DRAFT

ENVIRONMENTAL IMPACT STATEMENT

DESIGNATION OF THE ATCHAFALAYA RIVER BAR CHANNEL

OCEAN DREDGED MATERIAL DISPOSAL SITE

PURSUANT TO SECTION 102(c) OF THE MARINE PROTECTION, 

RESEARCH, AND SANCTUARIES ACT OF 1972

ST. MARY PARISH, LOUISIANA

Prepared by: 

U.S. Environmental Protection Agency 

Region 6 

1445 Ross Avenue 

Dallas, Texas 75202-2733 

In Cooperation with: 

U.S. Army Corps of Engineers

New Orleans District

Regional Planning and Environmental Division South 

7400 Leake Avenue 

New Orleans, Louisiana 70118-3651 

March 2013 
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Contents Page

Contents ..........................................................................................................................................................iii 

List of Figures..................................................................................................................................................xi

List of Tables ..................................................................................................................................................xi

Acronyms and Abbreviations .........................................................................................................................xii

EXECUTIVE SUMMARY......................................................................................................................... ...1 

1.0 INTRODUCTION.............................................................................................................................18 

1.1 PURPOSE AND NEED FOR THE PROPOSED ACTION.....................................................19

1.2 DESCRIPTION OF THE PROPOSED ACTION....................................................................20

1.3 PRIOR REPORTS AND PROJECTS......................................................................................22 

1.4 AUTHORITY FOR THE PROPOSED ACTION....................................................................23 

1.5 U.S. ARMY CORPS OF ENGINEERS....................................................................................24 

1.6 U.S. ENVIRONMENTAL PROTECTION AGENCY.............................................................24

1.7 COASTAL ZONE MANAGEMENT ACT..............................................................................25 

2.0 ALTERNATIVES..............................................................................................................................26 

2.1 NO-ACTION ALTERNATIVE.................................................................................................28 

2.2 SITE ALTERNATIVES...........................................................................................................29

2.2.1 Beneficial Use .....................................................................................................29 

2.2.1.1 Beach Nourishment ........................................................................31 

2.2.1.2 Marsh Creation...............................................................................32 

2.2.1.3 Island Creation – Single Point Unconfined

Discharge........................................................................................33 

2.2.1.4 Island Creation – Single Point Confined Discharge .......................33 

2.2.2 Screening Process for Ocean Placement Sites.....................................................34 

2.3 DEVELOPMENT OF ALTERNATIVE SITES USING THE SCREENING

TECHNIQUE – PHASE I ........................................................................................................35 

2.3.1 Ocean Placement Alternative Sites .....................................................................35

2.3.1.1 Nearshore Alternative Site 1 ..........................................................36 

2.3.1.2 Nearshore Alternative Site – ODMDS-West..................................36 

2.3.1.3 Mid-Shelf Alternative Site..............................................................37 

2.3.1.4 Deepwater Alternative Site............................................................38 

2.3.2 Zone of Siting Feasibility.....................................................................................39
iv

2.3.2.1 Limits Due to Cost of Transport ....................................................39 

2.3.2.2 Limits Due to Feasibility of Monitoring and

Surveillance .....................................................................................40 

2.3.2.3 Limits Due to Political Boundaries ................................................40 

2.3.2.4 Conclusion.....................................................................................41 

2.3.3 Characterization of Material and Site Sizing ......................................................41 

2.3.3.1 Characterization of the Materials Expected to Be

Dredged ..........................................................................................41 

2.3.3.1.1 Sediment Quality ............................................................42 

2.3.3.1.2 Water Quality .................................................................45 

2.3.3.2 Characterization of ODMDS-West ................................................48 

2.3.3.3 ODMDS Size Determination..........................................................48 

2.3.4 Establishment of Buffer Zones ...........................................................................49

2.3.4.1 Buffer Zone Assignment ................................................................49 

2.3.4.1.1 Biologically Sensitive Areas ...........................................49 

2.3.4.1.2 Beaches and Recreational Areas ....................................49 

2.3.4.1.3 Navigation Channel.........................................................49 

2.3.5 Results of Phase I Evaluation............................................................................ 49 

2.4 EVALUATION OF ELEVEN SPECIFIC CRITERIA – PHASE II.......................................50 

2.4.1 40 CFR 228.6(a) (#1) .........................................................................................50 

2.4.2 40 CFR 228.6(a) (#2) .........................................................................................51 

2.4.3 40 CFR 228.6(a) (#3)..........................................................................................52 

2.4.4 40 CFR 228.6(a) (#4) .........................................................................................52 

2.4.5 40 CFR 228.6(a) (#5)......................................................................................... 52 

2.4.6 40 CFR 228.6(a) (#6) ........................................................................................ 53 

2.4.7 40 CFR 228.6(a) (#7) .........................................................................................54 

2.4.8 40 CFR 228.6(a) (#8).........................................................................................55 

2.4.9 40 CFR 228.6(a) (#9) .........................................................................................57 

2.4.10 40 CFR 228.6(a) (#10).......................................................................................58

2.4.11 40 CFR 228.6(a) (#11).......................................................................................58

2.5 FINAL EVALUATION AND SITE SELECTION — PHASE III ........................................58

2.5.1 Five General Criteria...........................................................................................59 

2.5.1.1 40 CFR 228.5(a) (#1)....................................................................59 

2.5.1.2 40 CFR 228.5(b) (#2)....................................................................59 
v

2.5.1.3 40 CFR 228.5(c) (#3)....................................................................60 

2.5.1.4 40 CFR 228.5(d) (#4) ...................................................................60 

2.5.1.5 40 CFR 228.5(e) (#5) ...................................................................60 

2.6 IDENTIFICATION OF THE PREFERRED ALTERNATIVE .............................................61 

2.6.1 Evaluation of Constraints ...................................................................................61

2.6.1.1 Oceanographic Constraints...........................................................61 

2.6.1.2 Cultural and/or Historic Constraints ............................................61 

2.6.1.3 Nonliving Resources Constraints .................................................61 

2.6.1.4 Living Resources Constraints ......................................................62 

2.6.1.5 Environmental Quality Constraints..............................................62

2.6.1.6 Recreational Uses Constraints .....................................................62

2.6.2 Preferred Alternative..........................................................................................63 

3.0 AFFECTED ENVIRONMENT ....................................................................................................64

3.1 PHYSICAL ENVIRONMENT................................................................................................64 

3.1.1 Climate and Meteorology................................................................................... 64 

3.1.2 Air Quality .........................................................................................................64 

3.1.3 Oceanography.....................................................................................................66 

3.1.3.1 Water Masses ...............................................................................66

3.1.3.2 Circulation and Currents...............................................................68 

3.1.3.3 Waves and Tides...........................................................................69

3.1.3.4 Bathymetry.....................................................................................70 

3.1.4 Water Quality....................................................................................................71 

3.1.4.1 Temperature...................................................................................73

3.1.4.2 Salinity ..........................................................................................73

3.1.4.3 Dissolved Oxygen .........................................................................74 

3.1.4.4 pH...................................................................................................75 

3.1.4.5 Nutrients.........................................................................................75 

3.1.4.6 Turbidity and Suspended Solids....................................................75 

3.1.4.7 Trace Metals..................................................................................76 

3.1.4.8 Organic Compounds......................................................................77 

3.1.5 Sediments.............................................................................................................77

3.1.5.1 Sediment Quality and Characteristics ...........................................77 

3.1.5.1.1 Sediment Quality. .......................................................77 
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3.1.5.1.2 Sediment Characteristics.............................................79 

3.1.5.2 Sediment Transport ......................................................................80 

3.1.5.3 Hazardous, Toxic, or Reactive Wastes ........................................82

3.1.5.4 Oil and Gas....................................................................................83 

3.2 BIOLOGICAL ENVIRONMENT.... ......................................................................................84

3.2.1 Plankton .............................................................................................................84 

3.2.1.1 Phytoplankton................................................................................84 

3.2.1.2 Zooplankton ..................................................................................84

3.2.2 Benthos ..............................................................................................................84 

3.2.3 Finfish and Shellfish...........................................................................................85 

3.2.4 Essential Fish Habitat ........................................................................................86 

3.2.5 Mammals, Reptiles and Birds ............................................................................87 

3.2.6 Threatened and Endangered Species..................................................................88 

3.2.7 Marine Sanctuaries and Special Biological Resource Areas .............................91 

3.3 SOCIOECONOMIC ENVIRONMENT..................................................................................91

3.3.1 Demography and Economics .............................................................................92 

3.3.1.1 St. Mary Parish..............................................................................92

3.3.1.2 Terrebonne Parish .........................................................................93

3.3.2 Industry...............................................................................................................93 

3.3.2.1 St. Mary Parish..............................................................................93

3.3.2.2 Terrebonne Parish .........................................................................94

3.3.3 Employment........................................................................................................95 

3.3.3.1 St. Mary Parish..............................................................................95 

3.3.3.2 Terrebonne Parish .........................................................................95

3.3.4 Environmental Justice.........................................................................................96 

3.3.5 Recreation.......................................................................................................96 

3.3.6 Cultural and Historic Resources.........................................................................96 

3.3.7 Aesthetics (Visual Resources)........................................................................98 

3.3.8 Military Restrictions ..........................................................................................99 

4.0 ENVIRONMENTAL CHARACTERIZATION OF NO-ACTION AND PROPOSED

ALTERNATIVES.............................................................................................................................100 

4.1 PHYSICAL ENVIRONMENT ...............................................................................................100

4.1.1 Climate and Meteorology....................................................................................100
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4.1.1.1 No-Action Alternative ...................................................................100

4.1.1.2 Proposed ODMDS-West Alternative............................................100 

4.1.2 Air Quality...........................................................................................................101

4.1.2.1 No-Action Alternative....................................................................101

4.1.2.2 Proposed ODMDS-West Alternative ...........................................101 

4.1.3 Oceanography .....................................................................................................102

4.1.3.1 No-Action Alternative ...................................................................102

4.1.3.2 Proposed ODMDS-West Alternative............................................102 

4.1.4 Water Quality.....................................................................................................103 

4.1.4.1 Temperature ...................................................................................103

4.1.4.1.1 No-Action Alternative...............................................103

4.1.4.1.2 Proposed ODMDS-West Alternative........................103 

4.1.4.2 Salinity ..........................................................................................104

4.1.4.2.1 No-Action Alternative...............................................104

4.1.4.2.2 Proposed ODMDS-West Alternative.......................104 

4.1.4.3 Dissolved Oxygen.........................................................................104 

4.1.4.3.1 No-Action Alternative...............................................104

4.1.4.3.2 Proposed ODMDS-West Alternative.......................104 

4.1.4.4 pH..................................................................................................105

4.1.4.4.1 No-Action Alternative..............................................105

4.1.4.4.2 Proposed ODMDS-West Alternative.......................105 

4.1.4.5 Nutrients .......................................................................................105 

4.1.4.5.1 No-Action Alternative.............................................105

4.1.4.5.2 Proposed ODMDS-West Alternative.......................106 

4.1.4.6 Turbidity/Suspended Solids..........................................................106 

4.1.4.6.1 No-Action Alternative..............................................106

4.1.4.6.2 Proposed ODMDS-West Alternative .....................106 

4.1.4.7 Trace Metals .................................................................................106

4.1.4.7.1 No-Action Alternative.............................................106

4.1.4.7.2 Proposed ODMDS-West Alternative ......................107 

4.1.4.8 Organic Compounds......................................................................107

4.1.4.8.1 No-Action Alternative..............................................107

4.1.4.8.2 Proposed ODMDS-West Alternative......................107 

4.1.5 Sediments..........................................................................................................108 
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4.1.5.1 Sediment Quality and Characteristics...........................................108 

4.1.5.1.1 No-Action Alternative..............................................108

4.1.5.1.2 Proposed ODMDS-West Alternative ......................109 

4.1.5.2 Sediment Transport.......................................................................109 

4.1.5.2.1 No-Action Alternative..............................................109

4.1.5.2.2 Proposed ODMDS-West Alternative.......................110 

4.1.5.3 Hazardous, Toxic, or Radioactive Wastes ....................................110

4.1.5.3.1 No-Action Alternative..............................................110

4.1.5.3.2 Proposed ODMDS-West Alternative......................110 

4.1.5.4 Oil and Gas ..................................................................................110

4.1.5.4.1 No-Action Alternative..............................................110

4.1.5.4.2 Proposed ODMDS-West Alternative ......................111 

4.2 BIOLOGICAL ENVIRONMENT.........................................................................................111

4.2.1 Plankton ............................................................................................................111 

4.2.1.1 No-Action Alternative .................................................................111

4.2.1.2 Proposed ODMDS-West Alternative...........................................111 

4.2.2 Benthos ..............................................................................................................112 

4.2.2.1 No-Action Alternative...................................................................112

4.2.2.2 Proposed ODMDS-West Alternative...........................................113

4.2.3 Finfish and Shellfish .........................................................................................114 

4.2.3.1 No-Action Alternative...................................................................114

4.2.3.2 Proposed ODMDS-West Alternative...........................................115

4.2.4 Essential Fish Habitat .......................................................................................115 

4.2.4.1 No-Action Alternative...................................................................115

4.2.4.2 Proposed ODMDS-West Alternative............................................116

4.2.5 Mammals, Reptiles, and Birds ..........................................................................116 

4.2.5.1 No-Action Alternative ..................................................................116

4.2.5.2 Proposed ODMDS-West Alternative............................................116

4.2.6 Threatened and Endangered Species .................................................................117

4.2.6.1 No-Action Alternative ..................................................................117

4.2.6.2 Proposed ODMDS-West Alternative............................................117 

4.2.7 Marine Sanctuaries and Special Biological Resource Areas..............................117

4.2.7.1 No-Action Alternative ..................................................................117 

4.2.7.2 Proposed ODMDS-West Alternative............................................118
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4.3 SOCIOECONOMIC ENVIRONMENT.................................................................................118

4.3.1 Demography and Economics ............................................................................118 

4.3.1.1 No-Action Alternative ..................................................................118

4.3.1.2 Proposed ODMDS-West Alternative ...........................................118

4.3.2 Industry ..............................................................................................................118 

4.3.2.1 No-Action Alternative...................................................................118

4.3.2.2 Proposed ODMDS-West Alternative ...........................................119

4.3.3 Employment ......................................................................................................119 

4.3.3.1 No-Action Alternative...................................................................119

4.3.3.2 Proposed ODMDS-West Alternative...........................................120

4.3.4 Environmental Justice.......................................................................................120 

4.3.4.1 No-Action Alternative...................................................................120

4.3.4.2 Proposed ODMDS-West Alternative...........................................120

4.3.5 Recreation.......................................................................................................120 

4.3.5.1 No-Action Alternative...................................................................120

4.3.5.2 Proposed ODMDS-West Alternative...........................................121

4.3.6 Cultural and Historic Resources ........................................................................121

4.3.6.1 No-Action Alternative...................................................................121

4.3.6.2 Proposed ODMDS-West Alternative...........................................121

4.3.7 Aesthetics (Visual Resources).......................................................................122

4.3.7.1 No-Action Alternative...................................................................122

4.3.7.2 Proposed ODMDS-West Alternative...........................................122

4.4 CUMULATIVE IMPACTS ...................................................................................................122

4.5 ADVERSE ENVIRONMENTAL IMPACTS WHICH CANNOT BE AVOIDED...............124

4.6 THE RELATIONSHIP BETWEEN LOCAL SHORT-TERM USES OF THE

ENVIRONMENT AND THE MAINTENANCE AND ENHANCEMENT OF

LONG-TERM PRODUCTIVITY ..........................................................................................124 

4.7 ANY REVERSIBLE OR IRRETRIEVABLE COMMITMENT OF

RESOURCES..........................................................................................................................124

4.8 ENERGY AND NATURAL OR DEPLETABLE RESOURCES

REQUIREMENTS AND CONSERVATION POTENTIAL OF VARIOUS

ALTERNATIVES AND MITIGATION MEASURES..........................................................125

4.9 COMPLIANCE WITH COASTAL ZONE MANAGEMENT PLANS................................125
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5.0 COORDINATION....................................................................................................................126 

5.1 BACKGROUND................................................................................................................126 

5.2 EIS SCOPING...................................................................................................................126 

5.3 PUBLIC REVIEW PROCESS................................................................................................127 

5.4 MAILING LIST................................................................................................................127 

5.5 RULE-MAKING PROCESS............................................................................................127 

5.6 COASTAL ZONE CONSISTENCY................................................................................127 

6.0 PREPARERS..................................................................................................................................128 

7.0 REFERENCES. ..............................................................................................................................129 

APPENDIX A: 

 Site Management and Monitoring Plan 

APPENDIX B: 

 Scoping Report 
xi

Figures Page

1-1 Atchafalaya River and Atchafalaya River Bar Channel (ARBC).....................................2 

1-2 Proposed ODMDS-West...........................................................................................3 

1-3 Atchafalaya River Bar Channel Alternative ODMDS Locations...............................................6 

1-4 Zone of Siting Feasibility for the proposed ODMDS...........................................................10 

2.2-1 Bird Island-West BU Disposal Area with Fringe Marsh..............................................31

2.4-1 Atchafalaya Delta Wildlife Management Area (WMA)..............................................56

3.1-2 Oil and Gas Infrastructure Locations in the GOM Region Central Planning Area...............83 

Tables

1-1 Disposal History of ODMDS-East and ODMDS-West, 1992–2011 ........................................4 

2.0-1 Summary of the Screening Process and Evaluation Outcome for Array of Alternatives.........27 

2.2-1 Comparison of Incremental Costs Relative to the No-Action Alternative................................32

2.3-1 Dredged Material Quality Analytical Results ..........................................................................43 

2.3-2 2008 Disposal Area Sediment Analytical Results...................................................................44

2.3-3 Water Quality Conventional Parameters ..................................................................................46

2.3-4 Elutriate Analytical Results.......................................................................................................47

2.3-5 Water Quality Analytical Results ..............................................................................................47

3.1-1 Primary and Secondary NAAQS for the Seven Contaminants Established by EPA..............65 

3.2-1 EFH Species in the Project Area..........................................................................87 

3.3-1 Major Industry Earnings, St. Mary Parish, 2004–2006.............................................................94 

3.3-2 Major Industry Earnings, Terrebonne Parish, 2004–2006........................................................94 

3.3-3 Industry Employment, St. Mary Parish, 2001, 2005, and 2006...............................................95 

3.3-4 Industry Employment, Terrebonne Parish, 2001, 2005, and 2006 ...........................................96

4.1-1 Annual Emissions Totals for the ODMDS-West....................................................................102 
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Acronyms and Abbreviations

°C degrees Celsius

°F degrees Fahrenheit

μg/kg micrograms per kilogram

ARBC Atchafalaya River Bar Channel

BEA Bureau of Economic Analysis

BOD biochemical oxygen demand 

BU Beneficial Use

CEQ Council on Environmental Quality 

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act 

CFR Code of Federal Regulations 

cm centimeter

COD chemical oxygen demand 

CWA Clean Water Act of 1977

CZMA Coastal Zone Management Act

CZMP Coastal Zone Management Plan

DMRP Dredged Material Research Program

EFH Essential Fish Habitat

EIS Environmental Impact Statement

ER Engineering Regulation

ERDC Engineering Research and Development Center

ERL Effect Range – Low

ERLN Environmental Response Laboratory Network 

ETS Environmental Tracing Systems Limited

FMP Gulf of Mexico Fishery Management Plan

FONSI Finding of No Significant Impacts

FR Federal Register

ft feet/foot

FWPCA Federal Water Pollution Control Act

GIWW Gulf Intracoastal Waterway

HTRW hazardous, toxic, or radioactive waste

km kilometer

km2

 square kilometers
xiii

Louisiana Department of Environmental Quality LDEQ 

Louisiana Department of Natural Resources LDNR

m meter

mcy million cubic yards

mg/kg milligrams per kilogram

mg/L milligrams per liter

MLG Mean Low Gulf

MPRSA Marine Protection, Research, and Sanctuaries Act of 1972 

MVN New Orleans District (USACE)

NEPA National Environmental Policy Act

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric Administration 

O&M Operations and Maintenance 

ODMDS Ocean Dredged Material Disposal Site

ODR Ocean Dumping Regulations 

PAH polynuclear aromatic hydrocarbons 

PCB polychlorinated biphenyls 

ppt parts per thousand 

RIA Regional Implementation Agreement 

sec second

SMMP Site Management and Monitoring Plan

TKN total kjeldahl nitrogen

TOC total organic carbons 

TPH total petroleum hydrocarbons 

TSS total suspended solids

USACE U.S. Army Corps of Engineers 

USCG U.S. Coast Guard 

USDOE U.S. Department of Energy 

EPA U.S. Environmental Protection Agency 

USFWS U.S. Fish and Wildlife Service 

WQC Water Quality Criteria

WQS Water Quality Standards 

ZSF zone of siting feasibility
1

Executive Summary

INTRODUCTION

The Atchafalaya River and the Atchafalaya River Bar Channel (ARBC) (Figure 1-1) provide 

vessel access to Morgan City, the Gulf Intracoastal Waterway (GIWW), and Bayous Chene, 

Boeuf, and Black from the Gulf of Mexico. Vessels using the ARBC consist of oilfield supply 

boats, offshore tugs, fishing boats, and bargetows. 

The Atchafalaya River and Bayous Chene, Boeuf, and Black, Louisiana (Figure 1-1), project was 

authorized by the Rivers and Harbors Act of 1968 (Public Law 90-483). Historically, the 

Atchafalaya River and Bayous Chene, Boeuf, and Black, Louisiana, navigation channel has been 

dredged to 7.3 meters (m) (24 feet [ft]) Mean Low Gulf (MLG) which includes 6 m or 20 ft for 

the authorized channel dimension plus 0.6 m (2 ft) advanced maintenance and 0.6 m (2 ft) of 

allowable overdepth. Material removed from the ARBC suitable for beneficial use (i.e., between 

ARBC Stations 475+00 and 650+00) has been placed in one of two adjacent Bird Island disposal 

sites (Figure 1-2), pursuant to Section 404 of the Clean Water Act (CWA) of 1977. Material that 

could not be used beneficially (i.e., between ARBC Stations 650+00 and 1340+00) has been 

placed (prior to 2002) at the existing Marine Protection, Research, and Sanctuaries Act of 1972 

(MPRSA) Section 102(c) Ocean Dredged Material Disposal Site (ODMDS) on the east side of 

the channel (Figure 1-2). This ODMDS is referred to as ODMDS-East. Since 2002, however, 

material not suitable for beneficial use has been placed at a temporary (i.e., 5-year) ODMDS on 

the west side of the channel under the authority of MPRSA Section 103(b) (the ODMDS-West) 

(Figure 1-2). In 2007, the U.S. Army Corps of Engineers, New Orleans District (MVN) 

requested, and received, from the U.S. Environmental Protection Agency, Region 6 (EPA), a 5-

year extension for the continued use of the MPRSA Section 103(b) ODMDS-West. The 

approval for the ODMDS-West use expired in August 2012; therefore, the site can no longer 

accommodate shoal material dredged from the ARBC unless it is re-designated as a MPRSA 

Section 102(c) site by EPA. 

The ARBC is located in an area of heavy sedimentation. The bed load fraction of the sediment 

carried by the Atchafalaya River is deposited mainly in Atchafalaya Bay, resulting in delta 

accretion and progradation. Currently, the presence of fluid mud, or “fluff”, in the ARBC has 

made it very difficult to maintain the authorized 6-m (20-ft) channel through the ARBC. The 

fluff returns to the channel within weeks after maintenance dredging is complete and interferes 

with the passage of vessels. Although the MVN has committed to more frequent maintenance 

dredging in the ARBC to alleviate the fluff problems, recent annual Operations and Maintenance 

(O&M) budgets for this project have not allowed for more than a single bar channel maintenance 

dredging contract each year.

The average amount of material dredged from the ARBC for placement in the ODMDS-East and 

Bird Island-East between 1992 and 2002 was approximately 12.8 million cubic yards (mcy) per 

fiscal year, of which, approximately 10.9 mcy per fiscal year was placed in the ODMDS-East

(Table 1-1). The average amount of material dredged from the ARBC for placement in the 

ODMDS-West and Bird Island-West (since 2002) is about 12.6 mcy per fiscal year, of which, 

approximately 10.8 mcy per fiscal year is placed in the ODMDS-West (Table 1-1). 
2

Figure 1-1. Atchafalaya River and Atchafalaya River Bar Channel (ARBC) in the Atchafalaya River and 

Bayous Chene, Boeuf, and Black, Louisiana project. 

Figure 1-1 

ATCHAFALAYA RIVER AND BAYOUS 

CHENE, BOEUF, AND BLACK, LA

Atchafalaya River and Atchafalaya River 

Bay and Bar Channels 
3

Figure 1-2. Proposed Section 102(c) ODMDS-West, located on the west side of the ARBC. Also shown 

are the Section 404 Bird Island disposal sites and the Section 102(c) ODMDS-East. The proposed Section 

102(c) ODMDS-West will be “shorter” than the existing Section 103(b) ODMDS-West to accommodate 

the recent southwesterly expansion of the Section 404 Bird Island disposal site. 

Figure 1-2

ATCHAFALAYA RIVER

BAR CHANNEL

ODMDS and Bird Island Disposal Sites

Proposed 

Section 102(c)

ODMDS-West

(Existing 103(b) 

ODMDS-West)

Existing 

Section 404

Bird Island 

Disposal Site

Existing Section 

102(c)

ODMDS-East

Section 404

Bird Island 

Disposal Site

Expansion

(Separate

Project)

Proposed

Section 102 

ODMDS-West

Coordinates

“C”= 29°09’16”

 91°35’12”

 

“D”= 29°10’52”

 91°37’33”

“G”= 29°22’06” 

 91°27’38” 

“H”= 29°20’30” 

 91°25’13”

“G"

“H”

Section 404

Expansion

Coordinates

“A”= 29°23’14”

 91°26’35”

 

“B”= 29°21’38”

 91°24’14”

“G”= 29°22’06” 

 91°27’38” 

“H”= 29°20’30” 

 91°25’13” 

Existing

Section 404

Coordinates

“A”= 29°23’14”

 91°26’35”

 

“B”= 29°21’38”

 91°24’14”

“E”= 29°24’02” 

 91°25’53”

“F”= 29°22’25” 

 91°23’32”

Existing

Section 103 

ODMDS-West

Coordinates

“A”= 29°23’14”

 91°26’35”

 

“B”= 29°21’38”

 91°24’14

“C”= 29°09’16”

 91°35’12”

 

“D”= 29°10’52”

 91°37’33”
4

Table 1-1. Disposal history of the ODMDS-East, ODMDS-West, Bird Island-East, and Bird Island-West 

for material dredged from the ARBC from fiscal years 1992 to 2011. 

Fiscal 

Year

Cycle

ODMDS-East ODMDS-West Bird Island-East Bird Island-West Total CY

1992 9,630,972 0 1,000,000 0 10,630,972

1993 17,990,013 0 855,644 0 18,845,657

1994 10,594,042 0 658,670 0 11,252,712

1995 9,311,000 0 0 0 9,311,000

1996 11,589,416 0 3,019,163 0 14,608,579

1997 6,968,673 0 3,523,632 0 10,492,305

1998 10,942,132 0 2,208,674 0 13,150,806

1999 10,847,337 0 2,998,674 0 13,846,011

2000 10,749,971 0 2,237,039 0 12,987,010

2001 10,824,858 0 1,530,624 0 12,355,482

2002 9,168,753 6,797,817 1,176,384 2,584,433 20,664,827

2003 0 9,125,381 0 0 9,125,381

2004 0 14,820,423 0 1,918,795 16,739,218

2005 0 12,917,556 0 2,170,384 15,638,178

2006 0 8,168,569 0 1,360,348 9,528,917

2007 0 14,837,877 0 1,187,346 16,025,223

2008 0 9,545,797 0 1,791,290 11,337,087

2009 0 0 0 0 0

2010 0 11,246,103 0 2,200,425 13,446,528

2011 0 9,922,298 0 1,256,759 11,179,057

Total CY 71,091,140 97,381,821 19,208,504 14,469,780 251,164,950

Average 

CY 10,874,288 10,820,202 1,920,850 1,808,722 13,219,207

Concern has been expressed that maintenance-dredged material placed on the east side of the 

ARBC (particularly in the ODMDS-East) is rapidly transported back into the navigation channel 

by prevailing littoral currents. It is worth noting that the ODMDS-East is currently the only 

ODMDS located on the east side of a navigation channel along the Texas-Louisiana coast, which 

is dominated by the Louisiana-Texas Coastal Current which flows westward (downcoast) along 

the Louisiana coast in fall, winter, and spring. Following the MPRSA Section 103(b) 

designation of the ODMDS-West in 2002, the U.S. Army Corps of Engineers, Engineering 

Research and Development Center, performed monitoring studies to determine whether placing 

maintenance-dredged material on the west side of the channel was more effective at reducing 

shoaling in the channel, and thus, reducing the dredging frequency and costs. These studies 

found that while placing material on the west side of the ARBC did not eliminate shoaling, it did 

reduce runback of material into the channel and thus the shoaling rate, when compared to placing 

material on the east side of the channel (Teeter et al. 2003). These findings were corroborated in 

the report, “Sediment Disposal from the Atchafalaya Bar Channel, Atchafalaya Bay, St. Mary 

Parish, Louisiana,” prepared for MVN in 2007 (PBS&J 2007). 
5

The need for the proposed action (the permanent, MPRSA 102(c) designation of the ODMDSWest) is to reduce the amount and rate of shoal material runback into the ARBC (i.e., reduce the 

shoaling rate), and thus, decrease the overall annual maintenance dredging effort needed for the 

ARBC while providing vessels with a longer period of safe navigation access prior to a 

maintenance dredging event. The purpose is to provide an environmentally acceptable location 

for the placement of maintenance-dredged material from the ARBC.

There are currently the following authorized disposal areas in Atchafalaya Bay (Figures 1-2):

• CWA Section 404 Disposal Site named Bird Island-East – located east of the ARBC on 

the left descending bank and used annually for beneficial use prior to 2002. 

• CWA Section 404 Disposal Site named Bird Island-West – located west of the ARBC on 

the right descending bank and used annually for beneficial use since 2002. 

• MPRSA Section 102(c) designated ODMDS named ODMDS-East – located east of the 

ARBC on the left descending bank and used annually for placement prior to 2002. 

• MPRSA Section 103(b) designated ODMDS named ODMDS-West – located west of the 

ARBC on the right descending bank, used annually for placement since 2002 (expired as 

of August 2012). 

The existing ODMDS-West is located in Atchafalaya Bay, approximately 19 miles (30.6

kilometers [km]) from the mainland coast and the mouth of the Atchafalaya River (Figure 1-1). 

The ODMDS-West is rectangular, approximately 3 miles (4.8 km [2.6 nautical miles]) wide by 

18 miles (29 km [15.6 nautical miles]) long, and parallel (on the west side or right-descending 

bank) to the Atchafalaya River bar channel (ARBC) located within the Atchafalaya River and 

Bayous Chene, Boeuf, and Black, Louisiana project (Figures 1-1 and 1-2). The site encompasses 

approximately 35,000 acres (140 km2 [54 square miles]) of open water and ranges in depth from 

6 to 23 ft (1.8 to 7 m) MLG. 

The proposed Section 102(c) ODMDS-West retains the same width (3 miles) as the existing 

Section 103(b) ODMDS-West, but differs slightly at its upper end, resulting in an area only 16 

miles (26 km [14 nautical miles]) long (Figure 1-2). The resulting reduced area of the proposed 

Section 102(c) ODMDS-West, then, is approximately 31,000 acres (129 km2

 [48 square miles]). 

The reduced area of the proposed Section 102(c) ODMDS-West would accommodate the 

planned southwesterly expansion of an adjacent Bird Island disposal site that is currently used by 

USACE for beneficial use of maintenance-dredged material removed from the ARBC, pursuant 

to Section 404 of the Clean Water Act (CWA) of 1977, and that was recently cleared for 

expansion by USACE in a separate project (Figure 1-2). The continued progradation and 

accretion of the Atchafalaya Delta and related increases in the sediment bed load fraction (i.e., 

accelerated sedimentation) in nearshore portions of Atchafalaya Bay and the ARBC have 

allowed for additional beneficial use of maintenance-dredged material where practicable, and 

thus, the opportunity to expand the Section 404 Bird Island site in a southwesterly direction and 

into the footprint of the Section 103(b) ODMDS-West. 

Coordinates of the four corners of the proposed Section 102(c) ODMDS-West are as follows:

 Northwest Corner - 29°22′06′′ N, 91°27′38′′ W 

Northeast Corner - 29°20′30′′ N, 91°25′13′′ W 

Southeast Corner - 29°09′16′′ N, 91°35′12′′ W 

Southwest Corner - 29°10′52′′ N, 91°37′33′′ W 
6

ALTERNATIVES 

Multiple site alternatives have been evaluated for placement of maintenance-dredged material: 

the No-Action Alternative, non-ocean (beneficial use—marsh creation and beach nourishment)

placement alternative sites (BU), a nearshore alternative site, a mid-shelf alternative site, a 

deepwater alternative site, and the proposed ODMDS-West (Figure 1-3). The No-Action 

Alternative provides for the placement of maintenance dredged material at the MPRSA Section 

103(b) designated ODMDS-West located parallel and to the west of the navigation channel until 

July 31, 2012. Maintenance dredged material from the ARBC could also be placed into the 

MPRSA Section102(c) designated ODMDS-East located on the east side of the channel. In the 

absence of EPA action to permanently designate the ODMDS-West, the existing maintenance 

operations would continue to place maintenance dredged material into the current MPRSA 

Section 103(b) designated ODMDS-West until its designation expires on July 31, 2012, after 

which time maintenance dredged material would be placed in the MPRSA Section 102(c) 

designated ODMDS-East. As a result of disposal at ODMDS-East, sediment would enter the 

ARBC at a higher rate due to the net northwest transport of sediments.

Figure 1-3. Alternative disposal site locations for the ARBC. The proposed deepwater alternative site is 

not shown. 

Figure 1-3

Alternative Disposal Site 

Locations
7

Alternatives Screening

A screening process was used to identify reasonable action alternatives. In accordance with the 

Louisiana Coastal Resources Program (LCRP) Guideline 4.2, and Section 307 of the CZMA, BU 

options for placement of the maintenance-dredged material were considered in addition to 

placement of material into an ODMDS. Each of these BU options was considered in regards to 

feasibility, cost, and longevity. Potential ODMDS sites were evaluated through a three-phase 

screening process. The BU options considered were beach nourishment, marsh creation, single 

point unconfined island creation, and single point confined island creation.

The shoreline from Oyster Bayou to North Point of Point au Fer Island and the wash over area in 

the vicinity of Point au Fer have been identified as possible locations for beach nourishment. 

However, the maintenance material dredged from Station 650+00 and 1340+00 is a loose fluid 

mud (fluff) that is not considered suitable for beach nourishment. Due to these material 

constraints, as well as the cost constraints and safety issues associated with the distance to the 

beach nourishment area, this BU alternative was removed from further consideration.

Marsh creation was considered in the vicinity of the prograding Atchafalaya Delta. However, 

the distance to the placement area, the nature of the material and the system into which it would 

be placed, and the cost associated with the proposed effort make this BU alternative unfeasible. 

Unconfined open-water placement using single point discharge approximately every 2 miles 

along the entire length of the ARBC to create/establish islands for use by colonial nesting birds 

was also considered. However, the maintenance material removed from the majority of the 

channel consists of fluff, which is not suitable for creation of islands. Therefore, this BU 

alternative was removed from further consideration. 

Several options for confined placement to create/establish islands in the area of the existing 

ODMDS-East or proposed ODMDS-West were also considered. Confinement of the material 

would eventually allow some of the material to settle out. However, an accurate estimate of how 

much material and the time required for eventual mounding to occur is unknown. Additionally, 

in the high-energy environment of the Gulf, it is possible that containment dikes could breach. 

Because of the uncertainty associated with the feasibility of this alternative, as well as the 

potential for increased operational costs, this BU alternative was also eliminated from further 

consideration. 

Following elimination of potential BU alternatives, a three-phase screening process was initiated. 

Phase I of the process initiated review of ocean placement alternatives to identify those most 

appropriate for additional evaluation. This phase included definition of a zone of siting 

feasibility (ZSF), characterization of expected material and site sizing, and establishment of 

buffer zones for critical areas and resources. Phase II of the screening process addresses more 

site specific issues based on consideration of the 11 specific factors prescribed in 40 CFR Part 

228.6. Phase II is the final determination of the environmental suitability of each candidate site 

in accordance with the five general criteria for site selection (40 CFR Part 228.5).
8

Phase I Screening

Three types of ocean placement, nearshore, mid-shelf, and deepwater, were considered in Phase I 

of the screening process. Two nearshore sites were considered. The first was a new site, 

referred to as “Nearshore Alternative Site 1” and the existing ODMDS-West (Figure 1-3). One 

mid-shelf and one deepwater site were also considered (Figure 1-3). To avoid conflict with these 

and other permitted uses in the area, it was determined that an alternative nearshore ODMDS 

could be located approximately 9.2 miles south and 2.3 miles east of the center of the ODMDSEast. If similar placement techniques to those used at ODMDS-East are applied at the Nearshore 

Alternative Site 1, the environmental effects of the maintenance dredged material would 

probably be quite similar to those at the ODMDS-East. Surveillance and monitoring conditions 

for the Nearshore Alternative Site 1 would also be similar to those at the ODMDS-East. 

Therefore, selection of the alternative nearshore site would subject a new area of the ocean to the 

effects of maintenance dredged material placement while offering little environmental advantage 

over the proposed site. The nearshore alternative site ODMDS-West is located to the west of the 

ARBC and approximately parallel to the existing ODMDS-East. This site is similar to the 

existing ODMDS-East in both physical and biological characteristics and similar impacts would 

be expected to those experienced at the ODMDS-East when placement occurred at that site. 

Thus, the impacts at this site would be the same as the current impacts at the ODMDS-West 

under the MPRSA Section 103(b) authority. 

The mid-shelf area off the coastal Louisiana is a biologically productive area with oil and gas 

lease tracts and pipelines located throughout the region. Depths in the area of the alternate midshelf site are approximately 60 ft and the site would be approximately 32 miles from shore. The 

mid-shelf area is less dynamic than the nearshore area near the ODMDS-East and West and is 

subjected to a slower rate of erosion and transport. For these reasons, the maintenance dredged 

material that sloughs outside the immediate placement footprint could be thicker than that 

deposited at the ODMDS-East or West. Additionally, the material would be transported by 

barge or hopper dredge to the placement site and the material, composed mostly of silt and clay, 

would undergo a certain amount of compaction and dewatering en route to the site and could be 

cohesive enough to settle to the bottom in discrete masses, creating a mound on top of the natural 

sediment at the site. Because of the increased distance, cost and time to transport the material 

and to monitor onsite conditions would be increased. 

The deepwater region is the area seaward of the edge of the continental shelf at approximately 

the 360-ft contour, 84 miles from the ARBC. Dredged material placed at a deepwater site should 

be dispersed over a much larger area than at a mid-shelf or nearshore site because of the breakup 

of the descending plume and once sediments reach the bottom, they tend to remain in place and 

are subject to slow erosion and transport. The increased travel distance to a deepwater site 

would increase the costs and surveillance and monitoring would be possible, but difficult and 

costly.

Zone of Siting Feasibility

The constraints on a site relative to the ZSF are those related more to its feasibility from a 

utilitarian as opposed to a regulatory perspective, although there is some overlap. Primary 
9

among the geographical and physical constraints are those which would restrict the safe and 

economical use of the site, such as distance from the dredging area, dangerous structures or 

currents, interference with or from other vessels, political boundaries, and logistic constraints on 

monitoring and surveillance. Cost and safety issues involved in the transportation of dredged 

material were the limiting factors in determining the ZSF boundaries. Especially, a mid-shelf 

site and a site beyond the continental shelf would not be feasible because of dredging costs, 

safety, and limits on monitoring and surveillance. 

Based primarily on the efficiency of the dredging operation in terms of time, cost, and safety and 

the general uniformity of the area near the ARBC, the ZSF for the proposed ODMDS is an area

approximately 29 km (18 miles) long and 8 km (5 miles) wide adjacent to both sides of the 

ARBC (Figure 1-4). The ZSF thus encompasses an area of roughly 233 km2 (90 square miles). 

Characterization of Material and Site Sizing

Only material dredged from the navigation channel to maintain the authorized channel depth 

would be placed at the proposed ODMDS-West. The maintenance-dredged material is generally 

comprised of silt with some sand and clay (7-12 percent sand, 81-88 percent silt, and 6-7 percent

clay) (PBS&J 2008). Although metals, ammonia, and organic carbons were detected in sediment 

samples collected from the ARBC and reference sites for the 1996, 2002, and 2008 contaminant 

assessments, there is nothing in the chemical analyses, suspended particulate phase bioassays, 

solid phase bioassays, or bioaccumulation studies for those assessments that would indicate a 

concern (Espey, Huston & Associates, Inc. 1997; PBS&J 2002 and 2008). Based on the 

guidance provided by the Regional Implementation Agreement (RIA) among the EPA and the 

USACE, Galveston and New Orleans Districts (EPA/USACE 2003), the conclusion of this 

testing is that no significant adverse impacts are anticipated with the ocean placement of these 

sediments, and that the Limiting Permissible Concentration (40 CFR 227.29(a)) for the water 

column and solid phase, including bioaccumulation, are met. 

Elutriate and water samples were also collected from locations in the ARBC, and from the 

reference area located southeast of the channel in 1996, 2002, and 2008. Antimony, arsenic, 

cadmium, copper, nickel, selenium, and zinc were detected in elutriates from the ARBC sample 

locations and from the reference area (Espey, Huston & Associates, Inc. 1997; PBS&J 2002 and 

2008). None of the metals concentrations in the water samples was at or above the acute or 

chronic Water Quality Standards or Water Quality Criteria.

Surface sediments in the ODMDS-West are predominately silt and clay (IEC 1983; Dettman and 

Tracey 1990; Flemer et al. 1994; Trulli 1996; PBS&J 2002 and 2008). The size of the proposed 

ODMDS-West was determined based upon the need to maximize the discharge distance away 

from the ARBC to minimize the run back into the channel and to allow for adjacent pumping of 

the dredged material from within the reaches of the ARBC. As a result, the dimensions of the

proposed ODMDS-West were determined to be 29 km (18.0 miles) long (length of the ARBC) 

and 5 km (3.0 miles) wide (typically the pumping distance at which a hydraulic pipeline 

cutterhead suction dredge may no longer be cost effective without a booster pump, depending on 

the size of the dredge), which are within the ZSF boundaries described above. The site lends

itself to surveillance of individual dredged material placement operations and monitoring. 
10

Additionally, the orientation of the proposed ODMDS-West broadside to the prevailing currents 

in the area increases the chance that placed material will disperse away from the ARBC. 

Figure 1-4. Zone of Siting Feasibility (ZSF) in relation to the ODMDSs and the ARBC. Note 

the ZSF, outlined in red, encompasses an area on both sides of the ARBC. 

Figure 1-4 

Zone of Siting Feasibility for the 

Proposed ODMDS
11

Establishment of Buffer Zones 

Pre and post-maintenance dredging bathymetric surveys conducted annually by MVN show no 

accumulation of material in either the existing ODMDS-East or ODMDS-West (Creef, MVNOD, personal communication, 2012). These data indicate material dispersion at the placement 

sites. No marine sanctuaries occur within 46 km of the ARBC. The nearest point of land is 

North Point au Fer Island and it is approximately 3.7 km (2 miles) from the existing and 

proposed ODMDS. There are no beaches in the area of the proposed ODMDS-West. The 

candidate ODMDSs are located outside of the Navigation Channel and open-water approaches to 

the ARBC, therefore interference with navigation is not expected. Based on this, there are no 

buffer zones established. 

Evaluation of Eleven Specific Criteria – Phase II Screening

Criterion 1 - Geographical position, depth of water, bottom topography, and distance from 

coast. 

The ODMDS-West and ODMDS-East are located in the nearshore area of the plain. Except for

being located adjacent to the dredged channel, the area occupied by the ODMDSs is typical in 

depth and bottom topography to the continental shelf in the vicinity of the Atchafalaya River 

Delta.

Criterion 2 - Location in relation to breeding, spawning, nursery, feeding or passage areas of

living resources in adult or juvenile phases. 

The proposed ODMDS-West is located in a region dominated by species that are estuarinedependent (Darnell et al., 1983; Phillips and James, 1988; Day et al., 1989). Commercially 

important species likely found in the area include white shrimp, brown shrimp, Gulf menhaden, 

and sand sea trout. Commercially important shellfish and fish that inhabit the nearby bay 

environment include oyster, blue crab, black drum, white shrimp, and brown shrimp. The stress 

and possible mortality of individual organisms encountering adverse conditions during dredging 

and placement operations in the ODMDS-West would be negligible compared to the passage of 

the far greater majority of individuals crossing into or out of the estuary and at other locations. 

Additionally, any impact would also occur at any other ODMDS location near the ARBC.

Placement of material at the proposed ODMDS-West would have negligible effects on 

endangered and threatened species. Dredging operations might affect sea turtles through 

incidental take. If hopper dredges are used, there is a possibility of impact to sea turtles, as there 

would be no matter where the ODMDS is located. Hydraulic cutterhead pipeline dredging 

operations have not been identified as a source of sea turtle mortality. Hopper dredging will be 

conducted in accordance with all reasonable and prudent measures and implementing terms and 

conditions provided to MVN by the National Marine Fisheries Service (NMFS) in its 2007 

Biological Opinion (NMFS 2007), and any subsequent Biological Opinion, to avoid sea turtle

mortality.
12

Criterion 3 - Location in relation to beaches or other amenity areas. 

There are no recreational parks or beaches near the proposed ODMDS-West. It may be possible 

to observe the placement plume from boats in the vicinity during the active period of 

maintenance-dredged material placement within the site. The plume is expected to dissipate 

quickly after completion of the placement operations. Except for the minor effects of these 

limited observations, there should be no effects to the aesthetics of the area.

Criterion 4 - Types and quantities of wastes proposed to be disposed of and proposed methods of 

release, including methods of packaging the waste, if any. 

The material dredged from the ARBC is generally comprised of silt with some sand and clay (7-

12 percent sand, 81-88 percent silt, and 6-7 percent clay) (PBS&J 2008). Based on dredging 

records since 2002, the volume of maintenance-dredged material removed from the ARBC for 

placement in the ODMDS-West is approximately 10.8 mcy per fiscal year dredging cycle. 

Material is removed from the ARBC using a hydraulic cutterhead pipeline dredge and released 

within the ODMDS-West as uncohesive slurry. Any material disposed of at the site would be 

required to comply with the criteria of the Ocean Dumping Regulations (40 CFR Parts 220 to 

229). None of the material will be packaged in any way.

Criterion 5 - Feasibility of surveillance and monitoring. 

The proposed ODMDS-West is in relatively shallow water and is close to shore, which facilitates

surveillance and monitoring of the site. A site management plan incorporating monitoring 

requirements has been developed jointly by EPA and MVN for the proposed ODMDS-West and 

is included in Appendix A of this Draft Environmental Impact Statement. 

Criterion 6 - Dispersal, horizontal transport, and vertical mixing characteristics of the area,

including prevailing current velocity, if any. 

Current patterns in the vicinity of the proposed ODMDS-West are highly complex. Although 

tides, Loop current intrusions, and river flow may affect the local currents, these currents are 

influenced predominately by winds (Phillips and James 1988). Thus, the direction and velocity 

of the currents vary throughout the year. Net water flow in the winter is to the northwest; 

however, rapid flow reversals to the southeast occur periodically in concert with wind direction 

(Crout and Hamiter 1981; Phillips and James 1988; Walker and Hammack 2000). The near 

shore current patterns are somewhat more complex in summer. Net flow in summer can be 

either to the east or west (Crout and Hamiter 1981; Phillips and James 1988; Walker and 

Hammack 2000). Spinoff eddies from the Loop current occasionally enter the region, producing

flows to the southeast near the ARBC (Weissberg et al. 1980a, 1980b). Current speeds generally 

range from 10 to 30 centimeters per second in the vicinity of the ODMDS-West. Stagnant 

periods with little or no current motion, lasting as long as 6 days, have been recorded in April,

May, and July (Weissberg et al. 1980a, 1980b). 

In the absence of strong currents, the bulk of the maintenance-dredged material settles on the 

bottom of the particular area of a site being used at that time. A portion of the plume (fines) will 
13

be transported in the direction of the current over a wider area of the disposal site and, to some 

extent, outside the disposal site. This material will eventually settle over a wide area.

The maintenance-dredged material is proportionally very small compared to the sediment load 

delivered by the discharge of the Atchafalaya River to the area. During disposal operations, a 

temporary mound of maintenance-dredged material may be initially formed within the ODMDSWest. However, flow of the non-cohesive slurry and re-suspension of the maintenance-dredged 

material results in the disappearance of the mound through dispersal and horizontal transport. 

Based on analysis performed by Teeter et al. (2003), placement in ODMDS-West reduced 

runback to the channel; within approximately 10 weeks, the difference was made up through 

lateral inflow. The annual potential lateral source is estimated at approximately 30 mcy, which 

is a reasonable rate, given the parameters identified during the study. 

Criterion 7 - Existence and effects of current and previous discharges and dumping in the area

(including cumulative effects).

The area proposed for selection (the ODMDS-West) has been used for the disposal of 

maintenance-dredged material since 2002. Historical data collected from MVN bathymetric 

surveys conducted prior to and after disposal operations indicate there is no persistent mounding 

and the maintenance-dredged material is relatively quickly dispersed (Creef, MVN-OD, personal 

communication, 2012). No measurable effects from previous disposals have been noticed. 

Criterion 8 - Interference with shipping, fishing, recreation, mineral extraction, desalination, 

fish and shellfish culture, areas of special scientific importance and other legitimate uses of the

ocean. 

The proposed ODMDS-West is outside the navigation channel and therefore does not interfere 

with shipping. Smaller recreational and commercial fishing vessels will pass over the ODMDSWest. All dredging and placement operations are closely coordinated with the U.S. Coast Guard 

(USCG) with issuance of a Notice to Mariners to dredging operators and the shipping interests to 

avoid interference with traffic. Recreational fishing and boating takes place throughout the area 

of the ODMDS-West, specifically at Ship Shoal, Trinity and Tiger Shoals, and smaller fishing 

shoals and Point au Fer Reef. There may be some short-term interference with recreational 

activities at the ODMDS-West, particularly during disposal operations. This interference would 

be short-term and restricted to the relatively small area of the ODMDS-West being used for 

dredged material placement at any particular time.

There are numerous active oil and gas platform located in the west and south end the ODMDSWest and other platforms are located adjacent to the east, south, and west of the site. 

Additionally, several large natural gas pipelines cross the ODMDS-West. Because of the 

dispersive nature of the site, past experience with dredged material placement has not indicated 

interference with oil and gas exploration or production. 

No desalination or artificial finfish or shellfish culture facilities are located within the site. Fish 

and shellfish that naturally occur within the site may be affected by placement of dredge material 

at the site, particularly bottom-dwelling organisms that may be trapped and smothered. There 
14

are no Public Oyster Areas within the ODMDS-West, and the nearest oyster leases are 

approximately 4 miles east of the ARBC and ODMDSs, near Point au Fer (LDNR 2012). 

Effects of placement operations on oyster lease areas near Point au Fer would be minimal and 

consistent with natural conditions. 

Two areas designated as wildlife management areas or wildlife refuges and that are used for 

recreational use are located in the project area. The 140,000-acre Atchafalaya Delta Wildlife 

Management Area (WMA), managed by the Louisiana Department of Wildlife and Fisheries, 

(LDWF) encompasses the developing delta in Atchafalaya Bay. The Atchafalaya Delta WMA is 

located immediately adjacent to the upper end of the existing Section 103(b) ODMDS-West. 

The Shell Keys National Wildlife Refuge and Russell Sage - Marsh Island State Wildlife Refuge 

is located approximately 29 miles (47 km) west of the ODMDS-West. The transport of 

suspended materials from the ODMDS-West would mainly be parallel to the coastline, and 

concentrations of suspended materials produced during dredging operations are expected to be 

within background levels within a few miles or so of the ODMDS-West (May 1973). Suspended 

materials originating from the ODMDS-West may drift into adjacent portions of the Atchafalaya 

Delta WMA; however, the effects of these suspended materials would likely be indiscernible 

from ambient conditions in these areas. There have been no significant impacts to these areas 

from use of the interim-designated ODMDS-West, and no impacts are expected from its 

continued use. 

Various universities and state and Federal agencies have studied the biological, 

geomorphological, and hydrological development of the Atchafalaya Delta. Placement of 

dredged material into the ODMDS-West is not expected to interfere with any such studies. 

Criterion 9 - Existing water quality and ecology of the site as determined by available data or by

trend assessment or baseline surveys.

The water quality and ecology of the ODMDS-West generally reflect that of the nearshore region 

off the Louisiana coast affected by discharges from the Atchafalaya River. The variations in 

water quality depend on the amount and mixing of freshwater runoff that is highly variable 

(Phillips and James 1988). Data collected during the IEC (1983) surveys and the EPAEnvironmental Response Laboratory Network (Dettmann and Tracey 1990) survey are generally 

comparable to historic data (Phillips and James 1988). Similarly, water quality and sediment 

contaminant data from the 2008, 2002, and 1996 contaminant assessments all indicated no water 

quality impacts related to the placement of dredged material.

The nearshore macrofaunal assemblages near the ODMDS-West are typical of estuarine areas, 

with communities dominated by polychaete worms, small molluscs, and macrocrustaceans 

(Parker et al. 1980; Weissberg et al. 1980a, 1980b). Central Louisiana Gulf coastal waters are 

inhabited by numerous species of finfish and shellfish that can be characterized as estuaryrelated or demersal shelf inhabitants. Recreational fishing is popular in the vicinity of the 

ODMDS-West including fishing, crabbing, and shrimping.
15

Criterion 10 - Potentiality for the development or recruitment of nuisance species in the disposal 

site.

Past placement of maintenance-dredged material at the existing ODMDS-East and ODMDSWest has not resulted in the development or recruitment of nuisance species. Therefore, 

placement of maintenance-dredged material at the proposed ODMDS-West is not expected to 

result in development or recruitment of nuisance species.

Criterion 11 - Existence of or in close proximity to the site of significant natural or cultural

features of historical importance. 

The USACE Submerged Cultural Resource Database contains historical accounts that indicate 

historical use of the Atchafalaya Basin. In 1996, a remote sensing survey was on the ODMDSEast. This study found that while several anomaly clusters existed, which may represent 

shipwrecks, the geomorphologic and bathymetric data indicates that between 5 and 6 m (17 and 

21 ft) of sedimentation had occurred in the area between 1839 and 1996. Thus, it was concluded 

that the placement of maintenance-dredged materials in the proposed ODMDS-West would not 

add appreciably to the impact already induced by progradation of the Atchafalaya Delta during 

the last century. The results of the 1996 remote sensing study can be applied to the present study 

given its proximity to the previously designated ODMDS-East.

Evaluation of Five General Criteria — Phase III Screening

Criterion 1

The dumping of materials into the ocean will be permitted only at sites or in areas selected to 

minimize the interference of disposal activities with other activities in the marine environment, 

particularly avoiding areas of existing fisheries or shellfisheries, and regions of heavy 

commercial or recreational navigation. The ODMDS-West is located adjacent to and parallel to 

the ARBC, which reduces the distance that the maintenance-dredged material must be 

transported, minimizing interference with other activities in the marine environment. There have 

been no impacts to existing oyster leases located northeast of the ODMDS area near Point au Fer 

from the use of the existing ODMDS-East, or ODMDS-West (which has been used since 2002), 

and no impact is expected to occur in the future as a result of using the proposed ODMDS-West.

Criterion 2

Locations and boundaries of disposal sites will be so chosen that temporary perturbations in 

water quality or other environmental conditions during initial mixing caused by disposal 

operations anywhere within the site can be expected to be reduced to normal ambient seawater 

levels or to undetectable contaminant concentrations or effects before reaching any beach, 

shoreline, marine sanctuary, or known geographically limited fishery or shellfishery. Placement 

of maintenance-dredged material will produce a turbidity plume. This plume will disperse to the 

point where it would be indistinguishable from the turbidity naturally occurring in the area. 

There are no marine sanctuaries in the immediate vicinity of the proposed ODMDS-West

(USFWS 1981). The transport of suspended materials from the ODMDS would mainly be 
16

parallel to the coastline, and concentrations of suspended materials produced during dredging 

operations are expected to be within background levels within a few miles or so of the ODMDSWest (May 1973). There are no Public Oyster Areas within the ODMDS-East or ODMDS-West, 

and the nearest oyster leases are approximately 4 miles east of the ARBC and ODMDSs, near 

Point au Fer (LDNR 2012). The potential impact on oyster beds in nearby Atchafalaya Bay is 

expected to be minimal.

Criterion 3

If, at any time during or after disposal site evaluation studies, it is determined that existing 

disposal sites presently approved on an interim basis for ocean dumping do not meet the criteria 

for site selection set forth in 228.5–228.6, the use of such sites will be terminated as soon as 

suitable alternative disposal sites can be designated. This criterion does not apply to the 

proposed ODMDS-West since it is not an existing site approved on an interim basis. However, 

studies to date indicate that the proposed ODMDS-West meets the requirements of the MPRSA. 

Criterion 4

The sizes of ocean disposal sites will be limited in order to localize for identification and control 

any immediate adverse impacts and to permit the implementation of effective monitoring and 

surveillance programs to prevent adverse long-range impacts. The size, configuration, and 

location of any disposal site will be determined as a part of the disposal site evaluation or 

designation study. The size of the ODMDS-West has been identified to cover an area as small as 

possible to reasonably meet the criteria stated at 40 CFR 228.6(a) for the ARBC project and for 

efficient placement of material dredged from the ARBC. The size and location of the proposed 

ODMDS-West also minimizes the return of dredged material from the ODMDS to the channel. 

