.4.1 Eliminate Unreasonable Alternatives
Although the identification of innovative solutions is encouraged, the nature and
needs of the dredging project must be considered in determining the reasonableness of
alternatives. Alternatives that require sites that are not available, conflict with other site
uses, violate applicable environmental regulations, or are found to be clearly technically
or economically infeasible during the screening process, are eliminated from further
detailed consideration. An alternative may be considered unreasonable and therefore
eliminated from further consideration if the scoping process has determined it to be
unreasonable. The rationale for eliminating alternatives should be clearly documented in
the NEPA document. After application of these considerations by the lead agency6, those
alternatives that remain are scrutinized further for environmental, technical, and
economic feasibility.
3.4.2 Retain Reasonable Alternative(s)
The above evaluation will result in an identification of alternatives that are
reasonable from an environmental, technical, and economic standpoint. Each remaining
option is then carried forward for detailed evaluation via the NEPA/CWA/MPRSA
process. The final outcome of the detailed evaluation could be that the No-Action
alternative is selected or the project not continued.
6 See Guidance in 33 CFR 335-338 and ER 1105-2-100 and NEPA Regulations to define lead agency roles
and responsibilities.
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Framework for Dredged Material Management
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3.5 Detailed Assessment of Alternatives
For purposes of determining environmental acceptability, the detailed assessment
of alternatives should include the following:
Evaluation of the adequacy and timeliness of existing data.
Evaluation of the physical characteristics of the sediment.
Initial evaluation of sediment contamination.
Performing appropriate testing and assessments (to include required CWA or
MPRSA testing).
Evaluation of management options or control measures.
Prior to conducting a detailed analysis of alternatives, conducting appropriate
coordination between USAGE, USEPA, and other agencies as appropriate is critical to
ensure that any required sampling, testing, and evaluations are satisfactorily conducted.
Procedures for conducting the detailed evaluation of alternatives are described in
the following paragraphs. Since the procedures for conducting detailed evaluations for
open-water disposal, confined disposal, and beneficial use alternatives differ, additional
details are presented in Chapters 4, 5, and 6, respectively. A wide variety of technical
guidance documents are available and are referenced as appropriate in Chapters 4, 5, and
6. Computer-assisted management tools are also available for conducting many of the
detailed assessments, which may be required (Schroeder et al. 2004).
In addition to those considerations for environmental acceptability, a detailed
assessment of alternatives includes a comparative review of cost, technical feasibility,
and other factors, as appropriate. Even though these additional considerations would
normally be assessed as a part of the NEPA process for the project, they are beyond the
scope of this document.
3.5.1 Adequacy and Timeliness of Data
Projects for which all reasonable alternatives have been identified and adequately
evaluated still must be assessed in light of the CWA or MPRSA evaluation requirements.
For those projects in the operations and maintenance or permit renewal category for
which conditions have not changed, a preliminary assessment is made to determine the
adequacy and relevance of previous information for the continuance of the
dredging/disposal activities. If the existing data are sufficient to determine compliance
with CWA or MPRSA, no additional data are required prior to preparation of the CWA
or MPRSA evaluation and coordination of the Public Notice (see paragraph 3.6). For
new-work Federal navigation projects, new permit applications, or projects for which
information is insufficient, additional assessment following the framework as described
here and in Chapters 4, 5, and 6 are required to determine the environmentally acceptable
alternative(s).
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Framework for Dredged Material Management
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3.5.2 Evaluate Physical Characteristics of Sediment
Evaluation of the physical characteristics of sediments proposed for discharge is
necessary to determine potential environmental impacts of disposal, the need for
additional chemical or biological testing, as well as potential beneficial use of the
dredged material. If this information has not been gathered during the project evaluation
phase, it must be obtained at this point in the framework. The physical characteristics of
the dredged material include: particle-size distribution, water content or percent solids,
specific gravity of solids, and plasticity characteristics. The sediment physical
characteristics should also be evaluated from the standpoint of compatibility with
different kinds of biological communities likely to develop for the disposal environments
under consideration.
3.5.3 Conduct Initial Evaluation of Sediment Contamination
The initial screening for contamination is designed to determine, based on
available information, if the sediments to be dredged contain any contaminants in forms
and concentrations that are likely to cause unacceptable impacts to the environment.
During this screening procedure, specific contaminants of concern are identified in a site-
specific sediment, so that any subsequent evaluation is focused on the most pertinent
contaminants.
Initial considerations should include but are not limited to:
Potential routes by which contaminants could reasonably have been
introduced to the sediments.
Data from previous sediment chemical characterization and other tests of the
material or other similar material in the vicinity, provided the comparisons are
still appropriate.
Probability of contamination from agricultural and urban surface runoff.
Spills of contaminants in the area to be dredged.
Industrial and municipal waste discharges (past and present).
Source and prior use of dredged materials (e.g., beach nourishment).
Substantial natural deposits of minerals and other natural substances.
Under CWA, some materials may be excluded from testing as specified in 40
CFR 230.60. Under MPRSA, testing must be conducted unless the exclusions in 227.13
(b) are met.
If the material does not meet the exclusions, contaminants must be addressed with
respect to their potential for biological effects and/or release through applicable
pathways. If such potential exists, the specific tests and assessments for contaminant
pathways described in Section 3.5.4 will be required. If ocean-disposal alternatives are
being considered, particular attention must be given to the presence of certain prohibited
materials (40 CFR 227.6) other than as trace contaminants. Detailed guidance for
chemical testing and evaluation of sediments can be found in USEPA/USACE (1995).
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Framework for Dredged Material Management
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3.5.4 Perform Appropriate Testing and Assessments
Appropriate testing and assessments may be required to determine the physical
behavior of the material at the disposal site. Also, testing and assessments for one or
more potential contaminant pathways of concern may be required.
Physical testing and assessment should focus on both the short-term and long-
term physical behavior of the material. For open-water alternatives, these assessments
might include an analysis of water-column dispersion, mound development, and long-
term mound stability or dispersion. For confined alternatives, these assessments might
include an analysis of solids retention and storage requirements during disposal and long-
term consolidation behavior in the CDF. Guidance for conducting physical testing and
assessments is described in Chapters 4, 5, and 6.
Any contaminant testing should focus on those contaminant pathways where
contaminants may be of environmental concern, and the testing should be tailored to the
available disposal site. The considerations for identifying contaminant pathways of
concern for open-water disposal and confined disposal alternatives are discussed in
Chapters 4 and 5, respectively. For open-water alternatives, contaminant problems may
be related to either the water column or benthic environment, and the appropriate testing
and assessments would include required CWA or MPRSA testing. For confined sites,
potential contaminant problems may be either water quality related (return water effluent,
surface runoff, and groundwater leachate), contaminant uptake related (plant or animal),
or air related (gaseous release).
The identification of pathways of concern should be based on the initial
evaluation of sediment contamination and on the known characteristics of disposal sites
under consideration. One of the following determinations will result for each pathway:
If the initial evaluation of sediment contamination and site characteristics
reveals that the material can be excluded from further testing or that adequate
data already exist for a given contaminant pathway, then no additional
contaminant testing for that pathway is required.
In some cases, past evaluations of sediment contamination and site
characteristics may indicate that contaminants would clearly result in
unacceptable impacts through a given pathway. In this case, a determination
can be made without further testing that management actions or control
measures will be required for that pathway.
Finally, there may not be sufficient technical information to allow for a factual
determination for one or more pathways of concern. The potential impact of
specific contaminant pathways must then be evaluated using appropriate
testing and evaluations for those pathways. Risk assessment is employed
implicitly in making a factual determination, as an integral part of
development of many sediment and water quality criteria. If conventional
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Framework for Dredged Material Management
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pathway testing and evaluation does not yield a definitive determination,
however, risk assessment may be employed explicitly to reach a factual
determination (USEPA 1998; Moore, Bridges and Cura 1998).
Design of a testing program for the sediment to be dredged depends on the
pathways of concern for the alternative being evaluated. Protocols have been developed
to evaluate contaminant pathways of concern and consider the unique nature of dredged
material and the physicochemical conditions of each disposal site under consideration.
The testing guidelines that have been developed jointly by the USEPA and
USAGE incorporate a tiered approach and scientifically based decision process that uses
only the level of testing necessary to provide the technical information needed to assess
the potential chemical and biological effects of the proposed disposal activity. Detailed
testing procedures for evaluation of ocean disposal under the MPRSA are found in the
Ocean Testing Manual (USEP A/US ACE 1991), while detailed testing procedures for
evaluation of placement in U.S. waters under the CWA are found in the Inland Testing
Manual (USEP A/US ACE 1998). The Upland Testing Manual (US ACE 2003) provides
detailed procedures for evaluation of dredged material proposed for disposal at CDFs.
Other relevant procedures are available (Francingues et al. 1985; Lee et al. 1991). Testing
and evaluations for specific contaminant pathways for open-water and confined-disposal
alternatives is discussed in more detail in Chapters 4 and 5, respectively.
3.5.5 Evaluate Management Actions or Control Measures to Minimize
Impacts
In cases where results of tests or assessments indicate that the MPRSA impact
Criteria or CWA Guidelines for a given pathway will not be met, management actions
should be considered to reduce potential environmental impacts (33 CFR 335-338;
Francingues et al. 1985; Lee et al. 1991; Cullinane et al. 1986). Management actions or
control measures may be considered for physical and/or contaminant impacts.
Possible controls for open-water alternatives include operational modifications,
use of submerged discharge, treatment, lateral containment, and capping or contained
aquatic disposal. Possible controls for confined (diked) disposal include operational
modifications, treatment, and various site controls (e.g., covers and liners). Descriptions
of management and control measures for open-water and confined alternatives and
procedures for assessing site-specific effectiveness are given in Chapters 4 and 5,
respectively.
The effectiveness of management controls for contaminated sediments must be
carefully considered, since no disposal option and/or management action or control
measure is without risk. When considering the use of management actions or controls, the
following factors must be considered:
Probability of success of a given control.
Monitoring required to confirm the effectiveness of the control.
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Framework for Dredged Material Management
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Duration and significance of adverse effects should a given control prove to
be ineffective.
Availability, feasibility, timeliness, and cost of additional management actions
should they be required.
3.5.6 Retention of Environmentally Acceptable Alternatives
With the completion of detailed testing and assessments and the consideration of
management and control measures for the respective alternatives, a determination of
environmental acceptability is made. This determination must ensure that all applicable
standards or criteria are met. If control measures were considered, a determination of the
effectiveness of the control measure in meeting the standards or criteria must be made. If
all standards or criteria are met, the alternative can be considered environmentally
acceptable. At this point in the framework, socioeconomic, technical, and other
applicable environmental considerations must be evaluated prior to the selection of a
management alternative.
3.6 Alternative Selection
The detailed assessment of alternatives may result in one or more alternatives
which are environmentally acceptable. Weighing and balancing of all environmental,
technical, and economic factors must be conducted before the selection of the
preferred/proposed alternative by the lead agency. The process for conducting this
weighing and balancing is described in the implementing regulations of
NEPA/CWA/MPRSA.
The major steps for coordination and documentation associated with alternative
selection are illustrated in Flowchart 3-1. The coordination and documentation process
includes draft and final NEPA/CWA/MPRSA documents, Public Notices, and a final-
decision document which addresses comments on the draft NEPA/CWA/MPRSA
documents.
The selection of a preferred/proposed alternative is based on environmental
acceptability, technical feasibility, costs, and other factors, as appropriate. A detailed
discussion of factors in decision making other than environmental acceptability is beyond
the scope of this document. However, considerations in alternative selection, including a
description of the procedures to be followed with respect to NEPA, CWA, and MPRSA,
are discussed in Chapter 7. Once an alternative has been selected, proper coordination
and documentation has been completed, and a final-decision document has been issued,
the project should be in compliance with NEPA and all applicable environmental laws
and regulations.
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4.0 ASSESSMENT OF OPEN-WATER
DISPOSAL
This chapter describes the detailed assessment of open-water disposal including
testing and management options and control measures. The portion of the framework for
detailed assessment of open-water disposal alternatives is illustrated in Flowchart 3-2.
The paragraph numbers in the text are shown as appropriate in the flowchart. The
detailed assessment described in this chapter may be performed following a
determination of the need for such an assessment as described in Chapter 3.
4.1 Determination of Characteristics of Open-water Sites
A knowledge of site characteristics is necessary for assessments of potential
physical impacts and contaminant impacts. Information on site characteristics needed for
assessments may include the following:
Currents and wave climate.
Water depth and bathymetry.
Potential changes in circulation patterns or erosion patterns related to
refraction of waves around the disposal mound.
Bottom sediment physical characteristics including sediment grain-size
differences.
Sediment deposition versus erosion.
Salinity and temperature distributions.
Normal levels and fluctuations of background turbidity.
Chemical and biological characterization of the site and environs (e.g.,
relative abundance of various habitat types in the vicinity, relative adaptability
of the benthos to sediment deposition, presence of submerged aquatic
vegetation, and presence of unique, rare or endangered, or isolated
populations).
Potential for recolonization of the site.
Previous disposal operations.
Availability of suitable equipment for disposal at the site.
Ability to monitor the disposal site adequately for management decisions.
Technical capability to implement management options should they appear
desirable.
Ability to control placement of the material.
Volumetric capacity of the site.
Other site uses and potential conflicts with other activities (e.g., sport or
commercial fisheries, shipping lanes, and military use).
Established site management or monitoring requirements.
Public and regulatory acceptability to use of the site.
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4.1.1 Site Selection under MPRSA
The intent of the criteria for site selection is to avoid unacceptable, adverse
impacts on biota and other amenities. This requires that sufficient information be
assembled such that reasonable assurance can be given that the criteria will be met. As a
rule, the majority of amenities, such as fishing, shipping, mineral extraction, spawning,
breeding, nursery grounds, and cultural or historical features, may be addressed with
existing information. If so, primary concern is then directed to biological resources in and
adjacent to the proposed disposal site. These concerns are addressed by ensuring that any
geographically limited or especially significant living resources are not present within the
site nor outside the site in such a location as to be adversely impacted by movement of
material off the site if it is a dispersive site (USACE/USEPA 1984). Resources within the
site may suffer physical impacts from the deposition of the dredged material, and sites
should be designated/selected to ensure such impacts are acceptable.
The criteria provide that ocean dumping sites will be designated beyond the edge
of the continental shelf, wherever feasible, and at other sites that have been historically
used unless monitoring data or other information indicate the potential for significant
adverse impacts.
If little is known concerning the resources or the characteristics of the site and its
environs, appropriate investigations and studies must be performed. The USAGE has
prepared an ocean-site designation manual (Pequegnat, Gallaway, and Wright 1990),
which provides useful guidance and procedures for conducting the appropriate
investigations and studies. In addition, overview manuals for site designation have been
developed (USACE/USEPA 1984; USEPA 1986). Procedures for application of risk
assessment to the aquatic environment can be found in Cura et al. (2001).