The site lends itself to surveillance of individual dredged material placement operations and 

long-term monitoring. The configuration of the ODMDS-West limits its overall area to a

dimension of 26.0 km by 4.8 km (16.0 miles long by 3.0 miles) wide.

Criterion 5

The EPA will, wherever feasible, designate ocean dumping sites beyond the edge of the 

continental shelf and other such sites that have been historically used. In this area of the Gulf of 

Mexico, an ODMDS beyond the continental shelf would be at least 135 km (84 miles) from the 

area to be dredged. A dredged material placement site beyond the continental shelf would not be 

feasible due to, among other things, increased safety risks, increased cost of dredged material 

transportation, and increased costs for site characterization, monitoring, and surveillance studies. 

Preferred Alternative

Based on the studies and analysis, the preferred alternative is the MPRSA Section 102(c) 

designation of the ODMDS-West for continued placement of maintenance-dredged material. 

The majority of the proposed ODMDS-West has been used for the placement of maintenancedredged material since 2002. Continued use of the site would subject the area within the site 

boundaries to the same environmental effects that have existed since 2002. The proposed 

ODMDS-West site is located in a dynamic environment characterized by high variability in 
17

physical factors. Correspondingly, the organisms that occur there are adapted to natural stresses 

and are able to recover more rapidly than those organisms adapted to more stable conditions. 

No adverse environmental effects due to maintenance-dredged material placement were detected 

outside the ODMDS-East boundaries during the IEC (1983) surveys; nor were they indicated by 

the evaluation. Adverse environmental effects outside the boundaries of the proposed ODMDSWest were not detected during prior use of this site and therefore are not expected to result from 

continued use of the site. 
18

1.0 INTRODUCTION

Construction and maintenance of the 54-mile-long Atchafalaya River and Bayous Chene, Boeuf, 

and Black, Louisiana, navigation channel was authorized by the Rivers and Harbors Act of 1968, 

House Document 155, 90th Congress, 1st Session. Its authorized dimensions are a depth of 20 ft

relative to Mean Low Gulf by 400-ft bottom width. The primary purpose of the channel is to 

provide vessel access to Morgan City, Louisiana, from the Gulf of Mexico.

Material in the ARBC is removed with a hydraulic cutterhead dredge and the slurry is discharged 

through a floating pipeline into a dispersive site. Dredging records indicate that between 1957 

and 1973 dredged material was placed into open water on either side of the navigation channel 

(EPA 1998). Between 1974 and 2002 dredged material was placed into an ODMDS parallel to 

and east of the bar channel (the ODMDS-East). In 2002, the USACE, under the authority of 

Section 103(b) of MPRSA, began placing dredged material in a temporary ODMDS on the west 

side of the ARBC, hereafter referred to as the ODMDS-West (Figure 2). Following this 

designation, USACE, Engineering Research and Development Center (ERDC) performed 

monitoring studies to determine whether placing maintenance-dredged material on the west side 

of the channel was more effective at reducing shoaling in the channel and thus reducing the 

dredging frequency and costs. This study, “Final Report, Factors Affecting Fluff and Fluid Mud 

Accumulation in the Atchafalaya Bar Channel,” by Teeter et al. (2003), found that while placing 

material on the west side of the channel did not eliminate shoaling, it did reduce runback of 

material into the channel and thus the shoaling rate—by as much as 10 weeks—when compared 

to placing material on the east side of the channel. These findings were corroborated in the 

report, “Sediment Disposal from the Atchafalaya Bar Channel, Atchafalaya Bay, St. Mary 

Parish, Louisiana,” prepared for MVN in 2007 (PBS&J 2007). Final recommendations in the 

Teeter et al. study were to place the material in the westernmost portion of the ODMDS-West, 

since net sediment drift was to the northwest and this would reduce runback, the shoaling rate, 

and the required dredging frequency (Teeter et al. 2003). 

This document has been prepared to identify an ODMDS for permanent designation pursuant to

Section 102(c) of the MPRSA of 1972 for maintenance-dredged material removed from the 

ARBC following the findings of Teeter et al. It has also been prepared to meet the requirements 

of an Environmental Impact Statement (EIS) in accordance with the National Environmental 

Policy Act (NEPA) of 1969 and the Council on Environmental Quality’s (CEQ) regulations (40 

Code of Federal Regulations [CFR] 1500–1508), as reflected in the USACE Engineering 

Regulation, ER 200-2-2; the MPRSA (86 Stat. 1052), as amended; the EPA Ocean Dumping 

Regulations (ODR), 40 CFR 220 to 229; and other applicable Federal environmental legislation 

and regulations. 

The following sections include a discussion of the purpose and need for the proposed action, the 

authorities for the proposed action, alternatives to the proposed action, significant resources 

affected by the proposed action, and the potential impacts of the proposed action and 

alternatives. In addition, selection of an alternative will be based on evaluation of the 

environmental consequences of site selection and use in accordance with the 5 general (40 CFR 

228.5) and 11 specific criteria (40 CFR 228.6(a)), as required by the MPRSA.
19

1.1 PURPOSE AND NEED FOR THE PROPOSED ACTION

Historically, the Atchafalaya River and Bayous Chene, Boeuf, and Black, Louisiana, Navigation 

Channel has been dredged to 7.3 meters (m) (24 ft) MLG (6.1 m [20 ft] with 10.6 m [2 ft] 

advanced maintenance and 2 ft of allowable overdepth). Material removed from the ARBC that 

was suitable for beneficial use (BU) has been placed in one of two Bird Islands located adjacent 

to the ARBC. Material that could not be used beneficially has been placed (i.e., prior to 2002) at 

the existing MPRSA Section 102 (c) ODMDS on the east side of the channel. This ODMDS is 

referred to as ODMDS-East. Since 2002, however, material not suitable for BU has been placed 

at a temporary ODMDS on the west side of the channel under the authority of MPRSA Section 

103(b) (the ODMDS-West). 

The ARBC is located in an area of heavy sedimentation. The Atchafalaya River is a distributary 

of the Mississippi River and carries approximately 30 percent of the Mississippi River’s water 

and sediment load (Wells et al. 1981; USACE 2004). The bed load fraction of the sediment is 

deposited mainly in Atchafalaya Bay, resulting in active delta accretion and progradation (USGS 

2011). It is estimated that 7 percent of the total sediment load of the Atchafalaya River is 

deposited onto the shelf every year (Draut et al. 2005). Sediments that accumulate in the Gulf 

portion of the ARBC result from a combination of littoral transport and inputs from the 

Atchafalaya River. Currently, the presence of fluid mud or “fluff” (terms used interchangeably 

herein) in the ARBC has made it very difficult to maintain the authorized 6.1-m (20-ft) MLG 

channel through the ARBC. The fluff returns to the channel within weeks after maintenance 

dredging is complete and interferes with the passage of certain types of vessels. The USACE, 

New Orleans District (MVN) has committed to more frequent maintenance dredging in the 

ARBC to alleviate the fluff problems.

The ODMDS-East received final designation in 2000, under 65 FR 31492 (May 18, 2000). 

Historical use of the ODMDS-East between 1992 and 2002 is shown in Table 1-1. Historically, 

the ODMDS-East has received dredged material from the ARBC via a cutterhead hydraulic 

pipeline dredge, discharging directly into the site. The average amount of material placed in the 

ODMDS-East between 1992 and 2002 was approximately 10.9 mcy per fiscal year.

The ODMDS-West has been used for disposal of dredged materials since 2002 under the 

authority of MPRSA Section 103 (b). The ODMDS-West has received dredged material from 

the ARBC via a cutterhead hydraulic pipeline dredge, discharging directly into the western half 

of the site. The average amount of shoal material placed in the ODMDS-West (since 2002) is 

about 10.8 mcy per fiscal year which is placed at an average frequency of once every 7.4 months. 

This frequency and volume is expected to continue into the future. Dredged volumes placed in 

the ODMDS-West since 2002 are shown in Table 1-1. 

The EPA, Region 6 and MVN are proposing selection and permanent designation under MPRSA 

Section 102(c) of the ODMDS-West in response to concerns that maintenance-dredged material 

placed on the east side of the channel, and in particular into the existing ODMDS-East, is rapidly 

transported back into the navigation channel by prevailing littoral currents. The ODMDS-East is 

currently the only ODMDS on the east side of a navigation channel along the Texas-Louisiana 
20

coast, which is dominated by the Louisiana-Texas Coastal Current which flows mainly westward 

(downcoast) along the Louisiana coast in fall, winter, and spring. 

The need for the proposed action (the permanent, MPRSA Section 102(c) designation of the 

ODMDS-West) is to reduce the amount and rate of shoal material runback into the ARBC (i.e., 

reduce the shoaling rate), and thus, decrease the overall annual maintenance dredging effort 

needed for the ARBC while providing vessels with a longer period of safe navigation access 

between maintenance dredging events.

1.2 DESCRIPTION OF THE PROPOSED ACTION 

The proposed action is the permanent designation under Section 102(c) of the MPRSA for the 

ODMDS-West to receive maintenance-dredged material from the ARBC when ocean disposal is 

the preferred disposal alternative. The existing ODMDS (i.e., the ODMDS-West) is located in 

Atchafalaya Bay, approximately 19 miles (30.6 km) from the mainland coast and the mouth of 

the Atchafalaya River (Figure 1-1). The ODMDS-West is rectangular, approximately 3 miles 

(4.8 km [2.6 nautical miles]) wide by 18 miles (29 km [15.6 nautical miles]) long, and parallel 

(on the west side or right-descending bank) to the Atchafalaya River bar channel (ARBC) 

located within the Atchafalaya River and Bayous Chene, Boeuf, and Black, Louisiana project 

(Figures 1-1 and 1-2). The site encompasses approximately 35,000 acres (140 km2 [54 square 

miles]) of open water and ranges in depth from 6 to 23 ft (1.8 to 7 m) MLG. Since 2002, an 

average of 10.8 mcy of shoal material not suitable for beneficial use has been removed annually 

(i.e., each fiscal year) from the ARBC and placed at the ODMDS-West at an average frequency 

of once every 7.4 months under the authority of Section 103(b) of MPRSA. 

The proposed Section 102(c) ODMDS-West retains the same width (3 miles) as the existing 

Section 103(b) ODMDS-West, but differs slightly at its upper end, resulting in an area only 16 

miles (26 km [14 nautical miles]) long (Figure 1-2). The resulting reduced area of the proposed 

Section 102(c) ODMDS-West, then, is approximately 31,000 acres (129 km2

 [48 square miles]). 

The reduced area of the proposed Section 102(c) ODMDS-West would accommodate the 

planned southwesterly expansion of an adjacent Bird Island disposal site (the Bird Island-West)

that is currently used by USACE for beneficial use of maintenance-dredged material removed 

from the ARBC, pursuant to Section 404 of the Clean Water Act (CWA) of 1977, and that was 

recently cleared for expansion by USACE in a separate project (Figure 1-2). The continued 

progradation and accretion of the very dynamic Atchafalaya Delta and related increases in the 

sediment bed load fraction (i.e., accelerated sedimentation) in nearshore portions of Atchafalaya 

Bay and the ARBC have allowed for additional beneficial use of maintenance-dredged material 

where practicable, and thus, the opportunity to expand the Section 404 Bird Island site in a 

southwesterly direction and into the footprint of the Section 103(b) ODMDS-West. The 

permanent Section 102(c) designation of the ODMDS-West would not prohibit future 

consideration of beneficial use alternatives as the physical characteristics of the ARBC change. 

MVN will continue to explore the possibility of using greater amounts of shoal material from the 

ARBC beneficially, if and when the bed load composition in the channel becomes more 

conducive (higher percentage of sand) to marsh and/or island creation as active progradation of 

the Atchafalaya Delta continues. It is anticipated that additional modifications (e.g., further 

shortening of the site footprint) to the proposed ODMDS-West may be deemed appropriate to 
21

accommodate future expansion of the Bird Island-West site and/or other beneficial use efforts as 

greater quantities of suitable (courser-grained) material become available in the area. Any 

modifications to the ODMDS-West (or ODMDS-East) site in the future would require the 

preparation of the appropriate environmental compliance and supporting documentation. 

Coordinates of the four corners of the proposed Section 102(c) ODMDS-West are as follows: 

Northwest Corner - 29°22′06′′ N, 91°27′38′′ W; Northeast Corner - 29°20′30′′ N, 91°25′13′′ W; 

Southeast Corner - 29°09′16′′ N, 91°35′12′′ W; Southwest Corner - 29°10′52′′ N, 91°37′33′′ W.

Maintenance dredging of the ARBC is required on an approximately annual basis and only 

maintenance-dredged material from the ARBC navigation channel would be placed into the 

proposed ODMDS-West. Maintenance-dredged material would be removed using hydraulic

cutterhead pipeline dredges and/or hopper dredges. Cutterhead dredges would discharge dredged 

material into the proposed ODMDS-West as non-cohesive slurry through a floating pipeline. 

Hopper dredges would excavate material from the navigation channel and transport and place the 

maintenance-dredged material at the proposed ODMDS-West. The maintenance-dredged 

material is generally comprised of mainly silt and clay with some sand. Maintenance dredged 

material would be discharged into the proposed ODMDS-West in a manner that would ensure 

that direct impacts of the placement would be within the limits of the ODMDS. Approximately 

10.8 mcy of future maintenance-dredged material would be placed annually (i.e., each fiscal 

year) at an average frequency of once every 7.4 months, into the proposed ODMDS-West during 

maintenance cycles. The proposed ODMDS-West is situated in a high-energy erosional zone and

can generally accept large volumes of dredged material with little apparent net change to the

bottom. The dredged material discharged into this site will disperse relatively quickly because of

the high percentage of fine grain components and because of the location of the site in a high 

energy, nearshore area where waves, currents, winds, and tides constantly mix and redistribute 

sediments, and thus, the dredged material, over a wide area. The site is situated within the inlet

zone and is adjacent to the channel, providing easy access for dredged material placement

operations and reduced costs. 

With its permanent, Section 102(c) designation the ODMDS-West would remain the primary 

disposal options for maintenance-dredged material removed from the ARBC. However, the 

ODMDS-East would retain its Section 102(c) designation and would remain a secondary 

disposal option for future dredging efforts in the ARBC on those occasions when disposal to the 

east side of the channel may be warranted. 

It is the responsibility of the EPA and the USACE under MPRSA to manage and monitor each of 

the ODMDSs designated by the EPA pursuant to Section 102 of MPRSA. Section 102(c)(3) of 

MPRSA requires development of a Site Management and Monitoring Plan (SMMP) for each 

ODMDS and review and revision of the SMMP not less frequently than every 10 years. A Draft 

SMMP for the proposed Section 102(c) ODMDS-West and the existing Section 102(c) ODMDSEast has been developed jointly by EPA and MVN and is included in Appendix A of this Draft 

EIS. This SMMP is intended to provide management strategies for disposal in the ODMDSWest and ODMDS-East sites as they are utilized for ARBC improvement and maintenance 

dredging projects. Upon finalization of this SMMP, the SMMP provisions shall be requirements 

for all dredged material disposal activities at the site.
22

1.3 PRIOR REPORTS AND PROJECTS

The impacts of the initial work in the ARBC were described in the Final EIS titled, “Atchafalaya 

River and Bayous Chene, Boeuf, and Black, Louisiana,” filed with the Council on 

Environmental Quality on January 15, 1974. A Supplemental Final EIS on the channel was filed 

with the EPA on February 4, 1977. 

The EPA prepared a Draft EIS (DEIS) on the final designation of the ARBC ODMDS (ODMDSEast), in November 1983. In December 1989, the EPA determined that a Supplemental EIS was 

necessary to correct information deficiencies and to include more recent data. The EPA prepared 

a Supplemental DEIS, “Atchafalaya River Bar Channel Ocean Dredged Material Disposal Site 

Designation,” in December 1990, and a Supplemental Final EIS in November 1998. 

An Environmental Assessment for the expansion of the ODMDS-East titled, “EA #256: 

Proposed Expansion and Selection of the Atchafalaya River Bar Channel Ocean Dredged 

Material Disposal Site,” was prepared by MVN and the resulting Finding of No Significant 

Impacts (FONSI) was signed on February 4, 1997. 

An Environmental Assessment for the temporary designation of ODMDS-West titled, “EA #348: 

Atchafalaya River and Bayous Chene, Boeuf, and Black, Louisiana, Construction of Advanced 

Maintenance Test Sections and Additional Disposal Areas in Atchafalaya River Bar Channel,” 

was prepared by MVN with a FONSI signed in July 2002. This action designated the ODMDSWest for use under MPRSA Section 103(b). In 2007 this designation was extended for an 

additional five years to 2012. 

The following presents a brief review of additional studies and reports prepared to address fluffrelated concerns in the ARBC: 

A Draft Final Report for Region 6 Contaminated Sediment Study Phase III, September 1996 was

prepared by EPA. The EPA conducted a three-phase study to identify and characterize the 

contaminants found in or near ODMDSs found within EPA Region 6. The study included a 

literature search, survey in June/July 1995, and survey in June/July 1996. The Atchafalaya River 

was included in the 1996 survey. 

The Final Report, “Marine Remote Sensing Survey of the Atchafalaya Ocean Dredged Material 

Disposal Site, Louisiana” was completed in October 1998 by USACE (USACE 1998). This 

report summarizes the results of a Phase 1 remote sensing submerged cultural resource 

investigation. The survey found that most anomalies identified resulted from oil and gas 

industry debris. The report indicated that no further archeological investigations appeared to be 

warranted.

As a component of the 2002 EA (EA #348), the USACE ERDC presented study findings in a 

report titled, “Final Report, Factors Affecting Fluff and Fluid Mud Accumulation in the 

Atchafalaya Bar Channel.” The study was performed to investigate the movement of sediment 

in the ARBC. The study was performed by Teeter et al. (2003) and was released in August 

2003. 
23

In an effort to further understand sediment conditions in Atchafalaya Bay, a study was performed 

by Evans Hamilton Inc. and Environmental Tracing Systems Limited (ETS) on behalf of MVN. 

The report of this study, titled, “Final Report, Silt Sediment Transport Study to Investigate Fate 

and Efficiency of Dredging and Characterization of Lateral Dredge Disposal Sites; Tracer 

Report, Atchafalaya River Bayous Chene, Boeuf, and Black, Atchafalaya Bar Channel, St. Mary 

Parish, Louisiana,” was released in September 2006 (ETS 2006). 

In addition to the above reports, numerous scientific reports have been produced regarding the

Atchafalaya River, and particularly the ARBC. A report prepared by MVN titled “Evaluation 

Report, Managing Sediments in the Atchafalaya Bar Channel, Atchafalaya Bay, St. Mary Parish, 

Louisiana” was completed in June 2007. 

1.4 AUTHORITY FOR THE PROPOSED ACTION

The authority for designation of ODMDSs is the MPRSA of 1972 (86 Stat. 1052), as amended 

(33 USCA 1401 et seq.). Title I of the MPRSA, which is the act’s primary regulatory section, 

authorizes the Administrator of the EPA to establish permit programs for ocean disposal of nondredged materials (Section 102) and the Secretary of the Army acting through the USACE to 

establish permit programs for ocean disposal of dredged materials (Section 103). Title I also 

requires the EPA to establish criteria, based on the factors listed in Section 102(a), for the review 

and evaluation of permits under the EPA and USACE permit programs. Section 102(c) of Title I 

authorizes the EPA, considering criteria established pursuant to Section 102(a), to designate 

recommended ocean disposal sites or times for disposal of non-dredged and dredged materials. 

Section 103(b) of Title I of the MPRSA, as amended by Section 501 of the Water Resources 

Development Act of 1992 (PL 102-580, October 31, 1992), authorizes the Secretary of the 

Army, with the concurrence of the Administrator of the EPA, to select an alternative ODMDS. 

The criteria and factors established in Section 102(a) relating to site selection are used in 

selecting the alternative site. Placement of maintenance-dredged material at the alternative site

under authority of MPRSA Section 103(b) is limited to a period of five years unless the EPA

subsequently assigns a permanent designation to the site. An ODMDS selected pursuant to 

Section 103(b) may continue for an additional five years if no other feasible placement site has 

been designated by the EPA; the continued use of the alternative site is necessary to maintain 

navigation and facilitate interstate or international commerce; and the EPA determines that the

continued use of the site does not pose an unacceptable risk to human health, aquatic resources, 

or the environment. 

The Federal Water Pollution Control Act (FWPCA), passed in 1972, and later amended by the 

Clean Water Act of 1977 (CWA), and MPRSA passed in 1972, specifically addressed waste 

disposal in aquatic and marine environments. The FWPCA and the Water Quality Improvement 

Act of 1970 set up specific water-quality criteria to be used as guidelines in controlling 

discharges into marine and aquatic environments. These water-quality criteria applied to 

placement of dredged material only in cases where fixed pipelines were used to transport and 

discharge dredged material into the environment at discrete points. MPRSA specifically

regulates the transport and ultimate disposal of waste materials in the ocean. Under Title I of 
24

MPRSA, the primary regulatory vehicle of the Act, a permit program for the disposal of dredged 

and non-dredged materials was established that mandates determination of impacts and provides 

for enforcement of permit conditions. 

The August 1975 London Convention on the Prevention of Marine Pollution by Dumping of 

Wastes and Other Matter (Convention) is the principal international agreement governing ocean 

disposal. The Convention specifies that contracting nations will regulate disposal in the marine 

environment within their jurisdiction, disallowing all disposal without permits. The nature and 

quantities of all waste material and the circumstances of disposal must be periodically reported to 

the International Maritime Organization (formerly the Inter-Governmental Maritime 

Consultative Organization), which administers the Convention. 

In October 1973, the EPA issued the final Ocean Dumping Regulations and Criteria (the 

Regulations or Ocean Dumping Regulations or ODR), which were revised in January 1977 (40 

CFR Parts 220 to 229). These regulations established procedures and criteria for review of ocean 

disposal permit applications (Part 227); assessment of impacts of ocean disposal and alternative 

disposal methods; enforcement of permits; and designation and management of ocean disposal 

sites (Part 228). They also established procedures by which the EPA is authorized to designate 

ODMDSs, times for ocean disposal of acceptable materials under Section 102(c) of the MPRSA, 

and the criteria for site designation, including general and specific criteria for site selection.

1.5 U.S. ARMY CORPS OF ENGINEERS

The Atchafalaya River and the ARBC provide ship access to Morgan City, the Gulf Intracoastal

Waterway (GIWW), and Bayous Chene, Boeuf, and Black from the Gulf of Mexico. Vessels 

using the ARBC consist of oilfield supply boats, offshore tugs, fishing boats, and barges.

Construction and maintenance of the 54-mile-long Atchafalaya River Navigation Channel was 

authorized by the Rivers and Harbors Act of 1968, House Document 155, 90th Congress, 1st 

Session. Its authorized dimensions are a depth of 20 ft relative to MLG by 400-ft bottom width. 

As the Atchafalaya River is a major thoroughfare and a U.S. Congressionally authorized 

navigable waterway, the USACE is responsible for operations and maintenance of the channel. 

For the MVN to maintain the ARBC to its currently authorized depth, material is periodically 

removed from the channel. The MVN is requesting that EPA permanently designate the 

ODMDS-West for continued placement of maintenance-dredged material from the ARBC under 

MPRSA Section 102(c).

1.6 U.S. ENVIRONMENTAL PROTECTION AGENCY

The EPA is authorized by Congress to regulate ocean disposal and associated site designation, 

monitoring, and management, as stated specifically in 40 CFR 228.4(e) (1). Site designation by 

EPA does not authorize any dredging project nor does it permit placement of any dredged 

material. Sites are designated in areas where a need for ocean disposal has been indicated, based 

on past dredging demands and/or projected demands associated with new or expanded projects. 

However, site designation does not in and of itself preclude the consideration of other placement 

options, including BU options or the No-Action Alternative. Once designated as an approved 

ocean disposal site, the appropriateness of ocean disposal is determined on a case-by-case basis 

in accordance with the ocean disposal criteria. 
25

1.7 COASTAL ZONE MANAGEMENT ACT

The Coastal Zone Management Act (CZMA) of 1972, as amended (16 USC 1451 et seq.), states 

in Section 307 (1) (A) “Each Federal agency with activity within or outside the coastal zone that 

affects land or water use or natural resources of the coastal zone shall be carried out in a manner 

that is consistent to the maximum extent practicable with the enforceable policies of approved 

State management programs.” Louisiana has developed a Coastal Zone Management Plan 

(CZMP), which has been approved by the National Oceanic and Atmospheric Administration 

(NOAA), the designee of the Secretary of Commerce for the CZMP approval. This DEIS 

addresses consistency with this CZMP by assessing impacts to critical coastal zone habitats and 

resources, as presented in the Consistency Determination prepared by EPA and submitted to the 

Louisiana Department of Natural Resources (LDNR), Office of Coastal Management (OCM) on 

February 27, 2012. 
26

2.0 ALTERNATIVES

Multiple site alternatives have been evaluated for placement of maintenance-dredged material: 

the No-Action Alternative, non-ocean placement alternative sites (BU), a nearshore alternative 

site, a mid-shelf alternative site, a deepwater alternative site, and the proposed ODMDS-West.

The site selection process and evaluation of site alternatives described in this section are also 

summarized and presented in Table 2.0-1. 

There are currently the following authorized disposal areas in Atchafalaya Bay (see Figures 1-1 

and 1-2):

• CWA Section 404 Disposal Site named Bird Island-East – located east of the ARBC 

on the left descending bank and used annually for BU prior to 2002. 

• CWA Section 404 Disposal Site named Bird Island West – located west of the ARBC 

on the right descending bank and used annually for BU since 2002. 

• MPRSA Section 102(c) designated ODMDS named ODMDS-East – located east of 

the ARBC on the left descending bank and used annually for placement prior to 2002. 

• MPRSA Section 103(b) designated ODMDS named ODMDS-West – located west of 

the ARBC on the right descending bank, used annually for placement since 2002 

(expired as of August 2012). 

Several concurrent approaches were taken in the collection of data relative to the proposed 

project and surrounding area. A computerized literature search for pertinent information was 

conducted. Forms of materials referenced include monographs, journals and other serials,

conference and symposium proceedings, theses and dissertations, technical reports, governmentsponsored research reports, and informational materials from resource agencies.

Data available from work contracted by the USACE to private corporations and universities, and 

from USACE EISs and monitoring data from the existing ODMDS-East and ODMDS-West 

projects were obtained. The data provided by the USACE also offer (1) information on the 

characteristics and quantity of the material previously dredged and deposited at the historically 

used sites, and (2) expected characteristics of future maintenance-dredged material. This 

information aided in determining the compatibility of future maintenance-dredged material with 

that already at the existing site and the expected amounts of maintenance-dredged material. 

USACE personnel also provided information pertinent to physical and geographical constraints.
27

Table 2.0-1. Summary of the screening process and evaluation outcome for the original 

array of ODMDS alternatives. 

 

ALTERNATIVES

SCREENING PROCESS

Beneficial Use (BU)

Marsh Creation

Beach Nourishment

Island Creation-confined

Island Creation-unconfined

Ocean Placement

Nearshore (Alt 1; ODMDS-West)

Mid-shelf

Deepwater

No-Action/

ODMDS-East* 

Preliminary Screening

Outcome 

Eliminate

Retain

Phase I Screening

(ZSF)

Outcome 

Eliminate

Retain

Phase I Screening 

(continued)

Outcome 

Eliminate

Retain

Phase II Screening

(11 Criteria)

Outcome 

Eliminate

Retain

Phase II Screening

(5 Criteria)

Outcome 

Eliminate

Retain

FINAL ALTERNATIVES

FOR IMPACT ANALYSIS

ODMDS-West ODMDS-East

* The No-Action Alternative and ODMDS-East Alternative are the same.

**This site differs slightly in footprint size from the previously screened Nearshore-ODMDS-West (the Section 103(b) ODMDS-West). 

All Ocean Placement

Nearshore-ODMDS-West

ODMDS-West**

ODMDS-West

ODMDS-West ODMDS-East

ODMDS-East

ODMDS-East

ODMDS-East

ODMDS-East

Nearshore-Alt 1,

Mid-shelf, Deepwater

(Preferred Alternative)

All BU
28

Monitoring studies have been conducted at and near both the existing ODMDS-East and at the 

MPRSA Section 103 ODMDS-West. The results of these studies, conducted by the USACE and 

USACE contractors, along with other studies, provided the necessary site-specific data used to 

characterize the water and sediments in the zone of siting feasibility (ZSF) and the physical 

characteristics and contaminant concentrations of future maintenance material.

In addition to the information discussed above, navigation charts, Bureau of Ocean Energy 

Management, Regulation and Enforcement charts, EISs, and other documents, were identified 

and collected. The collected data were compiled, arranged according to the pertinent topics and 

examined. At that time, any data gaps were noted. None were sufficient to disallow completion 

of the selection process; i.e., sufficient information was available to apply the exclusion process 

and the five general and eleven specific criteria.

2.1 NO-ACTION ALTERNATIVE

The No-Action Alternative allows for the placement of maintenance-dredged material at the

MPRSA Section 103(b) designated ODMDS-West located parallel and to the west of the 

navigation channel until July 31, 2012. Maintenance-dredged material from the ARBC could 

also be placed into the MPRSA Section 102(c) designated ODMDS-East located on the east side 

of the channel.

ODMDS-East, as designated by 65 CFR 314.92 on May 18, 2000, is bounded by the following 

coordinates: 

Northwest Corner - 29°20′59.92′′N, 91°23′33.23′′W 

Northeast Corner - 29°20′43.94′′N, 91°23′09.73′′W 

Southeast Corner - 29°08′15.46′′N, 91°34′51.02′′W 

Southwest Corner - 29°07′59.43′′N, 91°34′27.51′′W 

ODMDS-East is approximately 29.8 km (18.5 miles) long and 0.8 km (0.5 mile) wide, and is 

located east of, and parallel to the ARBC. The center of the ODMDS-East is approximately 16 

miles from the mouth of the Atchafalaya River. North Point of Point au Fer Island is about 3.2 

km (2 miles) east of the northern end of the site. The average water depth at the site is 

approximately 4.9 m (16 ft) MLG. 

In the absence of EPA action to permanently designate the ODMDS-West, the existing 

maintenance operations can place maintenance-dredged material into the current MPRSA 

Section 103(b) designated ODMDS-West until its designation expires on July 31, 2012, after

which time maintenance-dredged material must be placed in the MPRSA Section 102(c) 

designated ODMDS-East. As a result of disposal at ODMDS-East, MVN predicts that sediment 

would likely enter the ARBC at a higher rate due to the net northwest transport of sediments, 

likely requiring an increased dredging frequency for the ARBC. 
29

2.2 SITE ALTERNATIVES

The following sections outline the screening process through which reasonable action 

alternatives were identified and evaluated (Table 2.0-1). In accordance with the Louisiana 

Coastal Resources Program (LCRP) Guideline 4.2, and Section 307 of the CZMA, BU options 

for placement of the maintenance-dredged material were considered in addition to placement of 

material into an ODMDS. Each of these BU options was considered in regards to feasibility, 

cost, and longevity. Potential ODMDS sites were evaluated through a three-phase screening 

process.

2.2.1 Beneficial Use

Compliance with the LCRP Guideline 4.2, and Section 307 of the CZMA requires that “Spoil 

shall be used beneficially to the maximum extent practicable to improve productivity or create 

new habitat, reduce or compensate for environmental damage done by dredging activities, or 

prevent environmental damage” [emphasis added]. Under provisions of the LCRP, for each 

dredging operation, a Consistency Determination is made wherein consideration is given to the 

BU of maintenance-dredged material to the maximum extent practicable.

On November 8, 2007, Congress reaffirmed the long-standing Federal position that the costs 

associated with dredging for construction, operation, or maintenance of an authorized Federal 

water resources project are limited to the most cost-effective means, consistent with economic, 

engineering, and environmental criteria, Water Resources Development Act of 2007, P.L. 101- 

114, 121 Stat. 1041 (WRDA of 2007) Section 2037(c)(A). Any costs associated with the 

beneficial use of dredged material above this Federal Standard is to be cost-shared with a 

nonfederal sponsor after entering into a Project Cooperation Agreement, pursuant to Section 

2037(c)(B) of the WRDA of 2007. Section 2038 of the WRDA of 2007 is an affirmation of the 

Congressional limitations on the Federal government’s financial responsibility relative to the 

beneficial use of dredged material as contained in Section 204 of the WRDA of 1992, 33 USC 

2326. 

MVN has historically used dredged material from the upper Atchafalaya Bay Channel (about 

Station 4355+59 to Station 350+00) and the Atchafalaya Bar Channel (about Station 350+00 to 

Station 475+00) beneficially for bird island creation on both sides of the channel. In 1991, the 

MVN incorporated the northern end of the ODMDS-East into an area designated under CWA 

Section 404 for the placement of suitable maintenance-dredged material from the ARBC 

originating between Station 475+00 and Station 675+00, to create islands for colonial nesting 

birds. This beneficial use-placement area is approximately 1.6 km2 (402 acres) in size. In 2002, 

the MVN created an additional beneficial use-placement area, approximately 8.9 km2 (2,195 

acres), for island creation. This site, Bird Island-West (Figure 2.2-1), was also designated under 

CWA Section 404, accommodating material dredged from about Station 475+00 to Station 

650+00 of the upper ARBC. To compensate for compaction and subsidence during the 

marsh/island creation process, maintenance-dredged material is mounded to a maximum height 

of 1.8 m (+6 ft) MLG. Placement at Bird Island-East has led to dense vegetation inhabited by 

mostly mottled ducks. Bird Island-West is mostly inhabited by terns, gulls, and skimmers. 
30

The Bird Island-West disposal site was recently cleared for expansion by MVN in a separate 

project, Proposed Expansion of Bird Island Placement Site (Public Notice mailed July 13, 2011). 

The continued progradation and accretion of the Atchafalaya Delta and related increases in the 

sediment bed load fraction (i.e., accelerated sedimentation) in nearshore portions of Atchafalaya 

Bay and the ARBC have allowed for additional beneficial use of maintenance-dredged material 

where practicable, and thus, the opportunity to expand the Section 404 Bird Island-West site in a 

southwesterly direction and into the footprint of the Section 103(b) ODMDS-West. The recently 

authorized Bird Island-West expansion site is composed of approximately 3,274 acres of 

presently shallow open water, and would accommodate approximately 1,000,000 cubic yards of 

dredged material from the upper reaches of the ARBC during each maintenance event.

The ARBC Federal Standard, or base plan for disposal, is placement of shoal material in the 

adjacent Section 103(b) ODMDS-West. As discussed above, the extreme upper end of the 

ODMDS-West area has been designated for creation of colonial seabird nesting sites due to the 

presence of suitable, sandy material in the adjacent bar channel dredging reach. However, 

beneficial use of ARBC shoal material removed from about Station 650+00 out into the Gulf of 

Mexico is not practicable, as historical data indicate that approximately 80 percent of the 

material from this bar dredging reach is composed of "fluff" (a dense sediment-laden fluid), 

which is so fluid when hydraulically pumped that it is not suitable for creating substantial 

wetlands or land features such as bird islands, nor is it appropriate for beach nourishment. The 

use of fluid mud for beneficial use-placement applications, then, is not based on sound 

engineering practices. Furthermore, the cost of pumping the sandier material from the lower

portion of the ARBC to a non-ODMDS beneficial use area exceeds the Federal Standard and is 

not economically justified. 

MVN has demonstrated a commitment to using dredged material from the upper Atchafalaya 

River Bar and Bay channels beneficially where practicable—the numerous bird islands and 

associated fringe marsh habitat that have been created provide foraging, breeding, nesting, and 

nursery areas, as well as refugia for a multitude of estuarine-dependent and commercially 

important fish and shellfish, migratory waterfowl, wildlife, and several species of wading, 

diving, and shore birds, and help to offset the substantial wetlands loss currently taking place in 

Louisiana. Irrespective of a permanently designated Section 102(c) ODMDS-West, MVN will 

continue to explore the possibility of using greater amounts of shoal material from the ARBC 

beneficially, if and when the bed load composition in the channel becomes more suitable (i.e., 

courser-grained) for marsh and/or island creation as active progradation of the Atchafalaya Delta 

continues. It is anticipated that additional modifications (e.g., further reduction of the site 

footprint) to the proposed ODMDS-West may be deemed appropriate to accommodate future

expansion of the Bird Island-West and/or other beneficial use efforts as greater quantities of 

suitable material become available in the area. Any modifications to the proposed ODMDSWest (or ODMDS-East) site in the future would require the preparation of the appropriate 

accompanying environmental compliance and supporting documentation. 
31

Figure 2.2-1. Bird Island-West BU disposal area with fringe marsh. 

2.2.1.1 Beach Nourishment

The shoreline from Oyster Bayou to North Point of Point au Fer Island and the wash over area in 

the vicinity of Point au Fer have been identified as possible locations for beach nourishment 

(Figure 1-3). Most of the maintenance-dredged material removed between Station 650+00 and 

Station 1340+00 is a loose fluid mud (fluff). This material is considered unsuitable for beach 

nourishment. When hydraulically pumped, it flows as a fluid and does not have the high sand 

component that is typically used for beach nourishment projects. Even though the maintenancedredged material pumped onto the shoreline would not provide a sandy beach, the shoreline and 

adjacent marshes would be nourished, to some extent, by the fines contained in the fluff. As the 

fluff is pumped onto the shoreline, the fines would eventually settle and provide a thin layer of 

fine material over the shoreline and adjacent marshes. The degree to which this type of 

placement would benefit the shoreline and adjacent marshes is also limited due to the high wave 

and current energy environment characteristic of the Gulf coastal shores. 

The shoreline from North Point of Point au Fer Island to Oyster Bay is approximately two and 

twenty miles, respectively, from the upper and lower ends of the proposed ODMDS-East. The 

estimated incremental costs, compared to placement of material in the ODMDS-East, for 

transportation of maintenance-dredged material annually removed from the ARBC for the 

purpose of beach nourishment at this site would be approximately $48.4 million including 20 

percent contingencies (Table 2.2-1).

Recognizing the above cost and material constraints, the distance from the ARBC to the 

shoreline creates additional technological and safety limitations. Rough weather and seas make 

the use of a long pipeline or hopper dredges impractical. Because of the shallow water depths 
32

near the shoreline, hopper dredges with suitable capacity for the ARBC maintenance dredging 

would require a pipeline for final transportation of material to the beaches. Also, hopper dredges 

capable of making beach landings do not have the capacity required to transport the large volume 

of material to be dredged from the ARBC. Moreover, studies on wave-sediment interaction in 

Atchafalaya Bay have found that fluid mud is correlated with wave dissipation (Sheremet et al. 

2005), suggesting that this type of sediment may serve a role in dampening wave energy during 

storm events when left on the bay bottom (as opposed to placement on the Point au Fer beach). 

For these reasons, this alternative is not considered feasible, as it is not economically justified 

nor is it based on sound engineering practices, and has been eliminated from further 

consideration (Table 2.0-1). 

2.2.1.2 Marsh Creation

Maintenance dredged material removed from the ARBC may also be used for marsh creation in 

the vicinity of the prograding Atchafalaya Delta (Figure 2.2-1). Pumping the maintenancedredged material from the ARBC to the proposed marsh creation site in Atchafalaya Bay would 

require the use of at least two boosters. Additionally, the nature of the material dredged from the 

ARBC makes it less suitable for marsh creation—use of fluid mud to create wetlands is not 

based on sound engineering practices. 

The additional transportation distances from the ARBC to this potential marsh creation area 

would be from 16 to 47 km (10 to 29 miles). The estimated incremental annual costs, compared 

to placement in ODMDS-East, for pumping maintenance-dredged material from the ARBC to 

unconfined marsh creation sites in Atchafalaya Bay, a distance in excess of 16 km (10 miles) 

would be approximately $66.7 million, including 20 percent contingencies (see Table 2.2-1).

Because of the long pumping distance and associated costs, combined with characteristics of the 

material that make it unsuitable for use in marsh creation, this alternative is not considered 

feasible and has been eliminated from further consideration (Table 2.0-1). However, as stated 

earlier, MVN will continue to explore the possibility of using greater amounts of shoal material 

from the ARBC beneficially, if and when the bed load composition in the channel becomes more 

Table 2.2-1

Comparison of Incremental Costs Relative to the No-Action Alternative

Alternative 

One-Way 

Transport 

Distance

(mi) 

Incremental 

Transport Cost 

(million $) 

Incremental 

Construction 

Cost 

(million $) 

Total 

Incremental 

Cost 

(million $) 

Non Ocean Disposal – Beneficial Use

Beach Nourishment 

Marsh Creation

Island Creation – Uncontained Single Point 

Discharge

Island Creation – Contained Single Point 

Discharge 

Ocean Placement 

ODMDS-West 

Nearshore Alternative Site 1

Mid-shelf Alternative 

Deepwater Alternative 

9.1

14.9

2 

 

2 

 

1.1

9.5

29.7

74 

$48.4

$66.7 

$26.0

$26.0

$0

$49.7

$113.0

$253 

$0

$0

$0

 

$115.6 to 

$127.0 

$0 

$0 

$0

$0 

$48.4

$66.7 

$26.0

$141.6 to 

$153.0

$0

$49.7 

$113.0

$253 
33

conducive (i.e., higher percentage of sand) to marsh and/or island creation as active progradation 

of the Atchafalaya Delta continues. 

2.2.1.3 Island Creation – Single Point Unconfined Discharge

Unconfined open-water placement using single point discharge approximately every 2 miles 

along the entire length of the ARBC (total length along the proposed ODMDS-West is about 29 

km [18 miles]) was also considered. The objective of such placement would be the creation/ 

establishment of islands for use by colonial nesting birds. 

The estimated incremental annual costs, compared to placement of material in ODMDS-East, for 

pumping maintenance-dredged material annually from the ARBC to unconfined single point 

discharge points located approximately every 3.2 km (2 miles) along the length of the ARBC 

(approximately 19 miles) would be approximately $26.0 million including 20 percent 

contingencies (see Table 2.2-1).

As previously described, the maintenance-dredged material removed from the ARBC between 

Station 475+00 and Station 650+00 has been deposited in the CWA Section 404 site for bird 

islands. However, most of the maintenance-dredged material removed from the ARBC (between 

Station 650+00 and Station 1340+00) is a loosely consolidated fluid mud that is not suitable for 

creation of islands. For this reason, this alternative is not considered feasible and has been 

eliminated from further consideration (Table 2.0-1). However, as stated earlier, MVN will 

continue to explore the possibility of using greater amounts of shoal material from the ARBC 

beneficially, if and when the bed load composition in the channel becomes more conducive (i.e., 

higher percentage of sand) to marsh and/or island creation as active progradation of the 

Atchafalaya Delta continues. 

2.2.1.4 Island Creation – Single Point Confined Discharge

Because of the poor physical characteristics of the maintenance-dredged material removed from 

the ARBC, discharge into confined placement sites located within either the existing ODMDSEast or proposed ODMDS-West was also considered. Each of the confined placement sites 

would be approximately 3.2 km (2 miles) long by 0.8 km (1⁄2 mile) wide. Maintenance dredged 

material removed from the northernmost half of the ARBC would be placed in a confined 

placement site with center located at approximately 6.4 km (4 miles) from the head of the 

ODMDS. Maintenance dredged material removed from the southernmost half of the ARBC 

would be placed into a confined placement site located approximately 19 km (12 miles) from the 

northernmost head of the ODMDS. Specific options considered include the following: 

• Confined placement using native material for dikes — a short-term option considering 

the amount of material needed and the time needed for compaction and dewatering. 

• Confined placement using sediment fences — a means of holding sediment, with 

appropriate materials (e.g., Christmas trees), long enough for dewatering and settlement. 
34

• Confined placement using shell dikes — less expensive than rock but the cost savings 

may be offset if a larger amount of material were required. Long-term dike survival 

would likely require maintenance.

• Confined placement using rock dikes — costly, however, considering several dredging 

cycles, the total costs may be more reasonable. Also, mobilization cost could be 

reduced by constructing a large rock enclosure and creating internal cells from native 

sediments for each dredge cycle.

• Confined placement using anchored geotextile tubes — has not been tested, but 

geotextile tubes have been used to hold sediment in shallow water situations. 

• Confined placement using plastic sheet piling — has installation advantages over rock, 

and the cost of the material is more reasonable. An additional advantage of sheet piling 

is its potential capability to provide additional confinement for additional placement of 

material after the sediment has compacted.

The estimated incremental costs, compared to placement at ODMDS-East, for construction of the 

above confined placement sites (approximately 3.2 by 0.8 km [2 miles by 1⁄2 mile], each) is 

approximately $115.6 to $127.0 million, including a 20 percent contingency, depending on the 

type of confined placement, as described above. The estimated incremental annual cost, 

compared to placement of material in ODMDS-East, for pumping maintenance-dredged material 

from the ARBC into two confined placement sites located adjacent to the ARBC is 

approximately $26.0 million including a 20 percent contingency (see Table 2.2-1).

Confinement of the material would eventually allow some of the material to settle out. However, 

an accurate estimate of how much material and the time required for eventual mounding to occur 

is unknown. In the high-energy environment of the Gulf, it is possible that containment dikes 

could breach and/or maintenance would add to the overall operational costs. 

Because of the uncertainty associated with the feasibility of this alternative, as well as the 

potential for increased operational costs, this alternative has been eliminated from further 

consideration (Table 2.0-1). 

2.2.2 Screening Process for Ocean Placement Sites

The procedure classically used to determine which potential site is the preferable site for ocean 

placement is basically a series of eliminations carried out in sequential order (Pequegnat 1984). 

The order used in the evaluation process is as follows: 

Phase I

This phase of the screening process is presented in Section 2.3. Because none of the BU sites 

were identified for further evaluation, the analysis focuses on ocean placement alternatives. This 

first screening phase was used to identify the most appropriate alternatives(s) for additional 

evaluation. 
35

1. Definition of ZSF. This is an initial screening procedure used to limit the geographic 

area of consideration and define the ZSF. Reasonable haul distance is a determining 

factor, as well a cost of monitoring and surveillance, and constraints imposed by 

political boundaries. 

2. Characterization of expected material and site sizing. The type, quantity and 

behavior of expected maintenance material is identified. This is compared to general 

sediment characteristics in the ZSF to delineate zones of incompatibility. The 

requisite size of the proposed ODMDS is determined based upon review and analysis 

of historic pre and post-placement bathymetric surveys that provided sufficient detail 

to determine the size of the site. In addition, determination of the size of the site also 

considered the potential for runback of newly placed material from the placement site 

back to the dredged channel.

3. Establish buffer zones for critical areas and resources. Numerical models may also 

be used to define appropriate buffer zones around critical areas and resources. In this 

document, critical areas and resources will be discussed in three general categories — 

biologically sensitive areas, beaches and recreational areas, and navigation channels.

Phase II

In this phase, more site-specific issues are resolved based on consideration of the eleven specific 

factors prescribed in 40 CFR Part 228.6. These criteria are addressed in Section 2.4 based on the 

evaluation of alternatives, presented in Section 4. 

Phase III – Final Evaluation and Site Selection

Based upon the evaluations conducted in Phases I and II, final determination of the 

environmental suitability of each candidate site will be made in accordance with the five general 

criteria for site selection (40 CFR Part 228.5). These criteria are addressed in Section 2.5 based 

on the evaluation of alternative impacts presented in Section 4. 

2.3 DEVELOPMENT OF ALTERNATIVE SITES USING THE

SCREENING TECHNIQUE – PHASE I

As noted in Section 2.2.2, a three-phase screening process was used to identify practical and 

reasonable alternative sites for the placement of maintenance-dredged material from the ARBC

(Table 2.0-1). Three types of ocean placement, nearshore, mid-shelf, and deepwater, were 

considered. The following sections describe the alternatives that were considered and the steps 

taken through the first phase of the screening process. 

2.3.1 Ocean Placement Alternative Sites

Three types of ocean placement were considered: nearshore, mid-shelf, and deepwater. Two 

nearshore sites were considered. The first was a new site, referred to as “Nearshore Alternative 

Site 1,” and the existing ODMDS-West. One mid-shelf and one deepwater site were also 
36

considered. Additional detail regarding each alternative ocean placement site is provided in the 

following sections. 

2.3.1.1 Nearshore Alternative Site 1

The Nearshore Alternative Site 1 is located to the east side of the ARBC, Gulfward of the 

existing ODMDS-East. Productive fishing banks, oil, and gas development facilities are located 

throughout the nearshore areas. To avoid conflict with these and other permitted uses in the area, 

it was determined that an alternative nearshore ODMDS could be located approximately 14.8 km 

(9.2 miles) south and 3.7 km (2.3 miles) east of the center of the ODMDS-East (centered at 

28°08′30′′ N and 91°25′30′′ W). Location of the Nearshore Alternative Site 1 is shown in Figure 

1-3. 

The Nearshore Alternative Site 1 would be deeper (6 m [19.7 ft] MLG) than the ODMDS-East 

(2.0 to 6.6 m [6.6 to 21.6 ft] MLG). This variance in depth would not be great enough to 

substantially change the physical stresses on the bottom sediment at the two locations. 

According to the information presented in Darnell et al. (1983) and Phillips and James (1988), 

the bottom sediments and biological characteristics of the two locations are practically identical. 

Thus, if similar placement techniques are applied at the Nearshore Alternative Site 1, the 

environmental effects of the maintenance-dredged material would probably be quite similar to 

those at the ODMDS-East. If hopper dredges or barges are used to transport the material to the 

new site, temporary mounding at the site would be expected, but wave action and storm events in 

the shallow area would rapidly spread the material to a uniform level. Surveillance and 

monitoring conditions for the Nearshore Alternative Site 1 would also be similar to those at the 

ODMDS-East.

The estimated incremental cost, compared to placement at ODMDS-East, for transportation of

maintenance-dredged material annually removed from the ARBC to Nearshore Alternative Site 1 

is $49.7 million including 20 percent contingencies. Selection of an alternative nearshore site 

would subject a new area of the ocean to the effects of maintenance-dredged material placement 

while offering little environmental advantage over the proposed ODMDS-West site.

2.3.1.2 Nearshore Alternative Site – ODMDS-West 

The nearshore alternative site ODMDS-West is located to the west of the ARBC and 

approximately parallel to the existing ODMDS-East. To avoid conflict with oil and gas facilities 

and infrastructure, productive fishing banks, and other permitted uses in the area, an alternative 

nearshore site could be located approximately 30.5 km (19 miles) off the coast, and adjacent to 

the channel. The location of the nearshore alternative site, ODMDS-West, is shown in Figure 1-

3. 

This site is similar to the existing ODMDS-East in both physical and biological characteristics. 

Similar impacts would be expected to those experienced at the ODMDS-East when placement 

occurred at that site. The impacts at this site would be the same as the current impacts at the 

ODMDS-West under the MPRSA Section 103(b) authority. 
37

Based on historic (1996 - 2010) maintenance dredging data, the average volume of material that 

was placed in the ODMDS-East is greater than the average volume of material placed in the 

ODMDS-West. Table 1-1 indicates that the amount of maintenance material placed in each site 

on an annual basis indicates that an average of 438,152 cy more material was placed into 

ODMDS-East compared to ODMDS-West each fiscal year. Assuming the historical dredge 

volumes are not influenced by an unidentified factor, such as budget constraints for maintenance 

dredging, the data indicate that maintenance-dredging volumes were higher when material was 

placed in the ODMDS-East. This indicates that assuming the per unit cost is constant, placement 

of material in the ODMDS-West would have a lower incremental cost compared to placement of 

the material in the ODMDS-East, despite the fact that there would be no difference in the 

distance for placement.

MVN analysis of pre and post-maintenance dredging surveys conducted annually at the 

ODMDS-West since 2002 reflected the fluid nature of maintenance-dredged material and the 

low probability it would form permanent mounds. The depth of sediment accumulation in three 

of the placement reaches in the ODMDS-West was evaluated before and after the year of 

greatest dredged material placement for each area.

The amount of dredged material added to ODMDS-West had the potential to make the water 3 

inches (7.6 centimeters [cm]) shallower. Surveys indicated the ODMDS was actually about 4 

inches (10.2 cm) shallower at the end of the dredge placement period for 2004. Although the 

depth of water was shallower than expected by 2.5 cm (1 inch) following placement, there was 

not significant mounding in the ODMDS-West during the period of greatest dredged material 

placement to this reach.

The amount of dredged material added to two reaches within ODMDS-West had the potential to 

make these two areas 17.8 and 20.3 cm (7 and 8 inches) shallower. However, annual MVN 

surveys of these reaches pre and post-dredged material placement indicated these areas were 

actually slightly deeper at the end than at the beginning of the dredged placement cycle. These 

data suggest that long-term measurable mounding of dredged material in these placement reaches 

is not anticipated.

2.3.1.3 Mid-Shelf Alternative Site

The mid-shelf area off the coastal Louisiana is a biologically productive area with oil and gas 

lease tracts and pipelines located throughout the region. The selection of an alternative mid-shelf 

site was based principally on avoidance of the oil and gas lease tracts and pipelines. It was

determined that an alternative site in the shape of a square with center coordinates of 

approximately 28°49′00′′ N and 91°27′30′′ W would avoid oil and gas facilities. Location of the 

mid-shelf alternative site is shown in Figure 1-3. 

Depths in the area of the alternate mid-shelf site are approximately 18 m (60 ft). The site would 

be approximately 51 km (32 miles) from shore, somewhat closer and due west of Ship Shoal. 

The mid-shelf area in the vicinity of the proposed alternative site is characterized by a gentle 

slope with no prominent bottom features. Sediments range from silty clay to silty sand 

(Weissberg et al. 1980a). 
38

The mid-shelf area, being of greater depth, is less dynamic than the nearshore area near the 

ODMDS-East and West. Maintenance dredged material placed in this area would be subjected to 

a slower rate of erosion and transport. As a result, the layers of mixed site sediments and 

maintenance-dredged material that sloughs outside the immediate placement footprint could be 

thicker than those deposited at the ODMDS-East or West.

The physical effects on bottom organisms at the mid-shelf site would be different from those 

occurring at the existing ODMDSs-East or West. Because the mid-shelf site would necessitate 

the use of barges to transport the maintenance-dredged material, the material would undergo a 

certain amount of compaction and dewatering en route to the site. Since the material dredged 

from the channel is mostly silt and clay, when the material is finally placed at the site, it could be 

cohesive enough to settle to the bottom in discrete masses. This combined with reduced winddriven currents and storm effects at the 18-m (60-ft) depth would create a mound on top of the 

natural sediment at the site. Some organisms would be covered and smothered during placement 

operations. Others will be able to work their way up through the material and recolonize the new 

sediment surface or other areas. Some plankton would be trapped or lost in the descending 

plume. Nekton should be able to avoid the plume entirely. The three-dimensional aspects of a 

mound of deposited material on an otherwise very flat sediment area might conceivably create 

new habitat for benthic organisms. This alternative site can occasionally be affected by the Gulf 

of Mexico hypoxic zone (water with a dissolved oxygen (DO) concentration less-than-or-equalto 2.0 milligrams per liter [mg/L]), and therefore planktonic, benthic, and nektonic organisms

may be more susceptible to the additional stresses associated with maintenance-dredged material 

placement.

The estimated incremental cost, compared to placement of material at ODMDS-East, for 

transportation of maintenance-dredged material annually removed from the ARBC to be 

deposited at the mid-shelf alternative site is $113.0 million including 20 percent contingencies. 

Impacts of the mid-shelf alternative site include the increased costs of maintenance-dredged 

material placement and onsite monitoring efforts. Use of a cutterhead pipeline dredge would no 

longer be feasible due to the transport distance and hopper dredges or barges would be required. 

Surveillance and monitoring methods would be similar to those necessary at the interim site, but 

costs would be higher due to the increased travel and sampling time. The greater distance and 

water depths might also require the use of large vessels and special equipment. 

2.3.1.4 Deepwater Alternative Site

The deepwater region is the area seaward of the edge of the continental shelf. The edge of the 

continental shelf off this part of Louisiana is at the approximately 110-m (360-ft)-depth contour 

(USACE 1996). Although this area is beyond the white and brown shrimp grounds, it contains 

the royal red shrimp grounds and major fish-harvest areas. Fishing banks, oil, gas pipelines and

structures are also located in the area. A deepwater placement site could be located beyond the 

continental shelf directly south of the existing ODMDS-East, approximately 135 km (84 miles) 

from the ARBC. No specific site within the area was selected for site-specific evaluation.
39

Due to a breakup of the descending plume, the maintenance-dredged material placed at a 

deepwater site should be dispersed over a much larger area than at a mid-shelf site or a nearshore 

site. Once the sediments reach bottom they may tend to remain in place, subject to slow erosion 

and transport. However, neither of the foregoing assumptions can be confirmed without specific 

information on the near surface and bottom currents at the specific site. The physical effects of

placement on bottom organisms, phytoplankton, zooplankton, and nekton should be similar to 

those at the existing ODMDS-East or the mid-shelf alternative site but lesser in magnitude. 

Some bottom organisms, phytoplankton, and zooplankton could be trapped and perish. Nekton 

would be affected to the extent of having to avoid the descending plume. This placement area 

occasionally is affected by the Gulf of Mexico hypoxic zone. Planktonic, benthic, and nektonic 

organisms may be more susceptible to the additional stresses associated with maintenancedredged material placement if disposal is carried out during hypoxic conditions in the overlying 

water column.

The increased travel distance would increase the costs, and the large number of oil and gas 

platforms in the area could increase the safety hazards of placement operations. Operating in 

open-ocean waters for long periods of time and navigation through dense oil and gas fields and 

their associated traffic increase the possibility of emergencies such as rough waters or storms and 

collisions without vessels, which could necessitate placement of the maintenance-dredged 

material prior to reaching the proposed ODMDS. Surveillance and monitoring would be 

possible, but difficult and costly. Surveillance could be carried out through reports, ship riders, 

shipboard “black boxes,” and over flights. Monitoring would require special equipment because 

of the need to operate in open-ocean and deepwater. The estimated incremental cost, compared 

to placement in ODMDS-East, for transportation of maintenance-dredged material annually 

removed from the ARBC to be deposited at the deepwater alternative site is $253.0 million 

including 20 percent contingencies. This annual maintenance dredged material placement cost is 

increased by the need to use hopper dredges and/or barges, as well as the additional costs 

associated with the long turnaround time between loading and unloading of the barges. 

2.3.2 Zone of Siting Feasibility

The constraints on a site relative to the ZSF are those related more to its feasibility from a 

utilitarian as opposed to a regulatory perspective, although there is some overlap. Primary 

among the geographical and physical constraints are those which would restrict the safe and 

economical use of the site, such as distance from the dredging area, dangerous structures or 

currents, interference with or from other vessels, political boundaries, and logistic constraints on 

monitoring and surveillance. 

2.3.2.1 Limits Due to Cost of Transport

The efficiency of the dredging operation, for the purposes of this report, depends only on the 

placement site location since all other factors will be relatively constant, no matter where the 

placement site is located. This efficiency can be broken down into several factors: (1) safety to 

personnel and dredges, (2) cost of dredging per cubic yard, (3) the time required for the dredge to 

complete the dredging operation and be ready to move to another area, and (4) down-time due to 

equipment failure. All of these factors are adversely affected by increasing the distance of the 
40

placement site from the ARBC. The last three of these factors can be directly correlated to the 

distance from dredging area to placement site, while the first is more complicated and sitespecific. Certainly, however, the safety of personnel and dredges is related to some measure of 

the exposure time to potential hazards (i.e., weather, other vessels/structures, etc.) and increasing 

exposure time in the offshore area would have an overall adverse impact on safety 

considerations. Selecting a mid-shelf alternative site, or a nearshore alternative site Gulfward of 

the existing ODMDS-East would result in increases to maintenance dredging costs and 

monitoring costs. 

The EPA (1986) states that ODMDSs should be located in an area that is within an economically 

and operationally feasible distance from the dredging site. Pequegnat et al. (1990) also cite 

operational and transportation costs as a limit on the location of an ODMDS. Therefore, since no 

significant reasons for moving the placement site further offshore, i.e., to a nearshore site 

Gulfward of the existing ODMDS-East, mid-shelf site, or to one beyond the edge of the 

continental shelf, have been demonstrated, and since economic and safety reasons discourage 

consideration of alternatives with greater transport distances, based on limits due to cost of 

transport, the areas parallel to and west and east of the ARBC are the most feasible ODMDS 

locations. 

2.3.2.2 Limits Due to Feasibility of Monitoring and Surveillance

The geographical constraints on the feasibility of a site for monitoring and surveillance are three: 

(1) size, (2) configuration, and (3) location. Based on historical practice, size and configuration 

are not pertinent to the ZSF analysis. The restrictions on location are (1) that the site be near 

enough to shore to allow safe and efficient monitoring by reasonably available vessels, and (2) 

that the site be located in water shallow enough to allow efficient benthic sampling by 

reasonably available vessels and equipment, since benthic impacts are of primary concern. The 

first restriction is eliminated by the fact that any distance feasible for hopper dredge use will also 

be feasible for reasonably available monitoring and surveillance vessels. The efficiency of 

getting good replication benthic sampling due to anchoring difficulties for vessels reasonably 

available puts a water depth limitation on the site of a maximum of approximately 30 m (100 ft) 

(Pequegnat et al. 1981). Also, any increase in water depth increases the benthic sampling time 

due to increased winch time in dropping and retrieving the grab sampler. However, along the 

shelf near the ARBC, depth limitations are not as restrictive as are the cost factors, although a 

mid-shelf site would be in approximately 18 m (60 ft) of water. A site well beyond the ZSF 

boundaries would place restrictions on monitoring and surveillance that would reduce the 

feasibility of such a site.

2.3.2.3 Limits Due to Political Boundaries

The Atchafalaya Bay is located in both St. Mary and Terrebonne parishes. The ARBC, however, 

is located in St. Mary Parish. The Louisiana State Seaward Boundaries, measured from the mean 

lower low water (MLLW) line, and which separate State from Federal waters, determines the 

jurisdiction over activities that occur in those waters; for instance, the seaward limit of each 

State’s Coastal Zone and the extent of waters from which states receive all revenues from oil and 

gas exploration. However, these particular political boundaries do not limit the ZSF boundaries. 
41

There are no Military Warning Areas within roughly 40 km (25 miles) of the ARBC 

(www.gomr.mms.gov/homepg/regulate/environ/MWA_boundries.pdf).

2.3.2.4 Conclusion

Pequegnat (1984) recommends additional criteria for selecting a site and develops criteria to 

identify generally suitable sites. For example, a minimum water depth of 18 m (60 ft) is 

recommended to assure that the material would remain in the placement area for a relatively long 

time. Should the dredged material contain pollutants, strong winter waves would not resuspend 

the contaminants. Also a minimum size of 3 square nautical miles is recommended, which 

would be adequate for placement of 26 to 40 mcy of material annually. However, when sitespecific information is available, it is not unreasonable to use that information to determine 

whether a site is suitable for the area of interest. Indeed, Pequegnat (1984) recommends that 

where existing sites are suitable for their areas, they should not be excluded from consideration 

just because they do not meet the criteria for an ideal ODMDS.

In this document, the cost and safety issues involved in the transportation of dredged material 

were the limiting factors in determining the ZSF boundaries. Especially, a mid-shelf site 

(approximately 51 km [32 miles] offshore) and a site beyond the continental shelf would not be 

feasible because of dredging costs, safety, and limits on monitoring and surveillance. However, 

the amount and quality of the material to be dredged allowed the selection of the chosen ZSF 

boundaries since deep water and larger placement sites were not necessary.

Based primarily on the efficiency of the dredging operation in terms of time, cost, and safety and 

the general uniformity of the area near the ARBC, the ZSF for the proposed ODMDS is an area 

approximately 29 km (18 miles) long and 8 km (5 miles) wide adjacent to both sides of the 

ARBC (Figure 1-4). The ZSF thus encompasses an area of roughly 233 km2 (90 square miles). 

All areas outside this ZSF are excluded, unless some other factor arises that excludes all of the 

ZSF.

2.3.3 Characterization of Material and Site Sizing

2.3.3.1 Characterization of the Materials Expected to Be Dredged

Only material dredged from the ARBC to maintain the authorized channel depth would be placed 

at the proposed ODMDS. The maintenance-dredged material is generally comprised of silt with 

some sand and clay (7-12 percent sand, 81-88 percent silt, and 6-7 percent clay) (PBS&J 2008). 

Grain size analyses of dredged material sediments based on the samples collected for the 2008, 

2002 and 1996 contaminant assessments are listed in Table 2.3-1, along with the results of 

chemical analyses.

The material to be removed from the ARBC navigation channel through maintenance dredging 

has been characterized by sampling and analysis of channel bottom sediments, performed to 

determine the acceptability and potential impacts of dredged material placement at BU sites and 

ODMDSs. Sediment, elutriate, and water quality sampling have been conducted to evaluate the 
42

environmental conditions and potential impacts of dredging the ARBC and material placement at 

the designated disposal areas. In February 2008, samples were collected at reference locations, 

the channel site, and within the ODMDS-West area (PBS&J 2008). Contaminant assessments 

for the channel and disposal areas were also performed under contract to MVN in 2002 (PBS&J

2002) and in 1996 (Espey, Huston & Associates, Inc. 1997). Results of the analyses are listed in 

Table 2.3-1 and Table 2.3-2. 

2.3.3.1.1 Sediment Quality

The February 2008 sampling event for the contaminant assessment included collection of 

sediment samples for analysis from three locations along the ARBC channel alignment, three 

locations in the proposed ODMDS-West disposal area (ODMDS-West sediment quality data are 

discussed in Section 3.1.5.1.1 of this DEIS), and the reference area southeast of the channel 

(Tables 2.3-1 and 2.3-2; PBS&J 2008). Arsenic, beryllium, cadmium, chromium, lead, nickel 

and zinc were detected at all channel locations and at the reference location. The observed 

concentration ranges of each of these metals in the channel sediments were similar to the 

concentrations in the reference area. Selenium was detected at one channel sample location, and 

was not detected in the reference area sample. Thallium was not detected in the channel sample 

locations, but was present at a concentration just above the detection limit at the reference 

location. Total and trivalent chromium results were identical for each sample, reflecting the 

absence of hexavalent chromium in the maintenance-dredged material and surrounding area. 

Ten samples for sediment quality were collected along the ARBC channel alignment for the 

2002 contaminant assessment, along with sampling of the reference area (Table 2.3-1; PBS&J 

2002). Overall, the observed metals concentrations were similar to the results of the ARBC

sampling conducted in 2008. Silver was detected in one channel sample and the reference area 

at concentrations just above the detection limit. Sixteen samples were collected for analysis of 

sediment quality during the 1996 contaminant assessment (Table 2.3-1; Espey, Huston & 

Associates, Inc. 1997). Arsenic, beryllium, cadmium, silver, thallium, and trivalent chromium 

were not detected in the 1996 analyses. In general, the concentrations of other metals were 

observed at ranges similar to those found in the 2008 and 2002 results, as well as the reference 

area concentrations for the 1996 sampling event (Table 2.3-1). Zinc was detected at 112 

milligrams per kilogram (mg/kg) in one sample, but the results do not indicate the presence of 

contamination based on the observed range and distribution of zinc concentrations. 

In addition to metals, sediment samples from the ARBC collected during the 2008, 2002 and 

1996 sampling events were also analyzed for inorganic and organic priority pollutants (Table 

2.3-1; Espey, Huston & Associates, Inc. 1997; PBS&J 2002; PBS&J 2008). Ammonia and total 

organic carbon were the only non-metals detected. Total organic carbon was detected at channel 

locations and reference area locations at concentrations below 5 percent during both the 2008 

and 2002 sampling events. No organic carbon was detected in any channel samples from the 

1996 contaminant assessment, with a detection limit of 0.1 percent. 
43

Table 2.3-1. Dredged Material Quality Analytical Results

Analyte Units

2008 Data 2002 Data 1996 Data

Range Detection

Rate

Reference

Area Range DetectionRate

Reference

Area Range DetectionRate

Reference

Area

Metals

Arsenic mg/kg 7-11 3/3 6.9 4-7 10/10 3 N/A N/A

Beryllium mg/kg 0.6-1.0 3/3 0.8 1-7 2/10 ND N/A N/A

Cadmium mg/kg 0.3-0.4 3/3 0.2 0.2-0.4 10/10 ND N/A N/A

Chromium(TOT) mg/kg 18-30 3/3 25 14-25 10/10 11 19-48 16/16 29

Chromium(III) mg/kg 18-30 3/3 25 14-25 10/10 11 N/A N/A

Copper mg/kg 14-20 3/3 15 14-27 10/10 7 14-36 16/16 14

Lead mg/kg 13-19 3/3 15 21-35 10/10 14 4-6 16/16 4

Nickel mg/kg 9-11 3/3 10 21-32 10/10 16 22-49 16/16 26

Selenium mg/kg 0.3 1/3 ND 1 1/10 ND ND 0/16 ND

Silver mg/kg N/A N/A 0.5 1/10 0.4 N/A N/A

Thallium mg/kg ND 0/3 0.2 0.2-1 10/10 ND N/A N/A

Zinc mg/kg 58-83 3/3 69 66-96 10/10 51 67-112 16/16 80

Organic Carbon and Ammonia

Ammonia – N mg/kg 248-292 3/3 243 5-190 10/10 9 1-29 16/16 5

TOC % 2.9-3.8 3/3 1.9 0.5-1.8 10/10 0.5 ND 16/16 ND

Organic Compounds

TPH mg/kg ND 0/3 ND 45-347 5/10 ND ND 0/16 ND

Chrysene μg/kg ND 0/3 ND ND 0/10 ND 35 1/16 ND

Fluoranthene μg/kg ND 0/3 ND ND 0/10 ND 46 1/16 ND

Pyrene μg/kg ND 0/3 ND ND 0/10 ND 32 1/16 ND

Bis (2-ethylhexyl)

phthalate μg/kg ND 0/3 ND 114-246 3/10 142 ND 0/16 ND

Grain Size Distribution

Gravel % 0-3 0 0-0.3 0 0 0

Sand % 7-12 8 1.8-10.2 22 3-45 3

Silt % 81-88 81 35-61 58 22-53 44

Clay % 6-7 11 37-60 20 33-67 53
44

Table 2.3-2 

2008 Disposal Area Sediment Analytical Results – ODMDS-West

Ammonia was detected at all ARBC sample locations and at the reference area during the 2008 

sampling event (PBS&J 2008). With observed concentrations ranging from just over 240 mg/kg 

to nearly 300 mg/kg at the channel and reference areas (Table 2.3-1), the results indicate the 

widespread presence of available nitrogen that has the potential to act as a nutrient for biological 

activity. Research on the distribution of organic nitrogen in the northern Gulf of Mexico 

indicates that riverine sources such as the Mississippi and Atchafalaya Rivers are the 

predominant sources of available nitrogen (Lopez-Veneroni and Cifuentes 1994). Changes in 

ammonia concentrations over time throughout the project are shown by comparison of the 2008 

data with the 2002 and 1996 sampling results for ammonia (Table 2.3-1). The 2002 data 

indicated a much greater variability in ammonia concentrations across the study area, with 

concentrations ranging from 5 to nearly 200 mg/kg, with lower concentrations present at select 

locations in the channel and at the reference area. Even lower concentrations were observed in 

the 1996 data, with a maximum observed concentration of 29 mg/kg from the channel, and 5 

mg/kg at the reference area. Because of the similarities in ammonia concentrations observed at 

the channel and reference area for the sampling events, dredged material placement is not 

expected to change the sediment quality in the disposal area. 

Sediments from the ARBC sampled to characterize dredged materials have also been analyzed to

determine concentrations of potential organic contaminants, including total petroleum 

hydrocarbons (TPH), polynuclear aromatic hydrocarbons (PAHs) and chlorinated pesticides, 

herbicides and polychlorinated biphenyls (PCBs) (Table 2.3-1). These compounds are present in 

emissions and discharges from a variety of industrial processes and pollution sources, and they 

may persist in the environment and bioaccumulate. Bis(2-ethylhexyl phthalate, a plasticizer and 

common laboratory contaminant, was detected in 3 of 10 channel samples and the reference 

Analyte Units Sample Locations Reference 

Area

DA-1 DA-2 DA-3

Metals 

Arsenic mg/kg 7.5 10.1 6.5 6.9 

Beryllium mg/kg 0.85 J ND 0.68 J 0.84 J 

Cadmium mg/kg 0.3 0.3 ND 0.2 

Chromium(TOT) mg/kg 26 32 22 25 

Chromium(III) mg/kg 26 32 22 25 

Copper mg/kg 17 21 12 15 

Lead mg/kg 11 22 14 15 

Nickel mg/kg 11 29 8 10 

Selenium mg/kg ND ND ND ND 

Thallium mg/kg 0.2 0.2 0.2 0.2 

Zinc mg/kg 74 78 90 63 

Organic Carbon and Ammonia 

Ammonia – N mg/kg 237 253 212 243 

Grain Size Distribution

Sand % 1-23 8

Silt % 21-33 81

Clay % 45-78 11
45

sample from the 2002 sampling event, with observed concentrations from just over 100 

micrograms per kilogram (μg/kg) to nearly 250 μg/kg. This compound was not detected in the 

2008 or 1996 sampling events. The PAHs chrysene, fluoranthene and pyrene were detected in 1 

of 16 channel samples from the 1996 event, with concentrations below 50 μg/kg. TPH was 

detected in 5 of 10 channel samples from 2002, with concentrations ranging up to nearly 350 

mg/kg. Chemical analyses, suspended particulate phase bioassays, solid phase bioassays, and 

bioaccumulation studies conducted in 2008 indicated no causes for concern (PBS&J, 2008). The 

NOAA Effect Range – Low (ERL) for arsenic was exceeded in some channel sediment samples 

from the 2008 contaminant assessment, but the bioassays and bioaccumulation studies conducted 

as part of the assessment indicated no concern. The presence of these organic compounds in 

limited sampling results from individual sampling events reflect the changing conditions over 

time, and do not indicate a persistent, contiguous area of organic sediment contamination in the 

channel and reference areas.

2.3.3.1.2 Water Quality

Conventional water quality parameters are summarized in Table 2.3-3. For the 2008, 2002 and 

1996 contaminant assessments, elutriate and water samples were collected from locations in the 

ARBC, and from the reference area located southeast of the channel (Espey, Huston & 

Associates, Inc. 1997; PBS&J 2002; PBS&J 2008). Elutriate and water quality results and 

applicable Water Quality Standards (WQS) and EPA Water Quality Criteria (WQC) are listed in 

Tables 2.3-4 and 2.3-5. Antimony, arsenic, cadmium, copper, nickel, selenium, and zinc were 

detected in elutriates from the channel sample locations and from the reference area. None of the 

metals concentrations in the water samples was at or above the acute or chronic WQS or WQC. 

Arsenic, cadmium, copper, lead, nickel and zinc were detected in elutriate samples from channel 

locations and the reference area in the 2002 sampling results. None of the detected 

concentrations were at or above existing WQS or WQC. Barium, chromium, copper, lead, and 

zinc were detected in elutriates of samples from the channel alignment in the 1996 contaminant

characterization effort but were below applicable WQS or WQC.

Ammonia was detected in all elutriate samples from the ARBC and the reference area for the 

2008 sampling event, but was present in concentrations below applicable water quality standards. 

No water quality standard has been determined for total organic carbons (TOC), and elutriate 

results for this parameter are provided to indicate potential interaction of dredged materials with 

waters of the disposal area. Concentrations of 3 to 5 mg/L were found in the elutriate samples 

from the channel locations, and 2 mg/L from the reference area in the 2008 results. For the 2002 

sampling event, ammonia was detected in all channel sample elutriates, with concentrations 

ranging from 2 to 5 mg/L. TOC in the 2002 data ranged from 6 to 64 mg/L, and TPH was 

detected in 5 of 10 elutriates, with concentrations ranging from 2 to 8 mg/L. The detected TPH 

concentrations in the 2002 elutriate samples are consistent with the detected concentrations in 

sediment samples for this parameter.

Analyses of water samples collected in 2008 resulted in detection of antimony, arsenic, 

cadmium, copper, nickel, selenium and zinc at the channel sample locations. None of the metals 

concentrations in the elutriates was at or above the applicable acute or chronic WQS or WQC. 

Arsenic, copper, lead, mercury, nickel and zinc were detected in water samples from channel 
46

locations and in the 2002 sampling results. Of these metals, lead and mercury were not detected 

at the reference area. None of the detected concentrations were at or above existing WQS or 

WQC. Barium, copper, lead, and zinc were detected in water samples from the channel 

alignment and reference area in the 1996 contaminant characterization effort, and none of the 

results exceeded applicable WQS or WQC.

Table 2.3-3. Water Quality Conventional Parameters.

Parameters Units 2008 2002 1996

Low High Low High Low High

Temperature oC 13.2 17.2 16.6 20.9 11.9 18.2

pH Standard Units 7.37 8.01 7.38 11.13* 7.25 8.35

Dissolved Oxygen mg/l 7.58 9.64 4.96 7.74 6.75 7.90

Salinity ppt 0.02 31.58 11.0 13.5 0.0 21.6

*High pH values recorded during the 2002 sampling event probably do not reflect actual conditions, based on alkalinity and 

buffering capacity of marine waters.
47

Table 2.3-4. Elutriate Analytical Results

Analyte Units

Federal Water

Quality Criteria

LA Water 

Quality 

Standards

2008 Data 2002 Data 1996 Data

Acute Chronic Acute Chronic Range

Frequency 

of 

Detections

Reference

Concentration Range

Frequency 

of 

Detections

Reference

Concentration Range

Frequency 

of 

Detections

Reference

Concentration

Arsenic μg/l N/A N/A N/A N/A 0.5-1 3/3 1 ND 0/10 NA NA NA

Beryllium μg/l 69 36 69 36 2-4 3/3 3 1-4 7/10 NA ND 0/16 NA

Cadmium μg/l 40 8.8 45.4 10 0.2-0.3 2/3 0.3 0.9-2 3/10 NA ND 0/16 NA

Chromium(TOT) μg/l N/A N/A N/A N/A ND 0/3 ND ND 0/10 NA 1-2 4/16 NA

Chromium(III) μg/l N/A N/A 515 103 ND 0/3 ND ND 0/10 NA NA NA

Copper μg/l 4.8 3.1 3.63 3.63 0.9-1.2 3/3 0.6 5 1/10 NA 1-7 10/16 NA

Lead μg/l 140 5.6 209 8.08 ND 0/3 ND 0.2-2 4/10 NA 1-5 4/16 NA

Nickel μg/l 74 8.2 74 8.2 2-5 3/3 3 0.6-6 4/10 NA ND 0/16 NA

Selenium μg/l 290 71 N/A N/A 2-5 3/3 5 ND 0/10 NA ND 0/16 NA

Silver μg/l 2.3 N/A N/A N/A ND 0/3 ND ND 0/10 NA ND 0/16 NA

Thallium μg/l N/A N/A N/A N/A ND 0/3 ND ND 0/10 NA NA NA

Zinc μg/l 90 81 90 81 2-12 3/3 1 0.2-8 10/10 NA 2-76 10/16 NA

Ammonia mg/l 17.2 2.58 N/A N/A 0.3-0.4 3/3 0.3 2-9 10/10 NA NA NA

TOC mg/l N/A N/A N/A N/A 3-5 3/3 3 5-64 10/10 NA NA NA

TPH mg/l N/A N/A N/A N/A ND 0/3 ND 2-8 4/10 NA ND 0/16 NA

Table 2.3-5. Water Quality Analytical Results.

Analyte Units

Federal Water

Quality Criteria

LA Water 

Quality 

Standards

2008 Data 2002 Data 1996 Data

Acute Chronic Acute Chronic Range

Frequency 

of 

Detections

Reference

Concentration Range

Frequency 

of 

Detections

Reference

Concentration Range

Frequency 

of 

Detections

Reference

Concentration

Arsenic μg/l N/A N/A N/A N/A 0.6-0.8 3/3 0.6 0.6-1.0 2/10 ND NA NA

Beryllium μg/l 69 36 69 36 1.3-2.2 3/3 2.1 0.1-1.1 10/10 0.1 ND 0/10 ND

Cadmium μg/l 40 8.8 45.4 10 0.25-0.27 2/3 ND ND 0/10 ND ND 0/10 ND

Chromium(TOT) μg/l N/A N/A N/A N/A 0.46-0.85 2/3 ND ND 0/10 ND 1.5-5.2 9/16 ND

Chromium(III) μg/l N/A N/A 515 103 0.46-0.85 2/3 ND ND 0/10 ND NA NA

Copper μg/l 4.8 3.1 3.63 3.63 0.8-1.2 3/3 0.6 0.1-9.3 8/10 2.8 1.5-15 8/16 ND

Lead μg/l 140 5.6 209 8.08 ND 0/3 ND 0.4-0.9 2/10 ND 1.6-9.4 16/16 1.9

Nickel μg/l 74 8.2 74 8.2 1.1-1.5 3/3 1.5 0.4-8.1 4/10 1.0 ND 0/10 ND

Selenium μg/l 290 71 N/A N/A 1.7-4.8 3/3 5.4 ND 0/10 ND ND 0/10 ND

Silver μg/l 2.3 N/A N/A N/A ND 0/3 ND ND 0/10 ND ND 0/10 ND

Thallium μg/l N/A N/A N/A N/A ND 0/3 ND 0.1 1/10 ND NA NA

Zinc μg/l 90 81 90 81 0.55-0.96 3/3 0.89 4-20 10/10 16 7-52 10/16 9.4

Ammonia mg/l 17.2 2.58 N/A N/A 1.3-1.6 3/3 1.8 0.1-0.2 10/10 0.1 NA NA

TOC mg/l N/A N/A N/A N/A 3.6-5.1 3/3 3.2 6-34 10/10 6 NA NA

TPH mg/l N/A N/A N/A N/A ND 0/3 ND 0.1-2.7 9/10 ND ND 0/10 ND
48

2.3.3.2 Characterization of ODMDS-West 

The ODMDS-West encompasses approximately 35,000 acres (140 km2 [54 square miles]) of 

shallow open water at depths ranging from 1.8 to 7 m (6 to 23 ft) and extends from 

approximately the entrance to Atchafalaya Bay, sloping gently at about 0.01 degree to the 

southwest on the western side of the existing navigation channel. Historically, surface sediments 

in the ODMDS-West were predominantly silt and clay (IEC 1983; Dettman and Tracey 1990; 

Flemer et al. 1994; Trulli 1996). More recently, grain size analysis of the sediments sampled as 

part of the contaminant assessments conducted by PBS&J (2008) found material from the 

ODMDS-West consisting of approximately 1-23 percent sand, 21-33 percent silt, and 45-78 

percent clay. 

2.3.3.3 ODMDS Size Determination

The size of the proposed ODMDS-West was determined based upon the need to: (1) maximize 

the discharge distance away from the ARBC to minimize the run back of the deposited dredged 

material into the channel; and (2) allow for adjacent pumping of the dredged material from 

within the reaches of the ARBC. As a result, the dimensions of the proposed ODMDS-West

were determined to be 29 km (18.0 miles) long (length of the ARBC) and 5 km (3.0 miles) wide 

(typically the pumping distance at which a hydraulic pipeline cutterhead suction dredge may no 

longer be cost effective without a booster pump, depending on the size of the dredge). 

The configuration of the proposed ODMDS-West is designed for efficient routine placement of 

dredged material from the ARBC and to minimize the return of dredged material placed in the 

ODMDS to the channel. This consideration led to the establishment of a long, narrow site 

parallel to the channel. The site lends itself to surveillance of individual dredged material 

placement operations and monitoring. The long, relatively narrow configuration of the proposed 

ODMDS-West limits its overall area. This site design can assist with calculating the 

conservation of elements in the dredged material between dredging and final placement 

operations. This calculation could be very valuable if an area of contamination is located in the 

proposed ODMDS-West. Conversely, the orientation of the proposed ODMDS-West broadside 

to the prevailing currents in the area increases the chance that placed material will disperse away 

from the ARBC.

As discussed in Section 1.2, the currently proposed Section 102(c) ODMDS-West differs slightly 

from the existing Section 103(b) ODMDS-West at its upper end, resulting in an area only 16 

miles (26 km [14 nautical miles]) long—2 miles shorter than the ZSF length described in Section 

2.3.2.4. The purpose of a shortened ODMDS-West is to accommodate the southwesterly 

expansion of an adjacent Bird Island disposal site that is currently used by USACE for beneficial 

use of maintenance-dredged material removed from the ARBC, pursuant to Section 404 of the 

Clean Water Act (CWA) of 1977, and that is currently proposed for expansion by USACE in a 

separate project (Figure 1-2).
49

2.3.4 Establishment of Buffer Zones

2.3.4.1 Buffer Zone Assignment

Pre and post-maintenance dredging bathymetric surveys conducted annually by MVN show no 

accumulation of material in either the ODMDS-East or ODMDS-West. These data indicate 

material dispersion at the placement sites. Based on the results of the surveys, accumulation 

modeling was not conducted. The information gained from this evaluation allowed the 

determination of the buffer zones discussed below. 

2.3.4.1.1 Biologically Sensitive Areas

No marine sanctuaries occur in the immediate vicinity of the ARBC. Shell Keys and Marsh 

Island Refuges are approximately 46 km (25 nautical miles) west of the ODMDS-East. Fishnet 

Bank, the closest protected Area of Biological Significance is approximately 90 nautical miles 

south of the ODMDS-East.

2.3.4.1.2 Beaches and Recreational Areas

The nearest point of land is North Point au Fer Island and it is approximately 3.7 km (2 miles) 

from the existing and proposed ODMDSs. There are no beaches in the area of the proposed 

ODMDS-West. The Atchafalaya Delta WMA is located immediately adjacent to the upper end 

of the ODMDS-West, and provides recreational opportunities in the area. The only recreational 

activities that would be affected are fishing and boating. Since these effects are minor and 

temporary, no buffer zones were required for recreational areas.

2.3.4.1.3 Navigation Channel

The potential ODMDSs should be located such that the transport and placement of dredged

materials do not interfere with ongoing navigation operations in authorized channels and 

waterways. The candidate ODMDSs are located outside of the Navigation Channel and openwater approaches to the ARBC, therefore interference with navigation is not expected. All 

dredging and placement operations are closely coordinated with the USCG with issuance of a 

Notice to Mariners to dredging operators and the shipping interests to avoid interference with 

traffic.

2.3.5 Results of Phase I Evaluation

Based on the Phase I evaluation, establishment of the ZSF indicates that two sites are available 

for ODMDS designation under MPRSA Section 102(c) (Table 2.0-1). These sites are the 

existing ODMDS-East and the site formerly designated under MPRSA 103(b), the ODMDSWest. Unless the ODMDS-West is re-designated as a permanent Section 102(c) site by EPA, as 

of August 2012 placement of maintenance-dredged material must return to ODMDS-East. The

alternative carried forward through Phases II and III of the analysis is ODMDS-West; however,

ODMDS-East is often referenced for comparison purposes. 
50

2.4 EVALUATION OF ELEVEN SPECIFIC CRITERIA – PHASE II

Eleven specific factors prescribed in 40 CFR Part 228.6 are used in evaluating the proposed 

ODMDS site to assure that the general criteria are met. Evaluation of the eleven specific criteria 

focuses on the ODMDS-West (Table 2.0-1). The ODMDS-East is referenced only for 

comparison purposes, as its use is essentially equivalent to the No-Action Alternative. The 

characteristics of the proposed ODMDS-West are reviewed below in terms of these eleven 

specific factors. 

2.4.1 40 CFR 228.6(a) (#1)

Geographical position, depth of water, bottom topography, and distance from coast. 

The proposed ODMDS-West is a 26.0-km-long by 4.8-km-wide (16.0-mile long by 3.0 milewide) rectangular area located west of and parallel to the ARBC (Figure 1-2), and bound by the 

following coordinates:

Northwest Corner - 29°22′06′′N, 91°27′38′′W 

Northeast Corner - 29°20′30′′N, 91°25′13′′W 

Southeast Corner - 29°09′16′′N, 91°35′12′′W 

Southwest Corner - 29°10′52′′N, 91°37′33′′W 

The depth of the site ranges from 1 to 7 m (4 to 23 ft) MLG, and the total area is approximately 

129 km2 (48 square miles). The center of the ODMDS-West is approximately 30 km (19 miles) 

from the mouth of the Atchafalaya River. North Point of Point au Fer Island is approximately 4 

km (2.5 miles) east of the northern end of the proposed site. Point au Fer Shell Reef, an area that 

has been subjected to extensive shell dredging, lies just shoreward of the proposed site. 

As designated by 65 CFR 314.92 on May 18, 2000, the existing ARBC ODMDS-East is 

approximately 29.8 km long by 0.8 km wide (18.5 miles long and 0.5 mile wide), located in a 

water depth averaging 4.9 m (16 ft). The ARBC ODMDS-East is bounded by the following 

coordinates (Figure 1-2):

Northwest Corner - 29°20′60′′N, 91°23′33′′W 

Northeast Corner - 29°20′44′′N, 91°23′10′′W 

Southeast Corner - 29°08′15′′N, 91°34′51′′W 

Southwest Corner - 29°07′59′′N, 91°34′28′′W 

 

The continental shelf is approximately 149 km (93 miles) wide in the vicinity of the Atchafalaya 

River Delta. It is a gently sloping (<1°) submarine plain with many isolated sea knolls and 

seamounts (Bureau of Land Management [BLM] 1987; Weissberg et al. 1980a, 1980b; Phillips 

and James 1988). The ODMDS-West is located in the nearshore area of the plain. Except for 

being located adjacent to the dredged channel, the area occupied by the ODMDS is typical in 

depth and bottom topography to the continental shelf in the vicinity of the Atchafalaya River 

Delta.
51

2.4.2 40 CFR 228.6(a) (#2)

Location in relation to breeding, spawning, nursery, feeding or passage areas of living resources 

in adult or juvenile phases. 

The northwestern Gulf of Mexico is a breeding, spawning, nursery, and feeding area for shrimp, 

menhaden, and bottom fish. Many of the species migrate seasonally between estuaries and the 

Gulf. Because the timing of species movements vary, some migration can occur at almost any 

time of the year (Day et al., 1989). 

The proposed ODMDS-West is located in a region dominated by species that are estuarinedependent (Darnell et al., 1983; Phillips and James, 1988; Day et al., 1989). Commercially 

important species likely found in the area include white shrimp, brown shrimp, Gulf menhaden, 

and sand sea trout. Commercially important shellfish and fish that inhabit the nearby bay 

environment include oyster, blue crab, black drum, white shrimp, and brown shrimp. 

Limited interferences with nearshore fisheries may occur during placement of maintenancedredged material. The Atchafalaya estuary has a broader expanse of direct connection with the 

open Gulf of Mexico than any other estuary along the Louisiana coast. A small portion of this 

passage route may impede movement/migration of some marine organisms (e.g., shrimp) during 

periods of active dredging and placement. The settling of dredged material and the sediment 

plume in and near the ODMDS might also impede localized movement/migration of marine 

organisms on the continental shelf. However, the effect of these impediments on the 

movement/migration of marine organism populations affected would be very small and probably 

undetectable. The stress and possible mortality of individual organisms encountering adverse 

conditions during dredging and placement operations in the ODMDS would be negligible 

compared to the passage of the far greater majority of individuals crossing into or out of the 

estuary and at other locations. Additionally, any impact would also occur at any other ODMDS 

location near the ARBC.

Placement of material at the proposed ODMDS-West would have negligible effects on 

endangered and threatened species. Occurrences of whales off Louisiana are considered rare and 

because the animals generally inhabit waters far deeper than those in the proposed ODMDS, it is 

unlikely that maintenance-dredged material placement operations would impact whales.

Sea turtles could potentially be found in the proposed ODMDS-West, although the persistent 

high turbidity makes the area unsuitable for regular use of this area by sea turtles, which 

generally depend on their sight to feed. Dredging operations might affect sea turtles through 

incidental take. Hopper dredging has been identified as a source of mortality to sea turtles in 

inshore waters (Dickerson and Nelson 1990; Magnuson et al. 1990; U.S. Fish and Wildlife 

Service [USFWS] and NMFS 1991, 1992), not placement operations. Designation of the 

ODMDS-West has been requested for the placement of future maintenance material dredged 

from the ARBC by hydraulic cutterhead pipeline dredging and hopper dredging. If hopper 

dredges are used, there is a possibility of impact to sea turtles, as there would be no matter where 

the ODMDS is located. Hydraulic cutterhead pipeline dredging
52

operations have not been identified as a source of sea turtle mortality. Hopper dredging will be 

conducted in accordance with all reasonable and prudent measures and implementing terms and 

conditions provided to MVN by NMFS in its 2007 Biological Opinion (NMFS 2007) and any 

subsequent Biological Opinion, to avoid sea turtle mortality.

2.4.3 40 CFR 228.6(a) (#3)

Location in relation to beaches or other amenity areas. 

The nearest point of land is North Point of Point au Fer Island that is approximately 4 km (2.5 

miles) from the northeast end of the proposed ODMDS-West. There are no recreational parks or 

beaches near the proposed ODMDS-West. It may be possible to observe the placement plume 

from boats in the vicinity during the active period of maintenance-dredged material placement 

within the site. The plume resulting from the placement of dredged material is not expected to 

be visible from land because of the distance from land and the existing turbid nature of the water 

in the area. The plume is expected to dissipate quickly after completion of the placement 

operations. Except for the minor effects of these limited observations, there should be no effects 

to the aesthetics of the area.

2.4.4 40 CFR 228.6(a) (#4)

Types and quantities of wastes proposed to be disposed of and proposed methods of release, 

including methods of packaging the waste, if any. 

Material dredged from the ARBC is mainly comprised of silt, with lesser amounts of sand and 

clay (Dettmann and Tracey 1990; PBS&J 2002; PBS&J 2002). Sediment sampling as part of 

the contaminant assessments conducted by PBS&J (2008) found dredged material from the 

ARBC consisting of approximately 7-12 percent sand, 81-88 percent silt, and 6-7 percent clay. 

Based on dredging records since 2002, the volume of maintenance-dredged material to be 

removed from the ARBC for disposal to the ODMDS-West is approximately 10.8 mcy per fiscal 

year. Material is removed from the ARBC using a hydraulic cutterhead pipeline dredge and 

released within the ODMDS as uncohesive slurry. The ARBC is dredged annually and the 

average length of the dredging contract is 60 to 90 days. It is expected that future disposal 

operations will follow the past disposal pattern with respect to types, quantities, and methods of 

release. Any material disposed of at the site would be required to comply with the criteria of the 

Ocean Dumping Regulations (40 CFR Pans 220 to 229). None of the material will be packaged 

in any way.

2.4.5 40 CFR 228.6(a) (#5)

Feasibility of surveillance and monitoring 

The proposed ODMDS-West is in relatively shallow water and is close to shore, which facilitates 

surveillance and monitoring of the site. Operational observations can be made using shore-based 

radar, aircraft, and day-use boats. A draft Site Management and Monitoring Plan (SMMP) 

incorporating monitoring requirements (the Site Monitoring Program) has been developed jointly 
53

by EPA and MVN for the proposed ODMDS-West and existing ODMDS-East. The primary 

purpose of the Site Monitoring Program is to evaluate the impact of dredged material on the 

marine environment. The SMMP is included in Appendix A of this DEIS. 

2.4.6 40 CFR 228.6(a) (#6)

Dispersal, horizontal transport, and vertical mixing characteristics of the area, including 

prevailing current velocity, if any.

Current patterns in the vicinity of the proposed ODMDS are highly complex. Although tides, 

Loop current intrusions, and river flow may affect the local currents, these currents are 

influenced predominately by winds (Phillips and James, 1988). Thus, the direction and velocity 

of the currents vary throughout the year. Winds are a particularly strong driving force in late 

autumn, winter, and early spring. Net water flow in the winter is to the northwest; however, 

rapid flow reversals to the southeast occur periodically in concert with wind direction (Crout and 

Hamiter 1981; Phillips and James 1988; Walker and Hammack 2000). The near shore current 

patterns are somewhat more complex in summer. In the absence of strong winds and the 

presence of a stratified water column, current patterns become considerably less distinct. Net 

flow in summer can be either to the east or west (Crout and Hamiter 1981; Phillips and James 

1988; Walker and Hammack 2000). Spinoff eddies from the Loop current occasionally enter the 

region, producing flows to the southeast near the ARBC (Weissberg et al. 1980a, 1980b). 

Current speeds generally range from 10 to 30 centimeters per second (cm/s) in the vicinity of the

proposed ODMDS. Minimum speeds of 5 to 30 cm/s occur in June, July, and August; whereas 

the highest recorded current speeds in the vicinity range from 70 to 140 cm/s and occur during 

strong winter storms (Weissberg et al. 1980a, 1980b). Stagnant periods with little or no current 

motion, lasting as long as 6 days, have been recorded in April, May, and July (Weissberg et al.

1980a, 1980b). Current speeds may reach 200 cm/s during hurricanes, which occur, on average, 

approximately once every four years (Weissberg et al. 1980a, 1980b; Phillips and James 1988; 

NOAA 2013a).

In the absence of strong currents, the bulk of the maintenance-dredged material settles on the 

bottom of the particular area of a site being used at that time. A portion of the plume (fines) will 

be transported in the direction of the current over a wider area of the disposal site and, to some 

extent, outside the disposal site. This material will eventually settle over a wide area. Plume 

measurements were taken by Schubel et al. (1978) during dredged material disposal operations at 

the ODMDS-East. Background suspended solids concentrations were approximately 100 mg/L 

and currents were to the southwest at 9 to 19 cm/s. During placement operations, suspended 

solids concentrations as high as 300 mg/L were found a quarter of a mile downcurrent from the 

end of the discharge pipe. During another set of observations made when current directions were 

to the west and to the northeast, suspended solids concentrations of 300 mg/L were measured at 

0.6 to 1.0 mile downcurrent from the end of the discharge pipe. For comparison purposes, total 

suspended solids (TSS) concentrations in this area of the continental shelf normally range 

between 250 to 400 mg/L. 
54

The maintenance-dredged material is proportionally very small compared to the sediment load 

delivered by the discharge of the Atchafalaya River to the area. During disposal operations, a 

temporary mound of maintenance-dredged material may be initially formed within the ODMDS. 

However, flow of the noncohesive slurry and resuspension of the maintenance-dredged material 

results in the disappearance of the mound through dispersal and horizontal transport. The net 

result would be the remixing of maintenance-dredged material with other materials from the 

original source. The natural sediment load of the Atchafalaya is estimated to be approximately 

40 to 50 percent of the combined discharge from the Mississippi and Atchafalaya Rivers, which 

is 210 million tons/year (Walker and Hammack 2000). 

According to a sediment budget modeled by Teeter et al. (2003) for a hypothetical 10-mcy shoal 

in the ARBC, placement of material in the ODMDS-West would reduce runback to the channel 

by 5 mcy but increase lateral inflow by the same amount, when compared to placement in 

ODMDS-East. Although placement in ODMDS-West reduced runback to the channel, within 

approximately 10 weeks, the difference was made up through lateral inflow. Based on this 

analysis, the annual potential lateral source is estimated at approximately 30 mcy, which is a 

reasonable rate, given the parameters identified during the study (Teeter et al. 2003). Thus, 

while placing material on the west side of the ARBC did not eliminate shoaling, it did reduce 

runback of material into the channel, when compared to placing material on the east side of the 

channel. The 10-week decrease in the amount of time it takes material to reenter the ARBC, 

then, would decrease the overall annual maintenance dredging effort (i.e., dredging frequency) 

needed for the ARBC while providing vessels with a longer period of safe navigation access 

between maintenance dredging events.

2.4.7 40 CFR 228.6(a) (#7)

Existence and effects of current and previous discharges and dumping in the area (including 

cumulative effects).

The area proposed for selection has been used for the disposal of maintenance-dredged material 

since 2002. Bathymetric surveys taken prior to and after disposal operations indicate there is no 

persistent mounding and the maintenance-dredged material is relatively quickly dispersed (see 

mounding discussion in Section 2.3.1.2). No measurable effects from previous disposals have 

been noticed. 

Studies conducted on the ODMDS-East in the early 1980s and 1990s did not identify effects 

from dredged material placement in the water column, sediments, or benthos of the site. These 

studies were conducted during placement activities, as well as 10 and 15 months following 

placement activities (USAC, 1996). Although these studies were conducted at the ODMDSEast, it is reasonable to expect that, because of the proximity of the proposed ODMDS-West, 

there would also be no effects from placement at ODMDS-West.
55

2.4.8 40 CFR 228.6(a) (#8)

Interference with shipping, fishing, recreation, mineral extraction, desalination, fish and 

shellfish culture, areas of special scientific importance and other legitimate uses of the ocean. 

The proposed ODMDS-West is outside the navigation channel and therefore does not interfere 

with shipping. The shallow nature of the continental shelf in the area requires ships to remain in 

the navigation channels away from the ODMDS-West. Smaller recreational and commercial 

fishing vessels will pass over the ODMDS-West without interference from dredged material 

mounds that may temporarily form and that are expected to be relatively low and to disperse 

relatively quickly. Hydraulic cutterhead dredges and disposal pipelines may cause minor 

interference, but are not expected to interfere with shipping traffic. All dredging and placement 

operations are closely coordinated with the USCG with issuance of a Notice to Mariners to 

dredging operators and the shipping interests to avoid interference with traffic.

Recreational fishing and boating takes place throughout the area of the ODMDS-West. Ship 

Shoal is located approximately 47 km (29 miles) east of the ODMDS-West; Trinity and Tiger 

Shoals are about 45 km (28 miles) west of the site. Smaller fishing shoals are within 4.7 km (2.9 

miles) of the ODMDS-West and Point au Fer Reef is located just north of the site. There may be 

some short-term interference with recreational activities at the ODMDS-West, particularly 

during disposal operations. The plumes of maintenance-dredged material and activities 

associated with the dredging operations could have a minor impact on targeted fish stocks, which 

may tend to avoid the area of active placement, temporarily affecting recreational fishing in the 

area. This interference would be short-term and restricted to the relatively small area of the 

ODMDS-West being used for dredged material placement at any particular time. Trawling and 

crabbing in the channel and near the placement area may experience interference during 

dredging operations.

There are numerous active oil and gas platform located in the west and south end the ODMDSWest and other platforms are located adjacent to the east, south, and west of the site.

Additionally, several large natural gas pipelines cross the ODMDS-West. Because of the 

dispersive nature of the site, past experience with dredged material placement has not indicated 

interference with oil and gas exploration or production. No other types of mineral extraction are 

taking place either within the site or within the general vicinity of the site. It is not expected that 

use of the site for placement of maintenance-dredged material would interfere with any other 

legitimate use of the ocean in this general area.

No desalination or artificial finfish or shellfish culture facilities are located within the site. The 

nearest oyster leases are located approximately 6 km (4 miles) east of the ODMDS-West, near 

Point au Fer (Ernie Dugas 1995, personal communication, Oyster Survey Section LDWF; 

USACE 1996; LDNR 2012). Fish and shellfish that naturally occur within the site may be 

affected by placement of dredge material at the site, particularly bottom-dwelling organisms that 

may be trapped and smothered. Material dispersed from the site is expected to settle in thin 

layers and be mixed with the naturally occurring sediments in the region. Thus, dispersion and 

transport of this material outside of the site should not adversely affect the fish and shellfish in 

the area. Additionally, because the transport of suspended material from the ODMDS-West
56

would be primarily parallel to the coastline and in a generally westward direction for much of the 

year, effect of placement operations on oyster lease areas near Point au Fer would be minimal 

and consistent with natural conditions. There have been no impacts to oyster leases from the use 

of the interim-designated ODMDS-West, thus no impact is expected from its continued use. 

Two areas designated as wildlife management areas or wildlife refuges and that are used for 

recreational use are located in the project area. The 140,000-acre Atchafalaya Delta WMA, 

managed by the LDWF, encompasses the developing delta in Atchafalaya Bay (Figure 2.4-1). 

The Atchafalaya Delta WMA is located immediately adjacent to the upper end of the existing 

Section 103(b) ODMDS-West. The Shell Keys National Wildlife Refuge and Russell Sage - 

Marsh Island State Wildlife Refuge is located approximately 29 miles (47 km) west of the 

ODMDS-West. The transport of suspended materials from the ODMDS-West would mainly be 

parallel to the coastline, and concentrations of suspended materials produced during dredging 

operations are expected to be within background levels within a few miles or so of the ODMDSWest (May 1973). Suspended materials originating from the ODMDS-West may drift into 

adjacent portions of the Atchafalaya Delta WMA; however, the effects of these suspended 

materials would likely be indiscernible from ambient conditions in these areas. There have been 

no significant impacts to these areas from use of the interim-designated ODMDS-West, and no 

impacts are expected from its continued use. 

Figure 2.4-1. Atchafalaya Delta Wildlife Management Area (WMA), adjacent

to the ODMDS-West and ODMDS-East (not drawn to scale). 

Atchafalaya Delta WMA

ODMDS-West

ODMDS-East

ARBC

Bay Channel

Bird Islands
57

Various universities and state and Federal agencies have studied the biological, 

geomorphological, and hydrological development of the Atchafalaya Delta. This includes 

scientific studies that are periodically carried out in the offshore region and the bays of the area. 

As the Atchafalaya Delta progrades from the Atchafalaya Bay into the Gulf of Mexico, it is 

likely that scientific interest in the area will continue. Placement of dredged material into the 

ODMDS-West is not expected to interfere with any such studies.

2.4.9 40 CFR 228.6(a) (#9)

Existing water quality and ecology of the site as determined by available data or by trend 

assessment or baseline surveys.

The water quality and ecology of the proposed ODMDS-West generally reflect that of the 

nearshore region off the Louisiana coast affected by discharges from the Atchafalaya River. The 

variations in water quality depend on the amount and mixing of freshwater runoff that is highly 

variable (Phillips and James 1988). Data collected during the IEC (1983) surveys and the EPAERLN (Dettmann and Tracey 1990) survey are generally comparable to historic data for the area 

as summarized in Phillips and James (1988). Neither the IEC (1983) nor the EPA-ERLN 

(Dettmann and Tracey 1990) water column data were taken during maintenance-dredged 

material placement operations; therefore, these data reflect ambient conditions. Similarly, water 

quality and sediment contaminant data from the 2008, 2002 and 1996 contaminant assessments 

all indicated no water quality impacts related to the placement of dredged material. Additional 

detail regarding these data, as well as additional discussion of water quality can be found in 

sections 4.1.4 and 4.1.5. 

Macrofaunal assemblages near the ARBC ODMDSs have been examined during benthic 

investigations of several proposed salt dome brine diffuser sites (Parker et al., 1980; Weissberg 

et al., 1980a, 1980b). These studies characterized nearshore assemblages typical of estuarine 

areas, with communities dominated by polychaete worms, small molluscs, and

macrocrustaceans. Most species displayed seasonal population fluctuations, with recruitment 

during winter and spring. Stations sampled by IEC (1983) in the vicinity of the ODMDS-East 

were further inshore and shallower than the proposed brine diffuser sites; however, the same 

general macrofaunal assemblage was found. During both surveys, polychaetes dominated the 

macrofauna.

Central Louisiana Gulf coastal waters are inhabited by numerous species of finfish and shellfish 

that can be characterized as estuary-related or demersal shelf inhabitants. Nektonic species and 

fast swimmers that may occur within the area of the ODMDS are attracted to oil rigs, which 

provide reef-like environments in the Gulf. Most, but not all, of the larger predators occur 

seasonally on the northern Gulf shelf, appearing in spring and leaving in the fall (Darnell et al.

1983). The density distribution of total fish and Penaeid shrimp catch in the northwestern Gulf 

has historically been highest off Louisiana (NMFS 2012). This may be directly attributable to 

the extensive estuarine nursery areas of Louisiana (Darnell et al. 1983; Darnell and Kleypas

1987). Recreational fishing, including fishing, crabbing, and shrimping, is popular in the vicinity 

of the ODMDSs. 
58

2.4.10 40 CFR 228.6(a) (#10)

Potentiality for the development or recruitment of nuisance species in the disposal site. 

Past placement of maintenance-dredged material at the existing ODMDS-East and ODMDSWest has not resulted in the development or recruitment of nuisance species. Therefore, 

placement of maintenance-dredged material at the proposed ODMDS-West is not expected to 

result in development or recruitment of nuisance species.

2.4.11 40 CFR 228.6(a) (#11)

Existence of or in close proximity to the site of significant natural or cultural features of 

historical importance. 

The USACE Submerged Cultural Resource Database contains historical accounts of 52 

shipwrecks in the Atchafalaya River and 7 shipwrecks in Atchafalaya Bay. These records

indicate historical use of the Atchafalaya Basin. In 1996, a remote sensing survey was 

conducted in the ODMDS-East. This study found that while several anomaly clusters existed, 

which may represent shipwrecks, the geomorphologic and bathymetric data indicates that 

between 5 and 6 m (17 and 21 ft) of sedimentation had occurred in the area between 1839 and 

1996. A vessel wrecked more than 157 years ago may have at least 5 m (17 ft) of sediment 

covering it. As a result of this survey, it was concluded that the placement of maintenancedredged materials in the proposed ODMDS-West would not add appreciably to the impact 

already induced by progradation of the Atchafalaya Delta during the last century. There is no 

other information suggesting the presence of significant natural or cultural resources of historical 

importance in the vicinity of the proposed ODMDS-West. The results of the 1996 remote 

sensing study can be applied to the present study given its proximity to the previously designated 

ODMDS-East.

2.5 FINAL EVALUATION AND SITE SELECTION — PHASE III 

Based upon the Phase I evaluation, the Nearshore Alternative Site 1, Mid-Shelf Alternative Site, 

and Deepwater Alternative Site were eliminated from consideration, primarily based on criteria 

used to establish the ZSF (Table 2.0-1). The ODMDS-East and ODMDS-West alternatives are 

considered reasonable. However, as previously described, use of the ODMDS-East site is 

essentially equivalent to the No-Action Alternative. The ODMDS-East is referenced only for 

comparison purposes. As with the Phase II evaluation, then, the third phase of evaluation

addresses only the ODMDS-West. The evaluation ensures that the site is environmentally

suitable in accordance with the five general criteria for site selection established by EPA (40 

CFR Part 228.5). The EPA has determined, based on the information and analyses in this Draft 

EIS, that the ODMDS-West site is acceptable under the five general criteria outline below. 
59

2.5.1 Five General Criteria

2.5.1.1 40 CFR 228.5(a) (#1)

The dumping of materials into the ocean will be permitted only at sites or in areas selected to 

minimize the interference of disposal activities with other activities in the marine environment, 

particularly avoiding areas of existing fisheries or shellfisheries, and regions of heavy 

commercial or recreational navigation. 

The ODMDS-West is located adjacent to and parallel to the ARBC. This location reduces the 

distance that the maintenance-dredged material must be transported, minimizing interference 

with other activities in the marine environment. There may be some short-term interference with 

fishing activities during placement operations. No interference with these or other marine 

activities is expected outside the brief periods of placement operations. There have been no 

impacts to existing oyster leases located northeast of the ODMDS area near Point au Fer from 

the use of the existing ODMDS-East, or ODMDS-West (which has been used since 2002), and 

no impact is expected to occur in the future as a result of using the proposed ODMDS-West.

2.5.1.2 40 CFR 228.5(b) (#2)

Locations and boundaries of disposal sites will be so chosen that temporary perturbations in 

water quality or other environmental conditions during initial mixing caused by disposal 

operations anywhere within the site can be expected to be reduced to normal ambient seawater 

levels or to undetectable contaminant concentrations or effects before reaching any beach, 

shoreline, marine sanctuary, or known geographically limited fishery or shellfishery.

Placement of maintenance-dredged material will produce a turbidity plume. This plume will 

disperse to the point where it would be indistinguishable from the turbidity naturally occurring in 

the area. Turbidity resulting from maintenance-dredged material placement is not expected to be 

distinguishable from the natural turbidity occurring in the vicinity of North Point and in 

Atchafalaya Bay, except temporarily. There are no marine sanctuaries in the immediate vicinity 

of the ODMDS (USFWS 1981). Fishnet Bank, the nearest protected Area of Biological 

Significance, is approximately 104 miles south of the ODMDS. Any impacts from placement of 

dredged material are expected to be minor. Based on the current regime noted in Section 3.1.3.2, 

the transport of suspended materials from the ODMDS would mainly be parallel to the coastline, 

and concentrations of suspended materials produced during dredging operations are expected to 

be within background levels within a few miles or so of the ODMDS (May 1973). There are no 

Public Oyster Areas within the ODMDS-East or ODMDS-West, and the nearest oyster leases are 

approximately 4 miles east of the ARBC and ODMDSs, near Point au Fer (LDNR 2012). The 

potential impact on oyster beds in nearby Atchafalaya Bay is expected to be minimal. These 

organisms, as well as others in the region, are naturally subjected to periodic episodes of high, 

suspended-solids concentrations from wave-induced resuspension of nearshore sediments and 

from the waters of the Atchafalaya River.
60

2.5.1.3 40 CFR 228.5(c) (#3)

If, at any time during or after disposal site evaluation studies, it is determined that existing 

disposal sites presently approved on an interim basis for ocean dumping do not meet the criteria 

for site selection set forth in 228.5–228.6, the use of such sites will be terminated as soon as 

suitable alternative disposal sites can be designated. 

This criterion does not apply to the proposed ODMDS-West since it is not an existing site 

approved on an interim basis. However, studies to date indicate that the proposed ODMDS 

meets the requirements of the MPRSA. Surveys of the site and vicinity indicated that water 

quality, sediments, and biological life were generally similar to surrounding areas. An existing 

designated ODMDS (the ODMDS-East) is located immediately across the navigation channel 

from the proposed site. No adverse environmental effects were detected outside the site 

boundaries during site investigation surveys (IEC 1983; Dettmann and Tracey 1990; Flemer et 

al. 1994; Trulli 1996) of ODMDS-West. 

2.5.1.4 40 CFR 228.5(d) (#4)

The sizes of ocean disposal sites will be limited in order to localize for identification and control 

any immediate adverse impacts and to permit the implementation of effective monitoring and 

surveillance programs to prevent adverse long-range impacts. The size, configuration, and 

location of any disposal site will be determined as a part of the disposal site evaluation or 

designation study. 

The size of the ODMDS-West has been identified to cover an area as small as possible to 

reasonably meet the criteria stated at 40 CFR 228.6(a) for the ARBC project and for efficient 

placement of material dredged from the ARBC. The size and location of the proposed ODMDS 

also minimizes the return of dredged material from the ODMDS to the channel. This 

consideration led to the establishment of a long site parallel to the channel with an area of 140 

km2 (54 square miles). The site lends itself to surveillance of individual dredged material 

placement operations and long-term monitoring. The configuration of the ODMDS-West limits 

its overall area to a dimension of 29.0 by 4.8 km (18.0 miles long by 3.0 miles) wide. The width 

of 4.8 km (3.0 miles) is typically the pumping distance at which a hydraulic pipeline cutterhead 

suction dredge may no longer be cost effective without a booster pump, depending on the size of 

the dredge. Teeter (2003) recommended westward disposal at the greatest practicable distance 

from the channel to minimize runback into the channel. The orientation of the ODMDS 

broadside to the prevailing currents in the area increases the chance that material placed in the 

ODMDS will be moved from the site before undesirable mounding can occur. 