4.1.2 Site Specification under CWA
The specification of disposal sites under the CWA is addressed specifically in the
Section 404 (b)(l) Guidelines. The Guidelines establish a sequential review of a proposed
project, the first step of which is avoidance of adverse impacts to the aquatic environment
through an evaluation of practicable alternatives which would have less impact on that
environment [40 CFR 230.10 (a)]. In general, the same concerns as given above for
ocean-site designation are applied to site specification under CWA. These include
potential impacts on physical and chemical characteristics of the aquatic ecosystem,
potential impacts on biological characteristics of the aquatic ecosystem, potential effects
on special aquatic sites, and potential effects on human-use characteristics (40 CFR 230
Subpart C-F).
The specification of an appropriate site under CWA takes into account that CWA
disposal sites may be located in estuaries, rivers, and lakes that may have limited
assimilative capacity. Geographic and operational constraints as well as site capacity may
severely constrain potentially available sites.
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There are also special concerns if the site is a special aquatic site (e.g., a wetland)
as defined in Section 404 (40 CFR 230 Subpart E). For example, if the proposed disposal
site is a special aquatic site and the activity for which disposal is required is not water-
dependent, the Guidelines presume that nonaquatic alternatives are available [40 CFR
230.10 (a) (3)].
Physical compatibility between the characteristics of the dredged material and
proposed disposal site is not the sole factor to be used in determining compliance with the
Guidelines. Other requirements of the Guidelines, specifically Section 230.10, must also
be considered in the evaluation of dredged materials. In addition, under Section
230.1 l(g), the Guidelines require that the cumulative impact of the individual discharges
of dredged material on the aquatic ecosystem be included in the evaluation of individual
permits. Therefore, dredged material disposal, like all other discharges of dredged or fill
material into waters of the United States, cannot be permitted unless it has been
demonstrated to comply with all requirements of the CWA Section 404(b)(l) Guidelines.
The USAGE and USEPA may jointly identify, in advance, sites generally suitable
or unsuitable for discharge of dredged material (40 CFR 230.80). The advanced
identification of sites does not permit or prohibit the discharge of dredged or fill material,
but does facilitate individual or general permit application and processing. Under the
authority of Section 404(c), however, USEPA may prohibit, withdraw, or restrict the
discharge of dredged or fill material if it determines that the discharge would have
unacceptable adverse effects. As mentioned previously, procedures for application of risk
assessment to the aquatic environment can also be found in Cura et al. (2001).
4.1.3 Site Monitoring
Site monitoring may be a requirement resulting from the site
designation/specification process, or may be required as a part of an established site
management plan. Detailed guidance on site-monitoring equipment and techniques and
on development of monitoring plans is available (Marine Board 1990; Pequegnat,
Gallaway, and Wright 1990; Fredette et al. 1990a, 1990b).
4.2 Evaluation of Direct Physical Effects and Site Capacity
An evaluation of direct physical impacts and site capacity should precede any
evaluations of potential contaminant impacts, since elimination of alternatives or sites
based on unacceptable physical impacts or inadequate site capacity is needed prior to
testing for contaminant effects.
4.2.1 Direct Physical Impacts
Direct physical impacts will almost always result from the disposal of dredged
material. Benthic organisms at the disposal site may be buried and may not be able to
migrate through the material. If the substrate is changed from what was previously
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present, the organisms which recolonize the site may be different from those present prior
to disposal.
Suspended solids may also affect water column organisms, although these effects
are uncommon because of the large dilution factor. Potential physical effects are
addressed during the site designation/specification process. If at all possible, a site should
not be located where significant undesirable effects will occur on or off the site. Prior to
disposal, the physical characteristics of the material should be evaluated to determine if it
is compatible with the use of a particular site. Models are frequently used to predict the
behavior of the material during and after disposal, and, in some instances, monitoring
may be needed to verify the model predictions. Both USAGE and USEPA have generated
a large database on potential physical effects through the large number of site-designation
surveys performed nationwide.
If site conditions and uses are unchanged, collection of additional data to evaluate
direct physical impacts would generally be unnecessary for evaluation of a proposed
discharge of material under MPRSA because such impacts were evaluated as a part of the
site-designation process as well as during the site monitoring and management activities.
However, for Section 404 open-water disposal, direct physical impacts must be
considered as a part of the site-specification process for the specific discharge. Under
both MPRSA and CWA, appropriate site management and monitoring concerns must be
addressed.
4.2.2 Site Capacity
The physical capacity of predominantly nondispersive sites to hold the dredged
material without (1) resuspension and transport of disposed material by surface waves or
(2) interference with navigation traffic or other operational conflicts, must also be
evaluated. This may involve (1) setting a maximum height for mounds of disposed
dredged material or (2) estimating mounding rates over the long term, taking into account
erosion and consolidation of the mound (Dortch et al. 1990; Scheffner 1991; Poindexter-
Rollings 1990). Site capacity of predominantly dispersive sites is not normally a concern.
4.2.3 Need for Management Actions
If the evaluation of direct physical impacts and evaluation of site capacity indicate
that the site is adequate, the evaluation of contaminant pathways can be initiated. If the
evaluations of direct physical impacts and site capacity indicate unacceptable impacts
will result, or that site capacity is inadequate, management actions are required to reduce
physical impacts. Management actions to reduce physical impacts to acceptable levels
may include operational modification, submerged discharge, lateral confinement, or thin-
layer placement. These same management approaches can be considered to extend the
physical capacity of the site. Management actions are described in paragraph 4.4. If the
management actions are determined to be effective, the evaluation of contaminant
pathways can be initiated. If not, then the open-water disposal alternative at the site under
consideration should be eliminated.
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4.3 Evaluation of Contaminant Pathways of Concern
The main emphasis of contaminant pathway testing for open-water disposal is
aimed at determining if a given dredged material is acceptable for open-water disposal
from the standpoint of contamination. If dredged material is found to be environmentally
unacceptable for disposal in the ocean, it also would probably be environmentally
unacceptable for disposal in Section 404 waters.
As shown in Figure 4-1, the potential contaminant pathways for open-water
disposal are water column and benthic. Water-column contaminant impacts must be
considered from the standpoint of water quality (chemical) and toxicity (biological).
Benthic impacts must be considered from the standpoint of toxicity and bioaccumulation.
A tiered approach to contaminant testing and assessments is described in detail in the
dredged material testing manuals for MPRSA and CWA (USEPA/USACE 1991;
USEP A/US ACE 1998; USAGE 2003).
**£fe£?^>A'iX
>L>«OJ -f~!*'S
Figure 4-1. Contaminant Pathways for Open-water Disposal
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4.3.1 Water-Column Impacts
Potential water-column contaminant effects are evaluated by comparing
contaminant release in an elutriate of the material to be disposed with applicable water-
quality criteria or standards as appropriate. In addition, acute water-column toxicity
bioassays considering initial mixing may be needed. The procedures to be used in
elutriate or water-column bioassays are provided in the MPRSA and CWA testing
manuals (USEP A/US ACE 1991; USEP A/US ACE 1998; US ACE 2003). For disposal
operations under the MPRSA, specific criteria for water quality and water-column
toxicity must be met, and specific allowances are specified for initial mixing
(USEPA/USACE 1991). For disposal operations under CWA, water quality and water-
column toxicity standards and allowances for initial mixing are specified by the States as
a part of the Section 401 water-quality certification requirements. Models are available
for mixing calculations (USEPA/USACE 1991; USEPA/USACE 1998; USACE 2003).
4.3.2 Benthic Impacts
In assessing potential benthic effects of contaminants under MPRSA, if the
exclusion criteria of 40 CFR 227.13 (b) are met, biological testing of the dredged material
is not necessary. If the exclusion criteria are not met, toxicity and bioaccumulation
information is required to evaluate the suitability of the material for disposal. If disposal
is under the authority of the CWA, a chemical comparison of the material to be disposed
and a reference sediment may be conducted. If contaminant concentrations in the dredged
material and an adjacent disposal site are substantially similar and contaminants will not
leave the adjacent disposal site or if controls are available to reduce contamination to
acceptable levels within the disposal site, no further evaluation may be required [40 CFR
230.60(c) and (d)]. If this is not the case, bioassays and bioaccumulation tests are
required to complete the evaluation.
Contaminants may affect benthic organisms through acute toxicity or by the
uptake of the contaminants (bioaccumulation). The evaluations compare acute toxicity
and/or bioaccumulation in benthic organisms exposed to the material to be disposed with
organisms exposed to a reference sediment. Procedures for conducting and interpreting
the acute toxicity and bioaccumulation evaluations are described in detail in the MPRSA
Ocean Testing Manual (USEPA/USACE 1991) and CWA Inland Testing Manual
(USEPA/USACE 1998). The Upland Testing Manual (USACE 2003) provides detailed
procedures for evaluation of dredged material proposed for disposal at CDFs.
4.3.3 Need for Contaminant Controls
If the contaminant pathway testing indicates that the impact Criteria or Guidelines
are met, the open-water disposal alternative is environmentally acceptable from the
standpoint of contaminant effects. If the impact Criteria or Guidelines are not met,
contaminant control measures must be considered to reduce impacts to acceptable levels
if the open-water alternative is to be further considered.
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Control measures to minimize contaminant impacts may include operational
modification, submerged discharge, lateral confinement, treatment, and capping. These
control measures are described in paragraph 4.4. If the control measures are determined
to be effective, then the alternative is environmentally acceptable from the standpoint of
contaminants. If not, then the open-water disposal alternative at the site under
consideration should be eliminated.
4.4 Evaluation of Management Actions and Controls for Open-water
Disposal
In cases where evaluations of direct physical impacts, site capacity, or
contaminant pathways indicate the Criteria or Guidelines will not be met when
conventional open-water disposal techniques are used, a variety of management actions
and contaminant control measures may be considered. Such techniques include
operational modifications, use of subaqueous discharge points, use of diffusers,
subaqueous lateral confinement of material, thin-layer placement, or capping of
contaminated material with clean material.
Descriptions of the commonly used management actions and contaminant
controls are given in the following paragraphs. Additional guidance on selection of
contaminant controls for open-water disposal is found in Francingues et al. (1985),
Cullinane et al. (1986), and Truitt (1987a and 1987b).
The primary consideration in selecting management or control options is to
identify the impacts to be addressed by the management or control options and choose an
option that best addresses the issue(s) of concern. The management and contaminant
controls discussed in this section are to be considered and implemented on both a site-
specific and case-specific basis. General considerations for each option are presented
within each section below. It is important to note that not all options work under all
situations or in all cases. Before any option is selected for implementation, a complete
review of the material-specific and site-specific conditions and circumstances should be
completed.
4.4.1 Modification of Dredging and Disposal Operations
Modifications of dredging and disposal operations can be an effective control for
both physical effects and water-column or benthic contaminant pathways. The purpose of
operational modification as a control is to reduce water-column dispersion and/or spread
of material on the bottom. The most obvious control measure for open-water disposal is a
modification in the technique or equipment used for placement. For example, if water-
column concentrations of dredged material exceed water-quality criteria or toxicity
criteria for a proposed hopper dredge discharge, an operational modification to clamshell
dredging with discharge from barges would reduce the water-column release. Discharge
of mechanically dredged material from barges also results in less spread of material as
compared with hopper discharge. Other operational modifications include constraints on
location of disposal, rate of disposal, and timing of disposal.
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4.4.2 Submerged Discharge
Submerged discharge is a control measure which may be considered to reduce
water-column impacts. The use of a submerged point of discharge reduces the area of
exposure in the water-column and the amount of material suspended in the water column
susceptible to dispersion. The use of submerged diffusers also reduces the exit velocities
for hydraulic placement, allowing more precise placement and reducing both
resuspension and spread of the discharged material. Considerations in evaluating
feasibility of a submerged discharge and/or use of a diffuser include water depth, bottom
topography, currents, type of dredge, and site capacity. Design specifications for
submerged diffusers are available, and the diffusers have been successfully used for
disposal operations (Neal, Henry, and Green 1978, Palermo 1994).
4.4.3 Lateral Containment
Lateral containment is a control measure which may be considered to reduce
benthic impacts. The use of subaqueous depressions or borrow pits or the construction of
subaqueous dikes can provide containment of material reaching the bottom during open-
water disposal, resulting in a reduced bottom area being affected by the placement. Such
techniques reduce the areal extent of a given disposal operation, thereby reducing both
physical benthic effects and the potential for release of contaminants. Considerations in
evaluating feasibility of lateral containment include type of dredge, water depth, bottom
topography, bottom sediment type, and site capacity.
Simply selecting a site amenable to lateral containment such as an existing bottom
depression or valley can be effective. Placement of material in constructed depressions
such as abandoned borrow pits has also been proposed. Submerged dikes or berms for
purposes of lateral containment have been constructed or proposed at several sites. Such a
proposal would not necessarily involve added expense to the project if the material used
for the berm comes from the same or another dredging project.
4.4.4 Thin-Layer Placement
The intentional spreading of hydraulically pumped dredged material overbroad
areas to achieve overburdens less than 12 inches thick has been termed "thin-layer"
placement. The objective of thin-layer placement is to minimize impacts on benthic
fauna and to speed their recovery, particularly in estuarine environments. This strategy is
based upon knowledge that a portion of the benthos can migrate upward through the
dredged material overburden, usually present as a fluid mud layer. This concept has been
developed and demonstrated in Mississippi Sound by the Mobile District. Results of
monitoring studies indicated that recovery was enhanced in shallow, turbid Gulf coast
estuaries. A distinction should be made between thin-layer placement in open-water
applications and high-pressure spray disposal on marsh surfaces. Although sometimes
referred to as thin-layer placement, the latter case involves different equipment
requirements and generally is suitable for relatively small volumes of dredged material,
whereas open-water thin-layer placement uses conventional hydraulic equipment (with
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modification of the discharge terminus for mobility) and is potentially suitable for large
quantities of dredged material. There are few references in the literature on this topic. A
brief discussion can be found in Nester and Rees (1988).
4.4.5 Capping and Contained Aquatic Disposal
Capping is the controlled placement of contaminated material at an open-water
site followed by a covering or cap of clean isolating material. Capping is a control
measure for the benthic contaminant pathway. Level bottom capping is a term used for
capping without means of lateral containment. If some form of lateral containment is
used in conjunction with the cap, the term contained aquatic disposal is used.
Considerations in evaluating the feasibility of capping include site bathymetry, water
depth, currents, wave climate, physical characteristics of contaminated sediment and
capping sediment, and placement equipment and techniques. Because long-term stability
of the cap is of concern, capping is generally considered to be more technically feasible
in low-energy environments. Precise placement of material is necessary for effective
capping, and use of other control measures such as submerged discharge and lateral
containment increase the effectiveness of capping. Guidelines and recommendations are
available for planning and design of capping projects (Palermo et al. 1998a and 1998b;
Fredette et al. 2000).
4.4.6 Treatment
Treatment of discharges into open water may be considered to reduce certain
water-column or benthic impacts. For example, the Japanese have used an effective in-
line dredged material treatment scheme for highly contaminated harbor sediments
(Barnard and Hand 1978). However, this strategy has not been widely applied, and its
effectiveness has not been demonstrated for solution of the problem of contaminant
release during open-water disposal.
4.4.7 Monitoring
Monitoring is a management action which may be used to establish the
effectiveness of other specific management actions and the need for modification of such
actions, the necessity of which is a case-by-case decision. Technical guidance for
monitoring open-water disposal sites (physical and biological) is available (Marine Board
1990; Fredette et al. 1990a, 1990b).
4.5 Retention of Environmentally Acceptable Open-water Alternatives
Once appropriate open-water assessments are complete, a determination of
environmental acceptability is made. This determination must ensure that all applicable
standards or criteria are met. If control measures were considered, a determination of the
effectiveness of the control measure in meeting the standards or criteria must be made. If
all standards or criteria are met, the open-water alternative can be considered
environmentally acceptable. At this point in the framework, other factors can be
considered in the selection of an alternative as described in paragraph 3.6 and Chapter 7.
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5.0 ASSESSMENT OF CONFINED (DIKED)
DISPOSAL
This part of the report describes detailed assessments for alternatives involving
confined (diked) disposal facilities (hereinafter referred to as CDFs). In general, disposal
of dredged material in CDFs is regulated under the CWA. It is also important to note that
the CDF itself must comply with the Guidelines if it is sited in waters of the United
States. In addition, there may be other regulatory requirements under NEPA and other
applicable laws and regulations on a case-by-case basis.
CDFs differ in their geohydrology, sediment chemistry, carrier water removal,
contaminant release rates, and contaminant pathways affected. Therefore, the testing and
assessments required will vary somewhat accordingly, although the procedures are based
on similar scientific and engineering principles. The framework for assessing confined
disposal is illustrated in Flowchart 3-3. The detailed assessments described in this chapter
may be performed following a determination of the need for such assessments as
described in Chapter 3.
5.1 Determination of Characteristics of Confined Sites
Site specification for CDFs in many ways can be more complex than for open-
water sites. Real estate considerations are a major factor in determining the availability of
potential sites. Most navigation project authorizations require the local project sponsors
to provide the lands, easements, and rights of way for CDFs; some authorizations require
the sponsor to provide dikes and site management. CDFs therefore represent a substantial
economic investment on the part of the sponsor. In many instances, the sponsors will only
provide sites which meet short-term requirements, and additional sites may be required in
the future. Another consideration for CDF site specification is the fact that such sites are
normally visible to the public and are viewed as a competing interest for land use,
especially in coastal areas where there is intense pressure for both development and
preservation of lands.
A knowledge of CDF site characteristics is necessary for assessments of potential
physical impacts and contaminant impacts. Information on site characteristics needed for
assessments includes the following:
Available area and volumetric storage capacity to contain the material for the
required life of the site.
Real estate considerations.
Site configuration and access.
Proximity to sensitive ecological environments.
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Topography to include potential changes in elevation and runoff patterns and
adjacent drainage.
Ability of the dredged material to eventually dry and oxidize.
Groundwater levels, flow and direction, and potential impact on groundwater
discharge and recharge.
Meteorology and climate.
Foundation soil properties and stratigraphy.
Potential groundwater receptors.
Potential alteration of the existing habitat type.
Potential for effluent, leachate, and surface runoff impacting adjacent ground
and surface water resources.
Potential for direct uptake and movement of contaminants into food webs.
Potential for volatilization of contaminants.
Potential for dust, noise, or odor problems.
Potential to implement management activities when deemed necessary.
Potential accessibility of the site by the public.
Contamination history of proposed site.
Field exploration programs are necessary to assess many of the above
considerations in determining the suitability of a site for use as a CDF. Foundation
explorations are especially important for dike design and groundwater assessments.
Additional information regarding sampling techniques and equipment and development
of field exploration programs for CDFs is given in EM 1110-2-5027 (US ACE 1987).
5.2 Evaluation of Direct Physical Impacts and Site Capacity
An evaluation of direct physical impacts and initial and long-term CDF site
capacity should precede any evaluations of contaminant impacts, since elimination of
alternatives based on unacceptable physical impacts or inadequate site capacity could
reduce the need for more expensive and involved testing for contaminant effects.
5.2.1 Direct Physical Impacts
Direct physical impacts because of construction of the CDF must be assessed.
Such impacts may include alteration of habitat, changes in hydrological conditions (e.g.,
circulation patterns in surface waters and groundwater recharge), restrictions to
navigation, and aesthetic, cultural, and land-use impacts. Guidance on evaluation of such
physical impacts in waters of the United States is available (40 CFR 230).
5.2.2 Initial Storage Capacity and Solids Retention
A CDF must be designed and operated to provide adequate initial storage volume
and surface area to hold the dredged material solids during an active filling operation and
if hydraulically filled, to retain suspended solids such that clarified water is discharged.
The required initial storage capacity and surface area is governed by zone, flocculent, and
compression-settling processes which occur in a CDF during placement of fine-grained
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dredged material. Procedures to evaluate the required surface area and volume during
active filling operations, to estimate effluent suspended solids concentrations, and to
design other features for CDFs are described in engineer manuals (USAGE 1983, 1987
and in preparation). Expert systems for evaluation of initial storage capacity and solids
retention are described in Hayes and Schroeder (1992).
5.2.3 Long-Term Storage Capacity
In addition to initial capacity during active filling, an evaluation of long-term
storage capacity is required if a CDF is intended for use over multiple dredging cycles.
The long-term storage capacity of a given site is dependent on the material consolidation
and desiccation properties, climate, and operational conditions. Procedures to evaluate
long-term storage capacity of CDFs are provided in Engineer Manuals (USAGE 1983,
1987 and in preparation). Expert systems for evaluation of long-term consolidation are
described in Schroeder et al. (2004).
5.2.4 Need for Management Actions
If the evaluation of direct physical impacts and evaluation of site capacity indicate
that the site is adequate, the remaining assessments can be conducted. If the evaluations
of direct physical impacts and site capacity indicate unacceptable impacts will result or
that site capacity is inadequate, management actions can be considered.
Management actions to minimize physical impacts of CDF construction may
include site management to reduce effluent solids discharge or dewatering of dredged
material between filling operations to extend capacity and reduce the need for a larger
site. Management actions are described in paragraph 5.4. If the management actions are
determined to be effective, the remaining assessments can then be conducted. If not, then
the confined-disposal alternative at the site under consideration should be eliminated.
5.3 Evaluation of Contaminant Pathways of Concern for CDFs
If the initial evaluation of sediment contamination described in paragraph 3.5.3
reveals that contaminants are not of concern for specific pathways, then no additional
contaminant testing is required for those pathways. However, if contaminants are of
concern, an analysis of appropriate pathways must be conducted that may include
possible testing.
5.3.1 Contaminant Pathways for CDFs
The possible migration pathways of contaminants from confined disposal
facilities in the upland environment are illustrated in Figure 5-1. These pathways include
effluent discharges to surface water during filling operations and subsequent settling and
dewatering, rainfall surface runoff, leachate into groundwater, volatilization to the
atmosphere, and direct uptake. Direct uptake includes plant uptake and subsequent
cycling through food webs and direct uptake by animal populations living in close
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VOLATILIZATION
PRECIPfTATION
BIOTURBATION
UNSATURATED
SATURATED
SEEPAGE
WEIR
INFILTRATION
4$>!&$Syi!i$$!Z!$8xi!$S!^
EFFLUENT
LEACHATE
Figure 5-1. Contaminant Pathways for Upland CDFs
association with the dredged material. Effects on surface water quality, groundwater
quality, air quality, plants, and animals depend on the characteristics of the dredged
material, management and operation of the site during and after filling, and the proximity
of the CDF to potential receptors of the contaminants.
Migration pathways affected by nearshore CDFs are illustrated in Figure 5-2 and
include all of the pathways previously discussed. Additional considerations for nearshore
sites (with one or more sides within the influence of water level fluctuations) are soluble
convection through the dike in the partially saturated zone and soluble diffusion from the
saturated zone through the dike. Groundwater seepage into or through the site can also be
a factor affecting contaminant migration. These additional potential fluxes primarily
affect the surface water pathway.
5.3.2 Geochemical Environments for CDFs
When dredged material is placed in an upland environment, physical and/or
chemical changes may occur (Francingues et al. 1985). The dredged material initially is
dark in color and reduced, with little oxygen. If the material is hydraulically placed in the
CDF, the ponded water will usually become oxygenated. This may affect the release of
contaminants in effluent discharged during hydraulic filling.
Once disposal operations are completed, and any ponded water has been removed
from the surface of the CDF, the exposed dredged material will become oxidized and
lighter in color. The dredged material may begin to crack as it dries out. Accumulation of
salts will develop on the surface of the dredged material and especially on the edge of the
cracks. Rainfall events will tend to dissolve and remove these salt accumulations in
surface runoff. Certain metal contaminants may become dissolved in surface runoff.
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VOLATILIZATION
PRECIPITATION
± BIOTURBATION
\
1
I
WBR -v
UNSATURATED /
INFILTRATION
_J
LEACHATE
Figure 5-2. Contaminant Pathways for Nearshore CDFs
During the drying process, organic complexes become oxidized and decompose.
Sulfide compounds also become oxidized to sulfate salts, and the pH may drop
drastically. These chemical transformations can release complex contaminants to surface
runoff, soil pore water, and leachate. In addition, plants and animals that colonize the
upland site may take up and bioaccumulate these released contaminants.
Volatilization of contaminants depends on the types of contaminants present in
the dredged material and the mass transfer rates of the contaminants from sediment to air,
water to air, and sediment to water. Release of the dredged material slurry above the
water level in the CDF surface will enhance volatilization as the slurry impacts the CDF
surface, creating turbulence and releasing dissolved gases. The transfer rate for organics
such as polychlorinated biphenyls (PCBs) from water to air is generally slower, but of
longer duration, than from sediment to air (Thibodeaux 1989).
CDFs constructed totally or partially in water will usually receive dredged
material until the final elevation is above the high-water elevation. Three distinct
physicochemical environments may eventually exist at such a site: upland (dry
unsaturated layer), intermediate (partially or intermittently saturated layer), and aquatic
(totally saturated layer) (Lee et al. 1991).
When material is initially placed in an in-water CDF, it will all be flooded or
saturated throughout the vertical profile. The saturated condition is anaerobic and
reduced, which favors immobility of contaminants, particularly heavy metals. After the
site is filled and dredging ceases, the dredged material above the water level begins to
dewater and consolidate through movement of water downward as leachate, upward and
out of the site as surface drainage or runoff, and laterally as seepage through the dike. As
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the material desiccates through evapotranspiration, it becomes aerobic and oxidized,
mobilizing some contaminants as described previously. At this point, the surface layer
has characteristics similar to that of material in an upland CDF.
The bottom of an in-water CDF below the low-tide or groundwater elevation
remains saturated and anaerobic, favoring insolubility and contaminant attraction to
particulate matter. After dewatering of the dredged material above the flooded zone
ceases and consolidation of the material in the flooded zone reaches its final state, water
movement through the flooded material is minimal and the potential for migration of
contaminants is low.
The intermediate layer between the saturated and unsaturated layers will be a
transition zone and may alternately be saturated and unsaturated as the water surface
fluctuates. The depth of this zone and the volume of dredged material affected depend on
the difference in tide elevations and on the permeability of the dike and of the dredged
material. With low-permeability material, the volume of CDF material impacted by this
pumping is very small compared with the in-water CDF's total volume.
5.3.3 Analysis of Pathways for CDFs
Guidance for analysis of contaminant pathways for CDFs is provided in the
Upland Testing Manual or UTM (USAGE 2003). This manual is a resource document
providing detailed testing procedures and approaches for evaluation of potential
contaminant migration pathways from diked confined disposal facilities (CDFs).
Consideration of pathways for migration of contaminants from the site and potential
contaminant impacts is required to determine the need for operational or engineered
measures to control contaminant releases. During the 1980s and 1990s, a number of
evaluation procedures and laboratory tests were developed for CDF pathway evaluations
and serve as the technical basis for procedures in the UTM (Environmental Laboratory
1987, Francingues and Averett 1988, Palermo et al. 1989, Brannon et al. 1990, and Myers
1990).
The UTM uses a tiered approach similar to that long used for evaluation of open
water placement of dredged material (USEP A/US ACE 1991 and 1998). The pathways of
concern for CDFs include effluent discharges to surface water during filling operations,
rainfall surface runoff, leachate into groundwater, volatilization to the atmosphere, and
direct uptake by plants and animals on site and subsequent cycling through food webs.
Additional discussion of the respective CDF pathways including appropriate testing
protocols and evaluation procedures are given in the following paragraphs.
5.3.4 Effluent Discharge
The effluent from a CDF may contain both dissolved and particulate-associated
contaminants. A large portion of the total contaminant concentration is tightly bound to
the particulates. Effluent from a CDF is considered a dredged material discharge under
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Section 404 of the CWA and is also subject to water quality certification under Section
401 State/Tribal water quality standards.
Prediction of effluent quality may be made using partitioning analysis (Estes,
Schroeder, and Bailey in preparation), or the effluent elutriate test procedure (Palermo
1985; Palermo and Thackston 1988, USEPA/USACE 1998, USAGE 2003). Partitioning
analysis provides an estimate of effluent concentrations that will result for measured
sediment and carrier water concentrations. This can be helpful in narrowing the
constituents of concern to those that appear to be present at concentrations that may be
environmentally problematic. The modified elutriate test simulates the geochemical and
physical processes occurring during confined disposal. This test provides additional
information on dissolved and particulate contaminant concentrations. The column settling
test (USAGE 1987) and expert system SETTLE (Hayes and Schroeder 1992) used for
CDF design provide an estimate of the effluent solids concentrations. Results of both
elutriate and settling tests can be used to predict a total concentration of contaminants in
the effluent. The predicted effluent quality, with allowance for any mixing zone, can be
compared directly with water quality standards. Computerized programs are also
available to compare predicted effluent concentrations with water quality criteria
(Palermo and Schroeder 1991).
Where water quality standards are unavailable or are predicted to be exceeded,
risk assessment may be necessary to further evaluate the environmental impacts
associated with the effluent discharge. Guidance regarding effluent toxicity bioassays
and ecological and human health risk assessment in aquatic environments can be found in
Brandon, Schroeder, and Lee (1997a) and Cura et al. (2001), respectively. The modified
elutriate test can be used to develop the water medium for bioassays if a biological
approach to evaluation of effluent quality is needed. These bioassays are conducted in a
manner similar to those for open-water disposal. The quality of a reference water (usually
the receiving water) should be considered in test interpretation.
If impacts of effluent contaminant concentrations are unacceptable, appropriate
controls should be considered. Control measures available for effluent discharge include
improved settling design or reduced flow to the containment area, chemical clarification
or filtration to remove particulate contaminants, and removal of dissolved contaminants
by more sophisticated treatment processes.
5.3.5 Surface Runoff
Immediately after material placement in a CDF and after ponding water is
decanted, the settled material may experience surface runoff. Rainfall during this initial
period will likely be erosive, and runoff will contain elevated solids concentrations.