2.5.1.5 40 CFR 228.5(e) (#5)

EPA will, wherever feasible, designate ocean dumping sites beyond the edge of the continental 

shelf and other such sites that have been historically used. 

In this area of the Gulf of Mexico, an ODMDS beyond the continental shelf would be at least 

135 km (84 miles) from the area to be dredged. A dredged material placement site beyond the 
61

continental shelf would not be feasible due to, among other things, increased safety risks, 

increased cost of dredged material transportation, and increased costs for site characterization, 

monitoring, and surveillance studies. 

2.6 IDENTIFICATION OF THE PREFERRED ALTERNATIVE

2.6.1 Evaluation of Constraints

2.6.1.1 Oceanographic Constraints

With time, material placed within the ODMDS during maintenance activities (see Section 

4.1.2.7) will disperse and be carried down current. Since net sediment transport is generally to 

the northwest, use of the ODMDS to the east of the channel (ODMDS-East) would increase the 

likelihood that the dredged material would be carried back into the channel. Therefore, all areas 

east of the channel are excluded from consideration for the ODMDS.

2.6.1.2 Cultural and/or Historic Constraints

A 1996 cultural and historic resources survey identified several anomaly clusters that could be

shipwrecks. However, these clusters currently lie under more than 5.5 m (18 ft) of sediment and 

thus the placement of dredged material would not affect these resources. Therefore, there are no 

constraints due to cultural or historic resources. 

2.6.1.3 Nonliving Resources Constraints

Local currents in the vicinity of the ODMDS-West are predominantly influenced by winds and, 

to a lesser degree, tides, Loop Current intrusions, and river flow. Net flow is to the northwest 

throughout most of the year (Wells et al. 1981; Weissberg et al. 1980a, 1980b). However, net 

flow in the summer can either be to the east or the west (Crout and Hamiter 1981; Weissberg et 

al. 1980a). Winds are a particularly strong driving force in the late autumn, winter, and early 

spring. Net water flow in the winter is to the northwest; however, rapid flow reversals to the 

southeast occur periodically and follow changes in wind direction (Weissberg et al. 1980a, b; 

Crout and Hamiter 1981). In the absence of strong winds and the presence of a stratified water 

column, current patterns become considerably less distinct (Weissberg et al. 1980a, 1980b). 

Tides may dominate current direction during winter periods of slack winds; however, tidal 

influences result in little or no net water or sediment displacement at the site.

The Atchafalaya River is a distributary of the Mississippi and presently carries about 30 percent

of the Mississippi River’s total water and sediment load (Wells et al. 1981; USACE 2004). 

Murray (1998) found the sediment plume from Atchafalaya Bay flowed to the west particularly 

during fall, winter and spring but its direction of travel could change rapidly with major wind 

direction shifts. The ARBC crosses a shallow, flat, reach of the inner Gulf of Mexico shelf with 

bottom sediment consisting of fine particles, easily resuspended into the water column. These 

resuspended sediments may be transported in several different directions depending on wind 

direction and strength, river flows, longshore currents and tides. Channel morphology (relatively 

deep compared to the surrounding inner shelf bottom) and its orientation (perpendicular to 
62

typical long shore currents) enhance the capture and retention of sediments. Several studies 

document fluff, or fluid mud, accumulations on the inner shelf and within the channel (Van 

Heerden and Kemp 2000). Sediments that accumulate in the Gulf portion of the ARBC result 

from a combination of littoral transport and inputs from the Atchafalaya River. Currently, the 

presence of fluff in the ARBC has made it very difficult to maintain the authorized 6-m (20-ft) 

MLG channel depth through the ARBC. The fluff returns to the channel within weeks after 

maintenance dredging is complete and interferes with the passage of certain types of vessels. A 

recent review of literature addressing the accumulation of sediment within the ARBC and 

options for placement of dredged material to reduce runback indicated that placement of the 

maintenance-dredged material on the west side of the ARBC (ODMDS-West) would reduce the 

frequency of maintenance dredging, over the long term (PBS&J 2007).

The Gulf of Mexico oil industry has changed dramatically over recent years and the status of oil 

and gas related activity will be dynamic until the price of these products stabilizes. Extensive oil 

and gas development occurs within the Atchafalaya River Delta and in the vicinity of the 

ODMDS-East and ODMDS-West. Placement of dredged material in the ODMDS-West will not 

directly affect oil and gas pipelines or other infrastructure.

2.6.1.4 Living Resources Constraints

The northwestern Gulf of Mexico is an important breeding, spawning, and nursery ground for 

many fish, shrimp, and crab species. The named shoals nearest to the site, Ship Shoal, Trinity, 

and Tiger Shoals, are approximately 47 km (29 miles) from the ODMDS-West. Smaller fishing 

shoals are within about 4.7 km (2.9 miles) and Point au Fer Reef is located just north of the site 

(NMFS, 1980). The area of the proposed ODMDS-West is dominated by estuarine species. 

Because the area is currently being used as an ODMDS, there would be no additional impacts to 

Essential Fish Habitat (EFH). The only marine fish with Critical Habitat near the ZSF is the 

Gulf Sturgeon, which has a present range of Lake Pontchartrain and the Pearl River system in 

Louisiana east to the Suwannee River in Florida (68 FR 13370). The nearest designated Critical 

Habitat is Lake Pontchartrain east of the Lake Pontchartrain Causeway. Therefore, potential 

impact to the Gulf sturgeon or its critical habitat is not a factor in ODMDS site selection.

2.6.1.5 Environmental Quality Constraints

As noted in the sections of this document that address characterization of the material to be 

dredged, water quality in the ZSF, the quality and characteristics of sediment in the ZSF, the 

environmental impacts of ocean placement in the preferred sites, and the existing conditions and 

impacts on the benthos, no environmental quality constraints on the maintenance material site

selection have been identified beyond those included in the buffer zone development for 

potential ODMDSs.

2.6.1.6 Recreational Uses Constraints

As noted in the discussion of the ZSF, the only recreational use that could potentially be affected 

by dredged material placement would be non-commercial fishing. Because there are no offshore 
63

platforms in the proposed ODMDS alternatives that attract game fish and contribute to 

recreational fishing opportunities, no recreation use buffer zone is needed. 

2.6.2 Preferred Alternative

Based on the studies and analysis, the preferred alternative is the MPRSA Section 102(c) 

designation of the ODMDS-West for continued placement of maintenance-dredged material.

The majority of the proposed ODMDS-West has been used for the placement of maintenancedredged material since 2002. Continued use of the site would subject the area within the site 

boundaries to the same environmental effects that have existed since 2002. Except for the 

periodic burial of bottom organisms and the temporary presence of a placement plume, these 

effects have been minimal. Relocation of the ODMDS away from the ODMDS-West would 

subject new open bay bottom to the effects of maintenance-dredged material placement.

The proposed ODMDS-West site is located in a dynamic environment characterized by high 

variability in physical factors. Correspondingly, the organisms that occur there are adapted to

natural stresses and are able to recover more rapidly than those organisms adapted to more stable 

conditions. 

The environmental characteristics of the ODMDS-West are practically identical to those of the 

existing ODMDS-East (EPA, EIS 1998). If similar placement techniques are applied at the west 

side alternative site as are currently used, the environmental effects of maintenance-dredged 

material placement would be expected to be similar to the current effects at the Section 103(b) 

ODMDS-West.

According to MVN analysis of annual pre and post-maintenance dredging surveys at the 

ODMDS-West, adverse environmental effects outside the boundaries of the proposed ODMDSWest were not detected during prior use of this site, and therefore, are not expected to result from 

continued use of the site. 

The proposed ODMDS-West was found to comply with the criteria for evaluation of ocean 

disposal sites established in 40 CFR Sections 228.5 and 228.6 of EPA’s Ocean Dumping 

Regulations. 

With its permanent, Section 102(c) designation the ODMDS-West would remain the primary 

disposal options for maintenance-dredged material removed from the ARBC. However, the 

ODMDS-East would retain its Section 102(c) designation and would remain a secondary

disposal option for future dredging efforts in the ARBC on those occasions when disposal to the 

east side of the channel may be warranted.
64

3.0 AFFECTED ENVIRONMENT

This section provides a brief description of the land and ocean areas near the ARBC. This is the

ODMDS study area as the term is used in this DEIS. Thus, this section provides information for 

a much broader area than the ZSF.

3.1 PHYSICAL ENVIRONMENT

3.1.1 Climate and Meteorology

The climate of the northern Gulf of Mexico and adjacent coastal areas is influenced by four

primary features: (1) the North American continental land mass, (2) the summer weather pattern 

known as the Bermuda high pressure cell, (3) subtropical latitudes, and (4) characteristically 

warm water temperatures of the northern Gulf of Mexico. The result is a humid, subtropical 

climate with mild winters and long, hot summers. The average monthly regional barometric

pressure typically ranges from a minimum of 1014–1016 millibars during the summer months to 

a maximum of approximately 1021 millibars during the winter. The low pressure conditions of 

summer occur when the equatorial trough shifts northward, while the winter high pressure trend 

reflects the presence and influence of continental cold air masses (MMS 1988). Coastal 

Louisiana has an annual mean air temperature of 23 degrees Celsius (°C) (73 degrees Fahrenheit 

[°F]). July and August are the warmest months, with a mean temperature of 29°C (84°F); 

January is the coldest month with a mean temperature of 17°C (63°F). 

Major rainstorms are associated with tropical disturbances and hurricanes in summer and early 

fall, and with frontal activity of extra tropical cyclones in late fall, winter, and spring. 

Convective thunder showers produce intense but localized rain in late spring and summer. 

Westerly winds in summer and northerly winds in winter frequently interrupt the normal pattern 

and bring drier weather. Rainfall is abundant in the area. Based on the 30-year average (1981-

2010), the average total annual precipitation is approximately 60.4 inches, with a monthly

average of 5.03 inches (NOAA 2013).

The study area is susceptible to tropical waves, tropical depressions, tropical storms, and 

hurricanes. Historical data from 1899 to 2012 indicate that 32 hurricanes and 43 tropical storms 

have made landfall along the Louisiana coastline (NOAA 2013a). The largest recent hurricanes 

were Katrina and Rita in 2005 (Category 3), Gustav in 2008, and most recently, Isaac in 2012, 

which resulted in substantial coastal land loss in the vicinity. Overall marsh loss (i.e., conversion 

to open water) resulting from Katrina and Rita throughout the entire Mississippi Deltaic Plain of 

southeastern Louisiana was as follows: fresh marsh—22 square miles; intermediate marsh—49 

square miles; brackish marsh—18 square miles; salt marsh—27 square miles (USGS 2006). 

Hurricanes Gustav and Isaac caused additional damage in the vicinity. 

3.1.2 Air Quality

The EPA, under the requirements of the Clean Air Act (CAA), has established National Ambient 

Air Quality Standards (NAAQS) for seven contaminants, referred to as “criteria” pollutants (40 

CFR 50). These are carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), particulate 
65

matter less than 10 microns in diameter (PM10), particulate matter less than 2.5 microns in 

diameter (PM2.5), lead (Pb), and sulfur dioxide (SO2). The NAAQS standards include primary 

and secondary standards. The primary standards were established at levels sufficient to protect 

public health with an adequate margin of safety. The secondary standards were established to 

protect the public welfare from the adverse effects associated with pollutants in the ambient air. 

The primary and secondary standards are presented in Table 3.1-1. 

The EPA Green Book Nonattainment Areas for Criteria Pollutants (Green Book) maintains a list 

of all areas within the United States that are currently designated “nonattainment” areas with 

respect to one or more criteria air pollutants. Nonattainment areas are discussed by county or 

metropolitan statistical area (MSA). MSAs are geographic locations, characterized by a large 

population nucleus, that are comprised of adjacent communities with a high degree of social and 

economic integration. MSAs are generally composed of multiple counties. Review of the Green 

Book indicates that St Mary Parish is currently in attainment for all Federal NAAQS pollutants, 

including the 8-hour ozone standard (EPA 2011a). This classification is maintained through the 

results of area-wide air quality monitoring studies. Therefore, further analysis required by the 

CAA general conformity rule (Section 176(c)) would not apply for the proposed Federal action.

Table 3.1-1. Primary and secondary NAAQS for the seven contaminants established by EPA. 

National Ambient Air Quality Standards [3][4]

Primary Standard Secondary Standard 

Criteria

Pollutant

Concentration

Limit

Averaging

Time 

Concentration

Limit

Averaging

Time 

Carbon monoxide 

9 ppmv

( 10 mg/m3 ) 8-hour (1)

None 

35 ppmv

( 40 mg/m3 ) 1-hour (1) 

Sulfur dioxide 

0.03 ppmv

( 80 μg/m3 )

Annual

(arithmetic mean) 0.5 ppmv

( 1300 μg/m3 ) 3-hour (1) 

0.14 ppmv

( 365 μg/m3 24-hour (1) 

Nitrogen dioxide 0.053 ppmv

( 100 μg/m3 )

Annual

(arithmetic mean) Same as primary 

Ozone 

0.075 ppmv

( 150 μg/m3 ) 8-hour (2) Same as primary 

0.12 ppmv

( 235 μg/m3 ) 1-hour (3) Same as primary 

Lead 

0.15 μg/m3 Rolling 3-month

average Same as primary 

1.5 μg/m3 Quarterly average Same as primary 
66

Particulate

Matter (PM10) 150 μg/m3 24-hour (4) Same as primary 

Particulate

Matter (PM2.5) 

15 μg/m3 Annual (5)

(arithmetic mean) Same as primary 

35 μg/m3 24-hour (6) Same as primary 

(1) Not to be exceeded more than once per year.

(2) The 3-year average of the fourth-highest daily maximum 8-hour average at each monitor within

the area over each year must not exceed 0.075 ppmv.

(3a) The expected number of days per calendar year with maximum hourly averages above

0.12 ppm must be equal to or less than 1.

(3b) As of June 15, 2007, the U.S. EPA revoked the 1-hour ozone standard in all areas except

for certain parts of 10 states.

(4) Not to be exceeded more than once per year on average over 3 years.

(5) The 3-year average of the weighted annual mean PM2.5 concentrations from single or multiple

community-oriented monitors must not exceed 15 μg/m3. 

(6) The 3-year average of the 98th percentile of 24-hour concentrations at each population-oriented

monitor within the area must not exceed 35.5 μg/m3. 

3.1.3 Oceanography

Physical oceanographic parameters influence the extent of water column mixing and sediment 

transport and affect the chemical environment at an ODMDS. Strong temperature or salinity 

gradients inhibit mixing of surface and bottom waters, whereas waves aid mixing. Waves of 

sufficient size may also resuspend bottom sediments, thereby affecting the turbidity of the water 

and contributing to sediment transport. Currents, especially bottom currents, influence the 

direction and influence the extent of sediment transport into and out of the ODMDS. Tidal 

currents may contribute to the transport of dredged material from a placement site.

3.1.3.1 Water Masses

Water masses in the nearshore Louisiana area are influenced by freshwater discharge from the 

Mississippi and Atchafalaya Rivers, coastal estuaries, and intrusions of Loop Current and 

associated water (Comiskey and Farmer 1981). Influences from riverine and estuarine 

discharges are greater in nearshore than in mid-shelf areas. Conversely, characteristics of water 

masses in the mid-shelf region are influenced to a greater extent by Gulf waters and broad scale 

circulation patterns. 

Atchafalaya Bay was once the delta system for the Mississippi River as it flowed into the Gulf of

Mexico prior to its re-routing through New Orleans to the east (Walker et al. 2003). Therefore, 

the area used to receive significantly more flow and sediment load and, as a result, the bay is 

very shallow with an average depth of 5 ft (1.5 m) MLG. Historically, this higher flow would 

have pushed much further into Atchafalaya Bay and the mixing zone where river water and 

seawater met would have been much further seaward than its current position. Over the past few 

decades, a series of flow control structures have been constructed on the Mississippi River to 

balance flow (and sediment load) between the Atchafalaya River and the Mississippi River. 

Under this flow balancing program, the Atchafalaya River receives about 30 percent of the ‘31° 

North-latitude’ combined flow of the Mississippi River and Red River (ETS 2006; Mead and 

Moody 2010). The river discharges into Atchafalaya Bay in southern Louisiana through two 

Table 3.1-1. Continued
67

outlets, Lower Atchafalaya (70 percent of the discharge) and Wax Lake (30 percent) (Neill and 

Allsion 2005). The Wax Lake Outlet diverts about 30-40 percent of the Atchafalaya River water 

(approximately 10-12 percent of the Mississippi River discharge; Roberts et al. 2003). 

River discharges and tidal movement influence the temperature and salinity regime, as well as

concentrations of nutrients, trace metals, and suspended sediments in nearshore waters (Murray

1976). Maximum combined seasonal discharge from the Mississippi and Atchafalaya Rivers 

occurs in April, with minimum discharge occurring in September. Runoff volumes from other 

tributaries feeding the northcentral Gulf are typically highest in May (Barrett et al. 1973). The 

Atchafalaya River, with a drainage basin of approximately 228,410 km2 when measured from 

just downstream of the confluence of the Red River and the Old River Control Structure to its 

outlets along the Gulf of Mexico, is one of the nation’s largest river systems in terms of flow 

(Demas et al. 2001). Based on river flow data for 2001–2003, from the Simmesport gage, which 

is located upstream of Morgan City, Atchafalaya River flows in dry months were between 

75,000-140,000 cubic feet per second (cfs) and between 200,000-450,000 cfs during the wetter 

months (ETS 2006). Annual mean river flow between 1935-2001 was 204,154 cfs (Walker et al. 

2002). 

In spring 2011, historic flooding occurred on the Mississippi River. With the volume of the 

Mississippi River flows reaching 1.5 million cfs and rising at Red River Landing and in close 

coordination with local, state and national partners and stakeholders, MVN commenced the 

partial opening of the Morganza Floodway on May 14, 2011. The Morganza Floodway is 

located 186 river miles above New Orleans on the west bank of Pointe Coupee Parish and is 

designed to divert a portion of the river's floodwaters southward guided by the East Atchafalaya 

River levee before joining the Atchafalaya River Basin Floodway near Krotz Springs, La. At 

peak operation, 17 of the 125 total bays were open and passed 182,000 cubic feet of water per 

second (USACE 2012). Peak discharge through the floodway occurred from May 18 to 22.

MVN began closing bays on May 24, 2011, and completed that operation on July 7. Besides 

inundating floodplains, agricultural fields, and homes, the flooded Mississippi and Atchafalaya 

Rivers delivered huge sediment loads to the Gulf of Mexico and Atchafalaya Bay. 

Coastal rivers may form distinct nearshore low salinity zones with widths determined by 

discharge volumes and turbulent mixing (Murray 1976). The extent of vertical and horizontal 

mixing within these low salinity zones will vary seasonally depending upon currents, winds and 

density differences between the freshwater plume and nearshore marine waters. Salinity 

generally increases with distance from shore and reflects the dilution of riverine water with

greater volumes of saline Gulf water. Consequently, salinities are generally higher further 

offshore of the existing and proposed sites (Weissberg et al. 1980a). Vertical stratification may 

occur where freshwater river discharges intermix with Gulf waters (Turgeon 1981; Fotheringham 

and Weissberg 1979) when low salinity waters from coastal rivers overlay colder, more saline 

bottom waters during a period of minimal vertical mixing (Fotheringham and Weissberg 1979). 

Vertical stratification of the water column in the vicinity of the dredging reaches and ODMDSs 

may occur in summer, while the water column is well-mixed during winter (Weissberg et al.

1980a, 1980b). Summer intrusions of high salinity bottom waters occur in the mid-shelf area 

(Fotheringham and Weissberg 1979), with a strong halocline evident during the summer at a 

depth of 7 to 8 m (23 to 26 ft) (Weissberg et al. 1980a). Prolonged vertical stratification during 

summer can promote oxygen depletion in bottom waters, resulting in mass mortalities of benthic 
68

organisms throughout large areas of the western and central Louisiana Shelf (Fotheringham and 

Weissberg 1979; Harper et al. 1981). Whether these intrusions are strong or occur frequently in 

the existing or proposed ODMDS-West is not clear, so it is not known if or how these intrusions 

of saline bottom waters affect the ODMDS-East or West. However, it should be noted that the 

ODMDS-West occurs in water that is between 2 and 7 m (6 and 23 ft) in depth; the more shallow 

water is not likely to allow for vertical stratification.

3.1.3.2 Circulation and Currents

Circulation in the Gulf of Mexico is complex and influenced by the Loop Current, tides, winds, 

and river discharge (U.S. Department of Energy [USDOE] 1978). The major feature of broad 

scale circulation in the Gulf is the Loop Current, which as a continuation of the Yucatan Current, 

enters the Gulf through the Yucatan Strait, penetrates up to 29°N in summer, turns clockwise, 

and leaves the Gulf through the Florida Straits. During winter, the Loop Current is confined to 

the southeastern Gulf, and passes through the Straits of Florida with little intrusion into the 

central Gulf (Hubertz 1967; Leipper 1970). Eddy-like rings pinched off from the Loop Current, 

have sufficient momentum to be major contributors to circulation in the central and western Gulf 

(Sturges and Leben 2000). These Gulf eddies may be higher in salinity than near-shore waters 

and may be zones of elevated nutrients relative to the surrounding Gulf waters. 

Local currents in the vicinity of the existing and proposed ODMDSs are predominantly 

influenced by winds and, to a lesser degree, tides, Loop Current intrusions, and river flow. Net 

flow is to the northwest throughout most of the year (Wells et al. 1981; Weissberg et al. 1980a, 

1980b). Prevailing south east winds break off warm core eddy’s from the Gulf Loop Current 

and carry this warm tropical water further west along the Texas and Louisiana coast lines as the 

Louisiana-Texas Coastal Current (LTCC). The LTCC is a major dynamic feature responsible for 

the distribution of fresh water, sediment and nutrients on the northwestern shelf of the Gulf of 

Mexico (Jarosz and Murray 2005). Studies have indicated that this current exhibits a distinct 

although asymmetric annual cycle during which it flows downcoast, i.e., westward along the 

Louisiana coast and then southward along the Texas coast in fall, winter, and spring; however, in 

summer, the flow reverses and moves upcoast (eastward) (Wiseman et al. 1999; Jarosz and 

Murray 2005; Rouse et al. 2005). 

Current speeds near the ODMDSs are typically 10.1 cm/s to 29 cm/s (0.33 to 0.98 ft/s [0.23 to 

0.67 mph]) to the northwest, although this pattern is affected by passage of cold fronts, when 

current flows to the east at speeds ranging from 70 to 140 cm/s during strong winter storms

(Weissberg et al. 1980a, 1980b; Wells and Kemp 1982). Walker et al. (2002) reported generally 

similar findings offshore of the ARBC. Frontal passages produce winds typically first from the 

southwest and then from the northwest. Teeter et al. (2003) report that these reversals occur 30 

to 40 times per year leading to set-up and set-down in water levels up to 2.3–3.3 ft (0.7–1.0 m) in 

height and the formation of wind-driven currents (Walker and Hammack 2000). Walker and 

Hammack concluded that these water level changes lead to large NW–SE exchanges of water 

between Atchafalaya Bay and the coastal ocean, and lead to increased resuspension and 

Suspended Particulate Material (SPM) concentrations. Current velocities near the landward end 

of the ARBC are 9.1 to 48.8 cm/s (0.3 to 1.6 ft/s [0.20 to 1.09 mph]) and pulse related to tidal 
69

changes. Currents do not fully reverse because of tide but change direction based on river flows 

to the south from Atchafalaya Bay and to the west from longshore drift. 

Nearshore current patterns are somewhat more complex in summer. Net flow in the summer can 

either be to the east or the west (Crout and Hamiter 1981; Weissberg et al. 1980a). Minimum 

speeds of 6.1 to 33.5 cm/s (0.2 to 1.1 ft/sec [0.20 to 0.75 mph]) occur during June, July, and 

August (Weissberg et al. 1980a, 1980b). 

Winds blowing towards the west occur 62 percent of the time (Walker and Hammack 2000) and 

these typically fair weather periods are characterized by small amounts of sediment transported 

to the west (Pepper et al. 1999). Winds are a particularly strong driving force in the late autumn, 

winter, and early spring. Net water flow in the winter is to the northwest; however, rapid flow 

reversals to the southeast occur periodically and follow changes in wind direction (Weissberg et 

al. 1980a, 1980b; Crout and Hamiter 1981). 

In the absence of strong winds and the presence of a stratified water column, current patterns 

become considerably less distinct. Stagnant periods with little or no current motion have been 

recorded in April, May, and July, and may last for as long as six days (Weissberg et al. 1980a, 

1980b). Tides may dominate current direction during winter periods of slack winds; however, 

tidal influences result in little or no net water or sediment displacement at the site.

With surface salinities during mean Atchafalaya River discharge ranging from 0.5 to 5 parts per 

thousand (ppt) along the channel, vertical stratification of salinity is common particularly in the 

ARBC, although not in the shallow waters adjacent to it (ETS 2006). This stratification is 

relatively persistent and at times reflects near-bottom flows moving landward at velocities up to 

45.7 cm/s (1.5 ft/s [1.02 mph]) in the channel under surface flows moving the opposite direction 

towards the sea (Teeter et al. 2003). Stratification and current flows in the channel are believed 

to play important roles in concentrating fluff both vertically and longitudinally in the channel. 

3.1.3.3 Waves and Tides

Waves in the northern Gulf are a combination of wind-generated waves and swell entering from 

the open Gulf. Wave direction generally follows the wind direction and its seasonal patterns; 

wind and wave directions are similar to each other during 80 percent of the year (Wiseman et al.

1975: cited in Wells et al., 1981). According to Wiseman et al. (1975), 93 percent of the waves 

are under 1.5 m (5 ft) high, and 41 percent of these lower height waves approach from the 

southeast quadrant. 

Tides are semidiurnal and diurnal with a mean range of 0.6 m (1.9 ft) near the landward end of 

the ARBC. Tidal currents are large relative to the remainder of the Louisiana-Texas coast with 

maximum surface current amplitudes of about 9.1 cm/s (0.3 ft/s [0.20 mph]) (DiMarco and Reid

1998). Tidal currents tend to increase as depth decreases nearer shore. The principal component 

of semidiurnal tides is the lunar component with a tidal ellipse oriented from north to south. 

Tidal flow within the tidal ellipse is clockwise. The principal lunar component of the 

semidiurnal tide propagates counterclockwise around the Gulf of Mexico. Diurnal tidal 
70

components exhibit strong vertical shear and a tidal ellipse that is oriented from north-northeast 

to south-southwest. 

3.1.3.4 Bathymetry 

The Atchafalaya River and Atchafalaya Bay lie along the general boundary between two 

physiographic regions: (1) the Chenier Plain and (2) the Deltaic Plain (Kolb and Van Lopik 

1958; Wells et al. 1981). The Chenier Plain, extending west from Marsh Island, Louisiana to 

East Bay, Texas has a relatively smooth and regular shoreline fronted by intermittent mudflats 

and breached by small inlets that connect with shallow marshy estuaries (Wells et al., 1981; 

Gosselink et al. 1979). The Chenier Plain system is a unique depositional environment 

consisting of successive beach and dune ridges lying on muddy marsh deposits that have been 

overlapped by younger mudflat marshes (Shepard 1973; Weissberg et al. 1980a). The Deltaic 

Plain is characterized by a shoreline with numerous bays and extensive marshes with numerous 

small lakes (Wells et al. 1981). 

Most of Louisiana is located in the vicinity of the Gulf coast geosyncline, the axis of which 

generally corresponds to the trend of the present coastline (Weissberg et al. 1980a, 1980b). The 

geosyncline has been gradually subsiding since the early Mesozoic Era in response to the large 

amount of deltaic sedimentation from the Mississippi River and its tributaries and the tectonic 

regime associated with the opening of the Gulf of Mexico. 

The continental shelf off eastern Louisiana has been completely overlapped by the Mississippi 

Delta during the past 500 years (Fisk et al. 1954). West of the Delta, a trough extends about 37 

km (20 nautical miles) to the shelf edge and can be traced down the gentle outer slope over 92 

km (50 nautical miles) until it emerges into the broad fan of the Mississippi Cone (Shepard

1973). Adjacent to this trough, the shelf off Atchafalaya Bay extends offshore to the shelf-break, 

which occurs at a depth of about 152 m (500 ft) (Shepard 1973). The shelf slopes gently 

basinward at about 0.04° to the continental slope. 

Louisiana’s coastal zone is covered predominantly by late quaternary sediments (Hall and 

Bouma 1976). The continental shelf west of the Mississippi Delta is blanketed by a thick layer 

of terrestrial sediments that grade from sand near the shore to silt and clay further offshore 

(Uchupi and Emery 1968). The nearshore coastal area of Louisiana is characterized by a 

shallow, gently sloping plain punctuated by sand and shell shoals. Several shoals are located 

near Atchafalaya Bay (Figure 1-3): (1) Ship Shoal, located 46 km (29 miles) east of the 

ODMDS-East, (2) Trinity Shoal, approximately 45 km (28 miles) west of the ODMDS-East, and 

(3) Tiger Shoal, located inshore of Trinity Shoal (NMFS 1980). Two unnamed shoals are 

located immediately west (approximately 4.7 km [2.9 miles]) of the seaward end of the 

ODMDS-East (NMFS 1980). The nearshore shoals typically rise 1.8 to 4 m (6 to 13 ft) from the 

bottom to a depth of 1.8 to 4 m (6 to 13 ft) below the water surface (NMFS 1980). Point au Fer 

Shell Reef is a massive shell reef that lies about 5.6 km (3.5 miles) shoreward of the ODMDSEast; this reef is roughly 0.9 km (0.58 mile) wide and extends nearly 37 km (23.0 miles) across 

the mouth of Atchafalaya Bay (USACE 1978). 
71

Two major types of deposition occur in the Louisiana coastal area (Coleman 1966; Hall and

Bouma 1976). One is a result of sediment input from present and former Mississippi River 

distributaries. Examples of this type of deposition are the Mississippi Delta and the present 

prograding Atchafalaya River Delta. The other depositional regime is a result of coastal 

sediment transport processes outside of the areas of deltaic sedimentation. These processes have 

produced features such as mud flats and the Chenier Plain west of Marsh Island.

The Atchafalaya River is a distributary of the Mississippi and has a natural sediment load 

estimated to be approximately 40 to 50 percent of the combined discharge from the Mississippi 

and Atchafalaya Rivers (Walker and Hammack 2000). Starting in about 1952, accelerated 

sedimentation in Atchafalaya Bay marked the beginning of subaqueous delta growth (Shlemon 

1975). From that time to 1973, prodelta clays and silty clays aggraded the bay bottom seaward 

of both the Lower Atchafalaya River outlet and the Wax Lake outlet. Since that time, sands have 

been prograding over finer delta clays and silts, and areas of emergent vegetation have expanded 

rapidly in Atchafalaya Bay (Roberts and Van Heerden 1982). With mean circulation and 

subsequent sediment transport in an east to west direction, longshore transport will continue to 

extend coastal progradation in that direction (Roberts and Van Heerden 1982; Neill and Allison 

2005). While some researchers have theorized the complete infilling of Atchafalaya Bay with 

the subaerial delta prograding onto the continental shelf within decades (Shelmon 1975; Roberts 

and Van Heerden 1982), Neill and Allison (2005) predict the final accretion to sea level and 

complete filling of the outer Atchafalaya Bay, with subsequent prograding over the surface of the 

adjacent shelf, on timescales of 100s of years. Neill and Allison attribute these less rapid 

predictions for subaerial delta growth to factors such as subsidence, benthic shear stresses during 

winter storms, dredged material disposal activities, and reduced sediment accumulation rates 

relative to further offshore.

3.1.4 Water Quality

The chemical parameters that reflect the affected environment and potential impacts of an 

ODMDS include suspended solids, nutrients important to phytoplankton growth (ammonia, 

nitrates and phosphates), dissolved and particulate trace elements (such as cadmium, mercury. 

and lead), and synthetic organic compounds (such as polychlorinated biphenyls [PCBs], 

chlorinated pesticides and herbicides, and phenolic compounds). High levels of suspended solids 

can reduce light penetration through the water column and inhibit phytoplankton productivity. 

Suspended solids may also block the respiratory structures of fishes and other organisms. 

Nutrients are essential for growth and reproduction of phytoplankton; however, under certain 

conditions and at elevated levels, these nutrients can promote eutrophication and subsequent 

depletion of dissolved oxygen. 

As part of its surface water quality monitoring program, the Louisiana Department of 

Environmental Quality (LDEQ) routinely monitors 25 parameters on a monthly or bimonthly 

basis using a fixed station, long-term network (Monitored Assessments) (LDEQ 1996). Based 

upon those data and the use of less-continuous information (Evaluated Assessments), such as fish 

tissue contaminants data, complaint investigations, and spill reports, the LDEQ has assessed 

water quality fitness for the following uses: primary contact recreation (swimming), secondary 

contact recreation (boating, fishing), fish and wildlife propagation, drinking water supply, and 
72

oyster propagation (LDEQ 1996). Based upon existing data and more subjective information, 

water quality is determined to either fully, partially, or, not support those uses. A designation of 

“threatened” is used for waters that fully support their designated uses but that may not fully 

support certain uses in the future because of anticipated sources or adverse trends in pollution. 

According to the Louisiana Department of Environmental Quality (LDEQ) 2010 Louisiana 

Water Quality Inventory: Integrated Report (305(b)/303(d) (LDEQ 2011), the Atchafalaya Bay 

and Delta and Gulf Waters to State 3 mile limit (segment LA010901_00)) fully support the 

designated water body uses for primary and secondary contact recreation uses. The segment 

does not support the designated use for fish and wildlife propogation or oyster propagation. 

Impairment of the oyster propogation use is due to pathogens (fecal coliform bacteria). 

Suspected sources of impairment of the oyster propogation use include permitted discharges, 

permitted petroleum/natural gas production activities, and natural sources. Impairment of the 

fish and wildlife propogation use is due to mercury in fish tissue. Suspected sources of 

impairment of the fish and wildlife propogation use include atmospheric deposition-toxics and 

unknown sources. As a result of the segment’s 303(d) listing (i.e., impaired water), and in 

accordance with Section 303(d) of the Federal Clean Water Act, the LDEQ is required to prepare 

a total maximum daily load (TMDL) for fecal coliform bacteria for the entire length of GrandTiger Pass. A TMDL is the amount of a pollutant that a waterbody can assimilate without 

exceeding the established water quality standard for that pollutant. Through a TMDL, pollutant 

loads can be allocated to point sources and nonpoint sources discharging to the waterbody, and 

target loads can then be calculated. 

In February 2008, water and sediment samples from the ARBC, a Reference Area, and the 

Section 103(b) ODMDS-West were collected for chemical and grain size analyses, water column 

toxicity bioassays, benthic toxicity tests/solid phase toxicity bioassays, and bioaccumulation tests 

(PBS&J 2008). Results of these analyses were evaluated pursuant to the EPA criteria at 40 CFR, 

Part 227 and 228. The evaluation indicates that the dredged material proposed for disposal into 

the proposed Section 102(c) ODMDS-West is suitable for open water disposal without special 

management conditions. 

On April 21, 2010, an explosion occurred onboard the mobile drilling platform Deepwater 

Horizon in the Gulf of Mexico. The rig sank approximately 52 miles southeast of Venice on 

April 22, 2010, causing a massive oil spill and continuous release of approximately 206 million 

gallons of crude oil over an 85-day period about 40 miles southeast of Federal navigation 

dredging areas at the mouth of the Mississippi River. In the wake of the Deepwater Horizon oil 

spill, MVN has been closely monitoring aerial reconnaissance surveys, shoreline assessment 

reports, drogue tracks, and other oil plume tracking and contaminant information available from 

the National Ocean Service, Office of Response and Restoration, ResponseLINK website 

(https://responselink.orr.noaa.gov/). 

A report entitled “Summary Report for Sub-Sea and Sub-Surface Oil and Dispersant Detection: 

Sampling and Monitoring” was prepared for the USCG Federal On-Scene Coordinator for the 

Deepwater Horizon incident by the Operational Science Advisory Team, and provided to MVN 

in December 2010. A review of the report’s sediment and water quality data revealed that oilrelated contaminants and dispersants from the incident did not impact the Atchafalaya Bay. 
73

A query of the USCG National Response Center database revealed no reported significant spills 

or other incidents of significant pollution in the vicinity of the ARBC and adjacent disposal areas 

from August 31, 2010 thru July 12, 2012. 

Based on MVN’s review of oil spill tracking and contaminant information pertaining to the 

Deepwater Horizon incident, the sampling and analyses performed in 2008 for the ARBC as part 

of the contaminant assessment, and the lack of any additional significant spills or incidents of 

pollution in the project vicinity since 2010, there is no reason to believe that dredged material 

from future maintenance events in the ARBC portion of the Atchafalaya River and Bayous 

Chene, Boeuf, and Black, Louisiana project would be unsuitable for open water disposal. 

3.1.4.1 Temperature

Factors influencing water temperatures in the study area include discharges from the Atchafalaya 

and Mississippi Rivers and ambient Gulf water temperatures. The latter are affected by the 

climate of the northern Gulf of Mexico and currents that affect the temperature distribution of 

Gulf waters, including the Loop Current and other local current patterns. Holland et al. (1983) 

observed Atchafalaya River temperatures ranging from 4.5°C to 32.0°C (40°F to 89°F). River 

water temperatures varied with season and river stage. Monthly average coastal water 

temperatures measured at Grand Isle, Louisiana range from 16.1°C (61°F) in January to 29.4°C 

in July and August (NOAA 2008). Water temperatures measured by PBS&J (2008) during the 

February 2008 sampling event for the contaminant assessment ranged from 13.2°C to 17.2°C

(56°F to 63°F), with temperature generally increasing with distance from the shoreline (Table 

2.3-3). The April 2002 temperature measurements along the ARBC indicated that the warmest 

waters occurred at the mid-point of the dredged channel, with lower water temperatures closer to 

shore and deeper waters (Table 2.3-3). Observed temperatures ranged from 16.6°C to 20.9°C 

(62°F to 21°F). Water temperatures measured during December 1996 also indicated increasing 

water temperatures with distance from shoreline, ranging from 11.9°C to 18.2°C (53°F to 65°F)

(Table 2.3-3). 

3.1.4.2 Salinity

Salinity of open marine waters is typically on the order of 35 ppt under normal conditions. 

Inputs of freshwater from the Atchafalaya and Mississippi Rivers affect the areal and temporal 

distribution of water salinity at the ARBC and disposal areas, with the variations related to 

regional current patterns and the volume of river discharges. River waters are typically much 

lower in salinity. Holland et al. (1983) observed total dissolved solids concentrations in lower 

Atchafalaya River waters ranging from 146 to 347 mg/L, which would be equivalent to salinity 

values of less than 1 ppt. The LATEX A-Team (1996) observed seasonal trends in salinity 

across the northern Gulf related to weather-related current patterns. They noted that typical 

salinities in November were lower along the northern coast, as low salinity river discharges 

diluted marine waters along the coast. During summer conditions, currents oriented along the

western Gulf coast confine river discharges to the central portion of the northern Gulf coast, 

decreasing salinities in the project area compared to shelf waters further west and south. Flemer 

et al. (1994) observed salinities in nearshore areas approaching freshwater conditions, while 

salinities near the offshore disposal areas were approximately 25 ppt. 
74

Salinity data collected from the project area during February 2008 as part of the contaminant 

assessment indicated salinities ranging from just below 6 ppt to nearly 32 ppt, with salinity 

generally increasing with distance from the shoreline along the ARBC and disposal areas, and 

the highest values observed at the reference location southeast of the channel (Table 2.3-3). Data 

from the April 2002 sampling event showed more homogeneous salinity distribution across the

area, with salinity ranging from 11 to 13.5 ppt (Table 2.3-3). The December 1996 salinity 

measurements along the channel ranged from 0 to nearly 22 ppt, with salinity increasing with 

distance from the shoreline (Table 2.3-3). ETS (2006) reported salinities ranging from only 0.5-

5 ppt along the ARBC creating a vertically stratified water column at the mixing zone where the 

two opposing water masses meet. These data reflect the localized influence of Atchafalaya River 

discharges on salinity in the project area, with seasonal variations observed similar to those 

described by Walker and Hammack (2000). 

3.1.4.3 Dissolved Oxygen

Dissolved oxygen concentrations in the project area were observed to generally range from 6 to 

7.5 mg/L (Flemer et al. 1994). These findings indicate that oxygen concentrations were above 

the range of values generally accepted as an indication of hypoxic conditions (<2 mg/L). 

Oxygen depletion has been described as a seasonally dominant feature in the north central Gulf 

of Mexico that reflects the influence of discharges from the Mississippi and Atchafalaya Rivers 

(Rabalais et al. 1991, 1992, 1994, 1995). However, other investigators have found complex 

relationships among inputs of organic matter, nutrients and development of hypoxic conditions 

in the northern Gulf of Mexico. Krug (2007) attributes development of the seasonal hypoxic 

zone to input of nutrients to the shallow marine environment related to wetland losses in 

Barartaria and Terrebonne Bays, as well as discharges from the Mississippi and Atchafalaya 

Rivers, with the input of the Atchafalaya River being of increased importance with increased

sediment deposition in Atchafalaya Bay and the nearby shelf since the flood event of 1973. 

Eadie et al. (1994) found a general correlation between increased nutrient loading in the 

Mississippi River discharge and primary productivity of the marine environment of the central 

Gulf shelf. Gordon and Goñi (2003) described a complex relationship between organic matter 

types deposited in shelf sediments near Atchafalaya bay, with contributions from grassy plant 

debris and soil organic matter related to river discharges and marine organic matter. Marine 

organic matter was found to have a significant contribution to shelf sediments present at depths 

greater than 10 m (33 ft), indicating primary productivity was important in at water depths 

greater than those present at the ARBC and the disposal areas.

Dissolved oxygen concentrations observed in the project area have not indicated the presence of 

hypoxic conditions (Table 2.3-3). Data from the February 2008 sampling efforts for the 

contaminant assessment show that dissolved oxygen concentrations in the project area ranged 

from 7.6 to 9.6 mg/L. At the salinities and water temperatures present during the sampling 

event, these concentrations indicate that the waters were near the saturation limit for dissolved

oxygen (Weiss 1970). The April 2002 measurements of dissolved oxygen at the ARBC ranged 

from 5 to 7.7 mg/L, with the higher concentrations generally observed closer to the shoreline. 

Based on the results, hypoxic conditions were not present in the study area during the sampling 
75

event. The December 1996 sampling data also reflect the presence of well oxygenated waters 

across the ARBC project area, with concentrations ranged from 6.7 to 7.7 mg/L. 

3.1.4.4 pH

The pH of marine waters is typically slightly alkaline, reflecting the buffering alkalinity 

produced by the carbonate system, with observed values in shallow waters typically between 7.8 

and 8.5 (Drever 1982). Data from the February 2008 sampling efforts for the contaminant 

assessment indicate that pH ranged from 7.5 to 8.1 across the study area (Table 2.3-3). Results 

for pH measurements from the December 1996 sampling event ranged from 7.2 to 8.3, reflecting

the neutral to mildly alkaline conditions expected in an area of marine waters influenced by the 

discharge of fresh water from the Atchafalaya River (Table 2.3-3). 

3.1.4.5 Nutrients

The discharge of the Atchafalaya River has a significant impact on the concentration of nutrients 

in the coastal zone, and these nutrient loadings contribute to the development of hypoxia that is 

observed on a seasonal basis in the north central Gulf. Caffrey and Day (1986) investigated 

variations in nutrient concentrations in Atchafalaya Bay during high spring discharge of the 

Atchafalaya River and during passage of cold fronts. The results illustrated how the physical 

factors of tides, winds, and river discharge interact to control nutrient concentrations. 

Atchafalaya River discharge waters typically have high suspended solids, nitrate, total 

phosphorus and total nitrogen concentrations compared to nearshore Gulf waters that are not 

influenced by riverine discharges. Holland et al. (1983) observed nutrient concentrations in the 

Atchafalaya River near its discharge to the Gulf of 0.02 to 0.72 mg/L total phosphorous and 0.6 

to 8.6 mg/L total nitrogen. Ammonia-nitrogen was detected in water samples from the February 

2008 sampling event at concentrations ranging from 1.3 to 1.8 mg/L (Table 2.3-5), less than the 

chronic water quality criteria of 2.58 mg/L (EPA 1989). Previously, ammonia-nitrogen was 

detected at up to 0.18 mg/L during the April 2002 sampling event (Table 2.3-5). The ammonianitrogen concentrations present in the water samples generally correlated with the observed 

concentrations in the associated sediment samples collected at each location for both events

(Tables 2.3-1 and 2.3-5). 

During the May 2011 flood event, stream-flow rates in the Mississippi and Atchafalaya Rivers 

were nearly twice that of normal conditions. This significantly increased the amount of nitrogen 

transported by the rivers into the Gulf of Mexico. According to USGS estimates, 164,000 metric 

tons of nitrogen (in the form of nitrite plus nitrate) were transported by the Mississippi and 

Atchafalaya Rivers to the northern Gulf (USGS 2012). The amount of nitrogen transported to 

the Gulf in May 2011 was 35 percent higher than average May nitrogen loads estimated in the 

last 32 years (Coastal Care 2012). 

3.1.4.6 Turbidity and Suspended Solids

Turbidity in this part of coastal Louisiana is influenced by resuspension of sediments and runoff 

from the Atchafalaya River (Walker and Hammack 2000). The discharge plume from the 

Atchafalaya River has been detected as far as 29 km (18 miles) offshore (Walker and Hammack 
76

2000). Concentrations of TSS commonly range from 250 to 400 mg/L in Atchafalaya Bay, but 

increase to more than 800 mg/L seaward of the Point au Fer Shell Reef with some measurements 

up to 2,300 mg/L in the ARBC (ETS 2006). The increase in concentration results from wave 

resuspension of soft sediments deposited rapidly as prodelta clays during calm weather periods. 

The concentrations of suspended sediments in the turbid zone decrease across the shelf to the 

plume edge approximately 25 to 28 km (15 to 17 miles) offshore. Outside the plume, typical 

shelf suspended sediment concentrations are 1 mg/L or less. The inorganic sediment fraction 

was 80 percent or more of the suspended solids by weight when the total suspended solids 

concentrations exceeded 10 mg/L (Walker 2001) distributions and concentrations of trace metals 

in the Gulf of Mexico are variable and probably related to land runoff, biological activity, manmade inputs and physical processes (Frey et al. 1981; Trefry 1981; Phillips and James 1988). 

The Atchafalaya River (including the Red River) carries about 30 percent of the volume and 40-

50 percent of the suspended sediment load of that in the Mississippi River (Mossa and Roberts 

1990; Myint and Walker 2002). Sediment loading to the shelf from the Atchafalaya River 

discharge increased greatly after the 1973 flood in the Mississippi River Basin, with annual 

sediment discharge to the estuarine and marine environment estimated at over 200 mcy per year 

(Krug 2007). In spring 2011, the flooded Mississippi and Atchafalaya Rivers delivered huge 

suspended sediment loads to the Gulf of Mexico and Atchafalaya Bay. Approximately two times 

more suspended sediment entered the Gulf of Mexico from the Atchafalaya River Basin than 

from the main stem of the Mississippi River (Welch et al. 2012). Recent studies by Khan et al. 

(2011) found that post-flood sediment accumulation was greatest in the Atchafalaya Basin (1.61 

± 0.96 g cm-2) compared to the Mississippi Delta, Barataria, and Terrebonne basins. Since the 

flood, the USGS has been monitoring sediment dynamics in the Atchafalaya River and Bay to 

understand the impacts on the basin’s ecosystem. 

3.1.4.7 Trace Metals

Distributions and concentrations of trace metals in the Gulf of Mexico are variable and probably 

related to land runoff, biological activity, man-made inputs and physical processes (Frey et al.

1981, Trefry 1981, Phillips and James 1988). Several trace elements are necessary 

micronutrients for life processes of organisms; however, metals such as mercury and cadmium 

can be toxic when present at elevated concentrations in water or in food sources. The major 

source of dissolved and particulate trace metals to the Gulf is discharge from the Mississippi and 

Atchafalaya Rivers. In previous studies of sediment quality in the project area, trace metal 

concentrations in waters from the ARBC and comparable reference stations were below 

detection limits (Dettmann and Tracey 1990; Trulli 1996). Results from sampling event for the 

2008 contaminant assessment detected antimony, arsenic, cadmium, chromium, copper, nickel 

selenium and zinc in waters at the ARBC area (Table 2.3-5; PBS&J 2008). None of the 

observed concentrations exceeded available Federal Water Quality Criteria for protection of 

aquatic life in marine environments or Louisiana Water Quality Standards for either acute or 

chronic effects (Table 2.3-5). One sample contained copper at approximately 30 percent of the 

applicable water quality standards, all other concentrations detected were at least an order of 

magnitude smaller than the Standards or Criteria. Results of the April 2002 and December 1996 

sampling events and contaminant assessments also did not detect any metals at concentrations at 

or above applicable water quality standards or criteria (Table 2.3-5; Espey, Huston & Associates, 

Inc. 1997; PBS&J 2002). 
77

3.1.4.8 Organic Compounds

Studies of water quality in the project area have found that concentrations of potential organic

contaminants were below detection limits for volatile organic compounds, semivolatile organic 

compounds, chlorinated pesticides and herbicides, and polychlorinated biphenyls (Dettmann and 

Tracey 1990; Trulli 1996). These organic contaminants were not detected in water samples 

collected from the project area during the February 2008, April 2002 and December 1996 

sampling events conducted for contaminant assessments (Table 2.3-5; Espey, Huston & 

Associates, Inc. 1997; PBS&J 2002; PBS&J 2008). TPH was detected in water samples from the 

April 2002 sampling event at concentrations up to 2.7 mg/L (Table 2.3-5). TPH was not 

detected in water samples collected during other sampling events, indicating the presence of 

petroleum in the environment has not persisted over time at these concentrations in the project 

area.

3.1.5 Sediments

3.1.5.1 Sediment Quality and Characteristics

3.1.5.1.1 Sediment Quality

The February 2008 sampling event for the contaminant assessment included collection of 

sediment samples for analysis from three locations in the proposed (ODMDS-West) disposal 

area, three locations along the ARBC channel alignment, and the reference area southeast of the 

channel (Tables 2.3-1 and 2.3-2; PBS&J 2008). Arsenic, beryllium, cadmium, chromium, lead, 

nickel and zinc were detected at most channel and disposal area locations and at the reference 

location. The observed concentration ranges of each of these metals in the channel and disposal 

area sediments were similar to the concentrations in the reference area. Selenium was detected at 

one channel sample location, and was not detected in the disposal area or reference area sample. 

Thallium was not detected in the channel sample locations, but was present at a concentration 

just above the detection limit at the disposal area and reference location. Total and trivalent 

chromium results were similar for each sample, reflecting the absence of hexavalent chromium 

in the maintenance-dredged material and surrounding area.

Ten samples for sediment quality were collected along the ARBC channel alignment for the 

2002 contaminant assessment, along with sampling of the reference area (Table 2.3-1; PBS&J 

2002). Overall, the observed metals concentrations were similar to the results of the channel 

sampling conducted in 2008. Silver was detected in one channel sample and the reference area 

at concentrations just above the detection limit. Sixteen samples were collected for analysis of 

sediment quality during the 1996 contaminant assessment (Table 2.3-1; Espey, Huston & 

Associates, Inc. 1997). Arsenic, beryllium, cadmium, silver, thallium, and trivalent chromium 

were not detected in the 1996 analyses. In general, the concentrations of other metals were 

observed at ranges similar to those found in the 2008 and 2002 results, as well as the reference 

area concentrations for the 1996 sampling event (Table 2.3-1). Zinc was detected at 112 

milligrams per kilogram (mg/kg) in one sample, but the results do not indicate the presence of 

contamination based on the observed range and distribution of zinc concentrations. 
78

In addition to metals, sediment samples from the ARBC and proposed ODMDS-West disposal 

area collected during the 2008, 2002 and 1996 sampling events were also analyzed for inorganic 

and organic priority pollutants (Tables 2.3-1 and 2.3-2; Espey, Huston & Associates, Inc. 1997; 

PBS&J 2002; PBS&J 2008). Ammonia and total organic carbon were the only non-metals 

detected. Total organic carbon was detected at channel and disposal area locations and reference 

area locations at concentrations below 5 percent during both the 2008 and 2002 sampling events. 

No organic carbon was detected in any channel samples from the 1996 contaminant assessment, 

with a detection limit of 0.1 percent. 

Ammonia was detected at all ARBC and disposal area locations and at the reference area during 

the 2008 sampling event (PBS&J 2008). With observed concentrations ranging from just over 

240 mg/kg to nearly 300 mg/kg at the channel and reference areas, and 212 mg/kg to 253 mg/kg 

at the disposal area (Tables 2.3-1 and 2.3-2), the results indicate the widespread presence of 

available nitrogen that has the potential to act as a nutrient for biological activity. Research on 

the distribution of organic nitrogen in the northern Gulf of Mexico indicates that riverine sources 

such as the Mississippi and Atchafalaya Rivers are the predominant sources of available nitrogen 

(Lopez-Veneroni and Cifuentes 1994). Changes in ammonia concentrations over time 

throughout the project are shown by comparison of the 2008 data with the 2002 and 1996 

sampling results for ammonia (Table 2.3-1). The 2002 data indicated a much greater variability 

in ammonia concentrations across the study area, with concentrations ranging from 5 to nearly 

200 mg/kg, with lower concentrations present at select locations in the ARBC and at the 

reference area. Even lower concentrations were observed in the 1996 data, with a maximum 

observed concentration of 29 mg/kg from the channel, and 5 mg/kg at the reference area. 

Because of the similarities in ammonia concentrations observed at the channel, disposal area, and 

reference area for the sampling events, dredged material placement is not expected to change the 

sediment quality in the disposal area. 

Sediments from the ARBC sampled to characterize dredged materials have also been analyzed to 

determine concentrations of potential organic contaminants, including total petroleum 

hydrocarbons (TPH), polynuclear aromatic hydrocarbons (PAHs) and chlorinated pesticides, 

herbicides and polychlorinated biphenyls (PCBs) (Table 2.3-1). These compounds are present in 

emissions and discharges from a variety of industrial processes and pollution sources, and they 

may persist in the environment and bioaccumulate. Bis (2-ethylhexyl) phthalate, a plasticizer 

and common laboratory contaminant, was detected in 3 of 10 channel samples and the reference 

sample from the 2002 sampling event, with observed concentrations from just over 100 

micrograms per kilogram (μg/kg) to nearly 250 μg/kg. This compound was not detected in the 

2008 or 1996 sampling events. The PAHs chrysene, fluoranthene and pyrene were detected in 1 

of 16 channel samples from the 1996 event, with concentrations below 50 μg/kg. TPH was 

detected in 5 of 10 channel samples from 2002, with concentrations ranging up to nearly 350 

mg/kg. Chemical analyses, suspended particulate phase bioassays, solid phase bioassays, and 

bioaccumulation studies conducted in 2008 indicated no causes for concern (PBS&J 2008). The 

NOAA Effect Range – Low (ERL) for arsenic was exceeded in some channel sediment samples 

from the 2008 contaminant assessment, but the bioassays and bioaccumulation studies conducted 

as part of the assessment indicated no concern. The presence of these organic compounds in 

limited sampling results from individual sampling events reflect the changing conditions over 
79

time, and do not indicate a persistent, contiguous area of organic sediment contamination in the 

channel and reference areas.

A report entitled “Summary Report for Sub-Sea and Sub-Surface Oil and Dispersant Detection: 

Sampling and Monitoring” was prepared for the USCG Federal On-Scene Coordinator for the 

Deepwater Horizon incident by the Operational Science Advisory Team, and provided to MVN 

in December 2010. A review of the report’s sediment quality data revealed that oil-related 

contaminants and dispersants from the incident did not impact the Atchafalaya Bay. 

A query of the USCG National Response Center database revealed no reported significant spills 

or other incidents of significant pollution in the vicinity of the ARBC and adjacent disposal areas 

from August 31, 2010 thru July 12, 2012. 

Based on MVN’s review of oil spill tracking and contaminant information pertaining to the 

Deepwater Horizon incident, the sampling and analyses performed in 2008 for the ARBC, and 

the lack of any additional significant spills or incidents of pollution in the project vicinity since 

2010, there is no reason to believe that dredged material from future maintenance events in the 

ARBC of the Atchafalaya River and Bayous Chene, Boeuf, and Black, Louisiana project would 

be unsuitable for open water disposal. 

3.1.5.1.2 Sediment Characteristics

Sediments on the shelf off the Atchafalaya Bay range from sand to clayey silt to silty clay. 

Nearshore sediments are predominately (>95 percent) silts and clays. Sediments become 

increasingly coarse in the seaward direction; at approximately the 10-m contour, sediments are 

predominately (>70 percent) sand (Hausknecht 1980; Weissburg et al. 1980b). Seaward of the 

10-m (35-ft) contour, sediments consist of clayey silts and silty clays. Grain size generally 

becomes coarser during the winter months due to the resuspension of silts and clays by storm 

turbulence (Hausknecht 1980). Sediments over this region are chiefly of terrigenous origin, 

containing less than 30 percent calcium carbonate (Uchupi and Emery 1968). The shelf also 

contains numerous hills largely composed of salt domes and partly of mud diapers (Uchupi and 

Emery 1968; Shepard 1973). 

The shelf in the vicinity of the ARBC is considered a dispersive area where maintenancedredged material is expected to erode because of the energy resulting from waves and currents 

(USACE 1996). The bottom sediments of the nearly flat (regional slope of about 0.03°) inner 

Gulf shelf surrounding the ARBC consist of fine muds and silts (Adams et al. 1982; Neill and 

Allison 2005). 