Geochemically speaking, the contaminant release is controlled by anaerobic conditions.
Once the surface is allowed to dry, the runoff will contain a lesser concentration of solids,
but the release is now controlled by aerobic conditions, and release of some dissolved
contaminants may be elevated. Runoff water quality requirements may be a condition of
the water quality certification or considered as part of the NEPA process.
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As for effluent, partitioning analysis may be used to provide an initial estimate of
runoff concentrations, and this can be done for both oxidized and unoxidized conditions
(Price, Schroeder, and Estes in preparation). There also is now available a simplified test
procedure for prediction of runoff quality (SLRP) (Price, Skogerboe and Lee 1998 and
USAGE 2003). A soil lysimeter testing protocol (Lee and Skogerboe 1983 and USAGE
2003) has also been used to predict surface runoff quality with good results. The
lysimeter is equipped with a rainfall simulator and can be used in the laboratory or
transported to the field site. The soil lysimeter is a more expensive and elaborate testing
protocol, requiring large volumes of sediment and approximately 8 months for test
completion.
Computerized programs are available to compare predicted runoff concentrations
with water quality criteria (Schroeder, Gibson, and Dardeau 1995). If runoff
concentrations exceed water quality standards, appropriate controls may include
placement of a surface cover or cap on the site, maintenance of ponded water conditions
(although this may conflict with other management goals), vegetation to stabilize the
surface, treatments such as liming to raise pH, or treatment of the runoff as for effluent
(Lee and Skogerboe 1987). Risk assessment may be used to evaluate the environmental
effects associated with runoff and determine the need for controls where standards are
predicted to be exceeded, or standards are not available (Cura, Wickwire and McArlde in
preparation). Procedures for evaluation of runoff toxicity bioassay tests can also be
found in Brandon, Schroeder, and Lee (1997b).
5.3.6 Leachate
Subsurface drainage from upland CDFs may reach adjacent aquifers or may enter
surface waters. Fine-grained dredged material tends to form its own disposal-area liner as
particles settle with percolation of water, but some time may be required for sufficient
consolidation to occur. Particulate transport in leachate is also minimal. Constituents
present in leachate are primarily found in the dissolved fraction.
Evaluation of the leachate quality from a CDF must include a prediction of which
contaminants may be released in leachate and the relative degree of release or mass of
contaminants (Schroeder 2000). Pore water analysis may provide a good preliminary
estimate of leachate quality. Partitioning analysis may also be used to estimate
concentrations of constituents in leachate, based on measured sediment concentrations
(Myers, Schroeder and Estes in preparation (a)). Experimental procedures have been
developed for prediction of leachate quality from dredged material (Myers and Brannon
1991; Brannon, Myers and Tardy 1994; Myers, Brannon and Tardy 1996, US ACE 2003).
These procedures are based on theoretical analysis and laboratory batch testing and
column testing, but have not been routinely applied due to the time required to perform
these tests and the associated cost.
The experimental testing procedures only give data on leachate quality. Estimates
of leachate quantity must be made by considering site-specific characteristics and
groundwater hydrology. Computerized procedures such as the USEPA Hydrologic
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Evaluation of Landfill Performance model (Schroeder et al. 1984) have also been used to
estimate water balance (budget) for dredged material CDFs (Palermo et al. 1989;
Francingues and Averett 1988). Additional procedures and computer estimating tools are
also available to estimate attenuation of contaminants in the subsurface (Schroeder and
Aziz 2003; Aziz and Schroeder 1999a; Aziz and Schroeder 1999b; Schroeder et al.
1994a; Schroeder et al. 1994b; Schroeder et al. 2004). Source terms for partitioning
analysis and attenuation calculations can be found in Streile et al. (1996).
If leachate concentrations exceed applicable criteria, or criteria are not available
and effects cannot be shown to be acceptable using risk assessment (USEPA 1998; Cura,
Wickwire and McArlde in preparation), controls for leachate must be considered. These
may include proper site specification to minimize potential movement of water into
aquifers, dewatering to reduce leachate generation, chemical modifications to retard or
immobilize contaminants, physical barriers such as clay and synthetic liners,
capping/vegetating the surface to reduce leachate production, or collection and treatment
of the leachate.
5.3.7 Plant and Animal Uptake
Some contaminants can be bioaccumulated in plant tissue and become further
available to the food chain. There are few reference values available specifically for
assessing the potential for adverse plant or animal uptake from dredged material. Criteria
established for sewage sludge are sometimes used, but apply to a limited number of
metals, and are based on conservative assumptions that are not directly applicable to a
disposal area. A computerized screening program has been developed which compares
measured sediment concentrations to available reference values. The
Diethylenetriamine-pentaacetic acid (DTPA) extract test has also been utilized to provide
a simplified assessment of the potential for plant and animal uptake (Lee et al. 1978;
Folsom, Lee, and Bates 1981; Lee, Folsom, and Engler 1982; Lee, Folsom, and Bates
1983; U.S. Army Engineer Waterways Experiment Station 1987, USAGE 2003). A
computerized program, the Plant Uptake Program (PUP) uses the results of the DTP A
extraction procedure to predict bioaccumulation of metals from freshwater dredged
material by freshwater plants and compare the results to a background or reference
sediment or soil (Folsom and Houck 1990).
If the contaminants are identified in the dredged material at levels, which cause a
concern, a more extensive evaluation may be performed based on a plant or animal
bioassay. Appropriate plant or animal species are grown in either a flooded or dry soil
condition using the appropriate experimental procedure and laboratory or field test
apparatus (Folsom and Lee 1985; Simmers, Rhett, and Lee 1986; American Society for
Testing and Materials (ASTM) 1997; USAGE 2003). Contaminant uptake is then
measured by chemical analysis of the biomass (tissue). Growth, phytotoxicity, and
bioaccumulation of contaminants are monitored during the growth period in the case of
the plant bioassay. An index species is also grown to serve as a mechanism to extrapolate
the results to allow use of other databases, such as metals uptake by agricultural food
crops. This indexing procedure provides information upon which a decision can be made
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regarding potential for human health effects and for beneficial uses of the site or dredged
material. Levels of contaminants in the biomass are compared with Federal criteria for
food or forage. Risk assessment may also be performed to evaluate the potential effects
of plant and animal uptake on sensitive species subject to primary or secondary exposure
(Cura, Wickwire, and McArlde in preparation).
From the test results, appropriate management strategies can be formulated
regarding where to place dredged material to minimize plant or animal uptake or how to
control and manage the species on the site so that desirable species that do not take up
and accumulate contaminants are allowed to colonize the site, while undesirable species
are removed or eliminated.
5.3.8 Volatilization to Air
Contaminant transport from in situ sediment to air is a relatively slow process,
because most contaminants must first be released to the water phase prior to reaching the
air. Potential for volatilization should be evaluated in accordance with regulatory
requirements of the Clean Air Act. Thibodeaux (1989) discusses volatilization of organic
chemicals during dredging and disposal and identifies four locales where volatilization
may occur:
Dredged material exposed directly to air.
Dredging site or other water area where suspended solids are elevated.
Ponded CDF with a quiescent, low-suspended solids concentration.
Dredged material covered with vegetation.
In cases where highly contaminated sediments are disposed, airborne emissions
must be considered to protect workers and others who could inhale contaminants released
through this pathway.
Rate equations based on chemical vapor equilibrium concepts and transport
phenomena fundamentals have been used to predict chemical flux (Thibodeaux 1989;
Semmler 1990). Computerized programs have been developed utilizing these rate
equations for the evaluation of volatile emissions from dredged material (Myers,
Schroeder and Estes in preparation (b)). Since the original publication of this document,
considerable effort has also been directed to testing procedures for direct measurement of
volatile emissions (Price et al. 1997; Price et al. 1998; Price et al. 1999, USACE 2003).
Emission rates are primarily dependent on the chemical concentration at the
source, the surface area of the source, and the degree to which the dredged material is in
direct contact with the air. The magnitude of release from exposed dredged material is
initially higher than for ponded conditions. This is of limited duration however.
Volatilization from ponded areas occurs at a lower rate, but is continuous, and may result
in a higher mass flux over time.
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Effects associated with volatilization of contaminants are evaluated based on
estimated exposure to selected receptors, and appropriate inhalation reference doses
(Myers, Schroeder and Estes in preparation (b)). Risk assessment may also be employed
in assessing the effects associated with exposure (Cura, Wickwire, and McArlde in
preparation).
5.3.9 Particulate Transport
Airborne transport of particulates from the surface of a CDF is also potentially of
concern. Exposure to contaminants may occur through inhalation of fine particles or
from direct contact with or ingestion of particles re-deposited in areas off-site. Tools to
quantify particulate transport are not well developed. Qualitative analysis of expected
surface conditions may identify periods when particulate transport will be of concern;
primarily when the material surface is dry, net precipitation is low, and prevailing winds
are sufficient to effect transport. Vegetation or surface covers may provide effective
control of particulate transport, although implementation may be logistically difficult due
to the size of the areas involved and the limited weight bearing capacity of the material
while it is still consolidating.
5.3.10 Need for Contaminant Controls
If the analysis of contaminant pathways and associated testing indicates that the
standards or Guidelines, as appropriate, are met, the CDF alternative is environmentally
acceptable from the standpoint of contaminant effects for that pathway. If the applicable
standards or Guidelines are not met, contaminant control measures can be considered to
reduce impacts to acceptable levels.
Control measures to minimize contaminant impacts may include operational
modification, treatment, site controls (e.g., liners or covers), and other site management
actions. These control measures are described in paragraph 5.4. If the control measures
are determined to be effective, then the alternative is environmentally acceptable from the
standpoint of contaminants. If there are no effective control measures for one or more
pathways, then disposal at the CDF under consideration should be eliminated.
5.4 Evaluation of Management Actions and Contaminant Control Measures
for CDFs
In cases where evaluations of direct physical impacts, site capacity, or
contaminant pathways indicate impacts will be unacceptable when conventional CDF
disposal techniques are used, management actions and contaminant control measures may
be considered. It should be noted that a CDF is neither a conventional wastewater
treatment facility nor a conventional solids-handling facility. The dredged materials
placed in CDFs typically contain 10 to 50 percent solids; therefore, an effective CDF
must incorporate features of both wastewater treatment and solids-handling facilities in a
combination that is unlike either (Averett et al. 1990).
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Descriptions of the commonly used management actions and contaminant
controls are given in the following paragraphs. Additional guidance on selection of
management actions and contaminant controls for CDFs is available (USAGE 1983, 1987
and in preparation; Francingues et al. 1985; Cullinane et al. 1986; Averett et al. 1990).
These references contain testing procedures and criteria needed for evaluating and
selecting appropriate contaminant control measures for CDFs, and should be consulted
for additional detailed discussions of the attributes of the various technologies.
Management actions may include managing or modifying the proposed placement
operation, modification of the CDF design or geometry, treatment of effluent, runoff, or
leachate discharges, and physical management such as covers, liners, or barrier systems
(USAGE 2003). Recent references relevant to application of management actions at
CDFs include USEPA (1994); National Research Council (1997); Permanent
International Association of Navigation Congresses (PIANC) (1996 and 2003); Palermo
and Averett (2000).
5.4.1 Management Actions for Physical Impacts and Storage Capacity
A number of management techniques have been developed and used that can
eliminate or minimize adverse direct physical impacts resulting from construction of
CDFs. These include:
Management of the CDF for dewatering the dredged material, thereby
reducing the volume of material and reducing the need for larger or additional
sites (USACE 1987).
Treatment of effluent to remove additional solids and reduce turbidity of the
discharge (USACE 1987).
Implementation of Disposal Area Reuse Management involving removal of
material from the CDF for some beneficial use, thereby restoring the capacity
of the CDF (US ACE 1987; Lee 1999; Olin-Estes and Palermo 2000a; Olin-
Estes and Palermo 2000b; Olin-Estes 2000; Lee 2000; Spaine et al. 2001; Lee
2001; Olin-Estes et al. 2002b).
Mitigation to include creation of alternative habitat and designated resource
management onsite.
Modification of site through landscaping and screening to improve site
aesthetics and features to protect cultural resources.
5.4.2 Treatment of Liquid Streams
The objective of liquid streams controls is to remove residual contaminants from
the liquids produced as discharges from a CDF operation such as:
Effluent discharges from active filling operations.
Surface runoff.
Leachate.
Water produced from dewatering or treatment processes.
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Contaminants in these streams will present a wide array of concentrations
depending on their source, and individual sources are often highly variable in
concentrations and flows. Most of the contaminants for these streams (with the exception
of leachate) are associated with the suspended solids and will be removed by effective
suspended solids removal. Another characteristic of these streams is their variety of
contaminants, both organic and inorganic, as well as potentially toxic contaminants.
These characteristics may require more than one treatment process. Commonly used
wastewater treatment processes are available to achieve effluent limits for most
contaminants. However, application of treatment processes for dredged material effluent
has been generally limited to removal of suspended solids and contaminants associated
with these particulates.
Liquid treatment technologies can be classified as metals removal processes,
organic treatment processes, and suspended solids removal processes. Many of these
processes concentrate contaminants into another phase, which may require special
treatment or disposal. This discussion focuses on suspended solids, toxic organics, and
heavy metals. Conventional contaminants, such as nutrients, ammonia, oxygen-
demanding materials, and oil and grease, may also be a concern for dredged material
effluents. Most of the processes for dissolved organics removal are suitable for these
contaminants.
5.4.2.1 Suspended Solids Removal
Suspended solids removal is the most important liquid streams technology
because it offers the greatest benefits in improving effluent quality not only by reducing
turbidity but also by removing particulate-associated contaminants. Suspended solids
removal processes differ from dewatering processes because for this application the
solids concentration is much lower than for a dredged material slurry. Settling
mechanisms for these streams are characterized by flocculent settling rather than zone or
compression settling. For CDF liquid streams, the solids remaining will be clay or
colloidal size material that may require flocculants to promote further settling in clarifiers
or sedimentation ponds. Chemical clarification using organic polyelectrolytes is a proven
technology for CDF effluents (Schroeder 1983). Filtration, permeable dikes, sand-filled
weirs, and wetlands have also been used on occasion for CDF demonstrations or pilot
evaluations. More detailed guidance on suspended solids removal processes as applied to
CDFs is available (USACE 1987; Cullinane et al. 1986).
5.4.2.2 Metals Removal
Metals removal processes that may be considered for application at CDFs are
similar to those commonly used for industrial applications. Flocculation is effective for
removal of metals associated with particulate matter. Polymers and inorganic flocculants
have been demonstrated to be effective for removal of suspended solids from dredging
effluents, but removal of dissolved heavy metals has not been evaluated in field
applications. Ion exchange and precipitation are probably two of the more efficient
metals removal processes, but they must generally be designed for specific metals and
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often require major investments in operational control for efficient operation. Natural ion-
exchange media, such as zeolites, may be effective but have not been demonstrated in
this application. Use of man-made wetlands for retention of heavy metals and other
contaminants from effluents could represent a viable option for certain sites and
contaminants (Fennessy and Mitsch 1989). Less likely choices include biological ion
exchange, electrocoagulation, and ultrafiltration. More detailed guidance on metals
treatment processes as applied to CDFs is available (Cullinane et al. 1986; Averett et al.
1990).
5.4.2.3 Organics Treatment
The applicability and effectiveness of options for treatment of dissolved organic
contaminants are mostly dependent on the concentration and flow of the liquid stream.
Mechanical biological wastewater treatment processes are typically not considered
because it is doubtful that sufficient organic matter would be available to support
biological growth and because operation of biological systems under the conditions of
fluctuating flows and temperatures would be difficult. Biological processes such as
nitrification, nutrient catabolism, and photosynthesis are important degradation
mechanisms for nutrients, oxygen-demanding materials, and other organics in CDFs. The
principal process for dissolved refractory organic contaminants that has been applied to
dredged material effluent is carbon adsorption, which was applied to a PCB spill on the
Duwamish Waterway in the 1970s (Blazevich et al. 1977). Air and steam stripping could
be used for volatile contaminants, but these are generally not a problem for contaminants
originating in most dredged sediments. Ultraviolet light (UV) and chemical oxidation
processes offer destruction of organic contaminants and are being extensively
investigated in the field for a wide range of contaminants. Created wetlands also offer
potential for retention and degradation of organics. The more effective organic treatment
process options are:
Carbon adsorption.
Chemical oxidation using ozone.
UV/hydrogen peroxide.
UV/ozone.
Oil separation.
Resin adsorption.
Steam stripping.
Created wetlands.
More detailed guidance on organics treatment processes as applied to CDFs is available
(Cullinane et al. 1986; Averett et al. 1990; USACE 1983 and USACE in preparation).
5.4.3 Site Controls
Site controls (e.g., surface covers and liners) can be effective control measures
applied at a CDF to prevent migration of contaminants from the dredged material
(Cullinane et al. 1986; Averett et al. 1990). The implementability and effectiveness of
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these controls is highly specific to the CDF location and the dredged material
characteristics.
Use of site controls such as liners, slurry walls, groundwater pumping, and
subsurface drainage are limited in most nearshore, in-water CDFs. Graded stone dikes
with sand or steel sheet pile cutoffs have been used or proposed at upland CDFs and a
few in-water CDFs to control leachate migration. The low permeability of fine-grained
sediments following compaction can reduce the need for liners in many cases, but it can
also limit the effectiveness and implementability of groundwater pumping and subsurface
drainage controls.
A cover can be highly effective in reducing leachate generation by avoiding
rainfall infiltration, isolation from bioturbation and uptake by plants and animals,
minimizing volatilization of contaminants from the surface, and eliminating detachment
and transport of contaminants by rainfall and runoff. A layer of clean material can
achieve the last three benefits mentioned. However, prevention of infiltration requires a
barrier of very low permeability, such as a flexible membrane or a compacted clay layer,
both of which are not easily or reliably implemented for CDFs. Other leachate control
measures include groundwater pumping, liners, subsurface drainage, sheet pile walls,
slurry walls, and surface drainage. Liners have not been used extensively for
contaminated dredged material sites because of the inherent low permeability of fine-
grained dredged material, the retention of contaminants on solids, and the difficulty and
expense of construction of a reliable liner system for wet dredged material, particularly
for in-water or nearshore sites. Leachate collection techniques, such as groundwater
pumping and subsurface drainage, have been evaluated in a limited number of situations,
but these techniques appear to have limited feasibility for in-water sites. Sheet pile walls
and slurry walls can be used to provide barriers to leachate and seepage movement from a
CDF. To be effective, the barrier should tie to a geologic formation with very low
permeability. Sheet pile walls are not leakproof and deteriorate over time; therefore, they
should not be considered as a primary containment measure. More detailed guidance on
site controls for CDFs is available (Cullinane et al. 1986; Averett et al. 1990; USACE
1983 and USACE in preparation).
5.4.4 Treatment of Dredged Material Solids
Treatment of the dredged material might be considered if this would facilitate
beneficial use of the material, or provide a cost effective alternative to treatment of the
various discharges from a CDF. A variety of treatment processes have been proposed for
dredged material solids (i.e., the mass of dredged material following placement within a
CDF) or dredged material slurries. These processes fall under one of the following
categories: bioremediation (use of bacteria, fungi, or enzymes to break down organic
contaminants), chemical treatment (e.g., oxidation, reduction, chelation, hydrolysis,
detoxification, nucleophilic substitution, and thionation processes), extraction (removal
of contaminants by dissolution in fluid), thermal (e.g., incineration), immobilization
(processes which limit the mobility of contaminants) and volume reduction (physical
separation of contaminated fractions).
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Some of these treatment processes have been applied in pilot-scale
demonstrations, and some have been applied full scale (Myers and Bowman 1999;
Myers, Bowman, and Myers 2003; Olin-Estes et al. 2002a; USAGE Los Angeles District
2002; USEPA 1999; Tetra Tech and Averett 1994). Recent work on phytoremediation of
lead contaminated sediments can be found in Lee and Price (2003). Potential for
biotreatement or phytoremediation of contaminated sediments is discussed in the
following references (Price and Lee 1999; Fredrickson et al.1999; Price, Lee and
Simmers 1999; Myers and Williford 2000).
The cost of treatment alternatives relative to the cost of conventional disposal is a
major constraint on their potential use. The potential for implementation of
immobilization processes is better than other treatment processes, because they are not as
sensitive to process-control conditions, and they are relatively cost effective techniques
for reducing contaminant mobility. The opportunity for applying these processes in situ
in a CDF is also an advantage.
The environmental pathway most affected by immobilization processes is
transport of contaminants as leachate to the groundwater or surface water. Most of the
immobilization processes fall into the category of solidification/stabilization (S/S).
Objectives of S/S are generally to improve the handling and physical characteristics of
the material, decrease the surface area of the sediment mass across which transfer or loss
of contaminants can occur, and/or limit the solubility of contaminants by pH adjustment
or sorption phenomena. Effectiveness of S/S processes is usually evaluated in terms of
reduction of leaching potential. Reductions are process and contaminant specific, with
immobilization of some contaminants accompanied by increased mobility of other
contaminants.
5.4.5 Site Operations
Site operations can be used as a control measure for CDFs to reduce the exposure
of material through the surface water, volatilization, and groundwater pathways.
Operational controls may include management of the site pond during and after disposal
operations. Mobilization of contaminants from dredged material depends on the oxidation
state of the solids. Most metals are much less mobile when maintained in an anaerobic
reduced condition. On the other hand, aerobic sediments generally improve conditions for
biodegradation of organic contaminants. Maintaining ponded water on the site may
decrease the rate at which volatilization occurs (though not necessarily the overall mass
flux) but produces a hydraulic gradient that increases the potential for movement of
leachate through the site. Whether to cultivate or inhibit plant and animal propagation is
also an issue. Management of the site both during filling and after disposal requires a
comprehensive understanding of the migration pathways and the effects various
contaminant controls have on the overall mass balance and rate of contaminant releases.
The decision to apply certain management options requires trade-offs for the site and
contaminant-specific conditions for the project.
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5.5 Retention of Environmentally Acceptable Confined Alternatives
Once appropriate confined-disposal tests and assessments are complete, a
determination of environmental acceptability can be made. This determination must
ensure that all applicable standards or criteria are met. If control measures were
considered, a determination of the effectiveness of the control measures in meeting the
standards or criteria must be made. If all standards or criteria are met, the confined-
disposal alternative can be considered environmentally acceptable. At this point, other
factors can be considered in the selection of an alternative as described in paragraph 3.6
and Chapter 7.
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6.0 ASSESSMENT OF BENEFICIAL USE
ALTERNATIVES
This chapter contains descriptions of various beneficial uses of dredged material
and assessment procedures for beneficial use alternatives. The framework for
assessments for beneficial uses is illustrated in Flowchart 3-4. The detailed assessments
described in this chapter may be performed following a determination of the need for
such assessments as described in Chapter 3.
6.1 Beneficial Use as an Alternative
Dredged material is a manageable, valuable soil resource, with beneficial uses of
such importance that plans for the ultimate use of disposal sites should be incorporated
into project plans and goals at the project's inception to the maximum extent possible. It
is the policy of the USAGE to fully consider all aspects of dredging and disposal
operations with a view toward maximizing public benefits. Integral to this analysis is a
requirement to provide full and equal consideration to all practicable alternatives,
including beneficial uses of dredged material (see for example 33 CFR 337.9).
Whenever the dredging cycle and beneficial use needs have been found to
coincide, beneficial use of dredged material has been considered as a management option.
In many cases, beneficial use of dredged material has been identified as the preferred
alternative. Unexpected new beneficial use needs may periodically arise (e.g., severe
beach erosion from severe storms) and other factors such as development of more cost-
effective dredging technologies may from time to time dictate a reevaluation of beneficial
use options.
Authorities and constraints related to the beneficial use of dredged material are in
a state of change. Provisions in the Water Resources Development Act of 1990 have now
assigned to the USAGE new authorities to pursue high-priority Fish and Wildlife
Restoration projects where such projects can most efficiently or appropriately be
accomplished in conjunction with existing or planned navigation projects. In addition,
this legislation has assigned such projects equal mission status with navigation and flood
control projects of the USAGE. Thus, future beneficial use applications may, on a case-
by-case basis, be either the preferred alternative for a navigation project, a cost-shared
(ranging from 25 to 100 percent total local funding) action undertaken in association with
the navigation project, or a separate, cost-shared project undertaken within the navigation
project boundaries.
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6.2 Identification of Beneficial Use Needs and Opportunities
The first step in assessment of beneficial use alternatives is to identify the local
needs and opportunities for beneficial use. This may involve surveys of activities which
may need material with certain characteristics or surveys of needs for certain site uses.
Likewise, if the dredged material from a project is known to have desirable
characteristics for a number of beneficial uses, then a survey of potential opportunities for
use of that material or specific placement sites should be made. A general description of
the major categories of beneficial use is given in the following paragraphs. Each of these
categories should be considered in identifying needs and opportunities for beneficial use
for the specific project conditions. Additional details on each of the categories are found
in EM 1110-2-5026 (USAGE 1986).
6.2.1 Habitat Restoration/Enhancement
Habitat development refers to the establishment and management of relatively
permanent and biologically productive plant and animal habitats. Use of dredged material
as the substrate for habitat development is one of the most common and most important
beneficial use categories. The use of dredged material for habitat development offers a
disposal technique that is an attractive and feasible alternative to more conventional
disposal options. Within various habitats, several distinct biological communities may
occur. For example, the development of a dredged material island may involve a wide
variety of wetland, upland, island, and aquatic habitats.
Wetland habitat is a broad category of periodically inundated communities,
characterized by vegetation which survives in wet soils. These are most commonly tidal
freshwater and saltwater marshes, bottomland hardwoods, freshwater swamps, and
freshwater riverine and lake habitats. Disposal of dredged material on a viable wetland so
that the wetland is destroyed and converted into a disposal site is never an
environmentally preferable alternative. However, restoration/enhancement of wetlands is
an alternative that can benefit the environment and has the potential of gaining wide
public acceptance when some other techniques cannot. In general, restoration of a former
wetland is more likely to be successful than creation of a new wetland where none had
existed previously (Kusler and Kentula 1990). In selecting a site, alteration of substrate
and changes in circulation and sedimentation patterns should be considered. In general,
the material used for wetland restoration should remain water-saturated, reduced, and
near neutral in pH. These characteristics have a great influence on the environmental
activity of any chemical contaminants which may be present. Extensive discussion on
and procedures regarding development of wetland sites can be found in Hayes et al.
(2000).
Upland habitat includes a broad category of terrestrial communities, characterized
by vegetation that is not normally subject to inundation. Types may range from bare
ground to mature forest. Regardless of the condition or location of a disposal area,
considerable potential exists to convert it into a more productive habitat. Small sites in
densely populated areas may be keyed to small animals adapted to urban life, such as
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seed-eating birds and small mammals. Larger tracts may be managed for a variety of
wildlife including waterfowl, game mammals, and rare or endangered species. The
knowledge that a disposal site will ultimately be developed into a useful area, be it a
residential area, a park, or wildlife habitat, improves public acceptance of the dredged
material disposal alternative.
Many island habitats have been created by placement of dredged material, varying
in size and characteristics and ranging in age from newly formed to those estimated to be
50 years old. The primary wildlife species utilizing dredged material islands as part of
their life requirements are species of colonial-nesting waterbirds. Natural islands have
been altered and developed to such a large extent that some areas no longer have coastal
islands that are still suitable wildlife habitat. Dredged material islands have provided this
vital habitat in many areas.
Aquatic habitats are typical submerged habitats extending from near sea, river, or
lake level down several feet. Aquatic habitat development is the establishment of
biological communities on dredged material placed at or below mean tide in coastal areas
and in permanent water in lakes and rivers. Potential developments include such
communities as tidal flats, seagrass meadows, oyster beds, clam flats, fishing reefs, and
freshwater aquatic plant establishment. The bottom of many water bodies potentially
could be altered using dredged material; this could simultaneously improve the
characteristics of the site for selected aquatic species.
6.2.2 Beach Nourishment
Shore erosion is a major problem along many ocean and estuary beaches and the
shoreline of the Great Lakes. Beach nourishment is usually accomplished by dredging
sand from inshore or offshore locations and transporting the sand by truck, by split-hull
hopper dredge, or by hydraulic pipeline to an eroding beach. These operations may result
in displacement of the substrate, changes in the topography or bathymetry of the borrow
and replenishment areas, and destruction of nonmotile benthic communities. However, a
well-planned beach nourishment operation can minimize these effects by taking
advantage of the resiliency of the beach and nearshore environment and its associated
biota, and by avoiding sensitive resources. When dredged material is used for beach
nourishment, it should closely match the sediment composition of the eroding beach and
be low in fine sediments, organic material, and pollutants. Beach nourishment and
protection can also be accomplished by placement of dredged material mounds or berms
on the bottom, where much of the material would be carried by wave action to the beach.
6.2.3 Aquaculture/Mariculture
Because of the increasing difficulty and expense of obtaining CDFs for use as
single purpose disposal areas, the development of a multiple-use strategy such as
aquaculture or mariculture is desirable. Dredged material containment sites commonly
possess structural features such as dikes and water control devices that may enhance their
suitability as aquaculture areas. It is possible that future site availability would be
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improved by increased value of acreage leased to dredging project sponsors because land-
owners could enter separate and profitable lease agreements with aquaculturists. See also
section 6.2.1.
6.2.4 Parks and Recreation
Of all types of beneficial uses, recreation on dredged material containment sites is
one of the most prevalent land uses in terms of actual acres. It is not surprising to find
many examples of such use since there is such a demand for recreational sites in urban
areas where much dredging occurs. The nature of recreation sites with requirements for
open space and lightweight structures is especially suited to the weak foundation
conditions associated with fine-grained dredged material. Recreational land also is
generally for public use, and high demand for public water-oriented recreation
encourages the development of recreational land use projects on dredged material.