During IEC (1983) surveys in December 1980 and May - June 1981, surficial sediments in the 

ODMDS-East were predominantly silts and clays. In December 1980 and May - June 1981, the 

percentage of fines (silt and clay) and sand ranged from 82 to 100 percent and from 0 to 18 

percent, respectively. The clay fraction was slightly higher in May - June than in December. 

This was probably a function of lower wave current energy in late spring and summer relative to 

winter, and inputs of fines from the river in spring. 
80

Surface sediments in the ODMDS-West are predominately silt and clay (IEC 1983; Dettman and 

Tracey 1990; Flemer et al. 1994; Trulli 1996; PBS&J 2008). Grain size analysis of the 

sediments sampled as part of the contaminant assessments conducted by PBS&J (2008) found 

material from the ODMDS-West consisting of approximately 1-23 percent sand, 21-33 percent

silt, and 45-78 percent clay (Table 2.3-2). 

The maintenance-dredged material in the ARBC is generally comprised of silt with some sand 

and clay (7-12 percent sand, 81-88 percent silt, and 6-7 percent clay) (PBS&J 2008). Finer 

sediments are generally found towards the south end of the channel. Grain size analyses of 

dredged material sediments based on the samples collected for the 2008, 2002 and 1996 

contaminant assessments are listed in Table 2.3-1, along with the results of chemical analyses. It 

is interesting to note that since the 1996 contaminant assessment, grain size distribution at the 

ARBC reference station (located southeast of the ARBC) has changed over time, with the silt 

component increasing from 44 percent in 1996 to 81 percent in 2008. This mirrors, somewhat, a 

similar trend in dredged material grain size distribution at the ARBC, where the silt component 

has increased from 22-53 percent in 1996 to 81-88 percent in 2008. While the naturally variable 

sediment characteristics in the vicinity make it difficult to make inferences as to what may cause 

the apparent changes in grain size here over time, it is possible that sediments from the ARBC—

particularly from the south end of the channel where finer sediments predominate—are 

occasionally (e.g., during winter cold fronts) transported in the direction of the reference station 

where they may ultimately settle and accumulate.

3.1.5.2 Sediment Transport

The Atchafalaya River and the expanding deltas at its outfall into the Gulf of Mexico provide 

sediment essential for offsetting coastal land loss. The actively prograding deltas in Atchafalaya 

Bay are one of the few remaining portion of Louisiana’s coastal region where land mass is being 

created. Prior to 1952, significant deltaic sedimentation was confined almost exclusively to the 

interior of the Atchafalaya Basin, with the major portion of the rivers sediment load being 

deposited in the many lakes, swamps, bayous and other catchments located throughout the basin. 

Two significant events took place between the 1940s and 1950s, which significantly altered the 

sedimentation patterns within the basin and increased the sediment load discharging into 

Atchafalaya Bay. First, the last of the major lakes in the southern Atchafalaya Basin (Grand 

Lake and Six-Mile Lake) was filled with delta deposits and second, the USACE constructed the 

Wax-Lake Outlet flood-conveyance channel from Six-Mile Lake to Atchafalaya Bay. These 

events both decreased the storage capacity and trapping efficiency of the basin while increasing 

the efficiency and ability for the river to deliver sediments, primarily as suspended load, to 

Atchafalaya Bay. Since this time over 150 km2 of new land has developed in Atchafalaya Bay

(OCPR 2011). The Atchafalaya and Wax Lake deltas have rapidly evolved through the 

processes of seaward channel extension and bifurcation as well as lobe fusion and upstream 

growth by coarse sediments (primarily fine sand). This process is characteristic of the early 

constructional phase of the delta cycle and signifies that the Atchafalaya-Wax Lake system is the 

latest lobe within the Mississippi River Delta Plain (Roberts et al. 2003). 

Atchafalaya River flows at Morgan City ranged from 2,124 to 3,964 cubic m/sec (75,000 to 

140,000 cubic ft/sec) during dry months (July through November) and up to 200,000 to 450,000 
81

cubic ft/sec during wetter months (December through June) over the period from 2001 to 2003

(ETS 2006). River flows transport large amounts of sediment into Atchafalaya Bay and into the 

vicinity of the ARBC. The ARBC is at the seaward end of the Atchafalaya River that receives 

about 30 percent of the volume and 40-50 percent of the suspended sediment load (and as much 

as 60 percent of the bedload [Hupp et al. 2008]) of that in the Mississippi River (Mossa and 

Roberts 1990; Myint and Walker 2002; Mead and Moody 2010). Teeter et al. (2003) report that 

the current freshwater river flow carries 94 million tons (9.55×107 kg) per year of sediment into 

the top of the Atchafalaya River Basin. The majority of this sediment is believed to be carried 

down the river and deposited in the basin and deltas which make up the Atchafalaya Bay. Huh et 

al. (1996) and Walker et al. (2002), respectively, predict 88 and 80 million tons of sediment per 

year enters Atchafalaya Bay of which Thomas et al. (1988) estimate 25 percent, or 

approximately 22 million tons (2.2 × 107 kg), remains in the bay itself. Teeter et al. (2003) 

estimate roughly 18 million tons of silt and 27 million tons of clay pass through the Bay near the 

landward end of the ARBC each year. More recent sediment flux estimates at Simmesport 

suggest a decreasing sediment supply to the basin due to declining sediment loads in the 

Mississippi and Red Rivers (Galler and Allison 2008; Hupp et al. 2008; Kirkeeng 2010; Meade 

and Moody 2010). However, data presented by both Roberts et al. (1997) and Twilley et al. 

(2008) describing the flux of sediment through the Wax Lake Outlet and past Morgan City do 

not show a similar decrease as that observed at Simmesport. Typical annual dredging for the 

ARBC is between 9-11 mcy/yr of dredged material (Teeter et al. 2003).

The Mississippi River flood of 2011 delivered vast quantities of sediments to the Gulf of Mexico 

and Atchafalaya Bay. Approximately two times more suspended sediment entered the Gulf of 

Mexico from the Atchafalaya River Basin than from the main stem of the Mississippi River 

(Welch et al. 2012). Recent studies by Khan et al. (2011) found that post-flood sediment 

accumulation was greatest in the Atchafalaya basin (1.61 ± 0.96 g cm-2) compared to the 

Mississippi Delta, Barataria, and Terrebonne basins. Since the flood, the USGS has been 

monitoring sediment dynamics, including sediment depositional patterns, in the Atchafalaya 

River and Bay to understand the impacts on delta development and the basin’s ecosystem.

The sediment-laden water from the Atchafalaya River creates a turbid plume usually directed 

towards the west along the shore that is visible from satellites. Murray (1998) found the 

sediment plume from Atchafalaya Bay flowed to the west particularly during fall, winter and 

spring but its direction of travel could change rapidly with major wind direction shifts. Annual 

loading of sediment discharges from the Atchafalaya River increased significantly with the 1973 

flood event, which increased the percentage of Mississippi River flow and sediment load 

captured by the Atchafalaya River. 

The ARBC crosses a shallow, flat, reach of the inner Gulf of Mexico shelf with bottom sediment 

consisting of fine particles, easily resuspended into the water column. These resuspended 

sediments may be transported in several different directions depending on wind direction and 

strength, river flows, longshore currents and tides. The erosive conditions that are favorable to 

repeated open-water, dispersive disposal of most maintenance-dredged material from the 

channel, facilitate transport of fine sediments into the channel. Channel morphology (relatively 

deep compared to the surrounding inner shelf bottom) and its orientation (perpendicular to 

typical long shore currents) enhance the capture and retention of sediments.
82

Cold front passages occur between October and April on three- to five-day cycles. Winter 

storms that occur 20 to 30 times each year may reverse the direction of flow generally towards 

the southeast (Walker and Hammack 2000); however, the direction of sediment transport may 

vary widely (Pepper et al. 1999). Turbidity, probably as a result of sediment resuspension, 

increases during these events when the wind is blowing offshore. Seventy to 80 percent of the 

sediment load in these situations is resuspended from the Gulf bottom by waves and the 

remainder is advected from Atchafalaya Bay (Walker and Hammack 2000). 

Several studies document fluff, or fluid mud, accumulations on the inner shelf and within the 

ARBC. Teeter et al. (2003) defines fluff as ‘sediment material with solids content and bulk 

density less than about 18.7 and 75 dry pound per cubic yard (300 and 1200 kg m–3), 

respectively, and a corresponding moisture content (water weight over sediment weight) above 

about 300 percent’. Teeter et al. (2003) suggest that fluff forms by the rapid deposition of finegrained silt and clay flocs from suspension and is maintained by periodic agitation (such as 

waves, currents or vessel navigation). Such material might not impede navigation, but left 

undisturbed, it settles, loses volume and converts to fluid mud, which in turn densifies into a 

fully-settled bed’. Observations by SCUBA over a 22-year period revealed unconsolidated mud 

layers on the shelf in the study area up to 0.9 m (3 ft) thick (Van Heerden and Kemp 2000). 

Measurements of fluff in the channel ranged from 0.9 to 3.5 m (3 to 11 ft) thick and could vary 

in the same location up to plus or minus 0.6 m (2 ft) over a 6-week period. They also report 

observing fluff washing out of the channel when vessels passed. Teeter et al. (2003) measured 

accumulations of fluff in the channel over a similar channel reach to that observed by Van 

Heerden and Kemp. Other studies reported development of fluff over the inner shelf, particularly 

during and after frontal passage. 

The transport of fine sediments, from both fluvial sources and littoral drift, contributes to the 

substantial shoaling that occurs in the ARBC. Persistent shoaling occurs in the vicinity of the 

mixing zone, where the freshwater and saline water meet. The meeting of the two sometime 

opposing water masses leads to a slowing down of water velocities increasing flocculation and 

settling of suspended sediment. According to ETS (2006), the mixing zone and resultant shoal is 

generally located in the ARBC around Channel Station 800+00 (18,000 m upstream of the 

seaward end of the channel). The average amount of shoal material dredged from the ARBC for 

placement in the ODMDS-East and Bird Island-East between 1996 and 2002 was approximately 

12.8 mcy per year, of which, approximately 10.9 mcy per year was placed in the ODMDS-East 

(Table 1). The average amount of material dredged from the ARBC for placement in the 

ODMDS-West and Bird Island-West (since 2002) is about 12.6 mcy per fiscal year, of which, 

approximately 10.8 mcy per fiscal year is placed in the ODMDS-West every 7.4 months (Table 

1-1).

3.1.5.3 Hazardous, Toxic, or Reactive Wastes

Dredged materials and sediments beneath navigable waters proposed for dredging qualify as 

Hazardous, Toxic, or Reactive Wastes (HTRW) per Engineering Regulations (ER) 1165-2-132 

(June 26, 1992), only if it is within the boundaries of an EPA-designated Comprehensive 

Environmental Response, Compensation, and Liability Act (CERCLA) or National Priority List 

(Superfund) site, or if it is within the boundaries of a site designated by a state for a response 
83

action under CERCLA. Neither the ARBC nor the proposed ODMDS are within the boundaries 

of such areas.

3.1.5.4 Oil and Gas

The Gulf of Mexico oil and gas industry has changed dramatically over recent years. Because

international as well as domestic policies shape the trends in exploration, rig utilization, and 

lease acreage, the status of oil and gas related activity will be dynamic until the price of these 

products stabilizes. 

The western and central portions of the Gulf of Mexico (GOM) region (offshore Texas, 

Louisiana, Mississippi, and Alabama) are major offshore oil and gas areas, and most of the 

equipment and facilities supporting offshore GOM oil and gas operations are located in these 

areas (BOEM 2011). Extensive oil and gas development occurs within the Atchafalaya River 

Delta and in the vicinity of the ODMDS-East and ODMDS-West. The ODMDS-West is located 

within three active lease blocks of the Eugene Island section, which is a small section of the Gulf 

of Mexico Inner Continental Shelf. There are numerous platforms within the ODMDS-West in 

the western and southwest areas. In addition there are several oil and gas lines crossing the 

ODMDS-West that consist of several gas lines, including a 51 cm (20-inch) and 76 cm (30-inch) 

ANR Gas line, a 56 cm (22-inch) Trunkline Gas line, a 51 cm (20-inch) Contango Operators, 

Inc., gas line, a 30-inch Enbridge Offshore Gas line. There are approximately 43 smaller 

gathering lines connecting wells and platforms that lie near and within the proposed disposal site. 

Currently there are a total of 48 pipeline structures located within the ODMDSs. Figure 3.1-2 

shows the offshore platforms within the GOM’s Central Planning Area, as well as key related 

onshore and offshore infrastructure which include ports, supply bases, shipyards, platform 

fabrication yards, pipe yards, oil refineries, gas processing facilities, helicopter pads, pipelines, 

and other infrastructure. 

Figure 3.1-2. Oil and gas infrastructure locations in the GOM region Central Planning Area (BOEM 2011)
84

3.2 BIOLOGICAL ENVIRONMENT

3.2.1 Plankton

3.2.1.1 Phytoplankton

The phytoplankton community in Louisiana coastal waters is diverse and productive, exhibiting 

large spatial and temporal fluctuations. Within coastal Louisiana waters, diatoms typically 

constitute 70 to 100 percent of the phytoplankton standing crop; dinoflagellates and blue-green 

algae contribute small and seasonally variable numbers to the assemblage. In contrast, bluegreen algae (especially Trichodesmium thiebauti) and coccolithophores (particularly Coccolithus 

huxleyi) are dominant components of the phytoplankton in offshore waters (Cromiskey and 

Farmer 1981). Cell density is highest in coastal bays and the neritic zone, and decreases seaward 

(Weissberg et al. 1980b). Both the mid-shelf area and nearshore areas have similar patterns of 

phytoplankton composition and biomass (Weissberg et al. 1980b). 

3.2.1.2 Zooplankton

Zooplankton in the northern Gulf can be characterized as inhabitants of any of five 

zoogeographic zones; oceanic, continental slope transition, central continental shelf, coastal 

neritic, and estuarine zone. These zones are geographically variable, and their boundaries may 

reflect influences from water masses and current patterns. Zooplankton communities in each of 

the five zones are dominated by copepods; however, the dominant species may vary between 

zones. For example, within coastal areas, temperate copepod species (e.g., Acartia tonsa, 

Paracalanus crassirostis, Eucalanus pileatus) are typically dominant, whereas tropicalsubtropical species (e.g., Euchaeta marina, Copilia mirabilis) are dominant in oceanic regions 

(Comiskey and Farmer 1981). Euphausiids, chaetognaths, and larval crustaceans also contribute 

substantially to zooplankton communities on the shelf. Zooplankton densities generally decrease 

with increased distance from shore (USDOE 1978; Comiskey and Farmer 1981). 

3.2.2 Benthos

Macroinfaunal assemblages in Louisiana shelf areas are composed of euryhaline organisms 

characteristic of the open bay and mud bottom habitats from Port Aransas, Texas to Mobile, 

Alabama (Parker et al. 1980). Polychaetes and, to a lesser extent, phoronids and pelecypods, 

generally are the most abundant macroinfaunal groups, comprising approximately 95 percent of 

the benthic population off Louisiana (Weissberg et al. 1980). 

Nearshore benthic organisms respond to seasonal changes in the hydrological regime, especially 

to winter and summer pulses of dissolved nutrients, which result in increases in plankton 

populations and subsequent increases in food supply. Variability in the abundance and 

composition of the benthos reflect seasonal changes in the nearshore environment. In contrast, 

the offshore hydrographic regime is more constant. Consequently, seasonal abundance patterns 

are less distinct in offshore regions (Comiskey and Farmer 1981). 
85

Macrofaunal assemblages near the ARBC ODMDSs have been examined during benthic

investigations of several proposed salt dome brine diffuser sites (Parker et al. 1980; Weissberg et 

al. 1980a, 1980b). These studies characterized nearshore assemblages typical of estuarine areas. 

Communities were dominated by polychaete worms (particularly Mediomastus sp., 

Aglaophamus sp., Paraprionospio sp., Magelona sp., and, Owenia sp.), small molluscs (Mulinia 

lateralis and Nassarius sp.), and macrocrustaceans (shrimp and crabs). Macrofaunal organisms 

consist mainly of deposit and suspension feeders; however, omnivores and carnivores were also 

well represented. The dominant organisms were small-bodied, opportunistic species capable of 

rapid colonization of disturbed sediment. Most species displayed seasonal population 

fluctuations. Recruitment occurred during winter and spring; populations declined during 

summer and autumn due to predation and environmental stresses such as sediment disturbance 

by storms or anoxic conditions in bottom waters.

Stations sampled by IEC (1983) in the vicinity of the ODMDS-East were further inshore and 

shallower than the proposed brine diffuser sites; however, the same general macrofaunal 

assemblage was found. During both surveys, polychaetes dominated the macrofauna, 

particularly Mediomastus californiensis, Cossura sp., and Paraprionospio pinnataa. During the 

December survey the little surf clam (M. lateralis) was very abundant at a station west of the 

site, probably as a result of seasonal recruitment characteristic of this species (Parker et al. 1980). 

By the following survey in late spring (May - June), M. lateralis was abundant only at one 

station within the site. Other common members of this assemblage were the carnivorous ribbon 

worms, Cerebratulus cf. lacteus (and other unidentified rhynchocoelans) and the snail, Nassarius 

acutus. 

3.2.3 Finfish and Shellfish

Numerous species of finfish and shellfish inhabit the waters off the central Louisiana coast and 

can be characterized as estuary-related or demersal shelf inhabitants. Estuarine-related species 

can be estuary-dependent species or low-salinity, tolerant species. Estuarine-dependent species 

typically are dependent upon the coastal bays, lagoons, and estuaries as low-salinity nursery 

areas for juveniles. These species include white shrimp (Litopenaeus setiferus), brown shrimp 

(Farfantepenaeus aztecus), Gulf menhaden (Brevoortia patronus), red drum (Sciaenops 

ocellatus), black drum (Pogonias cromis), spotted seatrout (Cynoscion nebulosus), sand seatrout 

(C. arenarius), sheepshead (Archosargus probatocephalus), silver perch (Bairdiella chrysoura), 

spot (Leiostomus xanthurus), striped mullet (Mugil cephalus) and blue crab (Callinectes sapidus) 

(Darnell et al. 1983). 

Demersal shelf residents are abundant fauna of the continental shelf. These species include 

broken-necked shrimp (Trachypenaeus similis), barred searobin (Prionotus martis), blackfin 

searobin (P. rubio), dwarf sand perch (Diplectrum bivittatum), sand perch (D. formosum), 

inshore lizardfish (Synodus foetens), pancake batfish (Halieutichthys aculeatus), and shoal 

flounder (Syacium gunteri) (Darnell et al. 1983). 

Nektonic species and fast swimmers that may occur within the area of the ODMDSs include 

sharks, tarpons, clupeids, carangids, dolphins, mackerels, wahoos, tunas, and billfishes. These 

species are also attracted to oil rigs, which provide reef-like environments in the Gulf. Most, but 
86

not all, of the larger predators occur seasonally on the northern Gulf shelf, appearing in spring 

and leaving in the fall (Darnell et al. 1983). 

Many species of shellfish inhabit Louisiana coastal waters and include white, pink 

(Farfantepenaeus duorarum), and brown shrimp, blue crab, lesser blue crab (C. similis), and 

swimming crabs (Portunus sp.) (Landry and Armstrong 1980).

Waters off central and western Louisiana shoreward of the 36-m (120-ft) isobaths are one of the 

most heavily fished areas in the world (NMFS 2012). Louisiana provides approximately 78

percent (approximately 1 billion pounds) of the total catch of finfish and shellfish in the Gulf of 

Mexico by weight and approximately 40 percent ($248 million) by value (NMFS 2012). Central 

Louisiana (which includes Atchafalaya Bay) contributes approximately 50 percent to these 

Louisiana totals (NMFS 2012). This may be directly attributable to the extensive estuarine

nursery areas of Louisiana, including the waters of Atchafalaya Bay (Darnell et al. 1983; Darnell 

and Kleypas 1987). In addition, the estuaries are also known to export considerable quantities of 

organic material, thereby enriching the adjacent continental shelf areas (Darnell and Soniat

1979). 

The most valuable species commercially harvested in waters off central Louisiana include white 

and brown shrimp, blue crab, Gulf menhaden, southern flounder (Paralichthys lethostigma), and 

Eastern oyster (Crassostrea virginica). Gulf menhaden, sheepshead, black drum, red drum, 

spotted seatrout, and sand seatrout are also commercially important species in the area. 

Recreational fishing, including fishing, crabbing, and shrimping, is popular in the vicinity of the 

ODMDSs. 

3.2.4 Essential Fish Habitat

The Magnuson-Stevens Fishery Conservation and Management Act of 1996 (MSFCMA) defines 

Essential Fish Habitat (EFH) as “those waters and substrate necessary to fish for spawning, 

breeding, feeding or growth to maturity.” The estuarine and marine waters in St. Mary Parish, as 

well as the northern Gulf of Mexico, are designated as EFH. In particular, EFH identified by the 

Gulf of Mexico Fishery Management Plan (FMP) in St. Mary Parish and adjoining waters—

including Atchafalaya Bay—include estuarine water column and estuarine water bottoms, 

including mud, rock, sand, intertidal vegetation, and shell substrates. No “Habitat Areas of 

Particular Concern” have been identified in the project vicinity. 

The proposed project is located within an area identified as EFH for brown shrimp

(Farfantepenaeus aztecus), white shrimp (Litopenaeus setiferus), red drum (Sciaenops 

ocellatus), lane snapper (Lutjanus synagris), king mackerel (Scomberomorus cavalla), cobia

(Rachycentron canadum), bonnethead shark (Sphyrna tiburo), and Atlantic sharpnose shark 

(Rhizoprionodon terraenovae) (Table 3.2-1).

In addition to being designated as EFH for the species listed in Table 3.2-1, the proposed project 

area provides nursery and foraging habitats that support a variety of economically important 

marine fishery species, such as Atlantic croaker, spotted seatrout, gulf menhaden, blue crab, and 

striped mullet. Some of these species serve as prey for other fish species managed under the 
87

MSFCMA by the Gulf of Mexico Fishery Management Council (i.e., mackerels, snappers, and 

groupers) and highly migratory species managed by NMFS (i.e., billfishes and sharks). 

Table 3.2-1. EFH species in the project area.

Common Name Life Stage EFH

brown shrimp

eggs

larvae/post larvae

juvenile 

planktonic, sand/shell/soft bottom, SAV

emergent marsh, oyster reef

white shrimp

eggs

larvae/post larvae

juvenile 

adult

9-34 m, planktonic, soft bottom, emergent marsh 

red drum 

larvae/post larvae

juvenile 

adults 

all estuaries planktonic, SAV, sand/shell/soft 

bottom, emergent marsh, pelagic 

lane snapper

eggs

larvae

juvenile 

4-130 m, reefs, sand/shell/soft bottom, SAV, 

mangrove

king mackerel

larvae

juvenile 

adults 

9-180 m, pelagic 

cobia juvenile 5-183 m, pelagic

bonnethead shark juvenile inlets, estuaries, coastal waters <25 m

Atlantic sharpnose shark juvenile <40 m, Atchafalaya delta 

3.2.5 Mammals, Reptiles and Birds

The diversity of marine mammals and reptiles is typically lower in nearshore regions than in the 

adjacent offshore regions of the northern Gulf (Bahr and Hebrard 1976). Several migratory bird 

species utilize nearshore areas for overwintering, breeding, and/or nesting, whereas offshore 

areas may be inhabited by strictly pelagic species.

Five species of sea turtles occur in the northern Gulf: green (Chelonia mydas), Kemp’s ridley

(Lepidochelys kempii), hawksbill (Eretmochelys imbricata), leatherback (Dermochelys coriacea) 

and loggerhead (Caretta caretta) (NMFS 2003). Feeding and nesting activities in the northcentral Gulf off Louisiana have been reported only for the Kemp’s ridley turtle. 
88

Several species of whales and dolphins occur in the northern Gulf. The only species of marine 

mammal common to nearshore waters is the Atlantic bottlenose dolphin (Tursiops truncatus), 

which occurs in greatest numbers within tidal passes, and feeds on shrimp and larger fish (Bahr 

and Hebrard 1976). The greatest numbers of mammals typically occur along the outer shelf and 

shelf-break. For example, the short-finned pilot whale (Globicephala macrorhyncus), sperm 

whale (Physeter catodon), and Atlantic spotted dolphin (Stenella plagiodon) are most common 

in outer shelf and open Gulf waters (USDOE 1978). 

Numerous species of oceanic birds and waterfowl may occur throughout the year in the 

nearshore region off Louisiana. Southern coastal Louisiana is within the Central Flyway and 

provides resting or overwintering grounds for a number of migratory species; e.g., blue and 

green winged teal (Anas discors and A. carolinensis), widgeon (A. americana), and canvasback 

(Aythya valisineria). Permanent residents of waters off the Louisiana coast, including those in 

the vicinity of the existing and proposed ODMDSs, may include frigatebirds (Fregata 

magnificens), gannets (Morus bassanus), and Audubon’s shearwaters (Puffinus lherminieri). 

Densities of birds are seasonally variable, generally increasing from October through December. 

Bird populations further offshore may consist of pelagic species such as frigatebirds, shearwaters 

(Puffinus griseus and P. lherminieri), and jaegers (Sterocoratius pomarinus and S. parasiticus).

3.2.6 Threatened and Endangered Species

According to a U.S. Fish and Wildlife Service (USFWS) letter dated July 1, 2011, which 

provided comments in accordance with the Fish and Wildlife Coordination Act (FWCA), 

Endangered Species Act (ESA), Bald and Golden Eagle Protection Act (BGEPA), and the 

Migratory Bird Treaty Act (MBTA) for those areas within MVN proposed FY12 Operations and 

Maintenance Dredging and Disposal Plans for federally-maintained navigation channels, 

protected species that may occur in the ARBC near the proposed project area include the piping 

plover (Charadrius melodus), West Indian manatee (Trichechus manatus), and sea turtles. The 

pallid sturgeon (Scaphirhynchus albus) may also occur in the project area. Brown pelicans and 

other colonial nesting wading birds and seabirds protected under the MBTA may be encountered 

in the project area as well.

Piping Plover 

The piping plover, as well as its designated critical habitat, occurs along the Louisiana coast 

(http://critical habitat.fws.gov/crithab). Piping plovers winter in Louisiana and may be present 

eight to ten months of the year (LDWF 2011). They depart for the wintering grounds from midJuly through late October and remain until late March or April. Piping plovers forage on 

intertidal beaches, mudflats, sand flats, algal flats, and wash-over passes with no or very sparse 

vegetation. They roost in unvegetated or sparsely vegetated areas, which may have debris, 

detritus, or micro-topographic relief offering refuge from high winds and cold weather. They 

also forage and roost in wrack deposited on beaches. Piping plovers occur along the Gulf of 

Mexico shoreline and on bird islands adjacent to the northernmost extent of the ARBC. Piping 

plovers could occur along the shoreline and in the intertidal of the project vicinity during winter 

migration, but are not permanent residents of the area. Construction activities associated with 
89

the proposed project may cause piping plovers occurring near the project area to be temporarily 

displaced to nearby areas containing foraging and loafing habitat. Piping plover designated 

critical habitat occurs on islands immediately north of the proposed work, but not directly within 

the ARBC dredging limits or the proposed disposal area. 

Pallid Sturgeon

The pallid sturgeon is an endangered fish found in Louisiana, in both the Mississippi and 

Atchafalaya Rivers (with known concentrations in the vicinity of the Old River Control Structure 

Complex); it is possibly found in the Red River as well. The pallid sturgeon is adapted to large, 

free-flowing, turbid rivers with a diverse assemblage of physical characteristics that are in a 

constant state of change. Detailed habitat requirements of this fish are not known, but it is 

believed to spawn in Louisiana. Pallid sturgeon, especially juveniles, appear to be at risk for 

entrainment in cutterhead dredges, because of their benthic holding behavior and their relatively 

low burst swimming speed (Hoover et al. 2005). The density of pallid sturgeon in the lower 

Atchafalaya River Delta is thought to be low; however, there have been limited sampling efforts 

in that area. Because pallid sturgeon are strictly freshwater fish, they are probably absent from 

the Atchafalaya River Delta during low river flows when more saline water from Atchafalaya 

Bay intrudes upriver to a greater extent. If project construction is planned during these events, 

impacts to pallid sturgeon due to dredging activities are unlikely. Although pallid sturgeons are 

unlikely to occur in the project area, USFWS has recently provided MVN with recommendations 

to further reduce the unlikely chance of encountering pallid sturgeons or other fish species while 

conducting dredging/disposal activities.

West Indian Manatee

West Indian manatees, also known as sea cows, are large aquatic mammals found in shallow, 

slow-moving rivers, estuaries, salt water bays, canals, and coastal areas. Range is generally 

restricted to the southeastern United States, although individuals may occasionally venture as far 

north as Massachusetts and as far west as Texas (USFWS 2011). They are rare visitors to coastal 

Louisiana, occasionally entering Lakes Pontchartrain and Maurepas, and associated coastal 

waters and streams during the summer months. Most manatee sightings in Louisiana occur east 

of the Mississippi River (Wilson 2003). They have also been reported in the Amite, Blind, 

Tchefuncte, and Tickfaw Rivers, and in canals within the adjacent coastal marshes of Louisiana. 

It is extremely unlikely that manatees would be found in the project area or elsewhere in the 

ARBC and the surrounding shallow open waters; however, if manatees are observed within 100 

yards of the “active work zone” during proposed dredging/disposal activities, MVN would 

implement the appropriate special operating conditions (e.g., no operation of moving equipment 

within 50 ft of a manatee; all vessels should operate at no wake/idle speeds within 100 yards of 

work area; siltation barriers, if used, should be re-secured and monitored; report manatee 

sightings or collisions), as provided by the USFWS, Lafayette, Louisiana Field Office. Special 

operating conditions for manatees would be included in any MVN plans and specifications 

developed prior to dredging/disposal activities. 
90

Sea Turtles

Loggerhead sea turtles nest within the coastal United States from Louisiana to Virginia, with 

major nesting concentrations occurring on the coastal islands of North Carolina, South Carolina, 

and Georgia, and on the Atlantic and Gulf coasts of Florida (NMFS/USFWS 2009). In 

Louisiana, loggerhead sea turtles are known to nest on the Chandeleur Island (LDWF 2011). 

Nesting and hatching for loggerheads in the Gulf of Mexico occur from May through November. 

Green sea turtles are more tropical in their distribution, and are rarely seen in Louisiana coastal 

waters (LDWF 2011). Nesting in the Southeastern U.S. occurs roughly from June through 

September (NMFS/USFWS 1991). Nesting within the project area is highly unlikely, as green 

sea turtles prefer to nest on high-energy beaches with deep sand and little organic content. 

Furthermore, the Minerals Management Service (1997) indicated that reports of green sea turtle 

nesting in the northern Gulf are “isolated and infrequent.” 

The most seriously endangered of the sea turtles, Kemp’s Ridley turtles occur mainly in bays and 

coastal waters of the Atlantic Ocean and Gulf of Mexico (NMFS/USFWS 1992a). Nesting 

occurs on the northeastern coast of Mexico and occasionally on Texas Gulf Coast beaches from 

April to July. No Kemp’s Ridley sea turtle nesting habitat occurs near the project site, and 

nesting has not been known to occur in the area. Along the Louisiana coast, turtles are generally 

found in shallow nearshore and inshore areas, and especially in salt marsh habitats, from May 

through October. 

The hawksbill is a small sea turtle, generally spending most of its life in tropical waters such as 

the warmer portions of the Atlantic Ocean, Gulf of Mexico, and Caribbean Sea (NMFS/USFWS 

1993). Hawksbills frequent rocky areas, coral reefs, shallow coastal areas, lagoons, narrow 

creeks, and passes. Nesting may occur on almost any undisturbed deep-sand beach in the 

tropics—in North America, the Caribbean coast of Mexico is a major nesting area. In the 

continental United States, nesting sites are restricted to Florida where nesting is sporadic at best 

(NMFS/USFWS, 1993). Due to the lack of suitable foraging and nesting habitats, there is a low 

probability of this species occurring within the project area. 

The leatherback sea turtle is the largest, deepest diving, and most migratory and wide ranging of 

all the sea turtles (NMFS/USFWS 1992). Leatherbacks are mainly pelagic, inhabiting the open 

ocean and seldom entering coastal waters except for nesting purposes. Nesting in the United 

States is mainly confined to the Florida coast, and no nesting has been reported from Louisiana 

(Gunter 1981). 

The National Marine Fisheries Service (NMFS) is responsible for aquatic marine endangered and 

threatened sea turtles. High levels of sediment in the water column and low prey availability 

probably preclude any high use of sea turtles in the lower Atchafalaya River (Baird 1997). 

However, a seasonal restriction has been recommended by NMFS (2003 and 2007) during formal

consultation undertaken pursuant to Section 7 of the ESA. This restriction was based on potential 

impacts of hopper dredging operations on species of threatened and endangered sea turtles. The

recommendation, which is part of a NMFS Regional Biological Opinion, is to restrict hopper 

dredging to the period from December 1 through March 31, during which sea turtle abundance is
91

at a minimum. This recommendation pertains to actual dredging operations, including placement 

of the dredge material in EPA-designated ODMDSs. Hopper dredging will be conducted in 

accordance with all reasonable and prudent measures and implementing terms and conditions 

provided to MVN by NMFS in its 2007 Biological Opinion (NMFS 2007), and any subsequent 

Biological Opinion, to avoid sea turtle mortality. According to the Regional Biological Opinion, 

the annual documented USACE incidental take per fiscal year for the Louisiana Coastal Area is 

expected to consist of 7 Kemp’s Ridleys, 3 green turtles, 1 hawksbill, and 15 loggerhead turtles. 

As of 2003, NMFS had not documented sea turtle takes from MVN dredging in the ARBC 

(NMFS 2003); however, MVN has developed internal protocols for managing, documenting, 

reporting, and coordinating incidental takes to ensure compliance with the provisions of the 

Regional Biological Opinion (NMFS 2007 and 2010). Hydraulic cutterhead pipeline dredging 

operations have not been identified as a source of sea turtle mortality. 

Brown Pelican/Colonial Nesting Wading Birds and Seabirds

The brown pelican (Pelecanus occidentalis), a year-round resident of coastal Louisiana that may 

occur in the project area, was removed from the Federal List of Endangered and Threatened 

Wildlife (i.e., “delisted”) by USFWS on November 17, 2009. Despite its recent delisting, brown 

pelicans—and other colonial nesting wading birds and seabirds—remain protected under the 

Migratory Bird Treaty Act of 1918. Portions of the proposed project area may contain habitats 

commonly inhabited by colonial nesting wading birds and seabirds. To minimize disturbance to 

pelicans and other colonial nesting birds and seabirds potentially occurring in the project area, 

MVN would observe restrictions on activity provided by the USFWS, Lafayette, Louisiana Field 

Office. Special operating conditions addressing pelicans and other colonial nesting wading birds 

and seabirds (reporting presence of birds and/or nests; no-work distance restrictions—2000 ft for 

brown pelicans, 1000 ft for colonial nesting wading birds, and 650 ft for terns, gulls, and black 

skimmers; bird nesting prevention and avoidance measures; marking discovered nests) would be 

included in any MVN plans and specifications developed prior to dredging/disposal activities. In 

addition, dredging/disposal activities would be restricted to non-nesting periods for colonial 

nesting wading birds and seabirds, when practicable. 

3.2.7 Marine Sanctuaries and Special Biological Resource Areas

No marine sanctuaries occur in the immediate vicinity of the either the existing or proposed 

ODMDSs. Shell Keys and Marsh Island Wildlife refuges are approximately 47 km (29 miles), 

west of the ODMDS-East (USFWS 1981). Fishnet Bank, the closest protected Area of 

Biological Significance, is approximately 104 miles south of the ODMDS-East.

3.3 SOCIOECONOMIC ENVIRONMENT

The Atchafalaya Bay is located in both St. Mary and Terrebonne Parishes. The ARBC, however, 

is located in St. Mary Parish. The Louisiana State Seaward Boundaries, measured from the 

MLLW line and which separate State from Federal waters determines the jurisdiction over 

activities that occur in those waters; for instance, the seaward limit of each State’s Coastal Zone 

and the extent of waters from which States receive all revenues from oil and gas exploration.
92

Socioeconomics describes the social and economic characteristics of the study area for the 

ARBC project. The principal socioeconomic study area of the ARBC project consists of the 

parishes of St. Mary and Terrebonne. Information regarding population, employment, income, 

and other economic conditions was obtained from the U.S. Census Bureau. Several demographic 

variables are analyzed to characterize the affect on community and surrounding area, including 

population size and distribution, the means and amount of employment, and income generation. 

The main census data resources are the U.S. Census Bureau and the Bureau of Economic 

Analysis (BEA) and include: (1) Demographic Profile Data Search – Summary File 1 of the 

2010 census and (2) 2008 Economic Census of Business.

Oil and gas and associated industries and the fishing industry are the two major economic 

contributors in this region of Louisiana. Both of these industries depend on reliable navigational 

channels to develop or harvest offshore resources and either transport these goods back to 

onshore ports or, in the case of the oil and gas industry, to service the facilities that operate 

offshore.

3.3.1 Demography and Economics

3.3.1.1 St. Mary Parish

St. Mary Parish has a total area of 2,898 km2 (1,119 square miles), comprising 1,587 km2 (613 

square miles) of land and 1,311 km2 (506 square miles) of water. The total area is 45.23 percent

water. As of the census of 2010, there were 54,650 people, 20,457 households, and 14,179

families residing in the parish (U.S. Census Bureau 2011). This population represents an 

increase of 1,150 since the 2000 Census count of 53,500 (U.S. Census Bureau 2011). The 

population density was 89 people per square mile (34/km2). There were 23,028 housing units at 

an average density of 14.5/km2 (38 per square mile). The racial makeup of the parish was 59

percent White, 32.5 percent Black or African American, 1.8 percent Native American, 1.7

percent Asian, 0.02 percent Pacific Islander, 2.6 percent from other races, and 2.0 percent from 

two or more races. Hispanic or Latino population was 5.3 percent of the population. Home 

languages were reported as 5.43 percent speaking French or Cajun French, 2.45 percent speaking

Spanish and 1.59 percent Vietnamese.

Of the 20,457 households, 29.3 percent had children under the age of 18 living with them, 44.8 

percent were married couples living together, 18.0 percent had a female householder with no 

husband present, and 30.7 percent were non-families. Individuals comprised 25.8 percent of all 

households and 25.5 percent of the households had someone living alone who was 65 years of 

age or older. The average household size was 2.63 and the average family size was 3.15. 

In the parish the population was spread out with 28.2 percent under the age of 20, 6.6 percent

from 20 to 24, 24.7 percent from 25 to 44, 27.4 percent from 45 to 64, and 12.8 percent who 

were 65 years of age or older. The median age was 37.5 years. Males and females comprised 

49.4 percent and 50.6 percent of the population, respectively. 

Median income (2010) for a household in the parish was $40,517, and the median income for a 

family was $48,065. Males had a median income of $49,333 versus $26,043 for females. The 
93

per capita income for the parish was $20,738. About 15.9 percent of families and 18.5 percent of 

the population were below the poverty line, including 29.1 percent of those under age 18 and

16.2 percent of those ages 65 or over. 

3.3.1.2 Terrebonne Parish

Terrebonne Parish was formed in 1822 from part of Lafourche Parish. The parish has a total area 

of 2,080 square miles (5,387 km2), of which 1,255 square miles (3,250 km2) of it is land and 825 

square miles (2,137 km2) of it (39.66 percent) is water. As of the census of 2010, there were 

111,860 people, 40,091 households, and 29,001 families residing in the parish (U.S. Census 

Bureau 2011). The population density was 34/km2 (89 people per square mile). There were 

43,887 housing units at an average density of 13.5/km2 (35 per square mile). The racial makeup 

of the parish was 70.3 percent White, 18.9 percent Black or African American, 5.7 percent

Native American, 1.0 percent Asian, 0.01 percent Pacific Islander, 2.0 percent from other races, 

and 2.1 percent from two or more races. Hispanic or Latino account for 4.0 percent of the 

population. Home language of French or Cajun French is reported at 10.7 percent, while 1.5

percent speak Spanish at home. 

There were 40,091 households out of which 32.7 percent had children under the age of 18 living 

with them, 49.9 percent were married couples living together, 15.7 percent had a female 

householder with no husband present, and 27.7 percent were non-families. According to the 

census, 21.9 percent of all households were made up of individuals and 7.4 percent had someone 

living alone who was 65 years of age or older. The average household size was 2.75 and the 

average family size was 3.20. 

In the parish the population was spread out with 28.9 percent under the age of 20, 7.2 percent

from 20 to 24, 26.8 percent from 25 to 44, 25.8 percent from 45 to 64, and 11.2 percent who 

were 65 years of age or older. The median age was 35 years. Males and females comprised 49.7

percent and 50.3 percent of the population, respectively.

The median income for a household in the parish was $48,860, and the median income for a 

family was $27,381. Males had a median income of $49,290 versus $28,230 for females. The 

per capita income for the parish was $23,589. About 13.1 percent of families and 16.8 percent of 

the population were below the poverty line, including 25.8 percent of those under age 18 and 9.0 

percent of those ages 65 or over. 

3.3.2 Industry

3.3.2.1 St. Mary Parish

Table 3.3-1 shows 2008 to 2010 industry earnings in St. Mary Parish. The top five earning 

industries are: (1) manufacturing; (2) transportation; (3) government and government enterprises; 

(4) agriculture and mining; and (5) professional and scientific services, management, and 

administrative and waste management services. From 2008 to 2010, total industry earnings 

decreased by almost 6 percent. Government and government enterprises grew the most in 

absolute terms over this period at over $11 million. The transportation, warehousing, and
94

utilities sector was second in absolute terms at nearly $7 million. In terms of percentage, the 

fastest growing industries from 2008 to 2010 were arts, entertainment, recreation, 

accommodation and food services (6 percent); and government and government enterprises (5 

percent). 

Table 3.3-1 

Major Industry Earnings, St. Mary Parish, 2008–2010 (in $1,000) 

3.3.2.2 Terrebonne Parish

Table 3.3-2 shows 2008 to 2010 industry earnings in Terrebonne Parish. The top five earning 

industries are: (1) agriculture and mining; (2) manufacturing; (3) government & government 

enterprises; (4) educational, health and social services; and (5) professional and scientific services, 

management, and administrative and waste management services. From 2008 to 2010, total industry 

earnings decreased by approximately 7 percent. Government and government enterprises grew the 

most in absolute terms over this period at almost $28 million. The educational, health and social 

services sector was second in absolute terms at $13 million. In terms of percentage, the fastest 

growing industries from 2008 to 2010 were finance, insurance, and real estate (16 percent); and 

government and government services (8 percent).

Table 3.3-2 

Major Industry Earnings, Terrebonne Parish, 2008–2010 (in $1,000) 

Industry 2008 2009 2010

Agriculture, forestry, fishing, and mining 

Construction

Manufacturing

Wholesale trade 

Retail trade 

Transportation, warehousing, utilities

Information

Finance, insurance, real estate

Professional, scientific, management, administrative and waste 

management

Educational, health and social services

Arts, entertainment, recreation, accommodation and food services

Other services (except public administration)

Government and government enterprises

592,116 

235,456 

522,018 

126,842 

221,134 

272,981 

20,307 

197,326 

316,497 

308,682

110,240 

146,063

363,208 

531,193 

228,121 

461,607 

114,967 

221,711 

258,815 

19,976 

186,937 

294,694

308,725 

108,649 

141,984

381,650 

431,266 

242,729 

361,757 

114,326 

219,277 

271,239 

19,721 

229,393 

327,326

322,155 

117,127 

136,373

391,029 

Source: Regional Economic Information System, Bureau of Economic Analysis, U.S. Department of Commerce, 

Table CA05 (NAICS), http://www.bea.gov/iTable

Industry 2008 2009 2010

Agriculture, forestry, fishing, and mining 

Construction

Manufacturing

Wholesale trade 

Retail trade

Transportation, warehousing, utilities

Information

Finance, insurance, real estate

Professional, scientific, management, administrative and waste 

management 

Educational, health and social services

Arts, entertainment, recreation, accommodation and food services

Other services (except public administration)

Government and government enterprises

253,682

69,484 

310,905

67,003

71,060 

286,709

7,587

108,135

133,134 

not shown

44,203

65,287

258,494

232,580

67,099

321,841

60,378

74,726

224,832

7,572

99,106

116,469

not shown

45,511

66,034

265,607

260,211 

72,196

313,861

62,767

72,601

223,062 

7,316 

107,320

109,183 

not shown

47,222

62,179

270,348

Source: Regional Economic Information System, Bureau of Economic Analysis, U.S. Department of Commerce, 

Table CA05 (NAICS), http://www.bea.gov/iTable

 

 

 

 

 

 

 

 

 

 

 

 

 
95

3.3.3 Employment

3.3.3.1 St. Mary Parish

Table 3.3-3 shows employment by major sector for 2008 to 2010. The table indicates a decline 

in total employment between the years 2008 and 2010. Government and government enterprises 

are the leading employment sector for the parish with manufacturing second. Virtually every 

employment sector saw a loss in number of jobs from 2008 to 2010. 

Table 3.3-3 

Industry Employment, St. Mary Parish, 2008–2010

3.3.3.2 Terrebonne Parish

Table 3.3-4 shows employment by major sector for 2008 to 2010. The table indicates a decline 

in total employment between the years 2008 and 2010. Retail is the largest employment sector

in the parish with government and government services second. Information; education, health, 

and social services; and government and government services were the only employment sectors 

that saw an increase in number of jobs from 2008 to 2010. 

Industry 2008 2009 2010

Agriculture, forestry, fishing, and mining 

Construction

Manufacturing

Wholesale trade 

Retail trade 

Transportation, warehousing, utilities

Information

Finance, insurance, real estate

Professional, scientific, management, administrative and waste 

management

Educational, health and social services 

Arts, entertainment, recreation, accommodation and food services

Other services (except public administration)

Government and government enterprises

Total Parish Employment (including other activities) 

3,146

1,877

4,803

1,054 

2,802

3,465

199

2,651

3,159

not shown

2,294

2,077

5,455 

34,849 

3,023 

1,741 

4,935 

992 

2,849 

2,967 

208 

2,512 

 2,840 

not shown

2,293 

2,028 

5,473 

33,835 

2,869 

1,753 

4,566 

1,017 

2,729 

2,818

201

2,614

 2,633

 

not shown

2,260 

1,933 

5,502 

33,207

Source: Regional Economic Information System, Bureau of Economic Analysis, U.S. Department of Commerce, 

Table CA25N (NAICS), http://www.bea.gov/iTable
96

Table 3.3-4 

Industry Employment, Terrebonne Parish, 2008–2010 

3.3.4 Environmental Justice

Executive Order 12898 (1994) on Environmental Justice requires that environmental analyses of 

proposed Federal actions address any disproportionately high and adverse human health or 

environmental effects on minority and low-income communities. Federal agencies’ responsibility 

under this order shall also apply equally to Native American programs. In addition, each Federal 

agency must ensure that public documents, notices, and hearings are readily accessible to the 

public. 

The project area falls partially within Census Tract 409, in St. Mary Parish. As noted in Section 

3.3.1.1, St. Mary Parish includes about 41 percent of the population as a minority and about 15.9 

percent of families and 18.5 percent of the population were below the poverty line, including 

29.1 percent of those under age 18 and 16.2 percent of those ages 65 or over. 

3.3.5 Recreation

Recreational activities that are popular in the vicinity of the project area include boating for 

pleasure, fishing, crabbing, shrimping, and passive recreational activities, such as observation of 

wildlife and nature study. 

3.3.6 Cultural and Historic Resources

The coastal area of Louisiana has been an important navigation route since prehistoric times. At 

present, there are two recorded shipwrecks in the coastal waters of Louisiana and numerous other 

wrecks reported for the rivers and bayous. At least 59 historic shipwrecks are recorded in the 

USACE submerged cultural resources database for the Atchafalaya River.

Industry 2008 2009 2010

Agriculture, forestry, fishing, and mining

Construction

Manufacturing

Wholesale trade 

Retail trade 

Transportation, warehousing, utilities 

Information 

Finance, insurance, real estate 

Professional, scientific, management, administrative and waste 

management

Educational, health and social services

Arts, entertainment, recreation, accommodation and food services

Other services (except public administration)

Government and government enterprises

Total Parish Employment (including other activities) 

7,094 

4,054 

6,638

2,122

7,767 

3,665

417

3,561

6,462

5,878 

5,338 

3,676 

7,285 

63,957

6,346 

3,730 

6,534 

1,997 

7,927 

3,407 

433 

3,320

5,728

5,931 

4,949 

3,555 

7,471 

61,328

5,578 

3,827 

6,208 

1,928 

7,705 

3,394 

425 

3,396

6,278

6,027 

4,966 

3,207 

7,519 

60,458

Source: Regional Economic Information System, Bureau of Economic Analysis, U.S. Department of Commerce, 

Table CA25N (NAICS), http://www.bea.gov/iTable
97

A brief navigational history of the coastal water of the Gulf of Mexico and an inventory of 

known shipwrecks in the study area is provided in the report entitled A History of Waterborne 

Commerce And Transportation Within the U.S. Army Corps of Engineers, New Orleans District 

and an Inventory of Known Underwater Cultural Resources prepared by Coastal Environments, 

Inc (Pearson et al. 1989). This study documents 52 shipwrecks in the Atchafalaya River and 

seven in the Bay. Information on these shipwrecks was obtained from various historic documents 

and cartographic data. The historic record represents an incomplete biased sample of the 

archaeological database as not all shipwrecks were recorded in documents.

The Atchafalaya River represents the largest north-south waterway between Bayou Teche to the 

west and the Mississippi River to the east. The River runs approximately 233 km (145 miles) 

from the Mississippi River to the Gulf. Historically, the upper end of the Atchafalaya River was 

connected to both the Mississippi and Red Rivers. It was not until the 1930s that this navigation 

route was altered by the construction of the east and west guide levees and the Old River control 

structure. In the 1880s, a railroad from Bayou Teche to New Orleans was built that ran 

approximately 201 km (125 miles). By 1885 the Morgan Railroad accounted for 90 percent of 

the commerce between the Teche region and New Orleans reducing the need for transportation 

by boat. It was not until the GIWW opened that shipping by boat became a viable alternative to 

the railroad.

Literature about the Atchafalaya River indicates a high probability for historic shipwrecks since 

it was along a historic shipping route. Due to the proximity of the proposed disposal site to the 

Atchafalaya River channel, shipwrecks are the cultural resource with the greatest potential for 

impact by use of an ODMDS adjacent to the ARBC.

The assessment of probability for significant underwater resources is determined by utilizing 

several data sets. These include (1) the number of known boat wrecks in a waterway as 

determined by the historical record, (2) the known intensity of vessel use and waterborne 

commerce on a waterway as documented in the historical literature, and (3) and the known 

natural and human impacts on shipwrecks along individual waterways. By utilizing these criteria, 

a range of probability zones can be assigned to various waterways and research can be designed 

to fit the needs of a particular area.

A Phase I marine remote sensing survey of the Atchafalaya Ocean Dredged Material Disposal 

Site was conducted from June to August of 1996 (Seidel et al. 1998). This survey was conducted 

to “insure that potential effects to submerged historic properties were adequately considered in 

Operations and Maintenance (O&M) dredging and disposal activities.” 

The survey results indicated that while numerous magnetic and side scan anomalies were located 

in the project area, most of these were attributable to modem debris, re-deposited debris from 

previous dredging operations, or signatures associated with pipelines and oil and gas field 

activities. The survey identified several anomaly clusters were that may have a moderate to high 

potential of representing submerged cultural resources, but evaluation of these anomalies was not 

possible without inspection by a diver or some other type of verification.
98

The results of the survey conducted in 1998 concluded that the “impact from the disposal of 

dredged materials in the Atchafalaya ODMDS is highly unlikely to add appreciably to the 

impacts already induced by the progradation that has occurred in the study area during the last 

century.” No further archeological investigations were recommended as a result of the surveys 

conducted. 

In September 2004, a Phase I marine archeological remote sensing survey of the proposed 

Atchafalaya River Bar Channel Fluff/Fluid Mud Pilot Plan project areas located in St. Mary 

Parish, Louisiana was conducted by R. Christopher Goodwin & Associates, Inc. (Randolph et al. 

2008). The project area included locations for a sump, main channel and cross channels, and two 

parallel channels located on the east and west sides of the main channel. 

This survey recorded a total of 3,134 magnetic perturbations, 207 acoustic anomalies, and 10 

sub-bottom profiler anomalies. A total of 163 target clusters were identified and analyzed to 

determine their likelihood of representing submerged cultural resources. Of the targets 

identified, Target 51 was identified as having the potential of representing a submerged cultural 

resource. Target 51 was located in the east parallel channel, and it was recommended that the 

target be avoided or that additional investigations be conducted to determine if it indeed 

represents a submerged cultural resource. The proposed permanent re-designation under Section 

102(c) of the Marine Protection, Research, and Sanctuaries Act (MPRSA) for the Atchafalaya 

River Bar Channel (ARBC), Ocean Dredged Material Disposal Site-West (ODMDS-West) to 

receive maintenance-dredged material from the ARBC will avoid Target 51. 

Research in archival and secondary sources provided good indications of the potential for 

historic shipwrecks in the project area, as well as the historic contexts within which these 

resources may be understood. Geological and geomorphological data also was compiled, 

providing information on site formation processes, as well as the potential for shipwreck 

preservation. Prior to commencing the remote sensing survey, reconnaissance of the project area 

was undertaken primarily to ascertain water depths and the presence of potential obstructions 

such as oil or gas platforms. This reconnaissance survey indicated more than 3 ft of sediment had 

deposited in some areas since the NOAA charts were prepared.

Section 106 of the National Historic Preservation Act (NHPA) requires all Federal agencies with 

jurisdiction over a federally assisted, or federally permitted undertaking to account for the effects 

of their undertakings on properties included in or eligible for the, National Register of Historic 

Places. To comply with Section 106 of the NHPA, consultation was initiated with the Louisiana 

State Historic Preservation Officer (LA SHPO) in a letter dated May 9, 2012, and with federally 

recognized tribes in a letter dated June 1, 2012. 

3.3.7 Aesthetics (Visual Resources)

The project area is located approximately 16 miles offshore of the mouth of the Atchafalaya 

River in Atchafalaya Bay. The open-water area is devoid of any type of development, save for 

some oil and gas platforms and related infrastructure in the vicinity. Industrial complexes, ship 

harbors, and marinas along the adjacent shoreline are generally out of view. Land-based 

thoroughfares in the vicinity offer no view sheds into the immediate project area. The area 
99

remains relatively natural and scenic and is a haven for recreational opportunities such as fishing 

and nature observation. View sheds to the project area are offered only from the ARBC, the 

surrounding bays, and the Gulf of Mexico.

3.3.8 Military Restrictions

No military restrictions would apply to the ARBC ODMDS selection process. There are no 

Military Warning Areas within 40 km (25 miles) of Atchafalaya River 

(www.gomr.mms.gov/homepg/regulate/environ/MWA_boundries.pdf).
100

4.0 ENVIRONMENTAL CHARACTERIZATION OF NO-ACTION

AND PROPOSED ALTERNATIVES

The impacts to the physical and biological environment that are discussed in this document are 

the result of maintenance-dredged material placement, not site designation per se. Site 

designation provides an acceptable ocean location for the placement of ARBC maintenancedredged material. The No-Action Alternative would allow maintenance-dredged material to be 

placed in the Section 103(b) ODMDS-West until July 31, 2012 after which, placement would 

revert to the Section 102(c) ODMDS-East. The proposed alternative is the permanent, Section 

102(c) designation of the ODMDS-West that would allow placement to continue to thereafter 

2012. It is believed that dredged material placed in the ODMDS-East returns to the ARBC at a 

higher rate than dredged material placed in the ODMDS-West. Section 102(c) designation of the 

ODMDS-West is intended to allow a long-term reduction in required dredging compared to the 

required dredging frequency if placement is returned to the ODMDS-East. Since the ODMDSEast and ODMDS-West are relatively close to each other and have very similar physical, 

chemical, and biological conditions, the primary difference between the No-Action Alternative 

(return of disposal to the ODMDS-East after July 31, 2012) and the proposed alternative is the 

expected long-term reduction of dredging and disposal if the proposed alternative is 

implemented. Consequently, impacts described below that are likely to result from maintenance 

dredging and disposal activities are expected to be less with the proposed alternative than with 

the No-Action Alternative. Impacts to the physical and biological environment with the 

proposed alternative would be the same as those historically and currently experienced at the 

Section 103(b) ODMDS-West.

4.1 PHYSICAL ENVIRONMENT

4.1.1 Climate and Meteorology

4.1.1.1 No-Action Alternative

The proposed work in the ARBC and subsequent maintenance-dredged material placement in the 

ODMDS-East is not expected to result in any changes to short-term or long-term meteorological 

conditions. 

4.1.1.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are the same as those of the No-Action Alternative

(ODMDS-East). No direct or indirect impacts are expected to climate or meteorological 

conditions. 
101

4.1.2 Air Quality

4.1.2.1 No-Action Alternative

With implementation of the ODMDS-East, direct and indirect impacts to ambient air quality 

within the project area—and possibly farther afield—are expected to be temporary, and primarily 

due to the emissions of construction equipment (i.e., fuel combustion and resulting engine 

exhausts). Due to the short duration of the proposed project and the nature of this construction 

equipment, any emissions increases or impacts to ambient air quality are expected to be shortterm and insignificant and are not expected to cause or contribute to a violation of Federal or 

State ambient air quality standards, nor would they alter the status of the parish regarding 

“attainment’ of NAAQS. The total volatile organic compound emissions for this project during 

construction are anticipated to be well below the de minimis level of 100 tons per year. Once all 

construction activities associated with the proposed action cease, air quality within the vicinity is 

expected to return to pre-construction conditions. 

4.1.2.2 Proposed ODMDS-West Alternative

With implementation of the proposed ODMDS-West, direct and indirect impacts to air quality 

would be the same as, or less than, those of the No-Action Alternative and similar to the de 

minimis impacts that have occurred here (i.e., the Section 103(b) ODMDS-West) during disposal 

operations since 2002. 

Emissions from dredging of the ARBC and disposal to the ODMDS-West have been estimated in 

terms of equipment engine (diesel) emissions calculated for volatile organic compounds (VOC) 

and nitrogen oxides, which are ozone precursors. Emissions from dredging activities were

estimated based on assumed equipment requirements, quantities of material to be removed, and 

the duration of dredging in the ARBC based on historical maintenance dredging operations. 

Dredging and disposal activities require a hydraulic dredge and multiple cranes, tug boats, 

barges, and support boats generally over a period of 90 days. Emissions were estimated using 

emissions factors derived from EPA’s Exhaust and Crankcase Emissions Factors for Nonroad 

Engine Modeling—Compression-Ignition (EPA 2010). Table 4.1-1 summarizes the results of the

emissions analyses for the ODMDS-West Alternative. Yearly emissions associated with 

implementing the ODMDS-West Alternative would be 3.9 tons per year of volatile organic 

compounds and 92.3 tons per year of nitrogen oxides. These emission quantities are below the 

CAA conformity threshold of 100 tons per year per pollutant. Consequently, the ODMDS-West 

Alternative would have a less than significant air quality impact. 

The lower average volumes historically dredged from the ARBC for ODMDS-West disposal 

compared to ODMDS-East disposal may result in reduced emissions per dredge cycle with the 

permanent implementation of the ODMDS-West.
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Table 4.1-1. Annual engine emissions totals for volatile organic compounds (VOC) and 

nitrogen oxides (NOx) with implementation of the ODMDS-West Alternative.

Total Calculated Emissions

Type of Construction Equipment – 

Engine Horsepower (hp) VOC tons/yr NOx tons/yr

Diesel Dredge – 9500 hp 3.078 69.255

Diesel Crane – 350 hp 0.063 2.079

Diesel Dozer – 100 hp 0.050 0.554

Diesel Derrick Crane – 175 hp 0.055 0.977

Diesel Tug Boat - 900 hp 0.243 5.468

Diesel Tug Boat - 600 hp 0.162 6.912

Anchor Barge – 125 hp 0.035 0.628

Skidder Barge – 100 hp 0.045 0.498

Diesel Crew Boat – 600 hp 0.108 3.564

Diesel Survey Boat – 400 hp 0.072 2.376

TOTALS 3.911 92.311

Emissions Formula: (lbs/hp-hr)x(hp)x(hr)x(days)x(# of units)/2000 = tons/yr

NOTE: The listed equipment is the type and number of equipment that may typically be used for a 

dredging and disposal project.

4.1.3 Oceanography

As described in the following subsections, the impacts of the ODMDS-West Alternative are the 

same as those of the No-Action Alternative. Only miniscule impacts to water masses, circulation 

and currents, waves and tides, and bathymetry are expected from use of the Proposed ODMDSWest Alternative or the No-Action Alternative.

4.1.3.1 No-Action Alternative

Placement of maintenance-dredged material in the ODMDS-East will not significantly change 

physical and chemical conditions in Atchafalaya Bay. Atchafalaya River discharge is a large 

contributor to the physical and chemical conditions in this area of the northern Gulf of Mexico. 

The area is dispersive and any mounding that is expected immediately following disposal is not 

expected to be persistent. Historical data collected during bathymetric surveys of the ODMDSEast conducted prior to and after MVN disposal operations indicate that there is no long-term 

mounding. Placement of maintenance-dredged material into the ODMDS-East would continue 

to result in material being transported back into the navigation channel by prevailing westerly 

currents.

4.1.3.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are similar to those of the No-Action Alternative. 

No net mounding has occurred from disposal at this site in the past, based on MVN analysis of 

pre and post-maintenance dredging surveys conducted annually at the Section 103(b) ODMDS-
103

West since 2002, and no future mounding is expected. Disposal of maintenance-dredged 

material into the ODMDS-West may reduce the amount and rate of material being transported 

back into the navigation channel by prevailing westerly currents. Subsequently, the reduced 

shoaling rate would decrease the overall annual maintenance dredging effort needed for the 

ARBC, as well as the amount of maintenance dredging required over the long term (Teeter et al.

2003). 

4.1.4 Water Quality

Placement of maintenance-dredged material should not appreciably degrade ambient water 

quality within or adjacent to the ODMDSs. In general, changes in water quality associated with 

placement are relatively short-term, with conditions returning to normal within a period of 

minutes to hours. Dredge material placement will likely cause temporary increases in turbidity 

and suspended solids concentrations, and a reduction in light penetration in the immediate 

vicinity; however, since the project area is a naturally turbid environment and resident biota are 

generally adapted to, and very tolerant of, high suspended sediment concentrations, the effects 

would be negligible. A reduction in light penetration may indirectly affect phytoplankton (i.e., 

primary) productivity in the area as the amount of photosynthesis carried out by phytoplankton is 

reduced. Localized temporary pH changes, as well as a reduction in dissolved oxygen levels, 

may also occur during maintenance events. No evidence of persistent alterations of near-bottom 

water quality at the ODMDS-East or adjacent waters were detected during IEC (1983) surveys. 

Results of several long-term studies at nearshore locations, summarized by Brannon (1978), 

indicate that maintenance-dredged materials have limited chronic impacts on the water quality at 

placement sites.

Based on MVN’s review of oil spill tracking and contaminant information pertaining to the 

Deepwater Horizon incident, the sampling and analyses performed in 2008 for the ARBC, and 

the lack of any additional significant spills or incidents of pollution in the project vicinity since 

2010, there is no reason to believe that dredged material from future maintenance events in the 

ARBC portion of the Atchafalaya River and Bayous Chene, Boeuf, and Black, Louisiana project 

would be unsuitable for open water disposal. 

4.1.4.1 Temperature

4.1.4.1.1 No-Action Alternative

Dredging and dredged material placement in the ODMDS-East will not change water 

temperatures in the ARBC or the ODMDS.

4.1.4.1.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are similar to, or slightly less than, those of the 

No-Action Alternative. No changes in water temperature are expected from dredging and 

disposal activities since the dredging frequency and average quantity of dredged material placed 

is expected to be less with the proposed action. 
104

4.1.4.2 Salinity

4.1.4.2.1 No-Action Alternative

Dredging and dredged material placement in the ODMDS-East will not significantly change 

salinity in the ARBC or the ODMDS.

4.1.4.2.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are the same as those of the No-Action 

Alternative. No changes in salinity are expected from dredging and placement activities since 

the dredging frequency and average quantity of dredged material placed will be less with the 

proposed action. 

4.1.4.3 Dissolved Oxygen

4.1.4.3.1 No-Action Alternative

With implementation of the No-Action Alternative there will be some localized disturbances to 

ambient dissolved oxygen levels in the project area; however, direct and indirect impacts will be 

short-lived. Materials with potential oxygen demand are generally present in dredged material. 

Their release following placement imposes both a chemical and biochemical oxygen demand 

(COD and BOD) on the water column. However, Schubel et al. (1978) showed that the effects 

of adding oxygen-demanding material to the water column are functions of the length of time the 

material resides in the water column and the amount of water available for dilution. In shallow 

water, like that at the ODMDS-East, approximately 95–99 percent of the dredged material is 

placed close to the discharge source and within several minutes after release. The remaining 1–5 

percent of the dredged material is deposited within a few hours after discharge (Schubel et al.

1978). Only a small percentage of the oxidizable components in dredged material are reactive on 

a time-scale comparable to the settling rate of the majority of the discharged particulate matter. 

The reduced forms of sulfur, iron, and manganese present in sediment interstitial waters place an 

immediate oxygen demand on the water column. The organic matter and sulfide minerals 

present in the dredged sediments also exert an oxygen demand, but on a longer time scale. Most 

of the decomposition of organic matter is accomplished by bacterial degradation; oxidation of

sulfide minerals is generally limited to surficial sediment layers. Once the dredged material is 

deposited, the oxygen demand on the overlying waters is dependent on the expulsion of 

interstitial water during compaction and, thereafter, is diffusion-limited (Schubel et al. 1978). 

4.1.4.3.2 Proposed ODMDS-West Alternative

Similar to the No-Action Alternative, continued use of the ODMDS-West for long-term 

placement of maintenance dredge material may cause localized and temporary declines in 

dissolved oxygen concentrations. When under conditions where stratification of the water 

column and hypoxic conditions exist, hypoxia may be exacerbated by the discharge of 

maintenance-dredged material. Since the proposed alternative is intended to reduce the need for 
105

maintenance dredging over the long term, declines in dissolved oxygen resulting from the 

disposal of dredged material will occur less frequently with the proposed alternative. Less 

frequent dredging and dredged material placement may reduce the possibility of lowered 

dissolved oxygen when hypoxic conditions are present. 

4.1.4.4 pH

4.1.4.4.1 No-Action Alternative

Dredging and dredged material placement in the ODMDS-East will not significantly change pH 

of waters in the ARBC or the disposal area. 

4.1.4.4.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are the same as those of the No-Action 

Alternative. No changes in water pH are expected from dredging and placement activities since 

the dredging frequency and quantity of dredge material placed will be less with the proposed 

action.

4.1.4.5 Nutrients

4.1.4.5.1 No-Action Alternative

Resolubilization of nutrients is common from both polluted and nonpolluted sediments dredged 

from coastal areas (Windom 1976). Results of elutriate tests performed on dredged materials 

from the Atchafalaya Bay Channel demonstrated releases of soluble organic nitrogen (total 

kjeldahl nitrogen [TKN]) and carbon (USACE 1978). 

Releases of nitrogen, especially ammonia-nitrogen, are common from dredged materials 

(Windom 1975). Coastal waters are characteristically limited with respect to nitrogen (Ryther 

and Dunstan 1971); therefore, localized releases may temporarily stimulate phytoplankton 

productivity (Ryther and Dunstan 1971). Elevated concentrations of ammonia, sufficient to 

cause toxicity to aquatic organisms, at the disposal site or adjacent areas are unlikely (Brannon

1978). Increased ammonia concentrations in the water column are ephemeral and subsequent 

decreases result from rapid dilution and mixing (Wright 1978). 

Localized increases in phosphorus concentrations following disposal are typically of short 

duration due to rapid adsorption onto suspended particulate matter, particularly clay particles 

(Wright 1978; Windom 1975). Chronic water quality problems resulting from long-term 

leaching of nutrients from dredged sediments are not expected (Brannon et al. 1978). 

Studies conducted at the ODMDS-East measured releases of ammonium and silicate species 

during dredged material disposal; however, concentrations were quickly diluted to background 

levels. Dissolved orthophosphate, ammonia, and silicate levels were not affected by disposal 

(Schubel et al. 1978; Heaton 1978). Observed ammonia concentrations in sediments at the 

ARBC, ODMDS-West, and the reference area indicate that dredged materials and undisturbed 
106

sediments have similar ammonia concentrations (PBS&J 2008). The observed ammonia 

concentrations in elutriate samples indicates that the dredged material placement would not be 

expected to result in the exceedance of applicable water quality criteria for chronic or acute

exposures to aquatic life.

4.1.4.5.2 Proposed ODMDS-West Alternative

Similar to the No-Action Alternative, continued use of ODMDS-West for placement of 

maintenance-dredged materials would not be expected to result in the exceedance of applicable 

water quality criteria for chronic or acute exposures of ammonia to aquatic life. If maintenance 

dredging frequency and the average quantity of dredged material are reduced as expected with

the proposed alternative, the frequency of nutrient loading events resulting from dredged 

material placement is expected to be less than the No-Action Alternative.

4.1.4.6 Turbidity/Suspended Solids

4.1.4.6.1 No-Action Alternative

Dredged material placement can result in a temporary increase of turbidity levels and suspended 

solid concentrations in the water column (USACE 1980). The duration of a turbidity plume will 

depend on particle size and density, currents, and turbulent mixing (Wright 1978). Dredged 

materials from the ARBC contain appreciable quantities of fines, which may remain suspended 

for periods of minutes to hours. Wright (1978) concluded that at most dredged material 

placement sites, increases in turbidity persisted for only a few hours and, in addition, “... storms, 

river discharge and other natural phenomena resulted in turbidity increases of much greater 

magnitude than those associated with disposal.” 

Studies conducted at the ODMDS-East during dredged material placement noted that turbidity 

plumes were of limited duration and areal extent (Heaton 1978; Schubel et al. 1978). 

4.1.4.6.2 Proposed ODMDS-West Alternative

Continued use of the ODMDS-West on an ongoing basis would be expected to result in similar 

or slightly less contributions to turbidity in the area as the No-Action Alternative, with transient 

and highly localized changes in turbidity in the project area associated with dredging and 

disposal operations. The proposed alternative is expected to lessen the frequency at which 

turbidity plumes resulting from dredged material disposal occur since the dredging frequency 

and the average quantity of material placed will be less with the proposed action. 

4.1.4.7 Trace Metals

4.1.4.7.1 No-Action Alternative

Measurements of trace metals in the water column and elutriate samples indicate that the 

placement of dredged materials in the past may have limited, transient impacts on water quality 

with respect to copper concentrations. Based on the 2008 sediment, water, and elutriate data
107

from the ARBC, ODMDS-West, and reference area, placement of maintenance-dredged 

materials from the project is not expected to have an observed direct impact on water quality that 

would result in the exceedance of applicable water quality criteria or standards because of trace 

metal concentrations.

4.1.4.7.2 Proposed ODMDS-West Alternative

Similar to the No-Action Alternative, and based on the 2008 sediment, water and elutriate data

from the ARBC, ODMDS-West, and reference area, placement of maintenance-dredged 

materials from the project is not expected to have an impact on water quality that would result in 

the exceedance of applicable water quality criteria or standards because of trace metal 

concentrations since the dredging frequency and average quantity of material placed will be less 

with the proposed action. 

4.1.4.8 Organic Compounds

4.1.4.8.1 No-Action Alternative

Synthetic organics, such as pesticides and polychlorinated biphenyls (PCBs) do not occur 

naturally in sediments, but result from anthropogenic contamination (Brannon 1978). 

Chlorinated hydrocarbons have low water solubility, and are rapidly bound to sediments with 

only small quantities released to interstitial waters (Burks and Engler 1978). 

Concentrations of pesticides and PCBs in waters overlying the ODMDS-East or West 

immediately following disposal have not been measured. However, IEC (1983) surveys within 

and around the existing ODMDS-East did not detect most chlorinated hydrocarbons in the water 

column; only dieldrin, the DDT derivative, p, p’-DDE, and the PCB, Arochlor 1254, were 

present above detection limits. All concentrations were below their respective EPA single 

measurement criterion (45 FR 79318 et seq.). Contaminant assessments conducted in 2008, 

2002, and 1996 did not detect concentrations of organic pollutants that exceeded any applicable 

water quality standards or criteria (Espey, Huston & Associates, Inc. 1997; PBS&J 2002; PBS&J 

2008). 

4.1.4.8.2 Proposed ODMDS-West Alternative

Similar to the No-Action Alternative, ongoing use of the ODMDS-West for dredged material 

placement is not expected to change water quality of the project area related to the presence of 

organic compounds in the dredged materials since the dredging frequency and average quantity 

of material placed will be less with the proposed action. 
108

4.1.5 Sediments

4.1.5.1 Sediment Quality and Characteristics

4.1.5.1.1 No-Action Alternative

Nearshore sediments are a major sink for riverine and anthropogenic trace metals (Trefry 1977). 

Sediments dredged from river mouths and coastal navigation channels, therefore, may contain 

levels of trace metals, which are elevated relative to estuarine sediments more removed from 

anthropogenic sources (Holmes 1973). However, releases of trace metals from sediments, and 

subsequent changes in placement site water quality, cannot be predicted solely on the basis of 

bulk chemical analysis of the dredged sediments (Windom 1975; Brannon et al. 1978). For 

example, studies conducted by the USACE Dredged Material Research Program (DMRP) 

(Brannon 1978), and by Windom (1975, 1976) demonstrate that following placement of dredged 

material, the concentrations of certain dissolved metals (e.g., copper, cadmium, and lead) in 

ODMDS waters may be regulated by adsorption onto soluble iron oxides. 

Studies at the ODMDS-East (Schubel et al. 1978; Heaton 1978) found no well-defined plume of

dissolved trace metals during dredged material placement, and no linear relationship between 

dissolved and particulate trace metals. A few anomalously high levels of manganese were 

observed; however, these were associated with high TSS concentrations (approximately 1,000 

mg/L) near the discharge point. Concentrations of dissolved zinc, copper, chromium, cadmium, 

and lead were low (usually below detection levels) throughout the Atchafalaya sampling area. 

Comparisons between concentrations in the dredged material plume and in reference water 

showed no apparent differences. Therefore, it may be concluded that no substantial release of 

these metals occurred during dredged material placement (Schubel et. al. 1978; Heaton 1978). 

Long-term solubilization of trace metals from dredged materials is minimal, and too small to 

produce significant adverse impacts to water quality (Brannon 1978; Windom 1975, 1976). For 

example, surveys conducted by IEC (1983) found the greatest particulate trace metal 

concentrations were associated with highest TSS concentrations. Dissolved trace metals 

exhibited an inverse relationship with TSS and particulate trace metal concentration, which may 

be caused by scavenging of metals from solution onto sediment particles (Brannon 1978; 

Windom 1975, 1976). Dissolved manganese and lead levels varied widely throughout the survey 

area; however, concentrations were comparable to those from previous studies. Total 

(particulate plus dissolved) trace metal concentrations were below their respective EPA

minimum marine water quality criteria (45 FR 79318 et sq.).

Elutriate tests are intended to indicate the potential for release of dissolved trace metals from 

dredged sediment during dredging or placement. Elutriate tests conducted by USACE (1978) on 

the dredged material from the ARBC indicated little or no release of trace metals except, for 

manganese, which is generally released in the elutriate test (Brannon 1978; Heaton 1978) or 

Louisiana WQS. IEC (1983) conducted elutriate tests on sediments outside and within the 

ODMDS-East. Except for zinc, which showed a slight release, results were similar to those of 
109

USACE (1978). Trace metals released from sediments within and outside the ODMDS-East 

were similar.

Elutriate tests were also conducted for the 1996 and 2002 contaminant assessments and for 

samples collected in February 2008. None of the elutriate samples exceeded water quality 

criteria or standards from the 2008 sampling event. One sample from the 2002 data and three 

samples from the 1996 data exceeded the chronic water quality criteria and the Louisiana acute 

and chronic water quality standard for copper. It should be noted that the elutriate concentrations 

that exceeded the standards were within an order of magnitude of the applicable water quality 

limits. Based on mass balance considerations and the relative volume of suspended sediment 

compared to the volume of the water column and residence time of water in the ODMDS, it was 

determined that any water quality effect would be temporary in nature would be met, via 

dilution, before the discharge plume reaches the boundaries of the ODMDS. 

There is nothing in the chemical analyses, suspended particulate phase bioassays, solid phase 

bioassays, or bioaccumulation study that would indicate a concern (PBS&J 2008). The NOAA 

ERL for arsenic was exceeded in some ARBC sediment samples from the 2008 contaminant 

assessment, but the bioassays and bioaccumulation studies conducted as part of the assessment 

indicated no concern. Therefore, based on the guidance provided by the Regional 

Implementation Agreement (RIA) among the EPA and the USACE, New Orleans and Galveston 

Districts (EPA/USACE 2003), the conclusion of this testing is that no significant adverse 

impacts are anticipated with the ocean placement of these sediments, and that the Limiting 

Permissible Concentration (40 CFR 227.29(a)) for the water column and solid phase, including 

bioaccumulation, are met.

4.1.5.1.2 Proposed ODMDS-West Alternative

Proposed use of the ODMDS-West on an ongoing basis would have similar effects or slightly 

less as the No-Action Alternative on the expected sediment quality in the project area since the 

dredging frequency and average quantity of material placed will be less with the proposed action. 

Previous elutriate sample results have indicated potential exceedance of water quality standards 

and criteria for copper that could represent temporary conditions that would not be expected to 

persist over time or outside of the ODMDS. In addition, the 2008 contaminant assessment did 

not identify any sediment, elutriate or water concentrations of toxic constituents that indicate 

potentially significant impacts of dredging or material disposal at the ARBC and designated 

disposal locations (PBS&J 2008). 

4.1.5.2 Sediment Transport

4.1.5.2.1 No-Action Alternative

Under the No-Action Alternative, maintenance-dredged material from the ARBC would be 

placed in the ODMDS-East. Based on historical dredging and disposal quantities, approximately 

12.8 mcy of shoal material would be dredged from the ARBC during annual maintenance events, 

of which, approximately 10.9 mcy of material would be placed in the ODMDS-East. Based on 

review of studies conducted in regards to accumulation of fluff in the ARBC (Van Heerden and 
110

Kemp 2000; Teeter et al. 2003; ETS 2006), placement of material at the ODMDS-East will result 

in increased dredging frequency over time. This is because under normal weather conditions, net 

sediment transport is most frequently (63 to 75 percent of the time) towards the west, except 

when cold fronts are passing (PBS&J 2007). Thus, continued placement of dredged material in 

the ODMDS-East is likely to increase the amount and rate of shoal material runback into the 

ARBC.

4.1.5.2.2 Proposed ODMDS-West Alternative

With this alternative, maintenance-dredged material from the ARBC would be placed in the 

ODMDS-West. Based on historical dredging and disposal quantities, approximately 12.6 mcy of 

shoal material would be dredged from the ARBC during annual maintenance events, of which, 

approximately 10.8 mcy of material would be placed in the ODMDS-West. Continued 

placement of maintenance-dredged material from the ARBC into the ODMDS-West will result

in less frequent dredging over the long term (see Table 1-1; PBS&J 2007; Teeter et al. 2003). As 

previously described, this is because, under normal weather conditions, net sediment transport is 

most frequently (63 to 75 percent of the time) towards the west, except when cold fronts are 

passing. Thus, although the shoaling rate will continue to be high because of the dynamic nature 

of the area, substantial dredged material runback into the ARBC is significantly reduced when

material is placed in the ODMDS-West.

4.1.5.3 Hazardous, Toxic, or Radioactive Wastes

4.1.5.3.1 No-Action Alternative

Neither the ARBC nor the proposed disposal areas are within the boundaries of an EPAdesignated CERCLA or National Priority List, or within the boundaries of a site designated by a 

state for a response action under CERCLA. No HTRW sites have been identified in the 

ODMDS-East. Thus, there is no potential for HTRW impacts from placement at the ODMDSEast. 

4.1.5.3.2 Proposed ODMDS-West Alternative

No HTRW sites have been identified in the ODMDS-West. Therefore, there is no potential for 

HTRW impacts from placement of dredged material at the ODMDS-West.

4.1.5.4 Oil and Gas

4.1.5.4.1 No-Action Alternative

Placement of dredged material in the ODMDS-East will not directly affect oil and gas pipelines 

or other infrastructure. In the future, access to pipeline structures may become limited due to 

shallow water depths caused by the natural deposition of sediments. However, this limitation is 

not a result of use of the ODMDS-East.
111

4.1.5.4.2 Proposed ODMDS-West Alternative

As noted for the No-Action Alternative, continued placement of dredged material in the 

ODMDS-West will not directly affect oil and gas pipelines or other infrastructure.

4.2 BIOLOGICAL ENVIRONMENT

In general, the placement of dredged material presents four potential problems to aquatic 

organisms: (1) temporary increases in turbidity, (2) changes in physical or chemical 

characteristics of the habitat, (3) smothering by burial, and (4) introduction of pollutants (Hirsch 

et al. 1978). The magnitude of adverse impacts on the existing fauna depends on the similarity 

of the dredged sediments to existing sediments, frequency of placement, thickness of the 

overburden, types of organisms present, and physical characteristics of the habitat (Pequegnat et 

al. 1990). It is often difficult to distinguish adverse effects caused by sediment placement from 

changes due to natural variability in habitat or species abundances (Wright 1978; Hirsch et al. 

1978). 

4.2.1 Plankton

4.2.1.1 No-Action Alternative

Direct and indirect effects of dredged material disposal on plankton are difficult to assess 

because of the high natural variability of populations. The influences of tidal and river 

discharges, as well as diel changes in zooplankton abundances, increase the difficulty of 

detecting disposal effects. Sullivan and Hancock (1977) concluded that, for most oceanic areas, 

natural plankton fluctuations are so large that field surveys would not be useful for detecting the 

impacts of dredged material disposal. 

Placement at the ODMDS-East would result in temporary increases in turbidity. Turbidity 

increases have been found to decrease productivity of phytoplankton in laboratory studies (Sherk

1971); however, the decrease in phytoplankton production has been found to be offset by the 

increase in nutrient content (Morton 1977; Kamykowski et al. 1977). BLM (1987) found total 

zooplankton production to be inversely related to turbidity. In past studies of the impacts of 

maintenance-dredged material placement from turbidity and nutrient release, the effects on 

plankton are both temporary and localized (May 1973; Odum and Wilson 1962; Brannon et al.

1978; Kraus 1991; Dragos and Peven 1994). Thus, the impacts of dredged material placement at 

the ODMDS-East are not expected to be significant.

4.2.1.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative would be similar to those of the No-Action 

Alternative. The temporary increases in turbidity could impact phytoplankton productivity and 

zooplankton production. Impacts would be temporary and localized and are, therefore, not 

expected to be significant. These impacts would be less over the long term with the proposed 

alternative due to anticipated reductions in ARBC dredging frequency and dredged material 

volumes. 
112

4.2.2 Benthos

4.2.2.1 No-Action Alternative

With implementation of the No-Action Alternative, there would be some direct and indirect 

impacts to benthos in the form of physically altered open water bottom habitat, and temporary 

increases in turbidity during disposal activities. Direct effects of dredged material disposal (i.e., 

burial of organisms) are restricted to the immediate area of an ODMDS (Hirsch et al. 1978). 

Previous investigations of the effects of burial of benthic infauna demonstrated that adverse

impacts are typically limited to non-motile species (Richardson et al. 1977); active or motile 

species are capable of burrowing up through 22.9 cm (9 inches) of overburden (Maurer et al.

1978). Nevertheless, maintenance-dredged material placement at an ODMDS will likely 

smother some epifaunal and infaunal organisms. Consequently, densities and diversity will 

temporarily decline (USACE 1978). However, benthic assemblages in the northern Gulf 

experience high natural variability in abundances and diversity due to seasonal changes in adult 

mortality and larval recruitment rates (Parker et al. 1980). Sediment particles that become 

suspended due to construction activities may impact filter-feeding benthic invertebrates by 

fouling feeding apparatuses if the concentration of such particles is excessively high. Clams and 

oysters, in particular, may experience a reduction in pumping rates with increased turbidity 

(Loosanoff 1961). Other lethal and non-lethal effects of turbidity include ingestion of non-food

particles by shellfish and polychaete worms; clogging of pores and gills; erosion of gills and

other apparatuses such as fins, tentacles, and cilia that may be used for locomotion and feeding;

burial of eggs and juveniles; and burial of substrates that may be needed for cover, attachment,

and reproduction. Indirect impacts to benthos may occur in water bottom areas adjacent to the 

ODMDS-East, as placed material disperses away from the ODMDS with the prevailing currents 

and settles in these other areas.

Recently deposited sediment will be recolonized by motile infaunal organisms burrowing up 

through the overburden, by species migrating from adjacent undisturbed areas, and/or by 

recruitment of larvae and juvenile forms (Hirsch et al. 1978). Specific recolonization patterns 

will be influenced by the composition of the new sediment and adjacent benthic communities 

(Oliver et al. 1977). 

Although sessile or slow moving benthic organisms may be smothered in areas of the ODMDSEast where dredged materials are deposited, the consequences of temporarily disrupting the 

benthic community at the ODMDS cannot be easily evaluated (Wright 1978). Hirsch et al. 

(1978) concluded that “the more naturally variable the environment, the less effect dredging and 

placement will have, because animals and plants common to the unstable areas are adapted to 

stressful conditions and have life cycles that allow them to withstand the stresses imposed by 

dredging and disposal. Habitat disruption can also be minimized by matching the physical 

characteristics of the maintenance-dredged materials to the substrate found at the disposal site.”

Both ODMDSs (East and West) are located in an area much of which is relatively shallow and 

that is naturally disturbed by wind-generated waves, sediment transport from river inflows, and 

current patterns. The sediments in this area are physically and chemically similar to those in the 

ODMDSs and the maintenance-dredged material. Because of the dynamic nature of the 
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environment, and the apparent absence of significant adverse effects on water or sediment 

quality, it is unlikely that previous dredged material placement activity at either ODMDS has 

measurably altered the benthic habitat or will do so as a result of placement. Some benthic 

species could potentially indirectly benefit from the abundance of introduced detritus, and 

subsequent food resources, from deposited dredge material.

Some benthic invertebrate mortality due to removal may occur during maintenance dredging of 

the ARBC prior to the ODMDS disposal event; however, these species would gradually 

recolonize the area. The time necessary for a benthic community to recover after dredging is 

highly variable; however, it is assumed that repopulation of benthic organisms would begin 

within a month of dredging. Benthic populations in clay bottoms would likely return to predredging levels within a year, while on sandy bottoms recovery would probably be faster. 

No causes for concern were indicated in the chemical analyses, suspended particulate phase 

bioassays, solid phase bioassays, or bioaccumulation study conducted in 2008 (PBS&J 2008). 

The NOAA ERL for arsenic was exceeded in some ARBC sediment samples from the 2008 

contaminant assessment, but the bioassays and bioaccumulation studies conducted as part of the

assessment indicated no concern. Therefore, no significant adverse impacts to resident benthos

at the ODMDS-East are anticipated with the ocean placement of these sediments.

No significant adverse impacts to benthic organisms, due to changes in water or sediment 

quality, were detected during a DMRP study of aquatic dredged material disposal impacts 

(Wright 1978). Results of IEC (1983) surveys indicated no long-term, persistent effects of 

disposal on benthic communities at the ODMDS-East. The macrofaunal assemblages within and 

around the ODMDS-East were characteristic of the general region and dominated by 

polychaetes. Many of the dominant organisms were small-bodied, opportunistic species capable 

of rapid recolonization of disturbed sediments. Large macroinvertebrates (mainly shrimp and 

crab) were also common throughout the area. 

4.2.2.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative on resident benthos are similar to those of the NoAction Alternative. Impacts to the benthic community would be the same as, or slightly less 

than, impacts from the No-Action Alternative, and would be expected to occur less frequently or 

with less intensity since the dredging frequency and average quantity of material placed will be

less with the proposed action. Based on MVN analysis of pre and post-maintenance dredging 

surveys conducted annually at the Section 103(d) ODMDS-West since 2002, the approximately 

10.8 mcy of dredged material expected to be placed in the proposed ODMDS-West during 

annual maintenance cycles has the potential to make the water 3 to 4 inches shallower. Soft 

substrates in this newly created subtidal habitat would eventually be re-colonized by motile 

benthic organisms burrowing up through the overburden, by species migrating from adjacent 

undisturbed areas, and/or by recruitment of larvae and juvenile forms. 
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4.2.3 Finfish and Shellfish

4.2.3.1 No-Action Alternative

With the continued placement of dredged material at the ODMDS-East, there may be some 

direct and indirect impacts to fisheries in the form of physically altered open water bottom 

habitat in the ODMDS and adjacent areas, and temporary increases in turbidity during disposal 

activities. Historically-impacted shallow open water bottom habitat would continue to be altered

during each maintenance dredging event. Data sufficient to characterize the effects of 

maintenance-dredged material placement on nekton inhabiting both the ODMDS-East and 

ODMDS-West are unavailable. However, DMRP studies suggest fish usually are not directly 

affected by maintenance-dredged material placement (Wright 1978). The mobility of nektonic 

organisms generally precludes adverse effects due to burial with sediment. No known unique 

nekton habitats or spawning areas occur within the ODMDSs. Adverse effects to motile nekton 

species from intermittent and localized placement at the sites would be negligible. Brown 

shrimp, white shrimp, and crabs may be directly impacted through the filling of shallow open 

water areas with dredged materials; however, these species could potentially indirectly benefit 

from the abundance of introduced detritus, and subsequent food resources, from these materials. 

Sediment particles that become suspended due to construction activities may impact filterfeeding shellfish species by fouling feeding apparatuses if the concentration of such particles is 

excessively high. Clams and oysters, in particular, may experience a reduction in pumping rates 

with increased turbidity (Loosanoff 1961). Since the project area is a naturally turbid 

environment and the majority of resident finfish and shellfish species are generally adapted to, 

and very tolerant of, high suspended sediment concentrations, the effects of turbidity and 

suspended solids on fisheries in the area would likely be negligible. 

Localized burial of benthic fauna may decrease the abundance of fish prey items, causing 

temporary declines in finfish abundance and diversity at the ODMDS. Results of DMRP studies 

assessing the effects of dredging on demersal fish were ambiguous. Wright (1978) reported that 

in some cases relatively higher numbers of fish occurred at an ODMDS after placement of 

dredged material. In other cases, short-term avoidance of ODMDSs by finfish was observed 

after placement. Wright (1978) concluded: “Some question exists as to whether this behavior 

represented avoidance of the (dredged) material or was the result of normal seasonality and the 

sampling techniques that were used.” 

Nearshore areas of the northern Gulf of Mexico, including the waters off Louisiana, support one 

of the most productive fisheries in the United States (see Section 3.2.3). Coastal areas with 

sand/silt substrates, including the ODMDS-East (and ODMDS-West), are used seasonally by 

many commercial species for feeding, breeding, and passage; however, none of these activities 

are unique or restricted to the ODMDS area. Fishing activities for demersal and pelagic fish and 

shrimp extend throughout the year, but activity is greatest in spring and summer. Consequently, 

some interference with commercial fishing from dredged material disposal in nearshore regions 

is inevitable. The ODMDSs represent only a small portion of the total fishing grounds of the 

northern Gulf of Mexico. Any adverse effects are likely to be restricted to the disposal site 

proper. Therefore, dredged material disposal at the ODMDS-East will potentially affect only a 

small percentage of fisheries resources during a given maintenance dredging and disposal cycle.
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Temporary placement (floating) of the dredge pipeline in open water areas of the ODMDS-East 

is not expected to significantly affect fish resources. 

There are no Public Oyster Areas within the ODMDS-East (or ODMDS-West), and the nearest 

oyster leases are approximately 4 miles east of the ARBC and ODMDSs, near Point au Fer

(LDNR 2012). Because the transport of suspended materials from the ODMDS is mainly 

parallel to the coastline and in a generally westward direction during most of the year, adverse 

effects of disposal operations on these oyster beds should be minimal. In addition, the oyster

beds are naturally subjected to periodic episodes of high, suspended solid concentrations from 

the waters of the Atchafalaya River. There have been no impacts to oyster leases from past use, 

and no impact is expected to result from any future use of the ODMDS-East.

As previously noted, no causes for concern were indicated in the chemical analyses, suspended 

particulate phase bioassays, solid phase bioassays, or bioaccumulation study conducted in 2008 

(PBS&J 2008). No significant adverse impacts to fisheries are anticipated with the ocean 

placement of dredged channel sediments into the ODMDS.

4.2.3.2 Proposed ODMDS-West Alternative

Previously-impacted open water bottom habitat would continue to be altered during each 

disposal event in the ODMDS-West. Based on MVN analysis of pre and post-maintenance 

dredging surveys conducted annually at the Section 103(d) ODMDS-West since 2002, the 

approximately 10.8 mcy of dredged material expected to be placed in the proposed ODMDSWest during annual maintenance cycles has the potential to make the water 3 to 4 inches 

shallower. Effects of maintenance-dredged material placement on nekton (e.g., finfish and 

shrimp species) and benthic fauna (e.g., crabs and oysters) in the ODMDS-West are expected to 

be negligible and at most equal to effects described for the No-Action Alternative since the 

dredging frequency and average quantity of material placed will be less with the proposed action. 

Temporary placement of the dredge pipeline in open water areas of the proposed ODMDS-West 

is not expected to significantly affect fish resources.

4.2.4 Essential Fish Habitat

4.2.4.1 No-Action Alternative

With implementation of the No-Action Alternative, initially some EFH for brown shrimp, white 

shrimp, red drum, lane snapper, king mackerel, cobia, bonnethead shark, and Atlantic sharpnose 

shark will be directly impacted in the ODMDS-East. The ODMDS-East site encompasses 

approximately 9.25 square miles of Atchafalaya Bay water bottoms. An evaluation of EFH in 

the project area was coordinated with NMFS. NMFS provided comments to MVN in a letter on 

October 19, 2011. General categories of EFH potentially impacted by the placement of dredged 

material in the ODMDS-East include estuarine water bottoms and estuarine water column. 

According to NMFS, potential adverse impacts to these categories of EFH are considered 

temporary and minor. Potential impacts include the disruption/smothering of mud/sand 

substrates and related benthic communities associated with estuarine soft water bottoms during a 
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maintenance event. Short term EFH impacts would include a temporary and localized increase 

in estuarine water column turbidity during the placement of dredged material in the ODMDS; 

however, the project area is a naturally turbid environment and increased turbidity is not 

expected to significantly affect EFH needs within the project area.

Dredged material disposal would create new subtidal habitat and EFH in the area, and may add 

nutrients and detritus to the existing food web and contribute to the overall productivity of the 

area. Thus, some positive direct and indirect impacts to EFH and EFH-dependent species are 

anticipated with placement in the ODMDS-East.

4.2.4.2 Proposed ODMDS-West Alternative

The proposed ODMDS-West site encompasses approximately 48 square miles of Atchafalaya 

Bay water bottoms. According to NMFS, this subtidal habitat is categorized as EFH. General 

categories of EFH potentially impacted by the placement of dredged material in the ODMDSWest include estuarine water bottoms and estuarine water column. According to NMFS, 

potential adverse impacts to these categories of EFH are considered temporary and minor. The 

impacts of the ODMDS-West Alternative to EFH are similar to those of the No-Action 

Alternative but are expected to occur less frequently and be less intensive because of the smaller 

amount of material placed per maintenance cycle. Impacts to EFH would be the same as the 

impacts currently experienced at the site. Previously-impacted estuarine water bottoms and 

estuarine water column would continue to be altered during each disposal event in the ODMDSWest. Based on MVN analysis of pre and post-maintenance dredging surveys conducted 

annually at the Section 103(d) ODMDS-West since 2002, the approximately 10.8 mcy of 

dredged material expected to be placed in the proposed ODMDS-West during annual 

maintenance cycles has the potential to make the water 3 to 4 inches shallower; thus, creating 

new subtidal habitat and EFH in the area. 

4.2.5 Mammals, Reptiles, and Birds 

4.2.5.1 No-Action Alternative

Specific effects of dredged material placement on marine mammals and reptiles have not been 

studied. Because of their relatively large size and the mobility of most species, direct impacts 

should be negligible at the ODMDS-East. In addition, the ODMDS represents only a small 

portion of the total range of the mammal and reptile species occurring in the north central Gulf of 

Mexico. Placement would not occur in geographically restricted feeding, breeding, or passage 

areas of mammals, birds, or reptiles. Sea turtle prey availability in the project area could be 

reduced temporarily because of turbidity. The placement of material should not jeopardize any 

marine turtles’ population or critical habitat.

4.2.5.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are similar in nature to those of the No-Action 

Alternative but are expected to occur less frequently, over the long term since the dredging 
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frequency and average dredged material placement quantity will be less with the proposed 

action.

4.2.6 Threatened and Endangered Species

4.2.6.1 No-Action Alternative

Infrequent and localized placement at the ODMDS-East would have no adverse impacts on the 

food sources, migratory passage, or breeding areas of threatened or endangered mammals, birds, 

turtles, or fish. These species do not commonly occur in the area, are relatively motile, and 

would be able to avoid the area during maintenance dredging and dredged material placement. 

The ODMDS-East does not contain critical habitat for federally-listed species. Reduced prey 

availability for some of the species may occur on a temporary basis. 

4.2.6.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are similar to those of the No-Action Alternative 

but would be expected to occur less frequently, over the long term. Impacts to threatened or 

endangered species would be the same as the impacts currently experienced at the site.

Although threatened or endangered species may occur within the general project vicinity, their 

presence within the open waters of the proposed project areas is unlikely. Furthermore, the 

proposed project area does not contain critical habitat for federally-listed species, and the open 

water areas and habitats surrounding the project area would allow them to easily avoid the 

project activities. The ARBC and existing Section 103(b) ODMDS-West have previously been 

disturbed and have undergone routine maintenance dredging/disposal events in the past. 

Therefore, the proposed action is unlikely to cause adverse direct or indirect impacts to (i.e., “not 

likely to adversely affect”) federally-listed threatened or endangered species, or their critical 

habitat, under the jurisdiction of USFWS. USFWS concurred with this determination in a letter 

dated January 26, 2012. Additionally, MVN has concluded that no critical habitat for any 

threatened, endangered, or candidate species under the purview of National Marine Fisheries 

Service, Protected Resources Division has been designated within the project area, and that there 

would be no adverse impacts (i.e., “no effect”) to any of the NMFS federally-listed species that 

could potentially occur within the project area. 

4.2.7 Marine Sanctuaries and Special Biological Resource Areas

4.2.7.1 No-Action Alternative

There are no marine sanctuaries or special biological resources in the immediate area of either 

ODMDS. Shell Keys and Marsh Island Wildlife Refuges are approximately 47 km (29 miles) 

west of the ODMDS-East. Fishnet Bank, the closest protected Area of Biological Significance, 

is approximately 167 km (104 miles) south of the ODMDS-East. Because of the substantial 

distance between the ODMDS-East and the nearest marine sanctuary, refuge, or Area of 

Biological Significance, no impacts to such areas are expected.
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4.2.7.2 Proposed ODMDS-West Alternative

The distance between the proposed ODMDS-West and the nearest marine sanctuary, refuge, or 

Area of Biological Significance is approximately a similar distance as described for the 

ODMDS-East. Therefore, the proposed ODMDS-West is not expected to impact such areas.

4.3 SOCIOECONOMIC ENVIRONMENT

4.3.1 Demography and Economics

4.3.1.1 No-Action Alternative

Demography and economics of St. Mary Parish and Terrebonne Parish are related to the overall 

level of economic activity in the region. Under the No-Action Alternative, the dredging and 

material placement actions are not expected to change the demographics and levels of economic 

activity in St. Mary and Terrebonne Parishes.

4.3.1.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are similar to those described for the No-Action

Alternative but are expected to occur with lower frequency over the long term than with the NoAction Alternative since the dredging frequency and the average dredged material placed will be 

less with the proposed action. Impacts to the levels of economic activity associated with 

commercial and recreational fisheries would be the same as currently experienced in the project 

area.

4.3.2 Industry

4.3.2.1 No-Action Alternative

Nearshore areas of the northern Gulf of Mexico support one of the most productive fisheries in 

the United States for shrimp, menhaden, and bottom fish including croaker, drum, and sea trout. 

Coastal areas with sand/silt substrates, including the ODMDS-East, are used seasonally by many 

commercial species for feeding, breeding, and passage activities; however, none of these 

activities are unique or restricted to these sites. Fishing for demersal and pelagic fish and shrimp 

extend throughout nearshore and shelf regions. Consequently, some interference between 

commercial fishing and maintenance-dredged material disposal in nearshore regions is 

inevitable. The ODMDS represents only a small portion of the total fishing grounds of the 

northern Gulf of Mexico and ODMDS use occurs for only a small portion of each year. Any 

adverse effects are likely to be restricted to the disposal sites. Therefore, maintenance-dredged

material disposal will potentially affect only a small percentage of this resource over relatively 

short periods of time. 

No causes for concern were indicated in the chemical analyses, suspended particulate phase 

bioassays, solid phase bioassays, or bioaccumulation study conducted in 2008 (PBS&J 2008). 
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The NOAA ERL for arsenic was exceeded in some ARBC sediment samples from the 2008 

contaminant assessment, but the bioassays and bioaccumulation studies conducted as part of the 

assessment indicated no concern. Therefore, no significant adverse impacts are anticipated with 

the ocean placement of these sediments. Commercial and recreational fisheries are, therefore, 

likely to be only slightly impacted by ODMDS use and only for a short time period.

The disposal of maintenance-dredged materials could present two potential hazards to 

navigation: (1) mounding within the disposal site, and (2) interference of the dredge and/or 

pipeline with vessel traffic.

Mounding and/or shoaling may temporarily occur within the ODMDS-East immediately 

following disposal. However, historical pre and post-dredging bathymetric data collected by 

MVN indicate that there is very little net mounding because of the fluid nature of the dredged 

material and the dispersive nature of the area. 

Hydraulic cutterhead dredges and disposal pipelines may cause minor and temporary 

interference by blocking sections of the ARBC, but are not expected to interfere significantly 

with shipping traffic. Barges or hopper dredges, if required, may potentially interfere with

shipping in the ARBC; however, these interferences are unlikely, as dredging operations are 

closely coordinated with representatives of the navigation industry and a Notice to Mariners is 

posted by the USCG. 

4.3.2.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are expected to be similar to those described for 

the No-Action Alternative but are expected to occur less frequently over the long term since the 

dredging frequency and average quantity of dredged material placed will be less with the 

proposed action. Impacts to commercial and recreational fisheries and to navigation would be 

the same as the impacts currently experienced at the site. The continued maintenance of the 

ARBC may cause temporary changes in operations by the oil and gas and transportation 

industries using the channel; however, dredging operations are coordinated with navigation 

interests to allow continued use of the waterway during maintenance dredging operations. 

4.3.3 Employment

4.3.3.1 No-Action Alternative

Disposal in the existing ODMDS-East will not affect employment in St. Mary Parish or 

Terrebonne Parish. The frequency of dredging would increase over the long term once dredged 

material placement shifted from the Section 103(b) ODMDS (ODMDS-West) back to the 

ODMDS-East. Employment by commercial fishing, oil and gas, and recreational service 

industries would not be impacted by the No-Action Alternative.
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4.3.3.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are similar to those of the No-Action Alternative. 

No direct impacts to employment would occur. While the frequency of dredging would be 

maintained at a lower rate over the long term with the permanent designation of the ODMDSWest, the overall employment in St. Mary and Terrebonne Parishes would not be affected by the 

change in activity level. Employment in other industries, including commercial fishing, oil and 

gas, and recreational services, would not be affected by the Section 102(c) designation of the 

ODMDS-West.

4.3.4 Environmental Justice

The EPA’s guidance for determining whether there is a minority community where 

environmental justice effects could occur gives both quantitative and qualitative measures: if the 

affected area’s minority population is over 50 percent, and if the minority population in the 

affected area is “meaningfully greater” than that in the general population. U.S. 2010 Census 

data was used to identify the percentage of minority and low income populations within the 

study area to determine whether environmental justice impacts would occur. Data indicated the 

percentage of individuals who are listed as minorities in the parishes of the study area. The 

demographic analysis also identified percentages of study area residents living below the poverty 

level.

4.3.4.1 No-Action Alternative

Under the No-Action Alternative dredging of the ARBC would continue and placement of the 

dredged material would shift to the ODMDS-East after July 31, 2012. There would be no impact 

to any populations, minority, low-income, or otherwise, because the project area is in open 

waters of Atchafalaya Bay and the Gulf of Mexico. Because there would be no disproportionate 

effect to minorities or low income populations, the No-Action Alternative would not have any 

impact relative to Environmental Justice.

4.3.4.2 Proposed ODMDS-West Alternative

The proposed ODMDS-West Alternative would not result in environmental justice impacts. As 

described for the No-Action Alternative, the ODMDS-West is located in open waters of 

Atchafalaya Bay and the Gulf of Mexico. No populations would be affected by continued use of 

the site for placement of maintenance-dredged material from the ARBC. Thus, there would not 

be a disproportionate impact to minority or low-income populations or property in the study area. 

4.3.5 Recreation

4.3.5.1 No-Action Alternative

With implementation of the No-Action Alternative, the recreational environment in and around 

the project site would experience limited short-term disruption imposed by the physical size and 
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working activities imposed by the floating dredge facility and associated dredge pipeline. 

Dredging activities would increase turbidity in the area where work is being performed and in 

the vicinity of the discharge pipe. This turbidity would disrupt some recreational activity 

occurring within the work area; however, these adverse impacts would be temporary and short 

lived. 

4.3.5.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are similar to those of the No-Action Alternative. 

Impacts to recreation would be the same or slightly less than the impacts currently experienced at 

the site but would be expected to occur less frequently or with less intensity since the dredging 

frequency and average quantity of material placed will be less with the proposed action. 

4.3.6 Cultural and Historic Resources

4.3.6.1 No-Action Alternative

The short-term and long-term impacts of placing maintenance-dredged material on top of 

submerged cultural resources have never been fully assessed. It has been assumed by some that 

once material had been deposited in an area that the damage, if any, had already been done. The 

waterways of the ARBC are dynamic, hence the need for maintenance dredging and for 

continual placement of dredged material in the same areas. However, adverse impacts to 

submerged cultural resources could result from placement of maintenance-dredged material on 

top of any significant cultural resources in the ODMDS area. Adverse impacts include: 1) 

increase weight of sediments on any significant shipwreck, and 2) localized burial of possible 

shipwrecks changing their environment and possibly increasing the rate of decay (USACE

2002). While temporary mounding of maintenance-dredged material may occur within the 

ODMDS, these mounds disperse fairly quickly. The placed sediments are reworked by waves 

and littoral currents and are moved out of the ODMDS, thus removing any additional over 

burden. 

Geomorphological and bathymetric data obtained during the 1996 survey discussed in Section 

3.3.5 indicates that between approximately 5 and 6 m (17 and 21 ft) of sedimentation has 

occurred in the area between 1839 and the present (USACE 2002). Based on these sedimentation 

rates, any vessel wrecked more than 157 years ago could be covered by at least 5 m (18 ft) of 

sediment. As a result of this survey, it appears the disposal of maintenance-dredged materials in 

the Atchafalaya ODMDS could not add appreciably to the impact already induced by delta 

progradation during the last century. Thus, potential impacts to cultural resources resulting from 

continued placement of maintenance-dredged material at the ODMDS-West or resumed 

placement at ODMDS-East are expected to be negligible.

4.3.6.2 Proposed ODMDS-West Alternative

The impacts from the ODMDS-West alternative are the same as those described for the NoAction Alternative. Impacts to cultural and historic resources would be the same as the impacts 

currently experienced at the ODMDS-West. Section 106 consultation with the LA SHPO was 
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initiated on May 9, 2012 and with federally recognized tribes on June 1, 2012. MVN requested 

concurrence with the determination that no historic properties would be affected (36 CFR Part 

800.4(d)(1)) with implementation of the proposed action. The LA SHPO concurred with the 

finding of no effect to historic properties on May 24, 2012. Consulting parties were given 30 

days to respond to this determination in accordance with 36 CFR 800. The Jena Band of 

Choctaw Indians concurred with the finding of no effect to historic properties in a letter dated July 

11, 2012. In the event that significant cultural and historic resources are encountered, work in the 

location of the site would be halted, and an MVN archeologist would be notified for evaluation 

and further consultation under Section 106 of the NHPA. 

4.3.7 Aesthetics (Visual Resources) 

4.3.7.1 No-Action Alternative

With implementation of the No-Action Alternative, there would be some direct impacts to 

aesthetic (visual) resources. The visual resources of the project corridor would be temporarily 

impacted by construction activities related to implementing the proposed action and by transport 

activities needed to move equipment and materials to and from the site. However, this 

temporary impact would most likely affect visual resources from boating and other water traffic 

only. Dredged material disposal in the ODMDS-East would create a temporary turbidity plume. 

The plume would not be visible from shore, and would disperse after disposal operations cease. 

The additional discoloration of naturally turbid waters would be minor, and likely, unnoticeable. 

No excessive noises or odors are expected.

4.3.7.2 Proposed ODMDS-West Alternative

The impacts of the ODMDS-West Alternative are similar to those of the No-Action Alternative. 

Impacts to visual resources would be the same or slightly less than those of the No-Action 

Alternative but would be expected to occur less frequently or with less intensity since the 

dredging frequency and average quantity of material placed will be less with the proposed action. 

4.4 CUMULATIVE IMPACTS

Cumulative impact has been defined by the CEQ as “the impact on the environment which 

results from the incremental impact of the action when added to other past, present, and 

reasonably foreseeable future actions regardless of what agency (Federal or non-Federal) or 

person undertakes such action.” Cumulative impacts can result from individually minor but 

collectively significant actions taking place over a period of time. 

No individual projects were determined as pertinent to the cumulative impacts from ODMDS 

site designation. However, types of activities can be addressed. Cumulative impacts could occur 

at the proposed ODMDS-West if the impacts of other activities in the area (e.g., shipping, 

recreational and commercial fishing, and oil and gas exploration and production) compounded 

the impacts of designation and, thus, placement of dredged material in the proposed ODMDSWest. To assess this, one must determine whether the impacts that are likely with these activities 

would affect the ecosystems impacted by dredged material placement in the ocean. The only 
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expected impacts from dredged material placement are localized, short-term, temporary impacts 

to the water column and longer-term but still temporary impacts to the water bottoms and 

associated benthos. Shipping and recreational and commercial fishing would impact neither of 

these resources unless there was a spill of fuels or cargo. There is no way to quantify these 

events but they are not common and would have to co-occur with placement, which is expected 

to occur on 1- to 5-year intervals, before cumulative impacts would occur. Cumulative impacts 

from oil and gas drilling and dredged material placement cannot be expected. There are 

platforms in the vicinity, and the pipelines that connect them to shore, that could potentially 

result in an oil spill. The long-term impacts of the Deepwater Horizon oil spill on coastal 

Louisiana are uncertain at this time. This spill, and any future oil spills, could potentially 

adversely impact USACE water resources projects and studies within the Louisiana coastal area. 

Potential impacts could include factors such as changes to existing or baseline conditions, as well 

as changes to future-without and future with project conditions. The USACE will continue to 

monitor and closely coordinate with other Federal and state resource agencies and local sponsors 

in determining how to best address any potential problems associated with the oil spill that may 

adversely impact USACE water resources development projects/studies. This could include 

revisions to proposed actions as well as the generation of supplemental environmental analysis 

and documentation for specific projects/studies as warranted by changing conditions. Additional 

environmental stressors such as hypoxia could add to impacts from ODMDS site designation. 

While the placement of dredged material could temporarily reduce the dissolved oxygen content 

of water column at the ODMDS-West during placement, as discussed in Section 3.4.3, the area 

of hypoxia in the Gulf of Mexico is quite large, ranging from Galveston to the Mississippi Delta, 

relative to the area of the proposed ODMDS-West. Thus the dredged material component of any 

cumulative impacts from oxygen demand is expected to be insignificant.

Dredging and placement of maintenance material, as well as these other types of activities and 

stressors, have been ongoing for decades off the Atchafalaya Bay with no indication of 

significant cumulative environmental deterioration. Placement of additional material in the 

proposed ODMDS-West, which should be very similar to that placed currently at the same site 

under Section 103(b), should not change the situation. The ODMDS-West would have no 

significant environmental justice or socioeconomic impacts and would not contribute to any 

cumulative environmental justice or socioeconomic impacts.

Previously-impacted open water bottom habitat, estuarine water bottom and associated EFH, and 

estuarine water column would continue to be altered during each ARBC maintenance dredging 

and disposal event with the continued use of the ODMDS-West upon the site’s Section 102(c) 

designation. Failure to designate the ODMDS-West pursuant to Section 102(c)—the No-Action 

Alternative—would result in a return to use of the ODMDS-East, after the ODMDS-West site’s 

expiration on July 31, 2012. While disposal to the smaller (6,000 acres) ODMDS-East would 

result in less water bottom impact in the short term, it has been demonstrated that dredged 

material placed in the ODMDS-East returns to the ARBC at a higher rate than dredged material 

placed in the ODMDS-West. Designation of the ODMDS-West is intended to allow a long-term 

reduction in required dredging compared to the required dredging frequency if placement is 

returned to the ODMDS-East. Consequently, long-term impacts that are likely to result from 

maintenance dredging disposal activities are expected to be less with the proposed alternative 

(ODMDS-West) than with the No-Action Alternative (ODMDS-East). 
124

4.5 ADVERSE ENVIRONMENTAL IMPACTS WHICH CANNOT BE 

AVOIDED

In general, few significant adverse impacts result from maintenance-dredged material placement.

Increases in turbidity, releases of nutrients or trace metals, disturbance of open water bottom 

habitat and associated reductions in benthic faunal abundance and diversity are short-term and 

localized effects that could occur. Results of DMRP studies indicate that impacts within the site 

are minimized when placement occurs in naturally variable, high-energy environments (Hirsch et 

al. 1978). The ODMDS-West is situated in a dynamic, nearshore environment; thus, long-term 

or cumulative impacts will be minimal, and mitigation measures should be unnecessary. Results 

of the IEC (1983) surveys at the ODMDS-East suggest that previous dredged material placement

has not caused significant degradation of the water or sediment quality or persistent changes in 

the composition of the fauna in areas adjacent to the ODMDS-East. The same would be 

expected for the ODMDS-West.

Limited interference with nearshore fisheries may occur from placement of dredged material. 

The ODMDS-West is located within passage areas of nekton that seasonally migrate to and from 

the estuaries, bays, and Gulf during various stages of their life cycle. Maintenance dredging and 

placement activities could be restricted to periods of the year when these migrations are 

diminished or periods of greater turbulence (i.e., more rapid sediment dispersion). However, the 

ODMDS represents only a small percentage of the total nearshore fishing grounds. Therefore, 

mitigating measures to reduce interferences with commercial or recreational fishing are not 

warranted.