Finally, legislation relating to wetlands, coastal zone management, and flood control is
biased in favor of this type of use. The recreational land use of dredged material
containment sites is one of the more promising and implementable beneficial uses of
dredged material, but is heavily dependent on financial backing at the local level.
6.2.5 Agriculture, Horticulture, and Forestry
Broad use of dredged material disposal sites has been made by the agriculture,
forestry, and horticulture industries. Some disposal sites, especially in river systems, have
provided livestock pastures following seeding or even natural colonization. Other uses
involve actively incorporating dredged material into marginal soils. An attractive
alternative for disposing of dredged material is to use this rich material to amend
marginal soils for agriculture, forestry, and horticulture purposes. By the addition of
dredged material, the physical and chemical characteristics of a marginal soil can be
altered to such an extent that water and nutrients become more available for crop growth.
In some cases, raising the elevation of the soil surface with a cover of dredged material
may improve surface drainage and reduce flooding, thereby lengthening the growing
season.
6.2.6 Strip Mine Reclamation and Landfill Cover for Solid Waste
Two beneficial uses of dredged material that are still fairly new concepts have
proven to be feasible in laboratory and field tests. These are the reclamation of
abandoned strip mine sites that are too acidic for standard reclamation practices and the
covering of solid waste landfills. Both uses would require large quantities of dewatered
dredged material that could be moderately contaminated and still be acceptable. Both
uses would ultimately provide nonconsumptive vegetative cover to unsightly areas, and
the areas could be further reclaimed for minimal-use recreation sites and/or wildlife
habitat.
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6.2.7 Industrial/Commercial Development
Industrial/commercial development near waterways can be aided by the
availability of hydraulic fill material from nearby dredging activities. The use of dredged
material to expand or enhance port-related facilities has generally received local support
because of the readily apparent potential benefits to the local economy. Approval of the
disposal operation is generally predicated on the advancement of the port development
project and not on the incidental need for proper disposal of the dredged sediments. Use
of dredged material to reclaim former industrial sites (brownfields) for other uses has also
been considered in some areas.
6.2.8 Material Transfer for Fill
Dredged material is commonly used in construction of dikes, levees, and CDFs.
Dredged material, pumped on site and dewatered, readily lends itself to these uses. By
using dredged material to build or increase capacity in CDFs, or for dikes and levees,
overall project costs may be reduced by not having to use off-site material for these
purposes. Some local and state agency and private use is made of dredged material for
dikes and levees in certain situations such as for erosion and flood protection. Thousands
of cubic yards of dredged material have been dewatered in holding areas, then provided
to public or private interests for fill material. Often, the material is provided free of
charge to make room in disposal sites for subsequent disposal.
6.2.9 Multipurpose Uses and Other Land-Use Concepts
With careful engineering design, construction, long-term coordination and
planning, and proper implementation of operational and maintenance procedures, a
disposal site having combinations of uses may be developed. A park and recreational
development built over an existing solid waste landfill using dredged material as a cover
is an example of how several of the beneficial uses discussed in the preceding sections
can be lumped into a multipurpose project. There are a number of actual and planned
examples of multipurpose sites. Often, multipurpose objectives do not involve substantial
cost increases to the dredging project when plans are made in the initial phases of design
and construction. Frequently, recreational use and wildlife and fish habitat can be
developed simultaneously on a disposal site. Potential problems with development of
multipurpose projects are usually related to conflicting user groups of the proposed
disposal/development site. Careful selection of compatible potential users can avoid
situations where the projected uses conflict.
6.3 Evaluate Physical Suitability of Material
Basic data on physical characteristics of the sediments to be dredged (see section
3.5.2) can often serve as an effective initial screen to determine if proposed beneficial use
options as identified above are sufficiently feasible to warrant more detailed evaluations.
Grain-size compatibility with the intended beneficial use is often a major consideration.
In most cases, clean, coarse-grained sediments (sands) are suitable for a wide range of
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beneficial uses. However, fine-grained sediments are also suitable for some beneficial
uses, such as wetland habitat development, soil creation and improvement and
construction blocks. Testing procedures to determine the suitability of dredged material
for beneficial uses is provided in Winfield and Lee (1999). Dredged material that is
contaminated may be useful for beneficial uses if some treatment is applied to reduce
contamination. Low-cost treatment alternatives include bioremediation and
phytoremediation. Procedures for determining the suitability of dredged material for
these remediation alternatives are provided by Fredrickson et al. (1999) and Price and
Lee (1999).
6.4 Logistical Considerations for Beneficial Use
A number of procedural and logistic factors can also greatly influence the
feasibility of specific beneficial use proposals. Examples of logistic considerations
include: distance of the proposed beneficial use site from the dredging project; site
accessibility; required equipment to dredge the channel (e.g., hopper dredge in high-
energy approach channels) versus equipment required to efficiently transport the material
to the site (e.g., quite often a pipeline dredge); material rehandling requirements; size of
project versus intended beneficial use and size of disposal site (e.g., a 30-in. dredge
required to efficiently move large volumes of shoal material may very quickly
overwhelm a small wetland restoration site); and timing of the beneficial use need (e.g.,
beach nourishment) versus maintenance dredging needs.
Less understood, but perhaps one of the greatest potential constraints to many
potential beneficial use proposals is what may collectively be termed real estate
considerations. These include state, county, and local land-use zoning laws (which can be
extremely variable and complex); issues of ownership of the material (e.g., Submerged
Lands Act); whether disposal sites are fee-owned or disposal is through easements; and
the closely related issue of sponsor requirements for acquiring and managing disposal
sites as contained in the project-specific authorizing legislation. A typical example would
be disposal sites acquired through easement by the project sponsor under his assigned
responsibility within the authorizing project legislation. Ownership of the material may
well reside with the landowner, not the Federal government or project sponsor, which
could eliminate further consideration of that site for certain beneficial uses. In some
cases, such constraints might be overcome if the sponsored landowners are willing to
renegotiate the real estate agreements. In other cases, however, specific Federal and/or
state/local legislation would be required to overcome such constraints.
6.5 Determination of Environmental Suitability
Generally speaking, highly contaminated sediments will not normally be suitable
for most proposed beneficial uses and particularly for proposed habitat
creation/restoration projects. Conversely, if the material is exempt from testing (e.g., 40
CFR 230.60) or testing indicates the material is suitable for open-water disposal, that
material would likely be deemed suitable for a wide range of beneficial use applications
from the standpoint of contamination. Most beneficial uses involve either open-water or
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confined placement as an integral part of the application or an initial step in developing
the application. Therefore, the testing and assessment procedures as well as compliance
with the overall 404 Guidelines themselves, must also be considered for beneficial uses
(see Chapters 4 and 5).
There is considerable interest in removing dredged material from confined
placement and using the material as a resource for construction material or topsoil to
restore capacity of existing CDFs. Many dredged materials currently contained in CDFs
will support desirable vegetation with little input other than fertilizer. Efforts to alter
undesirable dredged material characteristics by adding organic materials such as yard
litter (leaves, grass and tree trimmings) animal manures or other biosolids can provide
characteristics necessary to produce soil material for containerized plants, bedding plants
and turf grass. With local support to provide materials that are normally considered
waste (yard litter and biosolids), valuable soil materials can be produced for use in local
projects such as brownfield redevelopment, road construction, parks and recreation fields.
Since the purpose of most CDFs is to contain contaminated materials, the issue of reuse
poses some question as to the suitability of the material for beneficial uses outside the
CDF and there is currently no clear guidance specifically addressing suitability of
dredged material for beneficial uses. Some states have set standards for contaminants in
industrial waste materials and have included dredged material in that category. Other
criteria may be applicable, such as Ecological Soil Screening Levels or USEPA 503
Regulations for the application of biosolids, but the criteria for suitability will be
determined by the State or local authority where the dredged material will be used. The
Great Lakes Upland Testing and Evaluation for Beneficial Use project is an interagency
effort to compile existing guidance, criteria, testing recommendations and case studies to
facilitate consensus building in the regulatory and scientific communities for beneficial
use of dredged material. A briefing paper that also includes an extensive annotated
bibliography with references relevant to beneficial use of dredged material has been
published by the working group (Great Lakes Commission 2004).
For ongoing activities, periodic reevaluations are advisable to ensure that the
conditions regarding sediment contaminants have not changed since the last dredging
cycle. For new applications and particularly for habitat development applications, it will,
at times, be advisable (depending on the nature and source of the dredged material) to
conduct limited plant and/or animal bioassays to ensure that the material will not be
harmful to the target species. Examples of such situations may be when highly saline
material is to be used in a brackish or freshwater habitat development project, or if the
material is to be used for upland habitat development or portions of the site will be
emergent. In some cases, chloride and/or heavy metal toxicity may or may not be
problematic but should be sufficiently evaluated for this potential.
6.6 Retention of Environmentally Acceptable Beneficial Use Alternatives
Once appropriate assessments are complete, a determination of environmental
acceptability can be made. This determination must ensure that all applicable standards or
criteria are met. If control measures were considered, a determination of the effectiveness
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of the control measure in meeting the standards or criteria must be made. If all standards
or criteria are met, the beneficial use alternative can be considered environmentally
acceptable. At this point, other factors can be considered in the selection of an alternative
as discussed in paragraph 3.6 and Chapter 7.
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7.0 ALTERNATIVE SELECTION
Chapters 3 through 6 provide an objective framework for evaluating the
environmental acceptability of various management alternatives. In most cases, these
evaluations may result in one or more open-water, confined, or beneficial use alternatives
that clearly meet all applicable environmental standards and criteria and are, therefore,
environmentally acceptable. This chapter describes the alternative selection process. As
shown in Flowchart 3-1, the alternative selection process includes evaluation of socio-
economic, technical, management, and other environmental considerations, selection of a
preferred alternative, and appropriate environmental coordination and documentation.
7.1 Evaluation of Socioeconomic, Technical, and Other Applicable
Environmental Considerations
Over 30 major environmental statutes, Executive orders, and government
regulations exist that may, on a case-by-case basis, govern the manner in which dredged
material is managed and/or disposed. The major statutes are discussed in more detail in
Appendix B; however, procedures for meeting the requirements of these statutes are
beyond the scope of this document. While the intent of the statutes and this management
framework is to afford maximum environmental protection to each specific
environmental resource at potential risk, this must be pursued within the broader context
of overall environmental protection.
A final decision on the alternative or alternatives selected for a specific navigation
project or permit activity often requires weighing and balancing a much broader set of
relevant environmental, engineering, and economic factors. An in-depth discussion of
these broader decision-making principles is beyond the scope of this document, and the
reader is referred to applicable USAGE regulations (33 CFR 320-330; 33 CFR 335-338;
ER 1105-2-100) for further guidance and information on procedures used by the USAGE
in its required public interest analysis. However, several of these decision-making
concepts and considerations are particularly relevant to this document and to
considerations under NEPA, CWA, and MPRSA, and warrant a limited discussion.
7.1.1 Authorized Project Purposes
Navigation project status (i.e., new work or maintenance) may often influence the
range of available management alternatives for dredged material. For projects in the
planning stage (either new projects or projects undergoing reformulation studies),
USAGE policy is to maximize public benefits associated with the project. This is
accomplished through the development of a NED plan and is derived through an
incremental analysis of appropriate benefits versus costs. A wide range of potential
environmental benefits (e.g., beneficial use of dredged material, the environmentally
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preferred alternative(s)) may be pursued in such studies, assuming that they can be
incrementally justified, and, in turn, approved and authorized by Congress.
For existing projects requiring periodic maintenance, project benefits/purposes
have previously been established by Congress. With few exceptions, the USAGE cannot
unilaterally change or add to these project-specific purposes and benefits. As such,
USAGE policy is to maintain these established project purposes(s) and benefits in the
least-cost and environmentally acceptable manner. As discussed in Chapter 1, compliance
with the MPRSA Criteria and/or CWA Section 404(b)(l) Guidelines is a major factor in
arriving at a decision of "environmental acceptability."
7.1.2 Environmentally Preferred Alternative(s)
Technically, no one management option can be considered a panacea for dredged
material nor can it be ruled out a priori in project-specific evaluations other than for
sound economic, environmental, or engineering reasons. Thus, unless specifically
prohibited by Federal environmental statute, the intention of this document is to
encourage full and balanced consideration of all practicable alternatives for the
management of dredged material.
CEQ NEPA regulations (40 CFR 1505.2) require that the Record of Decision
(ROD) for an EIS specifically identify, where applicable, the alternative or alternatives
that were considered to be environmentally preferable. These regulations further require
the ROD to identify and discuss relevant economic and technical issues and agency
statutory missions, including any essential considerations of national policy that were
balanced by the agency in making its alternative(s) selection. All other factors being
equal, the environmentally preferable alternative should also be the
preferred/recommended alternative.
Unfortunately, hard and fast guidelines for identifying the alternative that is
preferable from an environmental standpoint would be difficult to develop and apply.
Such guidelines would require objective criteria or standards for comparing
environmental impacts and/or the value of resources in aquatic, upland, and wetland
environments. In some cases, such environmental impacts/benefits can be quantified
(e.g., impacts to commercially important shellfish beds). In many other cases, however,
the relative environmental costs of adverse impacts and the relative environmental value
of resources and environmental enhancements in various environments are largely
subjective.
Subjective comparison between alternatives found to be environmentally
acceptable is possible. Further, it is likely that one alternative would be clearly preferable
from an environmental standpoint. Environmental preferability may be based on lesser
adverse impacts or on greater environmental benefits, perhaps in the form of beneficial
use of dredged material. For example, if a clean sand is to be dredged, beach nourishment
is clearly an environmentally preferable alternative as compared with open-water or
confined disposal, assuming that there are beach nourishment needs. Or, if
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noncontaminated, fine-grained material is to be dredged, the creation of wetlands or other
beneficial use is clearly an environmentally preferable alternative as compared with
open-water or confined disposal, assuming that the beneficial use need is demonstrated.
Such comparisons will necessarily be qualitative even though many
characteristics of the dredged material and the disposal site are measured quantitatively.
The process depends heavily on professional judgment and subjective evaluation rather
than on strict adherence to numerical calculations.
7.1.3 Alternative Selection
In assessing suitable alternatives for dredged material disposal, both the MPRSA
and CWA specifically recognize that a balance must at times be struck between critical
navigation and environmental protection.
Section 404(b)(2) of the CWA requires appropriate balancing of established
environmental guidelines with the economic impacts, to navigation and anchorage of not
allowing the proposed disposal to proceed. The baseline for this analysis is that disposal
must not result in unacceptable adverse impact to the environment (Section 404(c)).
Section 103(b) of the MPRSA requires the USAGE to determine the need for
ocean disposal based on USEPA's established environmental criteria as well as on an
evaluation of the impact of permit denial on critical navigation and related economic
considerations. The baseline for this analysis is that the disposal must not result in
unreasonable environmental degradation or endangerment to human health (Section 103
(a)).