4.6 THE RELATIONSHIP BETWEEN LOCAL SHORT-TERM USES 

OF THE ENVIRONMENT AND THE MAINTENANCE AND 

ENHANCEMENT OF LONG-TERM PRODUCTIVITY

Long-term degradation of water or sediment quality, which might decrease the long-term 

productivity or value of resources, has not been detected within or adjacent to the ODMDS-East 

and is therefore not expected to occur at the ODMDS-West. Commercial fishing and 

sportfishing at and near the site should not be significantly impaired because the site constitutes a 

small percentage of the total fishing grounds. Adverse effects on the productivity of the 

nearshore region adjacent to the ODMDSs due to localized and intermittent disposal activities 

are considered negligible in comparison to the economic benefits derived from maintaining the 

ARBC.

4.7 ANY REVERSIBLE OR IRRETRIEVABLE COMMITMENT

OF RESOURCES

Irreversible or irretrievable resources committed to the proposed action include: 

1. Loss of energy resources used as fuel for dredges, pumps, and dredged material placement 

vessels.
125

2. Loss of economic resources due to costs of ocean disposal. 

3. Loss of benthic organisms due to burial. 

4.8 ENERGY AND NATURAL OR DEPLETABLE RESOURCES 

REQUIREMENTS AND CONSERVATION POTENTIAL OF 

VARIOUS ALTERNATIVES AND MITIGATION MEASURES

Within the bounds of the guidelines for site designation, the distance traveled by the dredges, 

which accounts for dredging and fuel requirements, is kept to a minimum with use of the 

ODMDS-West. Use of the ODMDS-West requires the least amount of energy for maintaining 

the ARBC because of reduced frequency of dredging over the long term when compared to use 

of the ODMDS-East.

4.9 COMPLIANCE WITH COASTAL ZONE MANAGEMENT

PLANS (CZMP)

It has been the policy of the State of Louisiana to put to BU, to the fullest extent possible, the use 

of dredged material under the purview of the Louisiana CZMP. However, MVN engineering 

studies have indicated that the transport of material from the ARBC for the purpose of marsh 

and/or island creation at a nearshore location would be cost and equipment prohibitive—

exceeding the current Federal Standard and not economically justified. Additionally, the 

material to be dredged is comprised of fine silt and clay and is very fluid. This material has little 

value for BU applications and its use is not based on sound engineering practices. 

MVN has clearly demonstrated a commitment to using dredged material from the upper 

Atchafalaya River Bar and Bay channels beneficially where practicable. The permanent Section 

102(c) designation of the ODMDS-West would not preclude future consideration of beneficial 

use alternatives as the physical characteristics of the ARBC change. As discussed earlier in this 

DEIS, MVN will continue to explore the possibility of using greater amounts of shoal material 

from the ARBC beneficially, if and when the bed load composition in the channel becomes more 

suitable (i.e., courser-grained) for marsh and/or island creation as active progradation of the 

Atchafalaya Delta continues. It is anticipated that additional modifications (e.g., further 

reduction of the site’s footprint) to the proposed ODMDS-West may be deemed appropriate to 

accommodate future expansion of the Bird Island-West site and/or other beneficial use efforts as 

greater quantities of suitable material become available in the area. Any modifications to the 

proposed ODMDS-West (or ODMDS-East) site in the future would require the preparation of 

the appropriate accompanying environmental compliance and supporting documentation. 
126

5.0 COORDINATION

5.1 BACKGROUND

The EPA, in cooperation with MVN, published a notice of intent (NOI) to prepare a Draft EIS 

for the designation of an ODMDS in the Gulf of Mexico off the mouth of the Atchafalaya River, 

St. Mary, Louisiana. The NOI was published in the Federal Register (Volume 76, Number 140) 

on July 21, 2011. The NOI requested comments concerning significant issues for evaluation in 

the EIS be provided to EPA. 

5.2 EIS SCOPING

The NEPA provides for an early and open public process for determining the scope of issues 

(problems, needs, and opportunities), resources, impacts, and alternatives to be addressed in the 

EIS. This process is referred to as “scoping.” Scoping is used to: a) identify the affected public 

and agency concerns; b) facilitate an efficient Draft EIS preparation process; c) define the issues 

and alternatives that will be examined in detail in the Draft EIS; and d) save time in the overall 

process by helping to ensure that the draft statement adequately address relevant issues. Scoping 

is a process, not an event, or a meeting; it continues throughout the Draft EIS process and may 

involve meetings, telephone conversations, and/or written comments. Scoping is a critical 

component of the overall public involvement program. 

Scoping was accomplished by correspondence with affected Federal, State, tribal, and local 

agencies, and with anticipated interested parties. Appropriate Federal, State, tribal, and local 

entities were invited to participate as a cooperating agency. The scoping process was initiated 

with the publishing of the NOI in the Federal Register (Volume 76, Number 140) on July 21, 

2011. Scoping continued with the distribution of a scoping input request letter and project 

information package on September 15, 2011, followed by a 45-day scoping comment period. 

Following the scoping period, a Scoping Report was prepared by EPA and MVN. The Scoping 

Report outlined the project background and scoping process to date and summarized the key 

issues identified by members of the public during the scoping period. The Scoping Report was 

distributed to all Federal, State, tribal, and local agencies and interested parties that provided 

comments during the scoping comment period and is included in Appendix B of this Draft EIS. 

The beneficial use of dredged material was the major issue identified during the EIS scoping 

process. The EPA supports the use of dredged material for beneficial purposes and is currently 

taking an active role in efforts to reduce wetland loss and coastal erosion in Louisiana. However, 

EPA has no authority to impose, either directly or indirectly, a blanket prohibition on ocean 

disposal of dredged material. More specifically, EPA is authorized by Section 102(c) of MPRSA 

to designate recommended sites or times for ODMDS disposal. The selection and evaluation of 

an ODMDS is based primarily on the general and specific criteria contained in Part 228 of the 

Ocean Dumping Regulations. In response to the EIS scoping comments, a non-ocean (i.e., 

beneficial use) disposal alternative discussion is included in Section 2.2 of this Draft EIS. 

However, it should be noted that this alternative discussion has been included based on the intent 
127

of NEPA which states that reasonable alternatives outside the jurisdiction of the responsible 

agency can be evaluated.

Implementation of a beneficial use alternative is considered under 40 CFR Part 227, Subpart C, 

Need for Ocean Dumping. The evaluation of beneficial use as well as other alternatives to ocean 

dumping are addressed during the USACE’s project review process. Prior to the disposal of 

dredged material at a designated site, the USACE applies the Part 227 criteria, including Subpart 

C, and evaluates compliance with the Ocean Dumping Regulations. 

5.3 PUBLIC REVIEW PROCESS

The Notice of Availability and request for public comments on this Draft EIS will be published 

in the Federal Register. The Draft EIS will be made available to interested agencies, groups, and 

individuals for a 45-day review and comment period. The Draft EIS may be viewed at the EPA 

website: http://www.epa.gov/region6/water/ecopro/current_action.html. 

5.4 MAILING LIST

Copies of this Draft EIS will be provided, by request, to Federal, state, parish, and local 

agencies; tribes; businesses; libraries; museums; universities; environmental organizations, 

groups and individuals; and scoping participants. The complete distribution list will be available 

upon request from the EPA at the following address: 

U.S. EPA, Region 6 

1445 Ross Avenue 

Dallas, Texas 75202-2733 

5.5 RULE-MAKING PROCESS

Concurrent with or shortly after distribution of this draft EIS, the EPA will publish a proposed 

rule-making in the Federal Register. The proposed rule-making has a 45-day review and 

comment period. A Final EIS will then be prepared, taking into account all comments received 

on the Draft EIS and proposed rule-making. The Final EIS has a 30-day review and comment 

period. The EPA’s final rule-making, which serves the same purpose as a Record of Decision, 

addresses comments received on the Final EIS. ODMDS designation (pursuant to Section 102(c) 

of MPRSA) becomes effective 30 days after publication of the final rule-making in the Federal 

Register. 

5.6 COASTAL ZONE CONSISTENCY

A Coastal Zone Consistency Determination was prepared by EPA and submitted to LDNR’s 

Office of Coastal Management (OCM) for consistency review on February 27, 2012. In a letter 

dated April 30, 2012, OCM concurred with the determination that the proposed action (the 

permanent, MPRSA 102(c) designation of the ODMDS-West) is consistent with the Louisiana 

Coastal Resources Program (LCRP). Usage of the ODMDS-West by MVN would still require 

individual evaluation and concurrence with consistency determinations on a case-by-case basis.
128

6.0 PREPARERS

This Draft EIS was coordinated and prepared by Mr. John Fiorentino (Biologist), MVN in 

cooperation with Dr. Jessica Franks (Dredge Material Management & Ocean Disposal 

Coordinator), EPA, Region 6. Much of the information contained herein is largely adapted from 

the 2009 Preliminary Draft EIS (Document No. 080178), prepared for MVN by PBS&J. 
129

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APPENDIX A

Site Management and Monitoring Plan
 

ATCHAFALAYA RIVER BAR CHANNEL, LOUISIANA

SITE MANAGEMENT PLAN

FOR THE MAINTENANCE DREDGING

OCEAN DREDGED MATERIAL DISPOSAL SITES EAST AND WEST

AS REQUIRED BY

SECTION 102 OF THE

MARINE PROTECTION, RESEARCH, AND SANCTUARIES ACT
2 

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3 

The following Site Management and Monitoring Plan for the Atchafalaya ocean dredged 

material disposal sites East and West complies with Section 102©(3) of the Marine Protection, 

Research and Sanctuaries Act of 1972 (33 U.S.C. Section 1401, et seq.) as amended by Section 

506of the Water Resources Development Act Amendments of 1992 (WRDA 92; public Law 

102-580), and has been approved by the following officials of Region 6 and the U. S. 

Environmental Protection Agency, and New Orleans District of the US Army corps of 

Engineers. 

_______________________________________ _____________________________ 

Ron Curry Date

Regional Administrator

Region 6 

U.S. Environmental Protection Agency 

_______________________________________ _____________________________ 

Edward R. Fleming Date

Colonel, Corps of Engineers 

New Orleans District

U.S. Army Corps of Engineers 

This plan goes into effect up on the date of the last signature for a period not to exceed 10 

years. The plan shall be reviewed and revised more frequently if site use and conditions at site 

indicate a need for revision. 
4 

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5 

SITE MANAGEMENT AND MONITORING PLAN

ATCHAFALAYA RIVER BAR CHANNEL, LOUISIANA

OCEAN DREDGED MATERIAL DISPOSAL SITES EAST AND WEST

TABLE OF CONTENTS

1.0 INTRODUCTION........................................................................................................................... 7

2.0 SITE MANAGEMENT .................................................................................................................. 7

2.1 Site Management Objectives ........................................................................................................ 8

2.2 Roles and Responsibilities ............................................................................................................ 9

2.3 Funding ......................................................................................................................................... 9

2.4 Baseline Assessment of Site Conditions and Disposal Site History ............................................. 9

2.4.1 Site Characterization for ODMDS-East ................................................................................ 9

2.4.2 Site Characterization for ODMDS-West ............................................................................ 10

2.4.3 Reference Site Characterization .......................................................................................... 11

2.4.4 Historical Use of ODMDS-East .......................................................................................... 11

2.4.5 Historical Use of ODMDS-West ........................................................................................ 13

2.5 Dredged Material Volumes ......................................................................................................... 14

2.6 Dredged Material Suitability ....................................................................................................... 14

2.7 Anticipated Site Use ................................................................................................................... 15

2.8 Special Management Conditions or Practices ............................................................................. 15

3.0 SITE MONITORING ................................................................................................................... 17

3.1 Baseline Monitoring .................................................................................................................... 19

3.2 Disposal Monitoring ................................................................................................................... 19

3.3 Bathymetric Surveys ................................................................................................................... 21

3.3.1 Routine Bathymetric Surveys ............................................................................................. 21

3.3.2 Bathymetric Surveys Conducted for Unauthorized Discharges .......................................... 22

3.4 Reporting and Data Formatting................................................................................................... 25

3.4.1 Project Initiation and Unauthorized Discharge Reporting. ................................................. 25

3.4.2 Post Disposal Summary Report .......................................................................................... 25

3.5 Summary of Past Monitoring Survey Results ............................................................................. 25

3.6 Environmental Effects Monitoring Reporting ............................................................................ 26

3.7 Future Monitoring Efforts ........................................................................................................... 25

4.0 SITE MANAGEMENT PLAN REVIEW AND REVISION .................................................... 25
6 

5.0 IMPLEMENTATION .................................................................................................................. 26

6.0 REFERENCES .............................................................................................................................. 27

LIST OF TABLES

Table 1. Disposal History of ODMDS-East 12

Table 2. Disposal History of ODMDS-West 13

Table 3: Sediment Composition 14

Table 4: Sediment Quality Assessment History 14

Table 5. Surveys Conducted at the Atchafalaya ODMDS-East and ODMDS-West 20

Table 6. ARBC ODMDS Monitoring Strategies and Action Thresholds 23

LIST OF FIGURES

Figure 1. Atchafalaya Bar Channel - ODMDS East and ODMDS West 16

Figure 2. Atchafalaya Bar Channel - Disposal Sites 18

LIST OF TERMS

ARBC Atchafalaya River Bar Channel

CFR Code of Federal Regulations

EA Environmental Assessment 

EIS Environmental Impact Statement

ERL Effects Range - Low

million cy 1,000,000 cubic yards 

MLLW NOAA Mean Lower Low Water datum

MPRSA Marine Protection, Research, and Sanctuaries Act of 1972 

MVN U. S. Army Corps of Engineers – Mississippi Valley, New Orleans District

NMFS National Marine Fisheries Service

ODMDS Ocean dredged material disposal site

RIA Regional Implementation Agreement

SMMP Site management and monitoring plan

SPI Sediment Profile Imaging

USACE U. S. Army Corps of Engineers 

USEPA U. S. Environmental Protection Agency 

WRDA Water Resources Development Act of 1992
7 

SITE MANAGEMENT AND MONITORING PLAN

ATCHAFALAYA RIVER BAR CHANNEL, LOUISIANA

OCEAN DREDGED MATERIAL DISPOSAL SITES EAST AND WEST

1.0 INTRODUCTION

It is the responsibility of the U.S. Environmental Protection Agency (EPA) and the U.S. Army 

Corps of Engineers (USACE) under the Marine Protection, Research, and Sanctuaries Act 

(MPRSA) of 1972 to manage and monitor each of the Ocean Dredged Material Disposal Sites 

(ODMDSs) designated by the EPA pursuant to Section 102 of MPRSA. Section 102(c)(3) of 

the MPRSA requires development of a Site Management and Monitoring Plan (SMMP) for 

each ODMDS and review and revision of the SMMP not less frequently than every 10 years. 

The 1996 document, Guidance Document for Development of Site Management Plans for 

Ocean Dredged Material Disposal Sites (EPA/USACE, 1996) and the EPA, Region 6 and 

USACE Mississippi Valley – New Orleans District ODMDS Regional Implementation 

Agreement (RIA) (EPA/USACE, 2003) have been used as guidance in developing this SMMP. 

This SMMP is intended to provide management and monitoring strategies for disposal in the 

ODMDS East and West locations utilized for Atchafalaya River Bar Channel (ARBC) 

improvement and maintenance dredging projects. Final designation of ODMDS-East was first 

sought in 1983. Upon review of the Environmental Impact Statement (EIS), EPA requested that 

additional surveys be conducted, which were included in the 1990 Supplemental EIS and 

eventually compiled into the 1997 Final EIS. ODMDS-East received its final designation in 

2000. However, use of the ODMDS-East site was discontinued in 2002 due to concerns with 

transport of material from this site back into the bar channel. This concern necessitated the 

creation of a new ocean disposal site, leading to the selection of ODMDS-West. The first 

SMMP specifically for ODMDS-West was published in 2002 as an appendix under 

Environmental Assessment #348, Atchafalaya River and Bayous Boeuf, Chene, and Black, LA 

Navigation Project as designated under MPRSA Section 103, but was never signed. The most 

current SMMP in use for all ARBC ODMDS projects was signed in 1996 and supported the use 

of only the ODMDS-East. This document supports the use of both the ODMDS-West as well as 

the ODMDS-East. This revision to the Atchafalaya Bar Channel ODMDS SMMP supersedes

all previous SMMPs for ARBC ODMDS projects. Upon finalization of this revised SMMP, the 

SMMP provisions shall be requirements for all dredged material disposal activities and 

monitoring activities at the site. The SMMP itself, however, does not authorize the use of any 

ODMDS for ocean disposal of dredged materials. Use of any ODMDS for ocean disposal of 

dredged materials is regulated under a permit (or contract specification) under MPRSA section 

103. All Section 103 (MPRSA) ocean disposal permits or contract specifications shall be 

conditioned as necessary to assure consistency with the SMMP. Nothing in this SMMP 

operates to relieve the USACE from statutory requirements (or to satisfy any such 

requirements) applicable to the authorization to use an ODMDS for ocean disposal of dredged 

material other than the requirement that any such use comply with the provisions of the SMMP. 

2.0 SITE MANAGEMENT

The Marine Protection, Research and Sanctuaries Act of 1972 (33 U.S.C. Section 1401, et seq.) 
8 

is the legislative authority regulating the disposal of dredged material into ocean waters, 

including the territorial sea. The transportation of dredged material for the purpose of 

placement into ocean waters is permitted by the USACE or, in the case of Federal projects, 

authorized for disposal under MPRSA Section 103(e), applying environmental criteria 

established by the EPA in the Ocean Dumping Regulations (40 CFR Parts 220-229). 

Section 228.3 of the Ocean Dumping Regulations established disposal site management 

responsibilities, stating that "management of a site consists of regulating times, rates, and 

methods of disposal and quantities and types of materials disposed of; developing and 

maintaining effective ambient monitoring programs for the site; conducting disposal site 

evaluation designation studies; and recommending modifications in site use and/or 

designation." 

This SMMP for the ARBC ODMDS East and West was developed jointly by EPA, Region 6 

and USACE Mississippi Valley - New Orleans District (MVN), in accordance with Section

102(c)(3) of the MPRSA, as amended by WRDA 92. At a minimum the SMMP shall include 

but not be limited to:

• A baseline assessment of conditions at the site;

• A program for monitoring the site;

• Special management conditions or practices to be implemented at each site that are 

necessary for the protection of the environment; 

• Consideration of the quantity and physical/chemical characteristics of dredged materials 

to be disposed of at the site; 

• Consideration of the anticipated use of the site over the long-term; and

• A schedule for review and revision of the plan. 

2.1 Site Management Objectives 

The purpose of ODMDS management is to ensure that placement activities do not unreasonably 

degrade or endanger human health, welfare, the marine environment, or economic potentialities. 

The specific management objectives for the ODMDSs are as follows: 

1. Ocean discharge of only that dredged material that satisfies the criteria set forth in 40 

CFR Part 227 Subparts B, C, D, E, and G and Part 228.4(e) and is suitable for 

unrestricted placement at the ODMDS;

2. Avoidance of excessive mounding either within the site boundaries or in areas adjacent 

to the site, as a direct result of placement operations.

These objectives will be achieved through the following measures: 

1. Regulation and administration of ocean dumping permits; 

2. Development and maintenance of a site monitoring program; 

3. Evaluation of permit compliance and monitoring results. 

The objective of the SMMP is to provide guidelines in making management decisions 

necessary to fulfill mandated responsibilities to protect the marine environment. The following 
9 

sections provide the framework for meeting these objectives.

2.2 Roles and Responsibilities

Development of SMMPs for ODMDSs within MVN’s area of operation is the joint

responsibility of EPA, Region 6 and the MVN. Both agencies are responsible for assuring that

all components of the SMMP are implementable, practical, and applicable to site management

decision-making. 

Specific responsibilities of EPA and the MVN are:

In accordance with Section 102 (c) of the MPRSA, EPA is responsible for designation/dedesignation of ODMDSs, for evaluating environmental effects of disposal of dredged material 

at these sites and for reviewing and concurring on dredged material suitability determinations.

The MVN is responsible for evaluating dredged material suitability and issuing MPRSA 

Section 103 permits, regulating site use, and developing and implementing disposal-monitoring 

program. 

Where use of an EPA-designated site is not feasible, the MVN may, with concurrence with

EPA, Region 6 select an alternative site in accordance with Section 103(b) of the MPRSA as

amended by Section 506 of WRDA 1992. 

2.3 Funding

Physical, chemical, and biological effects-based testing shall be undertaken on sediments to be 

deposited at the ODMDS. This testing will be conducted at least every 5 years, contingent on 

the availability of funds, or as necessary to address contaminant concerns due to unanticipated

events, and will be funded by the permittee if the project is permitted or MVN for Federal

projects. The permittee or MVN, as appropriate, shall also be responsible for costs associated

with placement site hydrographic monitoring. Should monitoring indicate that additional studies 

and/or tests are needed at the ODMDSs, the cost for such work would be shared by the 

permittee or MVN and EPA Region 6. Physical, chemical, and biological effects-based testing

at the ODMDS, or in the site environs after discharge that is not required as a result of

hydrographic monitoring, shall be funded by EPA Region 6. Federal funding of all aspects of 

this SMMP is contingent on availability of appropriated funds. 

2.4 Baseline Assessment of Site Conditions and Disposal Site History

The location of ODMDS-East and ODMDS-West, i.e., adjacent and parallel to the ARBC and

the rectangular configuration of the sites involves only short transport of the dredged material

from the channel to the sites, typically through a floating pipeline. This minimizes interference

with other activities such as fishing and navigation in the site environs during dredging and

disposal operations. The sites are also easily accessible for surveillance and monitoring. 

2.4.1 Site Characterization for ODMDS-East

The ARBC ODMDS-East is located east of and parallel to the Atchafalaya River and Bayous 

Chene, Boeuf, and Black, Louisiana bar channel and is approximately 18.5 miles long and 0.5 

miles wide (Figure 1). For the purposes of this SMMP, all coordinates are based upon the North 
10 

American Datum of 1983 unless otherwise noted. The coordinates of the rectangular-shaped 

site are as follows: 

29° 20' 59.92" N, 91° 23' 33.23" W

29° 20' 43.94" N, 91° 23' 09.73" W

29° 08' 15.46" N, 91° 34' 51.02" W

29° 07' 59.43" N, 91° 34' 27.51" W

The center of the site is approximately 19 miles from the mouth of the Atchafalaya River. North

Point of the Point Au Fer Island is about 2 miles east of the northern end of the site. Point au Fer

Shell Reef, and an area that has been subjected to extensive shell dredging, lies just shoreward

of ODMDS-East.

Baseline conditions at the ARBC ODMDS-East were assessed during the site designation 

process. Details of the baseline conditions, including descriptions of the marine environment in

the site vicinity and the physical, chemical, and biological characteristics of the sediments and

the water column at the site are contained in the “Supplemental Final Environmental Impact

Statement, Atchafalaya River Bar Channel, Ocean Dredged Material Disposal Site, St. Mary

Parish, Louisiana,” prepared by USEPA,

Region 6 in November 1998. 

2.4.2 Site Characterization for ODMDS-West

The ARBC ODMDS-West is located west of and parallel to the ARBC. It is approximately 16 

miles long and 3 miles wide (Figure 1). For the purposes of this SMMP, all coordinates are 

based upon the North American Datum of 1983 unless otherwise noted. The coordinates of the 

ODMDS-West are as follows: 

29° 22′ 06′′ N, 91° 27′ 38′′ W

29° 20′ 30′′ N, 91° 25′ 13′′ W

29° 09′ 16′′ N, 91° 35′ 12′′ W

29° 10′ 52′′ N, 91° 37′ 33′′ W

The center of the ODMDS-West is approximately 20 miles from the mouth of the Atchafalaya

River. North Point au Fer Island is approximately 2.5 miles east of the northern end of the site.

Point au Fer Shell Reef lies just shoreward of the ODMDS-West.

The ODMDS-West encompasses approximately 31,400 acres or 49 square miles of open water.

The inner limit of the ODMDS-West is 2,650 feet from the ARBC centerline. The site ranges

from 6 to 23 ft in depth. 

Baseline conditions at the ARBC ODMDS-West were assessed during the site designation 

process. Details of baseline conditions, including descriptions of the marine environment in the 

site vicinity and physical, chemical, and biological characteristics of the sediments and water

column at the site, are described in the “Draft Environmental Impact Statement, Atchafalaya

River Bar Channel, ODMDS-West Environmental impact Statement, St. Mary Parish, Louisiana 

(USEPA/USACE 2013).
11 

2.4.3 Reference Site Characterization 

Reference sampling stations for this project have been established based on the Area Approach. 

The sediment reference sampling stations are located southeast of the ARBC at the following 

coordinates (NAD 1983):

29° 07′ 00′′ N, 91° 31′ 30′′ W

29° 08′ 00′′ N, 91° 29′ 00′′ W

29° 09′ 00′′ N, 91° 27′ 00′′ W

2.4.4 Historical Use of ODMDS-East

As described in the “Site Management Plan Atchafalaya River Bar Channel Ocean Dredged 

Material Disposal Site (USACE 1996),” the 1977 interim ARBC ODMDS-East was a long, thin 

area that paralleled the bar channel reach of the navigation channel, shaped in order to simplify 

disposal from the bar channel that had been taking place since 1974. At the time of the site 

designation studies, no changes to the size of the site were recommended. However, MVN did 

recommend an alteration of the site’s footprint prior to designation and publication of the 

Supplemental Draft EIS on February 6, 1991. MVN called for extension of the ODMDS-East 

on both ends to plan for current and future increases to the length of the bar channel as the 

Atchafalaya Delta progrades gulfward. In the proposed rule, the ODMDS-East’s dimensions 

were 30.4 km (19 mi) long and 0.8 km (0.5 mi) wide. 

Later in 1991, the northernmost end of the ODMDS-East was converted to use as a CWA 

Section 404 beneficial use disposal area, with the intent of creating island habitat for colonial 

nesting seabirds. After these two alterations, the ODMDS-East’s dimensions are 29.6 km (18.5 

mi) long and 0.8 km (0.5 mi) wide. 

The ODMDS-East received final designation in 2000, under 65 FR 31492 (18 May 2000). The 

Rivers and Harbors Act of June 25, 1910 authorized MVN to construct and maintain the 

Atchafalaya River, Morgan City to the Gulf of Mexico, LA, project which provided a 

navigation channel 20 feet deep, 200 feet wide and 15.75 miles long from the 20-foot contour 

in the Atchafalaya Bay, approximately 4 miles beyond the mouth of the Atchafalaya River, to 

the 20-foot contour in the Gulf of Mexico. Traffic sufficient to warrant maintenance of the 

authorized navigation channel to full project dimensions did not immediately develop. The 

channel was progressively enlarged during maintenance events from 10- by 100-feet in 1939 to 

20- by 200-feet in 1974. 

The Rivers and Harbors Act of 1968 authorized construction of the Atchafalaya River and 

Bayous Chene, Boeuf, and Black, LA, project which incorporated the existing project and 

provided for an increase in channel width of the navigation channel in Atchafalaya Bay and bar 

to 400 feet. Construction of the channel in the bay and bar was initiated in April, 1974 and 

completed in December of the same year. History of disposal of dredged material from the 

Atchafalaya River Bar Channel prior to construction of the enlarged channel in 1974 is 

incomplete. Dredging records dating back to 1957 indicate that maintenance of discontinuous 

reaches of the bay and/or bar channel occurred on an annual basis from 1957 until 1974 except 

for 1961. It is likely that dredged material was placed unconfined in open water on either side 

of the navigation channel. 
12 

Table 1. Disposal History of ODMDS-East 

Start Date Finish Date

Volume Placed

(cubic yards)

7 Jun 73 21 Aug 73 3,557,062

11 Apr 74 6 Dec 74 14,409,109

1975 No Dredging 0

21 Aug 75 10 Feb 77 10,888,170

1977 No Dredging 0

1978 No Dredging 0

8 Dec 78 2 Apr 79 10,992,792

1980 No Dredging 0

4 Jul 81 10 Nov 81 9,236,530

1982 No Dredging 0

26 Jun 83 1 Nov 83 10,674,563

25 Sep 85 8 Feb 86 8,500,000

2 Jul 87 31 Aug 87 10,035,209

6 Aug 88 22 Nov 88 10,302,961

29 Jun 89 12 Sep 89 11,111,114

2 Aug 90 17 Nov 90 9,446,109

31 Jan 91 17 Apr 91 1,643,900

7 May 91 25 Sep 91 9,559,859

20-Feb-92 4-May-92 1,000,000

11-May-92 2-Dec-92 9,630,972

14-Mar-93 19-May-93 4,035,076

10-Jun-93 16-Sep-93 11,700,000

14-Aug-93 14-Sep-93 2,254,937

14-Apr-94 26-May-94 1,836,445

27-May-94 16-Oct-94 8,757,597

23-Jun-95 25-Oct-95 9,311,000

16-Apr-96 16-Dec-96 11,589,416

30-Sep-97 9-Dec-97 6,968,673

16-Aug-98 21-Nov-98 10,942,132

11-Aug-99 23-Oct-99 10,847,337

26-Jun-00 18-Aug-00 10,749,971

27-Feb-01 29-Apr-01 9,554,971

29-Apr-01 6-May-01 1,269,887

22 Sep 01 13 Apr 02 9,168,753

TOTAL 239,974,545

AVERAGE PER FISCAL YEAR CYCLE 8,274,984

Between 1974 and 1991, all of the dredged material removed during routine maintenance of the 

bar channel was placed in the ODMDS. Prior to the 1991 maintenance event, the 193-acre 

upper end of the ODMDS was incorporated into a 360-acre disposal area designated under 

Section 404 of the Clean Water Act for placement of dredged material for creation of islands 

for colonial nesting seabirds. Beginning with the 1991 maintenance event and during 

subsequent annual maintenance events, dredged material from the bar channel suitable for 

stacking has been used beneficially by deposition in the Section 404 site. Material not suitable 

for beneficial use has been placed in the ODMDS.
13 

Historical use of the ODMDS-East between 1973 and 2002 are depicted in Table 1. Available 

maintenance dredging contract information does not distinguish dredging work performed 

between the ARBC and other Atchafalaya River dredging reaches prior to 1973, therefore, 

disposal information prior to 1973 is not included. Historically, the ODMDS-East has received

dredged material from the ARBC via a cutterhead hydraulic pipeline dredge, discharging

directly into the site.

Table 2. Disposal History of ODMDS-West

Date of Disposal Operation Disposal 

Method Reach Dredged Volume Placed 

Start Finish (cubic yards)

21-Aug-02 27-Oct-02 Unconfined Sta. 650 to Sta. 1340 6,797,817

24-Nov-02 12-Feb-03 Unconfined Sta. 776 to Sta. 1355 9,125,381

10-Nov-03 12-Feb-04 Unconfined Sta. 650 to Sta. 1353 9,099,924

9-Apr-04 21-May-04 Unconfined Sta. 650 to Sta. 1216 5,720,499

8-Jan-05 27-Apr-05 Unconfined Sta. 650 to Sta. 1355 12,917,556

3-May-06 5-Jul-06 Unconfined Sta. 650 to Sta. 1355 8,168,569

4-Feb-07 27-Apr-07 Unconfined Sta. 650 to Sta. 1339 8,576,338

20-Jul-07 10-Dec-07 Unconfined Sta. 695 to Sta. 1244 6,261,539

17 Jun-08 26-Sep-08 Unconfined Sta. 650 to Sta. 1270 9,545,797

26-Aug-09 15-Jun-10 Unconfined Sta. 650 to Sta. 1355 11,246,103

8 Oct 10 11 Feb 11 Unconfined Sta. 650 to Sta. 1355 9,230,662

8 Aug 11 23 Sep 11 Unconfined Sta. 650 to Sta. 1355 319,179

27 Sep 11 18 Nov 11 Unconfined Sta. 650 to Sta. 1355 372,457

TOTAL 97,381,821

AVERAGE PER FISCAL YEAR CYCLE 10,820,202

2.4.5 Historical Use of ODMDS-West

The ARBC ODMDS-West has been used for disposal of dredged materials since 2002 under 

the authority of MPRSA Section 103 (b). As described in the “Draft Environmental Impact

Statement, Atchafalaya River Bar Channel, ODMDS-West Environmental impact Statement, St.

Mary Parish, Louisiana,” (EPA 2013) the proposed ARBC ODMDS-West was evaluated for the

continued placement of maintenance dredged material originating from the ARBC, at an

approximate average volume of 10.8 million cy per dredging cycle (Table 2). The ODMDSWest is situated in a high-energy erosional zone and can generally accept large volumes of

dredged material with little apparent net change to the bottom. The dredged material discharged

into this site will disperse relatively quickly because of the high percentage of fine grain

components and because of the location of the site in a high energy, nearshore area where

waves, currents, winds, and tides constantly mix and redistribute sediments, and thus, the 

dredged material, over a wide area. The site is situated within the inlet zone and is adjacent to

the channel, providing easy access for dredged material placement operations and reduced costs.

The size of the ODMDS-West was determined based upon: 1) the need to maximize the 

discharge distance away from the ARBC to minimize the run back of the deposited dredged
14 

material into the channel; and 2) the need to allow for adjacent pumping of the dredged material

from within the reaches of the ARBC. As a result, the dimensions of the proposed ODMDSWest were determined to be 16.0 miles long and 3.0 miles wide (typically the pumping distance

at which a hydraulic pipeline cutterhead suction dredge may no longer be cost effective without 

a booster pump, depending on the size of the dredge).

The ODMDS-West has received approximately 10.8 million cubic yards (mcy) per fiscal year 

dredging cycle at an average frequency of once every 7.4 months. This frequency and volume 

is expected to continue into the future. Material is dredged from the ARBC via a cutterhead 

hydraulic pipeline dredge, discharging no closer than 5,000 feet from the ARBC centerline in 

an effort to limit run-back of fluff material into the channel. Dredged volumes since 2002 are 

depicted in Table 2. 

Table 3: Sediment Composition

LOCATION % SAND % SILT % CLAY

Channel 9.5 82.6 6.9

ODMDS-West 13.6 28.7 57.7

ODMDS-East 44.6 33.1 22.3

Reference Area 8.0 80.9 11.1

2.5 Dredged Material Volumes

Since 1973, the ARBC has been dredged every year except 1975, 1977, 1978, 1980, and 1982, 

with the dredged material placed at the ODMDS-East, ODMDS-West, Bird Island-East (Section

404), and/or Bird-Island-West (Section 404). Both Bird Island-East and Bird Island-West are

Clean Water Act Section 404 designated dredged material disposal sites, abutting the northern 

boundary of the ODMDSs (Figure 2).

Since 1973, the annual quantity of material placed at either ODMDS has ranged from about 3.6

million cy to about 18 million cy, or averaging approximately 8.3 million cy for the ODMDS-East 

and 10.8 million cy for the ODMDS-West per fiscal year when maintenance dredging is 

required. The dredged material originating from the ARBC is predominantly made up of silts

with traces of sand and clay (Table 3), as confirmed from samples collected in February 2008 

(PBS&J, 2008). It is anticipated that annual maintenance of the ARBC will continue in the 

future as authorized channel dimensions will need to be maintained.

Table 4: Sediment Quality Assessment History

Date Type of Testing Reference

December 1996 Bulk Analyses & Toxicity Assessment EH&A, 1997

April 2002 Bulk Analyses, Toxicity, & Bioaccumulation Assess PBS&J, 2002

February 2008 Bulk Analyses, Toxicity, & Bioaccumulation Assess PBS&J, 2008

2.6 Dredged Material Suitability

On September 24, 1992, a RIA was executed between USEPA Region 6 and USACE-MVN

(USEPA/USACE, 2003). The RIA was revised and updated, and a new RIA issued November 3, 

2003. This RIA described protocols for evaluating the quality of the dredged material and
15 

implementation of the “GREEN BOOK” (USEPA/USACE, 1991). These protocols describe 

chemical parameters to be analyzed, as well as required detection limits. It also specifies how 

toxicity testing and bioaccumulation assessments are to be conducted, as well as organisms to be 

utilized. Since that time, all sediment evaluations have been conducted in accordance with the 

RIA. The dredged material from the ARBC has been evaluated several times to determine

suitability for offshore placement. This testing was performed to determine levels of metals and

organic constituents, as well as toxicity and bioaccumulation assessments. A history of the testing

performed on sediments destined for placement in the ODMDS-East and ODMDS-West is

summarized in Table 4. The results of the testing indicated that the material was suitable for

offshore placement without special management or handling during disposal operations. 

2.7 Anticipated Site Use

Maintenance dredging of the ARBC is required on an annual basis. Dredged material is 

typically removed using hydraulic cutterhead pipeline dredges and discharged as non-cohesive 

slurry though a floating pipeline. It is anticipated that if dredged material is removed by hopper 

dredge the material will be primarily discharged by agitation. It is anticipated that annual 

maintenance of the ARBC and disposal of dredged material into the ODMDS-East and the 

ODMDS-West will continue in the future. On the average, approximately 10.8 million cy of 

dredged material will be placed at the ODMDS-West and/or the ODMDS-East per fiscal year 

dredging cycle, estimated to be once every 7.4 months. 

2.8 Special Management Conditions or Practices

As previously discussed, evaluations of sediment quality have indicated that the material from

the channel is suitable for offshore placement. However, all operations shall be conducted such

that the dredged material remains within the bounds of the ODMDSs immediately following

descent to the ocean floor, and placed in a location to minimize return of the placed material

back into the ARBC. The 2003 fluid mud study found that sediment from the ARBC predominantly 

drifted to the northwest; therefore, when using the ODMDS-West, placement of dredged material no 

closer than 5,000 feet from the ARBC centerline is required for the greatest possible reduction of 

sediment runback into the channel while minimizing dredging cost increases associated with the 

addition of longer lengths of discharge pipeline. During disposal operations, a baffle plate may be 

positioned on the end of the discharge pipeline to ensure placement of dredged material within the 

western most portions of the designated boundary of the ODMDS. 

A seasonal hopper dredging restriction has been recommended by the National Marine Fisheries

Service (NMFS, 2007) during formal consultation undertaken pursuant to Section 7 of the 

Endangered Species Act. This restriction was based on potential impacts of hopper dredging

operations on several species of threatened and endangered sea turtles. The recommendation is

to restrict hopper dredging to the period from December 1 through March 31, during which sea

turtle abundance is at a minimum in the Gulf of Mexico. This recommendation pertains, 

however, only to actual hopper dredging operations. Hopper dredging would be conducted in 

accordance with all reasonable and prudent measures and implementing terms and conditions 

described in the 2007 Gulf of Mexico hopper dredging regional biological opinion (NMFS, 

2007). Hydraulic cutterhead dredges are exempt from these sea turtle protection measures 

because their operations are not known to result in injuries to sea turtles. 
16 

Figure 1. Atchafalaya Bar Channel - ODMDS East and ODMDS West. (Source: PBS&J 2008)
17 

3.0 SITE MONITORING

The MPRSA establishes the need for including a monitoring program as part of the Site 

Management and Monitoring Plan. Site monitoring is conducted to ensure the environmental 

integrity of a disposal site and the areas surrounding the site and to verify compliance with the 

site designation criteria, any special management conditions, and with permit requirements. 

Monitoring programs should be flexible, cost effective, and based on scientifically sound 

procedures and methods to meet site-specific monitoring needs. 

The intent of the monitoring program is to provide the following: 

1. Information indicating whether the disposal activities are occurring in compliance with 

the permit and site restrictions; 

2. Information indicating short-term and long-term fate of materials disposed of in the 

marine environment 

3. Information concerning the short-term and long-term environmental impacts of the 

disposal. 

The primary purpose of the Site Management and Monitoring Program is to determine whether 

dredged material site management practices, including disposal operations, at the sites need to 

be changed to avoid unreasonable degradation or endangerment of human health or welfare or 

the marine environment. Monitoring results will be used for making decisions, preventing 

unacceptable adverse effects beyond each site’s boundary, and ensuring regulatory compliance 

over the life of the ODMDS East and West. Emphasis will be placed on determining physical 

impacts, since, to date, dredged material from the ARBC has been determined to be acceptable 

for ocean placement; however, consideration of contaminants will also be included. 

Testing of dredged material is conducted based on “GREENBOOK” and RIA procedures; 

however it is necessary to verify the decisions made regarding the suitability of the dredged 

material are correct and that the material is not having an adverse impact to the environment. 

The size and location of the ARBC ODMDS East and West were determined pursuant to the 

General Criteria as listed in 40 CFR 228.5, and the Specific Criteria at 40 CFR 228.6(a). There 

are no significant environmental resources delineated within or immediately outside of the 

ODMDS East and West. The primary concern regarding ODMDS use is the potential for shortterm build up of dredged material, such that a hazard to navigation is presented. Since these

sites are dispersive in nature, it is expected that material will eventually be transported outside 

of the site boundaries. It is also expected that this material will not move in distinct mounds, 

but instead will blend with the surrounding environment causing a progressive transition to 

sediment containing a higher percentage of silt and clay. 
18 

Figure 2. Atchafalaya Bar Channel - Disposal Sites (coordinate system = NAD83).
19 

Discharges of dredged material outside of the ODMDS East and West boundaries will be 

treated as “unauthorized discharges.” Such discharges may occur as a result of dredging 

equipment malfunction during dredging operations with spillage of material outside of the 

ODMDS boundaries, or discharge of dredged material in close proximity to an ODMDS 

boundary such that it falls outside of the site during descent to the seafloor. While significant 

environmental resources were not identified immediately outside of the ODMDS East and West 

boundaries during site designation evaluations, unauthorized discharges may be detrimental to 

immobile or slow moving benthic organisms. A laboratory study conducted by Maurer et al. 

(1978) suggested that benthic organisms can burrow through 6-9 inches of dredged material 

without significant impacts to the benthic community. The formation and persistence of 

mounds above this 6-9 inch threshold, as a direct result of unauthorized discharges outside of 

the ODMDS boundaries, warrants additional investigation to determine if benthic communities 

have been adversely impacted.

3.1 Baseline Monitoring

Table 5 summarizes various site characterization surveys of the ODMDS-East and ODMDSWest conducted by the USACE, EPA, and others as part of the designation process and 

subsequent monitoring to evaluate the dredge material management effectiveness for the 

ODMDS East and West. These surveys will serve as the main body of data for future 

monitoring of the impacts associated with the use of the ARBC ODMDS East and West. 

3.2 Disposal Monitoring

The MVN will monitor and record the location of discharge points during dredging and 

disposal operations. At a minimum, the following information will be documented: 

a) Disposal vessel name 

b) Location of disposal points 

c) Estimated volume dispersed at disposal points 

d) Description of material disposed

e) Source of Dredged Material

f) Date, time and location at start of initiation and completion of disposal event 

All data will undergo appropriate Quality Assurance / Quality Control procedures, such that 

compiled information accurately captures dredging and disposal operations. Currently, the best 

available sources of data for cutterhead dredges are the contractor-furnished As-Built Drawing 

and Narrative Completion Report. When available, data from other cutterhead dredge 

monitoring systems (similar to those available for hopper dredges through the USACE 

Dredging Quality Management Support Center) will be used to supplement or in place of 

contractor-furnished data. Dredging and disposal data will be provided to the EPA R6 in the 

Post-Disposal Summary Report described in Section 3.4 of this SMMP. Should an unauthorized 

discharge occur outside of the ODMDS, MVN will notify the EPA Region 6 within a 

reasonable period of time upon discovery of the event. 
20 

Table 5. Surveys Conducted at the Atchafalaya ODMDS-East and ODMDS-West

Survey/Study Site Date Conducted by Objectives Reference

Analyses of native water, bed material, and elutriate samples 

of major Louisiana waterways, 1975

ODMDS-East 1976 USGS Channel bed toxicity & elutriate sample 

assessment

Demas 1976

Analyses of native water and dredged material from southern 

Louisiana waterways, 1975-76

ODMDS-East 1977 USGS Dredged material toxicity assessment Demas and 

Higgins 1977

Analyses of native water, core material, and elutriate 

samples collected from the Atchafalaya River and 

Atchafalaya Bay

ODMDS-East 1977 USGS Channel bed core material toxicity & 

elutriate sample assessment

Demas 1977

Bioassay and bioaccumulation testing of proposed dredge 

sediments in the Atchafalaya River, Louisiana

ODMDS-East Mar 1979 ERT Bioaccumulation and bioassay assessment Drawas et al. 

1979a

Bioassay testing of proposed dredge sediments in the 

Atchafalaya River, Louisiana

ODMDS-East June 

1979

ERT Bioassay assessment Drawas et al. 

1979b

Analyses of native water, bottom material, elutriate samples, 

and dredged material from selected southern Louisiana 

waterways and selected areas in the Gulf of Mexico, 1979-81

ODMDS-East 1983 USGS Dredged material toxicity assessment & 

elutriate sample assessment

Lurry 1983

Report of Field Study ODMDS-East 1983 IEC Acquire data for final site designation –

water, sediment, biological, and tissue 

analyses

IEC 1983

National Oceanic Survey Chart 11351 – Port au Fer to Marsh 

Island

ODMDS-East 1989 DOC, NOAA, 

NOS

Establish bathymetry for safe navigation DOC, NOAA, 

NOS 1989

Draft data report: results of toxicity tests on sediments 

collected from dredged navigation channels along the 

Louisiana Coast

ODMDS-East 1990 EPA, ERLN Bulk chemistry & toxicity analysis Dettmann 

and Tracey 

1990

Contaminant Assessment ODMDS-East Mar 1991 Anacon Water & elutriate analysis n/a

Benthic macrofaunal community structure in ocean dredged 

material disposal sites in Louisiana: Preliminary analysis

ODMDS-East 1994 EPA Water quality, sediment, toxicity, benthos Flemer et al. 

1994

Region VI Contaminated Sediment Study – Phase III ODMDS-East, 

ODMDS-West

June/July 

1996

Battelle Bulk sediment, toxicology, benthics, fish 

community, and tissue analysis in ODMDS 

and reference sites

Trulli 1996

Recommendations for Reduction of shoaling in the 

Atchafalaya River navigation bar channel

Bay, Channel 2000 Louisiana 

State 

University

Study of the nature and seasonality of fluff, 

and its response to ship traffic

van Heerden 

and Kemp 

2000

Factors affecting fluff and fluid mud accumulation in the 

Atchafalaya Bar Channel

Bay, Channel 2003 USACE Effects of disposal site location, channel 

enlargement, and structural measures on 

shoaling in the channel

Teeter et al. 

2003

Atchafalaya Bar Channel Fluff & Fluid Mud Study Bay, Channel Dec 2003 USACE, GVI Analysis of fate and transport pathways of 

fluid mud/fluff to determine appropriate 

management alternatives

GVI 2003

Silt sediment transport study to investigate fate and efficiency 

of dredging and characterization of lateral dredge disposal 

sites

ODMDS-East, 

ODMDS-West

2006 ETS Silt tracer study using fluorescents to 

evaluate effectiveness of dustpan dredging

ETS 2006
21 

3.3 Bathymetric Surveys

3.3.1 Routine Bathymetric Surveys

The ODMDS-West and the ODMDS-East are both located outside of the safety fairway for 

large vessel traffic, therefore, the mounding will be considered in regard to shallow-draft 

vessels, only. Since the sites are dispersive, movement of material from the site is expected to 

occur after disposal operations cease. It is expected that the material will not move in distinct 

mounds, but instead will blend with the surrounding environment causing a progressive 

transition to sediment containing a higher percentage of silt and clay. Considering the grain-size 

characteristics of typical maintenance dredged material from this channel, significant mounding 

is not expected subsequent to discharge operations. The threshold elevation for mounding of 

dredged material within the ODMDS East or West will be five (5) feet above the existing 

bottom elevation while maintaining at least two (2) feet of clearance between the top of the 

mound and the water’s surface. 

Discharge of dredged material in close proximity to an ODMDS boundary may result in a 

portion of the material falling outside of the ODMDS during descent to the seafloor. That 

portion of dredged material falling outside of the ODMDS during descent would be considered 

an unauthorized discharge. Such an unauthorized discharge may produce a mound that is 

partially within the ODMDS and partially outside of the ODMDS. For discharge points 

documented within 500 feet of an ODMDS boundary, the presence of a distinct seafloor mound 

– either in excess of 1 foot above background variation observed along a survey transect line 

that bisects the mound; or 6-9 inches above background variation on a transect line along the 

ODMDS boundary and parallel to the discharge point – may indicate that dredged material was 

partially discharged outside of the ODMDS. 

Bathymetric surveys will be used to monitor for mounding to ensure a navigation hazard is not 

produced, help determine if dredged material was discharged outside of the ODMDS 

boundaries, to assist in verification of material placement, and to monitor bathymetry changes 

and trends. Results from post and pre dredge bathymetry shall be provided to EPA Region 6 

when completed as part of the summary report (See Section 3.4).

Bathymetric surveys for each ARBC maintenance dredging contract will be obtained before the 

start of disposal operations, and within 45 days following completion of disposal operations. 

Bathymetric surveys shall be conducted by the MVN or site user along transects within the 

ODMDS. These transects shall primarily be oriented parallel to the channel and centered on the 

areas of discharge in the ODMDS (approximately 5,000 feet west of the channel centerline for 

the ODMDS West, and approximately 4,500 feet east of the channel centerline for the ODMDS 

East). Additional bathymetric survey transects will be performed parallel to, and 1,000 feet east 

and west of, these discharge-centered survey transect lines. The spacing of the transect line 

nearest to the ODMDS boundary may be adjusted to fall within or along the boundary line (i.e., 

less than 1,000 feet from the discharge-centered transect line).

The minimum performance standards from table 3-1 in Hydrographic Surveying shall be 

followed. Horizontal location of the survey lines and depth sounding points will be determined 

by an automated positioning system utilizing a differential global positioning system. The 
22 

vertical datum will be referenced to prescribed NOAA Mean Lower Low Water (MLLW) 

datum. The horizontal datum should be referenced to the local State Plane Coordinate System 

(SPCS) for that area or in Geographical Coordinates (latitude-longitude). The horizontal 

reference datum should be the North American Datum of 1983 (NAD 83). 

Bathymetric surveys shall be obtained using a USACE or contract survey vessel equipped with 

electronic surveying capabilities. The vessel must be equipped with positioning equipment with 

a horizontal precision of one (1) to three (3) meters. The fathometer, which shall display realtime depth on real-time location, must have a precision of approximately 0.5 feet. All data shall 

be collected using methodology described in Engineer Manual EM 1110-2-1003, dated January 

1, 2002 [http://140.194.76.129/publications/eng-manuals/em1110-2-1003/toc.htm]. 

Data Analysis

• If deposited dredged material is not mounding to heights greater than the 5-foot 

threshold height above the existing bottom elevation, while maintaining at least 2 feet of 

clearance between the top of the mound and the water’s surface, and there is no 

evidence of a significant discharge of dredged material outside of the ODMDS 

boundaries, then the management objectives are met.

• If mounding heights within the ODMDS exceed the safe navigation threshold (mounds 

greater than 5 feet high or with less than 2 feet of clearance from the water’s surface); or 

there is evidence of an unauthorized discharge (known discharge point within 500 feet 

of an ODMDS boundary and associated distinct mound with a height in excess of 1 foot 

within the ODMDS or 6-9 inches along the ODMDS boundary), subsequent advanced 

bathymetric surveys of the affected area will be performed to monitor mound dispersion 

or persistence. If these bathymetric surveys indicate that the dredged material has

dispersed, no further action is necessary. However, should the surveys indicate that a 

dredged material mound is persistent, MVN and EPA Region 6 will develop appropriate 

management actions. Such actions could include notifying mariners of a hazard, 

modifying future disposal operations to reduce the likelihood of mound formation, 

expansion or relocation of the ODMDS, or physically altering the mound. 

3.3.2 Bathymetric Surveys Conducted for Unauthorized Discharges

Discharges of dredged material outside of the ODMDS East and West boundaries will be 

treated as “unauthorized discharges”. Such discharges may occur as a result of dredging 

equipment malfunction during dredging operations with spillage of material outside of the 

ODMDS boundaries, or discharge of dredged material in close proximity to an ODMDS 

boundary such that it falls outside of the site during descent to the seafloor. In the event of an 

unauthorized discharge outside of the ODMDS, bathymetric surveys will be conducted to 

identify the extent of the affected area or estimate the quantity of dredged material associated 

with the discharge. In such situations, joint discussions between EPA Region 6 and MVN will 

determine management actions appropriate to resolve the unauthorized discharge. 
23 

Table 6. ARBC ODMDS Monitoring Strategies and Action Thresholds

Goal Technique Sponsor Rationale Frequency Action Threshold Management Options

Threshold Not Exceeded Threshold Exceeded

Monitor 

Bathymetric 

Trends

Routine 

Bathymetric 

Survey

Contractor/

USACE

Determine the extent 

of the disposal mound 

and movement of 

material beyond limits 

of ODMDS

Pre and post 

disposal (45 

days) for 

significant 

projects 

(>50,000cy)

(1)Mounding >5 ft; <2 ft draft 

allowance in shallow waters

(2) Evidence of an 

unauthorized discharge 

outside of ODMDS boundary 

Continue Monitoring Initiate Advanced Bathymetric 

Surveys of the affected area.

Advanced 

Bathymetric 

Survey

Contractor/

USACE

Determine changes in 

dispersion of material 

until impacts are no 

longer observed

As Needed (1)Mounding > 5 ft; <2 ft draft 

allowance in shallow waters

(2) Persistence of a mound 

(limited or no dispersion 

observed between surveys)

Continue Monitoring Consider various management 

options, ex.

(1)Modify disposal 

method/placement 

(2)Restrict disposal volumes

(3) expansion of ODMDS

(4) relocation of ODMDS

Ensure Safe 

Navigation 

Depth

Bathymetry Contractor/

USACE

Determine height of 

mound 

Post disposal 

(45 days) for 

significant 

projects 

(>50,000cy) 

Mound height >5 ft; <2 ft draft 

allowance in shallow waters

Continue Monitoring (1)Modify disposal 

method/placement 

(2)Direct disposal operators to 

avoid areas shallower than XX 

feet

(3)Physically level material 

shallower than 2 feet 

(4)Notify mariners of mound 

location and depth 

Project Disposal 

Monitoring

Post Disposal 

Summary 

Report

Contractor/

USACE

(1) Ensure

management 

requirements are 

being met;

(2) to assist in site 

monitoring

90 days after 

project 

completion

Disposal records required by 

SMMP are not submitted or 

are incomplete

Continue monitoring Request extension from EPA 

Region 6

ODMDS Trend 

Assessment

Water and 

Sediment 

Quality, 

Benthic 

Community 

Analysis 

(40CFR228.13) 

EPA Periodically evaluate 

the impact of disposal 

on the marine 

environment (40CFR 

228.9) 

Approximately 

every 10 years 

as funding

allows. 

(1) Absence from the site of 

pollution sensitive biota

(2) Progressive non-seasonal 

changes in water or sediment 

quality

Continue Monitoring (1)Conduct Environmental 

Effects Monitoring or 

Advanced Environmental 

Effects Monitoring 

(2)Review dredged material 

evaluation procedures

(3)Consider isolating dredged 

material (capping)
24 

Table 6 (continued). ARBC ODMDS Monitoring Strategies and Action Thresholds

Goal Technique Sponsor Rationale Frequency Action Threshold Management Options

Threshold Not Exceeded Threshold Exceeded

Environmental 

Effects 

Monitoring

Chemical 

Monitoring

EPA Determine if chemical 

contaminants are 

significantly elevated1

within and outside of 

site boundaries

Implement if 

(1) disposal 

footprint 

extends

significantly

beyond the 

site 

boundaries; or

(2) if Trend 

Assessment 

results warrant

Contaminants are found to be 

elevated1

Discontinue monitoring (1)Institute Advanced 

Environmental Effects 

Monitoring

(2)Implement case specific 

management options (ie. 

Remediation, limits on 

quantities or types of material)

Benthic 

Monitoring

Determine whether 

there are adverse 

changes in the benthic 

populations outside of 

the site and evaluate 

recovery rates

Adverse changes observed 

outside of the site that may 

endanger the marine 

environment

Advanced 

Environmental 

Effects 

Monitoring

Tissue 

Chemical 

Analysis

EPA Determine if the site is 

a source of adverse 

bioaccumulation 

which may endanger 

the marine 

environment

Implement if 

Environmental 

Effects 

Monitoring 

warrants

Benthic body burdens and risk 

assessment models indicate 

potential for food chain 

impacts

Discontinue monitoring (1) Discontinue site use

(2)Implement case specific 

management options (ie. 

Remediation, limits on 

quantities or types of material)

Benthic 

Monitoring

Determine if the site is 

a source of adverse 

sub-lethal2 changes in 

benthic organisms 

which may endanger 

the marine 

environment

Sub-lethal effects are 

unacceptable

1. Significantly elevated: Concentrations above the range of contaminant levels in dredged sediments that the Regional Administrator and the District Engineer found to be suitable for disposal at 

the ODMDS.

2. Examples of sub-lethal effects include without limitation the development of lesions, tumors, development abnormality, and/or decreased fecundity.
25 

3.4 Reporting and Data Formatting 

3.4.1 Project Initiation and Unauthorized Discharge Reporting. 

MVN should notify EPA within 15 days prior to the beginning of a dredging cycle or project 

disposal. Should an unauthorized discharge occur outside of the ODMDS boundaries, MVN 

will notify EPA Region 6 via email within a reasonable period of time upon discovery of the 

event.

3.4.2 Post Disposal Summary Report

A Post Disposal Summary Report will be provided to EPA Region 6 within 90 days after 

project completion (see Section 3.2). 

The report should include the following: 

• dredging project title; 

• permit number and expiration date (if applicable); 

• contract number; 

• name of contractor(s) conducting the work, 

• name and type of vessel(s); 

• disposal timeframes for each vessel; 

• estimated dredged material volumes placed, 

• disposal event dates and locations; 

• dates of pre- and post-disposal bathymetric surveys of the ODMDS; and 

• a narrative discussing MVN’s investigation of any unauthorized discharges. 