In practice, however, this level of decision making has generally been found to be
a "worst case" situation (i.e., the economic waiver provision of Section 103(d) of the
MPRSA has never been formally invoked). For Federal navigation projects, USAGE
standard policy is to select the least-cost, environmentally acceptable alternative.
Compliance with the MPRSA and/or CWA Section 404(b)(l) Guidelines is prerequisite
to a USAGE determination of an "environmentally acceptable" management alternative
for dredged material.
7.2 Environmental Coordination/Documentation/Recommended Alternative
The weighing and balancing of all environmental, technical, and economic factors
will result in selection of the preferred/proposed alternative by the lead agency.
Coordination and environmental documentation associated with alternative selection is
illustrated in Flowchart 3-1.
Documentation of this recommended plan occurs formally in either a draft NEPA
document (along with alternatives) or a Section 404 or 103 Public Notice. These
documents are available to the public and concerned agencies for review and comment.
In some instances, circulation of Public Notices and the NEPA document may occur
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simultaneously, although this is unusual. The draft NEPA document, as well as public
and agency comments used in making that selection, is circulated prior to the selection of
a recommended alternative. Specific evaluations of the 404(b)(l) Guidelines and the 103
Criteria must be made and are typically prepared as appendices to the NEPA document
and circulated concurrently. For construction projects, this process may take place
months or years before actual project construction begins. In such cases, another Public
Notice is often issued immediately prior to when the actual dredging and disposal are to
begin to ensure appropriate coordination.
USEPA's environmental review program is conducted pursuant to Section
102(2)(c) of NEPA and Section 309 of the Clean Air Act. These laws establish USEPA's
responsibility to review and comment upon the "environmental impact of any matter
relating to USEPA's duties and responsibilities." Under this authority, USEPA may
choose to review and comment on EISs, EAs, and other proposed Federal actions.
USEPA comments on NEPA documents are advisory, but by USAGE policy are given
great weight. In cases where USEPA and the USAGE cannot resolve differences, the
dispute may be referred by USEPA to CEQ.
Section 309 of the Clean Air Act also establishes that when the Administrator
determines that any legislation proposed by a federal agency, action or regulation falling
under the purview of the Administrator's review responsibilities is "unsatisfactory from
the standpoint of public health or welfare or environmental quality, he shall publish his
determination and the matter shall be referred to the Council on Environmental Quality."
Under CWA and MPRSA, Public Notices are the formal mechanism by which
USEPA concurs or does not concur with a recommended action, whether it is a proposed
permit or USAGE activity. In addition, under the CWA, a 404(q) elevation and/or a
404(c) veto of a permit may be undertaken by USEPA if differences between the
agencies cannot be resolved at an earlier stage. Under the MPRSA, if USEPA determines
that the Criteria are not met, the proposed action cannot proceed unless a waiver is
granted by USEPA.
NEPA review staff and CWA and/or MPRSA program staff are separate offices in
some USEPA regions; therefore, care should be taken to ensure that NEPA documents,
when prepared, are furnished to the appropriate program office for review as well as to
the NEPA review office. Within USEPA, NEPA reviewers and 404/103 staff also should
be coordinating closely. Often, the NEPA evaluation of the overall project may be
adequate, but program-specific information (e.g., sediment testing results and site
monitoring results) may need updating. Such updates may be accomplished by an EA and
Finding of No Significant Impact (FONSI) and/or by revision of the 404(b)(l) or 103
evaluation, rather than reopening the original EIS. It is recommended that these revisions
always be coordinated with USEPA.
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7.3 Final Decision Document
The completion of the NEPA process is documented in two ways depending upon
the determination of significance of impacts associated with the proposed activity. The
FONSI is prepared when an EA determines that preparation of an EIS is unnecessary.
The FONSI is the environmental decision document. In addition, a Statement of Findings
(SOF) is typically prepared upon completion of the evaluation process, including required
coordination, receipt or waiver of required certifications, and completion of appropriate
environmental documentation (e.g., the EA/FONSI and 404/103 evaluations). When an
EIS is prepared, a ROD is prepared which specifies the entire recommended action,
alternatives considered, and any comments that were received on the final EIS. The ROD,
not the final EIS, is the decision document. Typically the ROD is prepared in lieu of the
SOF, provided that the substantial parts of 33 CFR 337.6 are included in the ROD. These
documents are signed at various levels within the USAGE structure and allow the
USAGE to proceed with the proposed action. Preparation of the FONSI, ROD, and SOF
(if appropriate) typically occur after USEPA has provided comments on draft and/or final
documents. Copies of the FONSI and/or ROD should routinely be provided to the
USEPA NEPA review office as well as CWA/MPRSA program office.
The Public Notice also provides the formal opportunity for USEPA to exercise its
statutory environmental oversight under the CWA and MPRSA. Because of shared
enforcement responsibilities under the CWA and MPRSA between the USAGE and
USEPA, coordinating permit conditions or management restrictions is a good practice.
Each USAGE District and USEPA region should have acceptable arrangements and
practices that do not burden or delay the process.
65
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Streile, G. P., Shields, K. D., Stroh, J. L., Bagaasen, L. M., Whelan, G., McDonald, J. P.,
Droppo, J. G., and Buck, J. W. 1996. "Multimedia Environmental Pollutant Assessment
System (MEPAS): Source Term Formulations," PNL-11248, Pacific Northwest National
Laboratory, Richland, WA.
Tetra Tech, and Averett, D. 1994. "Options for Treatment and Disposal of
Contaminated Sediments from New York/ New Jersey Harbor," Miscellaneous Paper EL-
94-1, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.
Thibodeaux, L. J. 1989. "Theoretical Models for Evaluation of Volatile Emissions to
Air During Dredged Material Disposal with Applications to New Bedford Harbor,
Massachusetts," Miscellaneous Paper EL-89-3, U.S. Army Engineer Waterways
Experiment Station, Vicksburg, MS.
Truitt, C. L. 1987a. "Engineering Considerations for Subaqueous Dredged Material
Capping - Background and Preliminary Planning," Environmental Effects of Dredging
Technical Notes EEDP-01-3, U.S. Army Engineer Waterways Experiment Station,
Vicksburg, MS.
. 1987b. "Engineering Considerations for Subaqueous Dredged Material
Capping - Design Concepts and Placement Techniques," Environmental Effects of
Dredging Technical Notes EEDP-01-3, U.S. Army Engineer Waterways Experiment
Station, Vicksburg, MS.
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Turner, T. M. 1984. Fundamentals of Hydraulic Dredging. Council Maritime Press,
Centerville, MD.
U.S. Army Corps of Engineers (US ACE). 1983. "Dredging and Dredged Material
Disposal," Engineer Manual 1110-2-5025, Office, Chief of Engineers, Washington, DC.
. 1986. "Dredged Material Beneficial Uses," Engineer Manual 1110-2-
5026, Office, Chief of Engineers, Washington, DC.
. 1987. "Confined Disposal of Dredged Material," Engineer Manual 1110-
2-5027, Office, Chief of Engineers, Washington, DC.
. 2003. "Evaluation of Dredged Material Proposed for Disposal at Island,
Nearshore, or Upland Confined Disposal Facilities - Testing Manual," Technical Report
ERDC/EL TR-03-1, U.S. Army Engineer Research and Development Center, Vicksburg,
MS.
. In preparation. "Dredging and Dredged Material Management," Engineer
Manual 1110-2-XXXX, Office, Chief of Engineers, Washington, DC.
USAGE, Los Angeles District. 2002. "Los Angeles County Regional Dredged Material
Management Plan - Pilot Studies," Los Angeles District, Los Angeles, CA
USACE/U.S. Environmental Protection Agency (USEPA). 1984. "General Approach to
Designation Studies of Ocean Dredged Material Disposal Sites," U.S. Army Engineer
Water Resources Support Center, Ft. Belvoir, VA.
USEPA. 1986. "U.S. Environmental Protection Agency, Ocean Dumping Site
Designation Delegation Handbook," Office of Marine and Estuarine Protection,
Washington, DC.
. 1989. "Wetlands and 401 Certification, Opportunities and Guidelines for
States and Eligible Indian Tribes," Office of Water, U.S. Environmental Protection
Agency, Washington, DC.
. 1994. "Assessment and Remediation of Contaminated Sediments (ARCS)
Program - Remediation Guidance Document," EPA 905-R94-003, U.S. Environmental
Protection Agency, Great Lakes National Program Office, Chicago, IL.
. 1998. "Guidelines for Ecological Risk Assessment," EPA/630/R-95/002F,
Office of Research and Development, Washington, DC.
. 1999. "Fast Track Dredged Material Decontamination Demonstration for
the Port of New York and New Jersey," EPA 000-0-99000, U.S. Environmental
Protection Agency, Region 2.
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USEP A/US ACE. 1991. "Evaluation of Dredged Material Proposed for Ocean Disposal
(Testing Manual)," EPA-503/8-91/001, Office of Water, U.S. Environmental Protection
Agency, Washington, DC.
. 1995. "QA/QC Guidance for Sampling and Analysis of Sediments, Water,
and Tissues for Dredged Material Evaluations - Chemical Evaluations," EPA 823-B-95-
001, Office of Water, U.S. Environmental Protection Agency, Washington, DC.
. 1998. "Evaluation of Dredged Material Proposed for Discharge in Waters
of the U.S. - Testing manual," EPA-823 -B-98 -O04, Office of Water, U.S.
Environmental Protection Agency, Washington, D.C.
Winfield, L. E., and Lee, C. R. 1999. "Dredged Material Characterization Tests for
Beneficial Use Suitability," DOER Technical Notes Collection (TN DOER-C2), U.S.
Army Engineer Research and Development Center, Vicksburg, MS.
www.wes. army, mil/el/dots/doer
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APPENDIX A: GLOSSARY
Definitions of terms as they are used in this document are given below.
Aquatic environment
The geochemical environment in which dredged material is submerged under
water and remains water saturated after disposal is completed.
Aquatic ecosystem
Bodies of water, including wetlands, which serve as the habitat for interrelated
and interacting communities and populations of plants and animals.
Baseline
Belt of the seas measured from the line of ordinary low water along that portion
of the coast that is in direct contact with the open sea and the line marking the
seaward limit of inland waters (see Figure 1-1 in the main text).
Beneficial uses
Placement or use of dredged material for some productive purpose. Beneficial
uses may involve either the dredged material or the placement site as the integral
component of the beneficial use.
Bioaccumulation
The accumulation of contaminants in the tissues of organisms through any route,
including respiration, ingestion, or direct contact with contaminated water,
sediment, or dredged material.
Capping
The controlled, accurate placement of contaminated material at an open-water
site, followed by a covering or cap of clean isolating material.
Coastal zone
Includes coastal waters and the adjacent shorelands designated by a State as being
included within its approved coastal zone management program. The coastal zone
may include open waters, estuaries, bays, inlets, lagoons, marshes, swamps,
mangroves, beaches, dunes, bluffs, and coastal uplands. Coastal-zone uses can
include housing, recreation, wildlife habitat, resource extraction, fishing,
aquaculture, transportation, energy generation, commercial development, and
waste disposal.
Confined disposal
Placement of dredged material within diked nearshore or upland confined disposal
facilities (CDFs) that enclose the disposal area above any adjacent water surface,
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isolating the dredged material from adjacent waters during placement. Confined
disposal does not refer to subaqueous capping or contained aquatic disposal.
Confined disposal facility (CDF)
An engineered structure for containment of dredged material consisting of dikes
or other structures that enclose a disposal area above any adjacent water surface,
isolating the dredged material from adjacent waters during placement. Other
terms used for CDFs that appear in the literature include "confined disposal area,"
"confined disposal site," and "dredged material containment area."
Contained aquatic disposal
A form of capping which includes the added provision of some form of lateral
containment (for example, placement of the contaminated and capping materials
in bottom depressions or behind subaqueous berms) to minimize spread of the
materials on the bottom.
Contaminant
A chemical or biological substance in a form that can be incorporated into, onto,
or be ingested by and that harms aquatic organisms, consumers of aquatic
organisms, or users of the aquatic environment.
Contaminated sediment or contaminated dredged material
Contaminated sediments or contaminated dredged materials are defined as those
that have been demonstrated to cause an unacceptable adverse effect on human
health or the environment.
Control measure
See Management action.
Disposal site or area
A precise geographical area within which disposal of dredged material occurs.
Dredged material
Material excavated from waters of the United States or ocean waters. The term
dredged material refers to material which has been dredged from a water body,
while the term sediment refers to material in a water body prior to the dredging
process.
Dredged material discharge
The term dredged material discharge as used in this document means any addition
of dredged material into waters of the United States or ocean waters. The term
includes open- water discharges; discharges resulting from unconfined disposal
operations (such as beach nourishment or other beneficial uses); discharges from
confined disposal facilities that enter waters of the United States (such as effluent,
surface runoff, or leachate); and overflow from dredge hoppers, scows, or other
transport vessels.
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Effluent
Water that is discharged from a confined disposal facility during and as a result of
the filling or placement of dredged material.
Emergency
In the context of dredging operations, emergency is defined in 33 CFR Part 335.7
as a "situation which would result in an unacceptable hazard to life or navigation,
a significant loss of property, or an immediate and unforeseen significant
economic hardship if corrective action is not taken within a time period of less
than the normal time needed under standard procedures."
Federal project
Herein, any work or activity of any nature and for any purpose that is to be
performed by or for the Secretary of the Army acting through the Chief of
Engineers pursuant to Congressional authorizations. It does not include work
requested by any other Federal agency on a cost reimbursable basis.
Federal standard
The dredged material disposal alternative or alternatives identified by the U.S.
Army Corps of Engineers that represent the least costly alternatives consistent
with sound engineering practices and meet the environmental standards
established by the 404(b)(l) evaluation process or ocean-dumping criteria (33
CFR 335.7).
Habitat
The specific area or environment in which a particular type of plant or animal
lives. An organism's habitat provides all of the basic requirements for the
maintenance of life. Typical coastal habitats include beaches, marshes, rocky
shores, bottom sediments, mudflats, and the water itself.
Leachate
Water or any other liquid that may contain dissolved (leached) soluble materials,
such as organic salts and mineral salts, derived from a solid material. For
example, rainwater that percolates through a confined disposal facility and picks
up dissolved contaminants is considered leachate.
Level bottom capping
A form of capping in which the contaminated material is placed on the bottom in
a mounded configuration.
Local sponsor
sponsor
A public entity (e.g., port district) that sponsors Federal navigation projects. The
sponsor seeks to acquire or hold permits and approvals for disposal of dredged
material at a disposal site (USACE 1986).7
7 References cited in this appendix are included in the References at the end of the main text.
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Major federal action
Includes actions with effects that may be major and that are potentially subject to
Federal control and responsibility. Major refers to the context (meaning that the
action must be analyzed in several contexts, such as the effects on the
environment, society, regions, interests, and locality) and intensity (meaning the
severity of the impact). It can include.(a) new and continuing activities, projects,
and programs entirely or partly financed, assisted, conducted, regulated, or
approved by Federal agencies; (b) new or revised agency rules, regulations, plans,
policies, or procedures; and (c) legislative proposals. Action does not include
funding assistance solely in the form of general revenue-sharing funds where
there is no Federal agency control over the subsequent use of such funds. Action
does not include judicial or administrative civil or criminal enforcement action.
Management action
Those actions or measures that may be considered necessary to control or reduce
the potential physical or chemical effects of dredged material disposal.
Mitigation
Defined in the Council on Environmental Quality's regulation 40 CFR 1508.20
(a-e).
Open-water disposal
Placement of dredged material in rivers, lakes, estuaries, or oceans via pipeline or
surface release from hopper dredges or barges.
Record of decision
A comprehensive summary required by National Environmental Policy Act that
discusses the factors leading to U.S. Army Corps of Engineers (USAGE)
decisions on regulatory and Civil Works matters and is signed by the USAGE
District Engineer after completion of appropriate environmental analysis and
public involvement.
Regulations
In the context of the Marine Protection, Research, and Sanctuaries Act, means
those regulations published in the Code of Federal Regulations, Title 40, Parts
220-227, and Title 33, Parts 209, 320-330, and 335-338 for evaluating proposals
for dumping dredged material in the ocean. In the context of the Clean Water Act,
refers to regulations published in the Code of Federal Regulations, Title 40, Parts
230, 231, and 233, and Title 33, Parts 209, 320-330, and 335-338 for evaluating
proposals for the discharge of dredged material into waters falling under the
jurisdiction of the Clean Water Act.
Runoff
The liquid fraction of dredged material or the surface flow caused by precipitation
on upland or nearshore dredged material disposal sites.
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Sediment
Material, such as sand, silt, or clay, suspended in or settled on the bottom of a
water body. Sediment input to a body of water comes from natural sources, such
as erosion of soils and weathering of rock, or as the result of anthropogenic
activities, such as forest or agricultural practices, or construction activities. The
term dredged material refers to material which has been dredged from a water
body, while the term sediment refers to material in a water body prior to the
dredging process.
Suspended solids
Organic or inorganic particles that are suspended in water. The term includes
sand, silt, and clay particles as well as other solids, such as biological material,
suspended in the water column.
Territorial sea
The strip of water immediately adjacent to the coast of a nation measured from
the baseline as determined in accordance with the Convention on the territorial
sea and the contiguous zone (15 UST 1606; TIAS 5639), and extending a distance
of 3 nmi from the baseline.
Toxicity
Level of mortality or other end point demonstrated by a group of organisms that
has been affected by the properties of a substance, such as contaminated water,
sediment, or dredged material.
Toxic pollutant
Pollutants, or combinations of pollutants, including disease-causing agents, that
after discharge and upon exposure, ingestion, inhalation, or assimilation into any
organism, either directly from the environment or indirectly by ingestion through
food chains, will, on the basis of information available to the Administrator of the
U.S. Environmental Protection Agency, cause death, disease, behavioral
abnormalities, cancer, genetic mutations, physiological malfunctions, or physical
deformations in such organisms or their offspring.
Turbidity
An optical measure of the amount of material suspended in the water. Increasing
the turbidity of the water decreases the amount of light that penetrates the water
column. Very high levels of turbidity can be harmful to aquatic life (USAGE
1986).
Upland environment
The geochemical environment in which dredged material may become
unsaturated, dried out, and oxidized.
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Wetlands
Areas that are inundated or saturated by surface or groundwater at a frequency
and duration sufficient to support and that, under normal circumstances, do
support a prevalence of vegetation typically adapted for life in saturated-soil
conditions. Wetlands generally include swamps, marshes, bogs, and similar areas
(40 CFR Part 230).
Wetlands restoration
Involves either improving the condition of existing degraded wetlands so that the
functions that they provide are of a higher quality or reestablishing wetlands
where they formerly existed before they were drained or otherwise converted.
Zoning
To designate, by ordinances, areas of land reserved and regulated for specific land
uses.
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APPENDIX B: FEDERAL LEGISLATION AND
PROGRAMS
AN OVERVIEW OF THE LEGAL AND
POLICY FRAMEWORK
A number of Federal environmental Executive orders, regulations, and Federal
statutes control dredging and disposal operations. The General Survey Act of 1824
directed the U.S. Army Corps of Engineers (USAGE) to develop and improve harbors
and navigation, and Section 10 of the River and Harbor Act of 1899 required USAGE to
issue permits for any work in navigable waters. Dredging and disposal operations were
considered more fully by Congress in the major environmental statutes passed after 1969.
A brief discussion of these follows.
NATIONAL ENVIRONMENTAL POLICY ACT (NEPA) OF 1969
TheNEPA [(Pub. L. No. 91-190) (42 U. S. C. 4321 et seq.)] applies to major
Federal actions (e.g., proposals, permits, and legislation) that may significantly affect the
environment. USAGE activities in the areas of dredging and disposal, including
regulatory actions, come under the NEPA jurisdiction. It is through the NEPA process
that the dredged material disposal alternatives including no action, open-water disposal,
or confined disposal of dredged material are evaluated, documented, and publicly
disclosed.
A flowchart illustrating the NEPA process as it is applied to dredging projects is
shown in Flowchart B-l. The components of this process have been incorporated in the
framework for determining environmental acceptability of alternatives described in
Chapter 3 of the main text.
The NEPA requires that government use all practicable means, consistent with the
act and other essential considerations of national policy, to fulfill the requirements of the
act. This requirement specifically applies to Federal agencies, their plans, regulations,
programs, and facilities. The process that has been established under the guidelines of the
NEPA helps public officials to make decisions based on an understanding of their
environmental consequences and to take actions that protect, restore, and enhance the
environment. The public disclosure document in this process is the preparation of a report
that provides information about the environmental impact of a proposed action. This
document is either an Environmental Impact Statement (EIS) or an Environmental
Assessment (EA)/ Finding of No Significant Impact (FONSI).
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NEPA/MPRSA/CWA COMPLIANCE PROCESS FOR
DREDGING AND DISPOSAL PROJECTS
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PUBLIC NOTICE
IF AT ANY TIME IN THE EA PROCESS, THE
FEDERAL ACTION IS REASSESSED AS BEING
SIGNIFICANT, EIS SCOPING IS INTIATED.
EA -ENVIRONMENTALASSESSMENT
EIS/SEIS - ENVIRONMENTAL IMPACT STATEMENT/SUPPLEMENT
FONSI < FINDING OF NO SIGNIFICANT IMPACT
ROD - RECORD OF DECISION
Flowchart B-1. NEPA Process for Dredged Material Disposal Projects
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Existing Federal navigation projects and existing permits will have had an
environmental evaluation accomplished at some time in their history. Evaluation of
environmental acceptability of an alternative will have been done in the NEPA
compliance documents, in the Section 404 or Section 103 evaluations and the Public
Notice, and to some extent in the engineering or project reports. Existing project and
permit reevaluations will normally require a comparison of what is to be done with the
existing NEPA document discussed. If the alternative is to remain the same or was
discussed in detail in the NEPA document and there is no reason to believe any new
significant issues or information have raised since the issuance of the NEPA document,
then no additional NEPA coverage is warranted.
If, however, new significant issues such as new disposal options not addressed in
the EIS/EA, public interest concerns, or reason to believe significant new contaminants
are present, then NEPA requirements should be updated with either an EA/FONSI or a
supplement to the existing EIS. In either of the above cases whether additional NEPA
documentation is required or not, all other environmental laws and regulations must be
followed (see Appendix A for a discussion of necessary compliance). This is either done
in the compliance and coordination section of the EA/EIS or in the Section 404 or
Section 103 evaluations. If the former is done, the 404/103 evaluation should be\
appended to and discussed in the NEPA document. In either case, there is full public
disclosure of the information in the public review process for NEPA or in the Public
Notice for the 404/103 evaluation process and an opportunity for public comment prior to
selection of the preferred alternative.
Federal navigation projects involving new work (i.e., new channels or
improvements to existing channels) and new 404/103 permit applications will normally
not have complied with NEPA, and will require compliance with the Council on
Environmental Quality regulations for implementing NEPA. This will be initiated as
early in the evaluation process as possible. For a more detail discussion of the USAGE
regulations implementing NEPA, refer to 33 Code of Federal Regulations (CFR) Parts
230 and 325.
IMPLEMENTING REGULATIONS OF THE COUNCIL ON
ENVIRONMENTAL QUALITY (CEQ)
Subchapter II of the NEPA established the CEQ as part of the Executive Office of
the President. Exercising its mandate to oversee the implementation of the NEPA, in
1978 the CEQ issued regulations (40 CFR Parts 1500-1508) covering the procedural
provisions of the Act. The regulations state that the NEPA procedures are designed to
ensure that high-quality information on environmental consequences relative to
significant issues is available to public officials and private citizens before decisions are
made.
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FEDERAL WATER POLLUTION CONTROL ACT-1972 AND 1977 (CWA)
Under Section 404 of the CWA, USAGE authorizes discharges of dredged or fill
material in "waters of the United States." The USAGE jurisdiction includes most
freshwater areas, estuaries, and nearshore coastal areas including many wetlands inside
the 3-mile limit. Material dredged from waters of the United States and disposed in the
territorial sea is evaluated under MPRSA. In general, dredged material discharged as fill
(e.g., beach nourishment, island creation, or underwater berms) and placed within the
territorial sea is evaluated under the CWA.
The States also review permit applications for discharges in fresh water, estuaries,
and the territorial sea (along with Federal resource agencies). Under Section 401 of
CWA, these disposal operations must be certified by the affected State as complying with
applicable State water quality standards (USEPA 1989).8
MARINE PROTECTION, RESEARCH, AND SANCTUARIES ACT (MPRSA)
OF 1972
Under Section 103 of the MPRSA, USAGE must evaluate proposed projects that
require the transportation of dredged material for the purpose of disposal in the open
ocean beyond the baseline. The evaluation of these activities is based on Criteria
promulgated in 1977 by the U.S. Environmental Protection Agency (USEPA) after
consultation with USAGE and other Federal agencies. These Criteria are revised from
time to time to maintain compatibility with disposal constraints set forth in the London
Dumping Convention to which the United States is a signatory. Non-Corps Federal
projects and private projects that are approved receive an ocean-dumping permit from
USAGE. USAGE projects are evaluated in accordance with the same Criteria, but they do
not receive formal permits. If a permit does not comply with established Criteria, disposal
of the material cannot proceed unless a waiver is obtained from USEPA.
The USEPA has the primary responsibility for designating ocean-disposal sites
within and beyond the 3-mile limit, i.e., within and beyond the territorial sea. USAGE
can and has selected a few ocean- disposal sites, as in the Portland and Mobile Districts,
when USEPA does not have a designated site where one is needed by USAGE to carry
out its dredging responsibilities.
LONDON DUMPING CONVENTION (1972)
The London Dumping Convention (LDC) [Convention on the Prevention of
Marine Pollution by Dumping of Waste and Other Matter, December 29, 1972 (26 UST
2403:TIAS 8165)], to which the United States is a signatory, is an international treaty that
deals with marine-waste disposal. The Convention entered into force for the United
States on August 30, 1975. The LDC prescribes a duty to "take all practicable steps" to
prevent pollution resulting from ocean dumping. The dumping of wastes is regulated by
8 For purposes of this report Criteria (capitalized) refers to criteria developed by the Environmental
Protection Agency under Section 102 of MPRSA relating to the effects of the proposed disposal action.
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three annexes to the LDC. LDC jurisdiction includes all waters seaward of the baseline of
the territorial sea. The ocean-dumping Criteria developed under the MPRSA are required
by Section 102(a) to "apply the standards and criteria binding upon the United States
under the Convention, including its Annexes." These criteria must, at a minimum, reflect
the standards set forth by LDC. Therefore, the LDC places environmental constraints
upon the ocean disposal of dredged material and directly affects the policy, regulatory,
and technical aspects of the dredged material ocean-disposal program.
ADDITIONAL APPLICABLE FEDERAL LEGISLATION
COASTAL ZONE MANAGEMENT ACT
The Coastal Zone Management Act requires USAGE to coordinate permit review
and Federal projects with all State level coastal zone review agencies. Under this act,
coastal States are required to formulate a management program for the land and water
resources of its coastal zone, which extends out to the seaward limit of the territorial sea,
and submit it for approval to the Secretary of Commerce. After final approval by the
Secretary of Commerce of a State's management program, any applicant for a Federal
permit must have certification that the proposed disposal complies with the State's
approved program.
RIVERS AND HARBORS ACT OF 1899
The Rivers and Harbors Act of 1899 requires a USAGE permit for any work or
structure, including fill material discharges, in navigable waters of the United States. The
primary purpose of Section 10 is to ensure that private structures do not adversely affect
Federal interstate navigation. It empowers USAGE to review applications and issue
approved construction permits for dredging and fill projects for any structure in the water
(e.g., piers, pipelines, and bridges).
FISH AND WILDLIFE COORDINATION ACT OF 1958
The Fish and Wildlife Coordination Act of 1958 provides that, for any proposed
Federal project or permit that may affect a stream or other body of water, USAGE must
first consult with Federal and State fish and wildlife agencies. This consultation must
address the prevention of damages to wildlife resources and provide for the development
and improvement of wildlife resources.
ENDANGERED SPECIES ACT OF 1973
Section 7 of the Endangered Species Act of 1973 establishes a consultation
process between Federal agencies and the Secretaries of the Interior or Commerce for
conducting programs for the conservation and protection of endangered species. Pursuant
to this act, a biological assessment is performed to determine whether an endangered
species or a critical habitat will be impacted by a proposed action.
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WATER RESOURCES DEVELOPMENT ACT OF 1986
The passage of the Water Resources Development Act of 1986 created a
financing arrangement for dredging associated with navigation improvement and
maintenance projects. In a cost-sharing program between the local sponsors and USAGE,
local sponsors will finance one-half the cost of improvements and one-half the cost for
additional maintenance dredging resulting from the improvements. USAGE will finance
the other half of these costs. This tremendous amount of work, in addition to the annual
USAGE maintenance dredging requirements, the Navy's annual maintenance work, and
private dredging requirements, will have a significant impact on dredging and dredged
material disposal practices.
NATIONAL HISTORIC PRESERVATION ACT OF 1966
USAGE is directed to take into account the effects of the proposed project on any
site, building, structure, or object that is included or is eligible for inclusion in the
National Register of Historic Places. Comments from the Advisory Council on Historic
Preservation, both Federal and State, must be sought prior to granting a permit for
construction or disposal. Local historical and archeological societies may also be useful
sources of this kind of information about the site. Magnetometer surveys to locate any
possible objects of historic value under water may be required prior to the preparation of
an EIS.
OTHER FEDERAL STATUTES
Requirements of additional Federal statutes such as the Comprehensive
Environmental Response, Compensation, and Liability Act of 1980, Rivers and Harbors
Improvement Act of 1978, Submerged Lands Act of 1953, Rivers and Harbors, Flood
Control Acts of 1970, the National Fishing Enhancement Act of 1984, as amended,
should also be considered in the evaluation of proposed projects, as these requirements
may influence the disposal of dredged material in certain circumstances.
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