The report will be in the form of a narrative with the following sections: 1) introduction, 2) 

description of dredging and disposal operations, 3) description of pre- and post-disposal 

bathymetry including synopsis of findings, and 4) a summary. The summary will include a 

table with the following columns: ID (row identifier), ODMDS, Date of Disposal, Gross Cubic 

Yards Placed, and Discharge Location (Latitude (North) and Longitude (West). The narrative 

should also include relevant figures or maps (depicting all discharge points) that support 

MVN’s interpretation of project data. As-Built drawings with detailed construction information 

will be provided on CD. 

If applicable, the report should also include a narrative discussing any unauthorized discharges, 

indicate the time it occurred and when it was reported to the EPA Region 6, discuss the 

circumstances surrounding the discharge, and identify specific measures taken to prevent 

reoccurrence.

3.5 Summary of Past Monitoring Survey Results 

Previous surveys conducted regarding the Atchafalaya ODMDS-East and ODMDS-West are 

listed in Table 5. Results from investigations presented in the ODMDS East EIS, the ODMDS 

West EIS, and subsequent surveys will serve as a baseline for the monitoring of impacts from 

placement of dredged material within the ARBC ODMDS East and West locations. The 

existing data consists of multidisciplinary analyses including, but not limited to: water and 

sediment chemistry, sediment mapping, bathymetry, physical oceanographic conditions, and 
26 

biological studies related to benthic macroinvertebrates and fisheries. No adverse impacts to 

aquatic life have yet to be observed within the ODMDS or surrounding area. 

3.6 Environmental Effects Monitoring Reporting

Other federal and state agencies, academia, and non-government organizations conduct 

research in the Atchafalaya Bay. EPA Region 6 and MVN will periodically review the findings 

of these groups or request data that are relevant to the navigation channel, ODMDS, and project 

area to improve our understanding of site environs. Conversely, EPA Region 6 and MVN 

should make every effort to provide project reports and data to interested parties upon request. 

New or existing information that is relevant to management of the ODMDS should be 

incorporated into future versions of this SMMP. 

3.7 Future Monitoring Efforts

Changes in bathymetry at the ODMDS East or West will continue to be monitored in 

accordance with Section 3.3. Additionally, trend assessment surveys of the sediment, benthos 

and water column will continue to be performed periodically (approximately every 10 years) by

EPA as budgets allow. Should future disposal at the ODMDS East or West result in 

unacceptable adverse impacts, further studies may be required to determine the persistence of 

these impacts, the extent of the impacts within the marine system, and/or possible means of 

mitigation. In addition, the management plan presented may require revision based on the 

outcome of any monitoring program. 

4.0 SITE MANAGEMENT PLAN REVIEW AND REVISION

Pursuant to Section 102(c) of the MPRSA, as amended by WRDA 1992, the SMMP for the 

ARBC ODMDS East and West will be reviewed not less frequently than 10 years after adoption 

and every 10 years, thereafter.

Modifications or updates to the SMMP may be necessary, based on scheduled reviews, as 

specific needs are identified for the project, and/or if results from monitoring surveys or reports 

indicate that continued use of the ODMDS-East or -West would lead to unacceptable 

environmental impacts. 

Modifications or updates to the SMMP may be proposed by the MVN or EPA Region 6. 

Following a 30-day review period of the proposed changes(s), the modifications may be 

incorporated into the plan by mutual consent of both agencies.

5.0 IMPLEMENTATION

This plan is effective from the date of signature for a period not to exceed 10 years as outlined 

in Section 3.4. 
27 

6.0 REFERENCES

Anacon. 1991. Water & Elutriate Analysis. Prepared for United States Army Corps of 

Engineers, New Orleans District, March 1991. 

Demas, C.R., 1976, Analyses of native water, bed material, and elutriate samples of major 

Louisiana waterways, 1975: U.S. Geological Survey Open-File Report 76-853, 304 p. 

Demas, C.R., and Higgins, P.C., 1977, Analyses of native water and dredged material from 

southern Louisiana waterways, 1975-76: U.S. Geological Survey Open-File Report 77-

503, 180 p. 

Demas, C.R., 1977, Analyses of native water, core material, and elutriate samples collected 

from the Atchafalaya River and Atchafalaya Bay: U.S. Geological Survey Open-File 

Report 77-769, 17 p. 

Dettmann, E. H. and G. Tracey. 1990. Draft data report: results of toxicity tests on sediments 

collected from dredged navigation channels along the Louisiana Coast. U. S. 

Environmental Protection Agency, Office of Research and Development, 

Environmental Research Laboratory,-Narragansett, Narragansett, Rhode Island. 

Department of Commerece, National Oceanic and Atmospheric Administration, National 

Ocean Survey. 1989. NOS Chart 11351 (Point au Fer to Marsh island). National 

Oceanic and Atmospheric Administration, Washington, DC. 

Drawas, N. M., E. S. Iley, Jr., and R. D. Jones. 1979a. Bioassay and bioaccumulation testing of 

proposed dredge sediments in the Atchafalaya River, Louisiana. Summer. 

Environmental Research & Technolocy, Inc., Concord, MA. Prepared for United States 

Army Corps of Engineers, New Orleans District, Contract No. DACW29-78-D-0220. 

Drawas, N. M., E. S. Iley, Jr., and R. D. Jones. 1979b. Bioassay testing of proposed dredge 

sediments in the Atchafalaya River, Louisiana. Winter. Environmental Research & 

Technolocy, Inc., Concord, MA. Prepared for United States Army Corps of Engineers, 

New Orleans District, Contract No. DACW29-78-F-0220. 

Environmental Tracing Systems Ltd (ETS). 2006. Silt Sediment Transport Study to Investigate 

Fate and Efficiency of Dredging and Characterization of Lateral Dredge Disposal Sites: 

Tracer Report A. Atchafalaya River and Bayous Chene, Boeuf, and Black, Atchafalaya 

Bar Channel, St. Mary Parish, Louisiana. Prepared for the U.S. Army Engineer District, 

New Orleans, New Orleans, Louisiana, Mississippi Valley Division. 99 pp. 

Espey, Houston & Associates, Inc. (EH&A). 1997. Atchafalaya River and Bayous Chene,

Bouef, and Black, Louisiana Contaminant Assessment, Prepared for the U.S. Army

Corps of Engineers, New Orleans District, February 1997. 
28 

Flemer, D. A., J. P. Patrick, Jr., J. R. Clark, B. F. Ruth, C. M. Bundrick, and G. Gaton. 1994. 

Benthic macrofaunal community structure in ocean dredged material disposal sites in 

Louisiana: Preliminary analysis. Final Report: November 1994. Submitted to U. S. 

Environmental Protection Agency, Region VI, Dallas, TX. 

GeoVal, Inc. 2003. Atchafalaya Bar Channel Fluff & Fluid Mud Study, Morgan City, 

Louisiana. Prepared for the U. S. Army Corps of Engineers, New Orleans District, 

December 2003. 145 pp. 

Interstate Electronics Corporation (IEC). 1983. Report of Field Survey. Appendix A, Draft 

Environmental Impact Statement, Atchafalaya River Bar Channel Ocean Dredged 

Material Disposal Site Designation. Environmental Protection Agency, Office of Water 

Criteria and Standards Divison. 50pp. 

Lurry, D.L., 1983, Analyses of native water, bottom material, elutriate samples, and dredged 

material from selected southern Louisiana waterways and selected areas in the Gulf of 

Mexico, 1979-81: U.S. Geological Survey Open-File Report 82-690, 105 p. 

Maurer, D. L., R. T. Kleck, J. C. Tinsman, W. A. Leathem, C. A. Wethe, M. Huntzinger, C. 

Lord, and T. M. Church. VERTICAL MIGRATION OF BENTHOS IN SIMULATED 

DREDGED MATERIAL OVERBURDENS VOL. I: MARINE BENTHOS. University 

of Delaware, Lewas, DE.. Prepared for the U. S. Army Corps of Engineers, Chief of 

Engineers, Washington, D. C. 

National Marine Fisheries Service (NMFS). 2007. Revision 2 to the November 19, 2003 

Biological Opinion concerning Dredging of Gulf of Mexico Navigation Channels and

Sand Mining (“Borrow”) Areas Using Hopper Dredges by COE Galveston, New

Orleans, Mobile, and Jacksonville Districts (Consultation Number F/SER/2000/01287). 

PBS&J. 2002. Atchafalaya River and Bayous Chene, Bouef, and Black, LA Contaminant 

Assessment, Prepared for the U.S. Army Corps of Engineers, New Orleans District,

August 2002. 

PBS&J. 2008. Atchafalaya River and Bayous Chene, Bouef, and Black, Louisiana - Bar

Channel Contaminant Assessment, Prepared for the U.S. Army Corps of Engineers,

Galveston District and New Orleans District, June 2008. 

Teeter, A.M., T. Fagerburg, T. Waller, H. Benson, D. Brister, and R. McAdory. 2003. Factors 

Affecting Fluff and Fluid Mud Accumulation in the Atchafalaya Bar Channel Final 

Draft. Prepared for the U.S. Army Engineer District, New Orleans, New Orleans, 

Louisiana. 98 pp with additional plates and appendix. 

Trulli, W. R. 1996. Region VI sediment study, Phase III. Prepared for U. S. Environmental 

Protection Agency. Battelle Ocean Sciences, Duxbury, MA. 
29 

U.S. Army Corps of Engineers. 1996. Site Management Plan for the Atchafalaya River Bar 

Channel Ocean Dredged Material Disposal Site. 18 pp. 

U.S. Environmental Protection Agency/U.S. Army Corps of Engineers (USEPA/USACE). 1991. 

Evaluation of Dredged Material Proposed for Ocean Disposal, Testing Manual (Green

Book). EPA-503/8-91/001. 201 pp. plus appendices. 

———. 1996. Guidance document for development of site management plans for ocean

dredged material disposal sites. Office of Water (4504F), Environmental Protection

Agency, Washington, D.C.

———. 2003. Regional Implementation Agreement for Testing and Reporting Requirements for

Ocean Disposal of Dredged Material Off the Louisiana and Texas Coasts Under Section

103 of the Marine Protection, Research and Sanctuaries Act. U.S. Environmental 

Protection Agency, Region 6 and U.S. Army Corps of Engineers, Galveston and New

Orleans Districts.

———. 2013.Draft Environmental Impact Statement for the Designation of the Atchafalaya 

River Bar Channel Ocean Dredged Material Disposal Site Pursuant to Section 102(c) of 

the Marine Protection, Research, and Sanctuaries Act of 1972, St. Mary Parish, 

Louisiana. 141 pp. 
APPENDIX B

Scoping Report
SCOPING REPORT

Designation of the Atchafalaya River Bar Channel

Ocean Dredged Material Disposal Site

Pursuant to Section 102 of the Marine Protection, 

Research, and Sanctuaries Act of 1972

St. Mary Parish, Louisiana

December 2011
1

SCOPING REPORT

Designation of the Atchafalaya River Bar Channel

Ocean Dredged Material Disposal Site

Pursuant to Section 102 of the Marine Protection, 

Research, and Sanctuaries Act of 1972

St. Mary Parish, Louisiana

November 2011

1.0 INTRODUCTION

The National Environmental Policy Act (NEPA) of 1969 established a nationwide policy to 

include in every recommendation or report on proposals for major Federal actions significantly 

affecting the environment, a detailed statement of the environmental impact of the proposed 

action. Such detailed statements are referred to as environmental impact statements (EIS).

The U.S. Environmental Protection Agency, Region 6 (EPA), in cooperation with the U.S. Army 

Corps of Engineers (USACE), New Orleans District (CEMVN), published a notice of intent 

(NOI) to prepare a draft EIS for the designation of an Ocean Dredged Material Disposal Site 

(ODMDS) in the Gulf of Mexico off the mouth of the Atchafalaya River, St. Mary, Louisiana.

The NOI was published in the Federal Register (Volume 76, Number 140) on July 21, 2011.

The EPA, Region 6, in accordance with EPA’s October 29, 1998 Notice of Policy and 

Procedures for Voluntary Preparation of National Environmental Policy Documents (63 FR 

58045), and in cooperation with CEMVN, will prepare an EIS for the designation of an ODMDS 

in the Gulf of Mexico off the mouth of the Atchafalaya River, St. Mary Parish, Louisiana. An 

EIS is needed to provide the information necessary to designate an ODMDS. The NOI was 

issued Pursuant to Section 102(c) of the Marine Protection, Research and Sanctuaries Act of 

1972 (MPRSA), and 40 CFR Part 228 (Criteria for the Management of Disposal Sites for Ocean 

Dumping).

The CEMVN and EPA are proposing the permanent designation of an ODMDS, pursuant to 

Section 102(c) of MPRSA, located in the Gulf of Mexico off the mouth of the Atchafalaya River, 

for the continued disposal of dredged material removed from the bar channel of the federallyauthorized and maintained project, Atchafalaya River and Bayous Chene, Boeuf, and Black, 

Louisiana. Since 2002, shoal material removed from the Atchafalaya River bar channel (ARBC) 

not suitable for beneficial use has been placed at a temporary ODMDS on the west side of the 

channel (the ODMDS-West) under the authority of Section 103(b) of MPRSA. In 2007, USACE 

requested, and received from EPA, a 5-year extension for the continued use of the MPRSA 

Section 103(b) ODMDS-West. The approval for ODMDS-West use is scheduled to expire in 
2

August 2012, at which time it can no longer receive shoal material dredged from the ARBC 

unless it is re-designated as a MPRSA Section 102(c) site by EPA.

The NEPA provides for an early and open public process for determining the scope of issues

(problems, needs, and opportunities), resources, impacts, and alternatives to be addressed in the 

EIS. This process is referred to as “scoping.” Scoping is used to: a) identify the affected public 

and agency concerns; b) facilitate an efficient draft EIS preparation process; c) define the issues 

and alternatives that will be examined in detail in the draft EIS; and d) save time in the overall 

process by helping to ensure that the draft statement adequately address relevant issues. Scoping 

is a process, not an event, or a meeting; it continues throughout the draft EIS process and may 

involve meetings, telephone conversations, and/or written comments. Scoping is a critical 

component of the overall public involvement program.

Scoping was accomplished by correspondence with affected Federal, State, tribal, and local 

agencies, and with anticipated interested parties. Appropriate Federal, State, tribal, and local 

entities were invited to participate as a cooperating agency. The scoping process was initiated 

with the publishing of the NOI in the Federal Register (Volume 76, Number 140) on July 21, 

2011. Scoping continued with the distribution of a scoping input request letter and project 

information package on September 15, 2011, followed by a 45-day scoping comment period.

This Scoping Report outlines the project background and scoping process to date, and 

summarizes the key issues identified by members of the public during the initial scoping period.

Section 6.0 of this report contains a detailed summary of comments received.

2.0 STUDY AUTHORITY

The authority for designation of ocean disposal sites is the MPRSA of 1972 (86 Stat. 10S2), as 

amended (33 U.S.C.A. 1401 et seq.). Title I of the MPRSA, which is the Act's primary 

regulatory section, authorizes the Administrator of the EPA to establish permit programs for 

ocean disposal of non-dredged materials (Section 102) and the Secretary of the Army acting 

through the USACE to establish permit programs for ocean disposal of dredged materials 

(Section 103). Title I also requires the EPA to establish criteria, based on the factors listed in 

Section 102(a), for the review and evaluation of permits under the EPA and USACE permit 

programs. Section 1 02( c) of Title I authorizes the EPA, considering criteria established 

pursuant to Section 102(a), to designate recommended ocean disposal sites or times for dumping 

of non-dredged and dredged materials. Section 103(b) of Title I of the MPRSA, as amended by 

Section 501 of the Water Resources Development Act of 1992 (P.L. 102-S80, October 31, 1992), 

authorizes the Secretary of the Army, with the concurrence of the Administrator of the EPA, to 

select an alternative ODMDS. The criteria and factors established in Section 102(a) relating to 

site selection are used in selecting the alternative site. Disposal of dredged material at the 

alternative site is limited to a period of 5 years unless the EPA pursuant to Section 102(c) 

subsequently designates the site. An ODMDS selected pursuant to Section 103(b) may continue 

for an additional 5 years if no other feasible disposal site has been designated by the EPA; the 

continued use of the alternative site is necessary to maintain navigation and facilitate interstate or 

international commerce; and the EPA determines that the continued use of the site does not pose 

an unacceptable risk to human health, aquatic resources, or the environment.
3

Construction and maintenance of the Federal navigation project, Atchafalaya River and Bayous 

Chene, Boeuf, and Black, Louisiana, was authorized by the Rivers and Harbors Act of 1968, House 

Document 155, 90th congress, 1st Session, which provides for the following plan of improvement: 

a) a channel 20 feet deep over a bottom width of 400 feet from the vicinity of the U.S.

Highway 90 crossing over Bayou Boeuf to the Gulf of Mexico via the Gulf Intracoastal 

Waterway (GIWW), Bayou Chene, the Avoca Island-Cutoff Bayou drainage channel, the 

Lower Atchafalaya River, and the existing project across Atchafalaya Bay to the 20-footdepth contour in the Gulf of Mexico. The channel width in Bayou Boeuf is reduced to 

300 feet where necessary because of industrial development on both sides of the bayou.

b) a 20-foot-deep by 400-foot-wide channel in Bayou Black and the GIWW from the 

major shipyard on Bayou Black at U.S. Highway 90 to Bayou Chene. Construction of the 

inland portions of Bayous Boeuf and Black was completed in June 1978. Construction of

the Bayou Chene and Avoca Island-Cutoff reach was completed in September 1981. The 

navigation channel is maintained to project dimensions of-24 feet MLG (2 feet of 

advanced maintenance plus 2 feet of allowable over-depth) by 400 feet.

3.0 PURPOSE AND NEED

The ARBC is located in an area of heavy sedimentation. The bed load fraction of the sediment 

carried by the Atchafalaya River is deposited mainly in Atchafalaya Bay, resulting in delta 

accretion and progradation. The ARBC must receive periodic maintenance dredging to ensure 

safe navigation access to Morgan City, the Gulf Intracoastal Waterway, and Bayous Chene, 

Boeuf, and Black from the Gulf of Mexico. Prior to 2002, shoal material that could not be used 

beneficially was placed at an existing MPRSA Section 102(c) site on the east side of the ARBC 

(the ODMDS-East). Concern has been expressed, and USACE studies have shown, that 

maintenance-dredged material—especially fluid mud, or “fluff—placed on the east side of the 

ARBC (particularly at the ODMDS-East) is rapidly transported back into the navigation channel 

by prevailing littoral currents. Following the MPRSA Section 103(b) designation of the 

ODMDS-West in 2002, the USACE, Engineering Research and Development Center, performed 

monitoring studies to determine whether placing maintenance-dredged material on the west side 

of the channel was more effective at reducing shoaling in the channel, thus, reducing the 

dredging frequency and costs. These studies found that while placing material on the west side of 

the ARBC did not eliminate shoaling, it did reduce runback of material into the channel, when 

compared to placing material on the east side of the channel. These findings were corroborated 

by the results of more recent studies on sediment transport in the project area performed on 

behalf of USACE in 2006.

The need for the proposed action (the permanent, MPRSA Section 102(c) designation of the 

ODMDS-West) is to reduce the amount and rate of shoal material runback into the ARBC (i.e., 

reduce the shoaling rate), and thus, decrease the overall annual maintenance dredging effort 

needed for the ARBC while providing vessels with a longer period of safe navigation access 

between maintenance dredging events.
4

4.0 PROPOSED ACTION

The USACE and EPA are proposing the permanent, Section 102(c) designation of the ODMDSWest for the disposal of maintenance-dredged material from the ARBC when ocean disposal is 

the preferred disposal alternative. The proposed Section 102(c) ODMDS-West retains the same 

width (3 miles) as the existing Section 103(b) ODMDS-West, but differs slightly at its upper 

end, resulting in an area only 16 miles [26 km (14 nautical miles)] long. The resulting reduced 

area of the proposed Section 102(c) ODMDS-West, then, is approximately 32,000 acres [129

km2 (50 square miles)]. The reduced size of the proposed Section 102(c) ODMDS-West would

accommodate the southwesterly expansion of an adjacent Bird Island disposal site that is 

currently used by USACE for beneficial use of maintenance-dredged material removed from the 

ARBC, pursuant to Section 404 of the Clean Water Act (CWA) of 1977, and that is currently 

proposed for expansion by USACE in a separate project (Proposed Expansion of Bird Island 

Placement Site - Public Notice mailed July 13, 2011). The continued progradation and accretion 

of the Atchafalaya Delta and related increases in the sediment bed load fraction (i.e., accelerated 

sedimentation) in nearshore portions of Atchafalaya Bay and the ARBC have allowed for 

additional beneficial use of maintenance-dredged material where practicable, and thus, the 

opportunity to expand the Section 404 Bird Island site in a southwesterly direction and into the 

footprint of the Section 103(b) ODMDS-West.

Coordinates of the four corners of the proposed Section 102(c) ODMDS-West are as follows: 

Northwest Corner - 29°22′06′′N, 91°27′38′′W; Northeast Corner - 29°20′30′′N, 91°25′13′′W; 

Southeast Corner - 29°09′16′′N, 91°35′12′′W; Southwest Corner - 29°10′52′′N, 91°37′33′′W.

Other site alternatives considered include the “no action” alternative, defined as not designating 

an ocean disposal site; non-ocean (beneficial use) placement alternatives; a nearshore area 

disposal site; a mid-shelf area disposal site; and a deepwater area disposal site. The goal of the 

site selection process is to select a location which minimizes the risk of harm to the marine 

environment and human health and facilitates the necessary dredging and subsequent placement 

of dredged sediments. The site must meet selection criteria specified in EPA’s Ocean Dumping 

Regulations. The preparation of an EIS is an integral part of the site designation process. The EIS 

will present information to evaluate the suitability of potential sites and disposal alternatives. It 

will be based on available information as well as new material developed specifically for this site 

designation and will succinctly document the considerations made in locating the ODMDS at a 

specific location.

5.0 SCOPING PROCESS

The NEPA affords all persons, organizations and government agencies the right to review and 

comment on proposed major Federal actions that are evaluated by a NEPA document. This is 

known as the “scoping process.” The scoping process is the initial step in the preparation of the 

EIS and will help identify (1) the range of actions (project, procedural changes) (2) alternatives 

(both those to be rigorously explored and evaluated and those that may be eliminated), and (3) 

the range of environmental resources considered in the evaluation of environmental impacts.
5

A Scoping Input Request Letter requesting comments regarding the scope of the study was sent 

to Federal, state, and local agencies; and interested groups and individuals on September 15, 

2011 (refer to Appendix A for the complete mailing list). Scoping comments were received by 

CEMVN and EPA over a 45-day period in response to the Scoping Input Request Letter.

This Scoping Report presents and summarizes the comments received following the publishing 

of the NOI on July 21, 2011, including the 45-day scoping comment period beginning September 

15, 2011 and ending October 31, 2011. The Scoping Report indicates where in the EIS individual 

comments would likely be addressed. The Scoping Report will be mailed out to all individuals 

and agencies that provided comments during the scoping period, and will also be appended to the 

draft EIS when that document becomes available. In addition, the Scoping Report can be viewed 

at the following web address: http://www.epa.gov/region6/water/ecopro/current_action.html.

6.0 SCOPING COMMENTS

Scoping comments document the public’s concerns about the scope of the proposed course of 

action as well as identify significant resources and suggested alternatives. Scoping comments 

will be considered during the study process and in preparation of the draft EIS. A total of 11

written comments were received during the scoping period. Letters were received from 4 Federal 

agencies, 3 state agencies, 2 tribes, and 1 individual (2 letters) (Appendix B).

Table 1 summarizes each scoping comment and indicates by EIS subject matter, where an 

individual comment would likely be addressed in the draft EIS. EIS categories include: Purpose 

and Need for Action; Alternatives; Affected Environment; Environmental Consequences; 

Consultation and Coordination; and Cumulative Impact. Compliance with Regulations (Federal, 

state and local environmental laws and regulations) is also included in this latter category. An 

individual scoping comment may be categorized under more than one EIS subject matter 

heading.

7.0 SCOPING PARTICIPANTS

Scoping comments were received from the following agencies, tribes, and individuals during the 

scoping period:

National Marine Fisheries Service, Habitat Conservation Division

National Park Service

Natural Resources Conservation Service

U.S. Fish and Wildlife Service

Louisiana Department of Wildlife and Fisheries, Office of Wildlife

Louisiana Department of Natural Resources, Office of Coastal Management

Louisiana Department of Environmental Quality, Business and Community Outreach Division

Choctaw Nation of Oklahoma

Alabama-Coushatta Tribe of Texas

Mr. William A. Fontenot

Mr. William A. Fontenot, on behalf of the Delta Chapter of the Sierra Club
6

Table 1: Consolidated comments and location in DEIS where they will be discussed.

Location in DEIS:

PN – Purpose and Needs Alt – Alternatives AE – Affected Environment EC – Environmental Consequences CC

– Consultation and Coordination CI – Cumulative impact. Copies of all written comments are provided in 

Appendix B.

Location in DEIS Comments

PN Alt AE EC CC CI

X

X

X

X

X

X

X

X

X

X

X

By letter dated October 19, 2011, Virginia M. Fay, Acting Assistant Regional Administrator, 

National Marine Fisheries Service comments:

(1) The NMFS concurs with the initial evaluation provided in the package that material 

removed from the bar channel is not suitable for wetland development and its disposal 

at the proposed location is not expected to have significant impacts to EFH and related 

marine fishery resources.

(2) Coordination responsibilities for projects potentially impacting EFH would be fulfilled 

through our review and comment on project related documents prepared in fulfillment 

of the National Environmental Policy Act.

(3) General categories of EFH potentially impacted by the proposed dredging and disposal 

activities include estuarine water bottoms and estuarine water column. Fishery 

management plans for these species have been developed by the Gulf of Mexico 

Fishery Management Council. Potential adverse impacts to these categories of EFH are 

considered temporary and minor such as disruption of benthic communities and 

increased turbidity of the water column.

(4) In addition to being designated as EFH for the species listed, the proposed project area

provides nursery and foraging habitats that support a variety of economically important 

marine fishery species, such as Atlantic croaker, spotted seatrout, gulf menhaden, blue 

crab, and striped mullet.

(5) The NMFS recommends the draft EIS identify EFH and related marine fishery 

resources of concern and address potential impacts to those resources for all 

alternatives being evaluated.

By email dated August 17, 2011, Steven Wright, National Park Service, Southeast Regional 

Office, Planning and Compliance Division comments:

(1) Based on the information provided in the Subject Notice of Intent, the National Park 

Service has no comments at this time. We appreciate the opportunity to provide input 

regarding the resources and issues that will be evaluated.

By letter dated September 20, 2011, W. Britt Paul, Acting State Conservationist, Natural 

Resources Conservation Service comments:

(1) The project map submitted with your request indicates that the proposed construction 

areas will not impact prime farmland and therefore is exempt from the rules and 

regulations of the Farmland Protection Policy Act (FPPA)—Subtitle I of Title XV, 

Section 1539-1549. Furthermore, we do not predict impacts to NRCS work in the 

vicinity.

(2) For specific information about the soils found in the project area, please visit our 

website at: http://websoilsurvey.nrcs.usda.gov/
7

Table 1: Consolidated comments and location in DEIS where they will be discussed.

Location in DEIS:

PN – Purpose and Needs Alt – Alternatives AE – Affected Environment EC – Environmental Consequences CC

– Consultation and Coordination CI – Cumulative impact. Copies of all written comments are provided in 

Appendix B.

Location in DEIS Comments

PN Alt AE EC CC CI

X

X

X

X

X

X

X

X

X

By letter dated October 25, 2011, Brad Rieck, Acting Field Supervisor, Louisiana Ecological 

Services Office, U.S. Fish and Wildlife Service comments:

(1) The proposed project would be located in an area where the threatened piping plover 

(Charadrius melodus) may be present. Construction activities may cause piping 

plovers occurring near the project area to be temporarily displaced to nearby areas 

containing foraging and loafing habitat. Piping plover designated critical habitat occurs 

on islands immediately north of the proposed work, but not directly within the dredging 

limits or the disposal area.

(2) Federally listed as an endangered species, the West Indian manatee (Trichechus 

manatus) may occur in the project area. Manatees may infrequently be observed in the 

Mississippi River and coastal areas of southeastern Louisiana.

(3) The endangered pallid sturgeon (Scaphirhynchus albus) may also occur in the project 

area. The density of pallid sturgeon in the lower portion of the Atchafalaya Delta is 

thought to be low; however, there have been limited sampling efforts in that area.

Furthermore, the pallid sturgeon is believed to be a strictly freshwater fish, and is 

probably completely absent from the Atchafalaya River Delta during low river flows 

when more saline water from Atchafalaya Bay intrudes upriver to a greater extent.

(4) Endangered and threatened sea turtles forage in the nearshore waters, bays, and sounds 

of Louisiana. The National Marine Fisheries Service (NMFS) is responsible for aquatic 

marine threatened or endangered species. Please contact Eric Hawk (727/824-5312) at 

the NMFS Regional Office in St. Petersburg, Florida, for information concerning those 

species in the aquatic environment. When sea turtles leave the aquatic environment and 

come ashore to nest, however, the Service is responsible for consultation. Accordingly, 

we recommend that you contact this office if your activities would occur on beach 

areas during sea turtle nesting season (depending on the species in question).

(5) The proposed project would be located in an area where colonial nesting waterbirds 

may be present. Until a new, comprehensive coast-wide survey is conducted to 

determine the location of newly-established nesting colonies, we recommend that a 

qualified biologist inspect the proposed work site for the presence of undocumented 

nesting colonies during the nesting season. For areas containing nesting 

shorebirds/seabirds species (i.e., gulls, terns, plovers, and skimmers) all activity 

occurring within 650 feet of a nesting colony should be restricted to the non-nesting 

period, depending on the species present, and no part of the project should occur 

outside those windows. We recommend that on-site contract personnel be informed of 

the need to identify colonial nesting birds and their nests, and should avoid affecting 

them during the breeding season (i.e., the time period outside the activity window). A 

complete list of those species and their respective project activity window is available 

upon request.

(6) The proposed project is located immediately south of the Louisiana Department of 

Wildlife and Fisheries’ (LDWF) Atchafalaya Delta Wildlife Management Area (Main 

Delta), in St. Mary Parish. That Wildlife Management Area (WMA) consists of 

approximately 15,000 acres of fresh marsh and scrub-shrub, which provide habitat for 

numerous waterfowl, alligators, furbearers, and fish. Trapping for furbearers and 

commercial fishing are permitted. Numerous species of non-game amphibians, reptiles, 

birds, mammals, and invertebrates also utilize the area. Recreational uses of the area 

include fishing, hunting, birding, and camping..
8

Table 1: Consolidated comments and location in DEIS where they will be discussed.

Location in EIS:

PN – Purpose and Needs Alt – Alternatives AE – Affected Environment EC – Environmental Consequences CC

– Consultation and Coordination CI – Cumulative impact. Copies of all written comments are provided in 

Appendix B.

Location in EIS Comments

PN Alt AE EC CC CI

X

X

X

X

X

X

X

X

X

X (7) The proposed project is not expected to impact the WMA, but because of the very near 

proximity of the project, all work plans should be provided to the LDWF for their 

review.

(8) The permanent ODMDS-West would have the same type of impact as the temporary 

site, but over a slightly smaller area. Some benthic organisms will be buried and killed 

by dredged material, but they are expected to recolonize from nearby populations. The 

increase in turbidity expected during disposal operations would be temporary, and 

impacts to nekton would be minimal because animals in this area are adapted to the 

normally turbid conditions in the Atchafalaya River delta.

(9) The Service recognizes the economic importance of commercial navigation and thus 

the need for periodic dredging of several sections of the Atchafalaya River navigation 

channel, including the ARBC, to maintain safe operating conditions for those vessels.

By letter dated October 11, 2011, Kyle Balkum, Biologist Program Manager, Louisiana 

Department of Wildlife and Fisheries, Office of Wildlife comments:

(1) The LDWF supports the permanent designation of the ODMDS as long as it can be 

modified as needed. Since the bar channel is part of a prograding delta system that is 

very dynamic, ODMDS may not be the only option for future maintenance dredging in 

this area. LDWF supports the ability to use alternative techniques for disposal in this

area if deemed appropriate.

(2) The LDWF does not oppose a permanent designation of an ODMDS site in the bar 

channel. However, LDWF recommends more beneficial use of dredged material such 

as the creation of bird nesting islands and marsh nourishment within the boundary of 

the Atchafalaya Delta Wildlife Management Area. The proper use of dredge material 

will provide improved habitat conditions for wildlife and fishery resources.

By letter dated August 22, 2011, Keith Lovell, Administrator, Interagency Affairs/Field Services 

Division, Louisiana Department of Natural Resources, Office of Coastal Management (OCM) 

comments:

(1) The OCM recognizes the importance of maintaining navigation to Louisiana’s ports, 

and fully understands the need for appropriate disposal sites for dredged material; 

however, OCM can not endorse a disposal site which does not result in the beneficial 

use of material for wetland creation, restoration, and/or protection. The LCRP requires 

beneficial use of all dredged material, to the maximum extent practicable, in order to 

help slow the dramatic loss of coastal wetlands our state is extending. Our concern is 

that by awarding this site a permanent designation, the U.S. Army Corps of Engineers 

– New Orleans District is provided with a non-beneficial and less costly alternative to 

beneficial use of this dredged material.

(2) The long-term indirect impacts of creating a permanent ODMDS is not complimentary 

to the mission of this Office. At this time OCM can not fully support the designation of 

a permanent ODMDS on the west side of the ARBC. The OCM strongly encourages 

EPA to fully evaluate these indirect effects of this action on the natural and human 

environment of Louisiana.
9

Table 1: Consolidated comments and location in DEIS where they will be discussed.

Location in DEIS:

PN – Purpose and Needs Alt – Alternatives AE – Affected Environment EC – Environmental Consequences CC

– Consultation and Coordination CI – Cumulative impact. Copies of all written comments are provided in 

Appendix B.

Location in DEIS Comments

PN Alt AE EC CC CI

X

X

X

X

X

X

X

By email dated September 23, 2011, Beth Altazan-Dixon, Louisiana Department of 

Environmental Quality, Business and Community Outreach Division comments:

(1) After reviewing your request, the Department has no objections based of the 

information provided in your submittal.

(2) Currently, St Mary Parish is classified as attainment with the National Ambient Air 

Quality Standards and has no general conformity determination obligations.

By letter dated October 20, 2011, Ian Thompson, Director Historic Preservation Department, 

Choctaw Nation of Oklahoma comments:

(1) The Choctaw Nation of Oklahoma has reviewed project(s) and based on the 

information provided to the best of our knowledge it will have no adverse effect on any 

historic properties in the project’ area of potential effect. However, should construction 

expose buried archaeological or building materials such as chipped stone, tools, 

pottery, bone, historic crockery, glass or metal items, or should it uncover evidence of 

buried historic building materials such as rock foundation, brick, or hand poured 

concrete, this office should be contacted immediately.

By letter dated October 12, 2011, Bryant Celestine, Historic Preservation Office, AlabamaCoushatta Tribe of Texas comments:

(1) Upon review of your September 15, 2011 submission, St. Mary Parish exists beyond 

our scope of interest for the state of Louisiana. Therefore, no impacts to cultural assets 

of the Alabama-Coushatta Tribe of Texas will occur in conjunction with this proposal.

By letter dated August 16, 2011, Mr. William Fontenot comments (Several comments made by 

Mr. Fontenot were specific to ongoing and proposed USACE beneficial use-disposal efforts in 

bird islands located east and west of the ARBC. As these are separate USACE projects and are 

not covered in this DEIS; but rather, other NEPA-related documents, these comments are not 

presented in this Scoping Report.):

(1) The Atchafalaya River shipping channel and the spoil disposal areas are located in the 

middle of the Atchafalaya Delta Wildlife Management Area.

(2) The EPA and Corps of Engineers need to provide more information in the draft EIS on 

all other projects and developments that are directly or indirectly connected with the 

Atchafalaya Bar Channel and Spoil Disposal Area and any of their potential or real 

cumulative impacts. For instance, the 18-mile Atchafalaya Bar Channel and spoil 

disposal areas are identified by the EPA as part of the larger project called the Bayous 

Chene, Boeuf, Black and Atchafalaya River Project, which is more than 53 miles long.

If the Atchafalaya Bar Channel did not exist then the Chene, Boeuf and Black project 

and most of the development related to the oil and gas industry from Intracoastal City 

in the western end of Vermillion Bay to Port Fourchom, just west of Grand Isle, would 

not exist today. 
10

Table 1: Consolidated comments and location in DEIS where they will be discussed.

Location in DEIS:

PN – Purpose and Needs Alt – Alternatives AE – Affected Environment EC – Environmental Consequences CC

– Consultation and Coordination CI – Cumulative impact. Copies of all written comments are provided in 

Appendix B.

Location in DEIS Comments

PN Alt AE EC CC CI

X

X

X

X

(3) These navigation projects, and especially the Chene, Boeuf, Black and Atchafalaya 

River Navigation Project are intimately connected together as the primary pathway for 

the massive offshore drilling rigs that are built at Amelia and moved down the 

Atchafalaya Bar Channel to the deeper waters of the Gulf of Mexico. Without the 

deeper Atchafalaya Bar Channel none of the massive rigs would have been built at the 

complex of construction sites in Amelia. Probably most of the support facilities along 

the Intracoastal Navigation Canal from Grand Isle to Intracoastal City would also not 

have been built without the Atchafalaya Bay Bar Canal.

(4) The EIS being developed by the EPA and Corps of Engineers should provide the 

information on the cumulative and comprehensive impacts to coastal resources, 

including water, wetlands and especially fish and wildlife and their habitat from all 

related projects and development as a result of the Atchafalaya Bar Channel. Adverse 

impacts have happened from the deepening of navigation channels, such as from the 

many tons of toxic and hazardous waste dumped and buried at dozens of locations as 

well as many hundreds of acres of highly-productive wetlands and coastal waters that 

have been filled in or dramatically altered. No comprehensive assessments of all of 

these coastal-altering activities have been pulled together before now and no effort has 

been made to determine the cumulative adverse impacts from navigation and mineral 

exploration, drilling and development on water quality, wetlands, fish and wildlife 

resources as well as their habitat.

(5) Federal laws and court rulings have given us some excellent examples of how and why 

comprehensive and cumulative impacts need to be identified and evaluated when 

projects like dredging and the placement of spoil is being considered. Federal laws like 

the National Environmental Policy Act, the Clean water Act and the National Marine 

Policy Act provide opportunities for federal officials to insure that their work will not 

only improve the productivity of agencies and projects but help to protect our natural 

resources for present and future generations. Over the last eighty years Louisiana has 

lost more than one million acres of coastal land and wetlands. Most of these losses are 

the direct result of failure of officials on projects—like the Bayous Chene, Boeuf and 

Black and the Atchafalaya River navigation channel—to consider or evaluate land 

losses from dredging and filling of waters and the failure to provide for bank 

stabilization. 

(6) Since this project is on state land, the bed of Atchafalaya Bay, and since this bay is 

under the jurisdiction of the State Land Office and the Louisiana Department of 

Wildlife and Fisheries, I expect both the EPA and the Corps of Engineers to develop a 

close working relationship with officials in these and other relevant state agencies.

Whenever our various public officials can work together they are usually more 

productive.
11

Table 1: Consolidated comments and location in DEIS where they will be discussed.

Location in DEIS:

PN – Purpose and Needs Alt – Alternatives AE – Affected Environment EC – Environmental Consequences CC

– Consultation and Coordination CI – Cumulative impact. Copies of all written comments are provided in 

Appendix B.

Location in DEIS Comments

PN Alt AE EC CC CI

X

X X

X

X X

By letter dated November 8, 2011, Mr. William Fontenot, Conservation Chair, Delta Chapter of 

the Sierra Club comments:

(1) After reading the many documents which are available to us the Executive Committee 

of the Delta Chapter of the Sierra Club believes that the Environmental Protection 

Agency and the Corps of Engineers were correct in their determination that an 

Environmental Impact Statement should be prepared on the disposal of dredged 

material in Atchafalaya Bay.

(2) The primary reason for this extensive navigation project in south central Louisiana is to 

facilitate the movement of the massive oil well drilling structures which are built at the 

various construction sites along the Intracoastal Waterway near Amelia, Louisiana and 

then transported on the project known as the Atchafalaya, Chene, Boeuf and Black 

navigation project to their drilling locations in the Gulf of Mexico. 

(3) Over the last eighty years Louisiana has lost more than a million acres of coastal lands 

and wetlands. A considerable amount of this loss of critical habitat for fish and wildlife 

resources and for the areas needed to buffer Louisiana from hurricanes has happened in 

the Morgan City area.

(4) Inasmuch as Jean Lafitte National Historical Park is one of many interest which has 

been notified of this type of activity, so should the Atchafalaya National Heritage Area, 

also a program of the Department of the Interior/National Park Service. In 2006 the

U.S. Congress passed legislation which created the Atchafalaya National Heritage Area 

which includes more than 10 million acres in fourteen parishes, including the

Atchafalaya Floodway, Atchafalaya River Basin and the Atchafalaya Bay.
12

APPENDIX A

Mailing List for Scoping Input Request Letter
13

MAILING LIST FOR SCOPING INPUT REQEST LETTER

Federal Agencies

U.S. Environmental Protection (EPA), Region VI, Office of Planning and Coordination

EPA, Region VI, Marine and Wetlands Section

EPA, Region VI, Groundwater/UIC Section

EPA, Region VI, Air Planning Section

EPA, Office of Federal Activities

U.S. Fish & Wildlife Service

National Oceanic and Atmospheric Administration (NOAA), National Marine Fisheries Service 

(NMFS), Habitat Conservation Division

NMFS, Protected Species Division 

NOAA, Program, Planning & Integration

Natural Resources Conservation Service

Federal Emergency Management Agency, Region VI 

National Register of Historic Places

Council on Environmental Quality

U.S. Department of Housing and Urban Development

U.S. Advisory Council on Historic Preservation

Federal Highway Administration

U.S. Army Corps of Engineers (USACE), Policy Review Branch

USACE, Vicksburg District

U.S. Department of Interior, National Park Service, Jean Lafitte Historical Park

U.S. Department of Interior, Office of Environmental Policy and Compliance

U.S. Department of Energy, Office of Environmental Compliance

U.S. Department of Transportation, Federal Aviation Administration, Southwest Region

Tribes

Alabama Coushatta Tribe of Texas

Caddo Nation of Oklahoma

Choctaw Nation of Oklahoma

Coushatta Tribe of Louisiana

Chitimacha Tribe of Louisiana

Jena Band of Choctaw Indians

Mississippi Band of Choctaw Indians

Quapaw Tribe of Oklahoma

Seminole Tribe of Florida

Seminole Nation of Oklahoma

Tunica-Biloxi Tribe of Louisiana

State Agencies and Officials

Louisiana Department of Wildlife and Fisheries 

Louisiana Department of Natural Resources, Office of Coastal Management 

Louisiana Department of Natural Resources, Office of Conservation

Louisiana Department of Natural Resources, Coastal Restoration Division

Louisiana Department of Natural Resources, Title & Records Section
14

Louisiana Department of Environmental Quality 

Louisiana State Historic Preservation Officer 

Louisiana Department of Health and Hospitals

Louisiana Department of Public Works

Louisiana Department of Transportation and Development

Louisiana Department of Agriculture and Forestry

Louisiana Department of Culture, Recreation & Tourism

Louisiana Division of Administration

Louisiana State Attorney General’s Office

Louisiana State Board of Commerce & Industry, Research Division

Governor’s Office for Coastal Activities

Honorable Bobby Jindal

Honorable David Vitter

Honorable Mary Landrieu

Honorable “Steve” Scalise

Honorable Charles W. Boustany Jr.

Honorable Sam Jones

Honorable Simone Champagne

Honorable “Charlie” Melancon

Honorable “Butch” Gautreaux

Honorable “Joe” Harrison

Honorable John Flemming

Honorable Rodney Alexander

Honorable William “Bill” Cassidy

Secretary of State Jay Dardenne

Interested Businesses, Groups, and Individuals

Natural Resources Defense Council, Inc.

Louisiana Audubon Council

Earl K. Long Library

Port Aggregates, Inc.

State Library of Louisiana

Avoyelles Parish Library

The Waterways Journal

Mr. David M. Frank

Coalition of Coastal Parishes

Atchafalaya Basin Levee District

Coalition to Restore Coastal Louisiana

Mr. William A. Fontenot

Louisiana Nature Conservancy

St. Mary Land & Exploration Co.

Tulane University Libraries, Louisiana Collection

Times-Picayune

Grayling Hadnott

Rory Nettles
15

State-Times/Morning Advocate

Dr. Michael P. Evans

National Wildlife Federation

Mr. Josh Gilman, PE, D.WRE

Mr. Joseph V. Frank III

Bernard McMenamy Cont. Inc.

Kansas City Southern Railway Company

Engineering Development Group

Mr. Sean M. Duffy

American Rivers, Inc.

Norfolk Southern

Ducks Unlimited

B.W. Farrell Inc.

Trigon Exploration Inc.

Robert P. Waldron Inc.

Mr. George Strain, Continental Land and Fur Co. Inc.

Williams-McWilliams Co. Inc.

Ford Construction Company 

Luhr Bros. Inc.

Massaman Construction Company

Audubon Society, New Orleans

Mr. George Pivach, Jr.

Circle Inc.

Mr. “Wally” Gator Landry, Crucial, Inc.

Mr. Dean Wolcott, BDR

Mr. John Snell, WVUE-TV

Mr. Bobby Brennan

Port of New Orleans

Pontchartrain Materials Corp.

Mr. Darwin Lee, LADNR

Berry Brothers General Contractors

Penny Crappell, Town of Berwick

Mr. John Taliancich

Mr. Jay Vincent

Tulane University, Army ROTC

Kim Holden, Fox 8 Live, WVUE-TV

J.H. Menge & Co.

Aux LLC

Mr. Louis A. Ratcliff, Town of Berwick

Mr. Allen J. Benoit, Town of Berwick

Entergy

Bonnet Carre Rod & Gun Club, Environmental Committee

Mr. Bob Breck, Fox 8 Live, WVUE-TV

Gulf Restoration Network

Mr. Gary Beadle, Town of Berwick

Mr. Damon Robison, Town of Berwick
16

Mr. Edgar Thomas, Jr., Town of Berwick

Mr. Troy M. Lombardo, Town of Berwick

Tennessee Gas Pipeline

Ms. Kathy Pitre

Supervisor U.S. Coast Guard

Mr. Larry P. Bergeron, City of Morgan City

Mr. Luke P. Manfre, City of Morgan City

Mr. Carl Kraemer, City of Morgan City

Ms. “Peg” M. Rentrop, City of Patterson

Mr. Dave Lowery, City of Patterson

Robert Joseph Moreau, Ph.D.

Mr. Duval H. Arthur, Jr.

Town of Berwick

Leslie R. Suazo

KWBJ Channel 39

Mr. “Tim” Hymel, City of Morgan City

Mr. “Ron” Bias, City of Morgan City

KQKI/KDLP

Diamond Services Corporation

Mr. L.L. “Larry” Mendoza, Jr., City of Patterson

Mr. “Mike” Accardo, City of Patterson

Ms. Barbara Dodds

Mr. Mike Plaisance, Plaisance Dragline & Dredging Co. Inc.

Mr. Donald Landry

Morgan City Daily Review

Mr. Timothy I. “Tim” Matte, City of Morgan City

Mr. Louis J. Tamporello, Jr., City of Morgan City

St. Mary Journal

Mr. Rodney A. Grogan, City of Patterson

Mr. “Joe” Russo, III, City of Patterson

Ms. Claire D. Sawyer, City of Patterson

Mr. William L. Yeats, Jr.

WHC Inc.

Mr. Charlie Mestayer

Mr. Clarence A. Vappie, Town of Baldwin

Mr. Mike J. Caesar, Town of Baldwin

Mr. Carol J. Vining, St. Mary Parish

Mr. Paul P. Naquin, St. Mary Parish

Mr. Dale J. Rogers, City of Franklin

Mr. Merlin Price, St. Mary Parish Council

Mr. Eugene P. Foulcard, City of Franklin

Capt. K.C. Siverd

CF Bean Corporation

Ms. Lorraine Thibodaux, Town of Baldwin

H. Gene St. Germain, Town of Baldwin

Mr. Wayne J. Breaux, Town of Baldwin
17

Mr. Raymond Harris, Jr., City of Franklin

Mr. Chuck D. Autin, City of Franklin

Carr Oil Company, Inc.

Mr. Logan J. Fromenthal, Jr., City of Franklin

Mr. “Chuck” Walters, City of Franklin

CL Jack Stelly & Associates Inc.

Mr. “Mike” Lancelin, Town of Baldwin

Mr. Herbert E. Druilhet, Jr., Town of Baldwin

Cultural & Historical/Research & Development

Mr. Raymond Harris, Jr., City of Franklin

Mr. Lester “Motor Totor” Levine, City of Franklin

Mr. Ken Singleton, City of Franklin

St. Mary Parish Police Jury

Mr. Glen J. Hidalgo, City of Franklin

Mr. David Hanagriff, City of Franklin

Mr. Kevin J. Voisin, City of Franklin

Mr. Joseph H. Garrison, Sr., City of Franklin

Mr. Steve F. Bierhorst, City of Franklin

Mr. Daniel Oakley

Louisiana State University, Government Documents

Mr. Craig A. Johnson, LSU, Louisiana Geographic Information Center

Mr. Neil Minor, City of Franklin

District Conservationist, St. Mary Parish

Mr. Craig Mathews, City of Franklin

Mr. Gary Duhon, City of Franklin

Dr. Charles Wilson, LSU, Office of Sea Grant Development

Mr. Jim Wilkins, LSU, Sea Grant Legal Program

Ms. Stephanie Zumo, State of Louisiana

Mr. Kenny P. Scelfo, Sr., City of Franklin

Mr. Charles “Butch” Middleton, City of Franklin

Mr. Albert Foulcard, City of Franklin

St. Mary Parish Library

Port of Greater Baton Rouge

Louisiana State University, Department of Geography and Anthropology

Mr. Mike Strain, Louisiana Department of Agriculture and Forestry

Mr. Randy Lanctot, Louisiana Wildlife Federation

Mr. Carl J. Brevelle, USDA Forest Service

Hydro Consultants Inc.

Arkansas State Bank Department

Leigh Haynie, Atchafalaya Basinkeeper

G. Paul Kemp, Ph D., National Audubon Society, Gulf Coast Initiative

Mr. Andrew Harrison, Jr., Harrison Law, LLC.

East Baton Rouge City-Parish Council
18

APPENDIX B

Scoping Comment Letters
19 

Ms. Joan Exnicios, Acting Chief 

Environmental Planning and Compliance Branch 

Planning, Programs, and Management Division 

New Orleans District, U.S. Army Corps of Engineers 

Post Office Box 60267 

New Orleans, Louisiana 70160-0267 

Dear Ms. Exnicios: 

UNITEC STATES CEPAFITMENT OF COMMEFICE 

National Oceanic and Atmospheric Administration 

NATIONAL MARINE FISHEASES SERVICE 

Southeast Regional Office 

263 13th Avenue South 

St. Petersburg, Florida 3 3 70 1 

October 19,2011 F/SER46/KC:Jk 

225/389-0508 

NOAA's National Marine Fisheries Service (NMFS) has received your letter dated September 15, 2011, 

transmitting the Information Package titled, "AtcbafaJaya River Bar Channel Ocean Dredged 

Material Disposal Site (ODMDS)." The New Orleans District (1\0D) and U.S. Environmental 

Protection Agency are proposing the permanent designation of an Ocean Dredged Material Disposal Sites 

pursuant to Section 102(c) of the Marine Protection. Research, and Sanctuaries Act of 1972, located in the 

Gulf of Mexico off the mouth of the Atchafalaya River. Dredge material removed from the Atchafalaya 

River Bar Channel of the federally auihorized Atchafalaya River and Bayous Chene, Boeuf, and Black, 

Louisiana, would be disposed along it's west side or right descending bankline (ODMDS-West). 

According to the transmittal letter, an Environmental Impact Statement (EIS) would be prepared to 

evaluate the use of the ODMDS-West. 

Based on the infonnation provided in the Information Package, the proposed disposal site encompasses 

54 square miles of Atchafalaya Bay water bottoms. It should be noted that th.is subtidal habitat is 

categorized as essential fish habitat (EFH) under provisions of the Magnuson-Stevens F1shery 

Conservation and Management Act (Magnuson-Stevens Act). 'NlvlFS concurs with the initial evaluation 

provided in the package that material removed from the bar channel is not suitable for wetland 

development and its disposal at the proposed location is not expected to have significant impacts to EFH 

and related marine fishery resources. Nevertheless, NMFS has a "findings" with the NOD under 

provisions of Magnuson-Stevens Act that coordination responsibilities for projects potentially impacting 

EFH would be fulftlled through our review and comment on project related documents prepared in 

fulfillment of the National Envirorunental Policy Act. 

General categories ofEFH potentially impacted by the proposed dredging and dredge disposal activities 

include estuarine water bottoms and estuarine water column. Detailed information on federally managed 

fisheries and their EFH is provided in the 2005 generic amendment of the Fishery Management Plans for 

the Gulf of Mexico prepared by the Gulf ofMexieo Fishery Management Council (GMFMC). Potential 

adverse impacts to these categories of EFH are considered temporary and minor such as the disruption of 

benthic communities and increased turbidity of the water colwnn. 

NMFS recommends the draft EIS identify EFH and related marine fishery resources of concern and 

address potential impacts to those resomces for all alternatives being evaluated (i.e., both nearshore and 

offshore sites). ln addition, NMFS recommends the draft EIS evaluate EFH and marine fisheries in 
20 

separate sections. The EFH section of the draft document should include the following information 

provided in Table 1 below. 

Tab! e I EFH spec1es, 1 e stages, an dh a b1tat assoc1at WJt . propose - est. . . ed . h d ODMDSW 

Species Life stae:e Essential Fish Habitat 

eggs planktonic, sand/shelVsoft bottom, SA V, brown shrimp larvae/post larvae 

emergent marsh, oyster reef juvenile 

eggs 

white shrimp larvae/post larvae 9-34 m, planktonic, soft bottom, emergent marsh juvenile 

adult 

larvae/post larvae 

all estuaries planktonic, SAY, sand/sheW soft red drum juvenile 

adults bottom, emergent marsh, pelagic 

eggs 4- 130 m, reefs, sand/shell/ soft bottom, SA V, la11e snapper larvae 

juvenile mangrove 

larvae 

king mackerel juvenile 9-180 m, pelagic 

adults 

cobia iuvenile 5-183 m. pelagic 

bonnethead shark iuvenile inlets, estuaries, coastal waters <25 m 

Atlantic sharpnose juvenile <40 m, Atchafalaya delta shark 

In addition to being designated as EFH for the species listed in Table I, the proposed project area 

provides nursery and foraging habitats that support a variety of economically important marine fishery 

species such as Atlantic croaker, spotted seatrout, gulf menhaden, blue crab, and striped mullet. Some of 

these species serve as prey for other fish species managed under the Magnuson-Stevens Act by the 

GMFMC (i.e., mackerels, snappers, and groupers) and highly migratory species managed by NMFS (i.e., 

billfishes and sharks). This information should he detailed in the draft EIS. 

We appreciate the opportunity to review and comment on the Ir.fonnation Package. 

c: 

FWS. La(Byettc, Walther .EP~ Dallas, Mtck 

LA uWF, Balkum 

LA DNR. Lovell 

F/SER4, Dale 

f/SER.46, Swofford 

Files 

2 

Sincerely, 

Virginic: M. Fay 

Acting Assistant Regional Administrator 

Habitat Conservation Division 
21 

United States Departme t of the Interior 

FISH ANP WILDLIFE ER VICE 

Colonel Edward R. Fie 

District Commander 

U.S. Army Corps of En 'neers 

Post Office Box 60267 

New Orleans, Louisiana 70160-0267 

Dear Colonel Fleming, 

646 Cajundome vd. 

Suite400 

Lafayette, Louisiana 70506 

October 25, 2 11 

us. PJSB • WlL.DLIP£ SS8VlC£ 

~ 

~ ~ .... ,.t:. 

The U.S. Fish and Wild 'fe Service (Service) has review the September 1 5, 2011 , letter from the 

United States Army Co s of Engineers (Corps), New Or eans District, in which the Corps and the 

U.S. Environmental Pro ection Agency, Region 6 (EPA) ropose the permanent designation of an 

Ocean Dredged Materia Disposal Site (ODMDS) in the ulf of Mexico off the mouth of the 

Atchafalaya River, St. ary Parish, Louisiana. The EPA and the Corps intend to jointly prepare an 

Environmental Impact atement (ElS) to evaluate altern tives and potential environmental impacts 

due to the permanent de ignation of an existing tempora ODM DS. We offer the following 

comments under the aut ority of the Endangered Species Act of 1973 (87 Stat. 884, as amended; 16 

U.S.C. 153 1 et seq.), th National Environmental Policy ct of 1969 (83 Stat. 852, as amended; 42 

U.S.C. 4321 - 4347), an the Fish and Wildlife Coordinat on Act (FWCA) ( 48 Stat. 401, as amended; 

16 U.S.C. 661 et seq.). 

Prior to 2002, shoal mat rial dredged from the Atcbafala a River Bar Channel (ARBC) that was 

deemed unsuitable for b neficial use by the Corps was d posited in an existing site on the east side of 

the cha1mel (ODMUS- st). According to the U.S. Ann Corps of Engineers, when dredged motcriol 

was deposited in the 0 MDS-East, some of the material was eventually transported back into the 

channel, exacerbating regular shoaling from riverine ediment input. In 2002, a site on the west 

side of the channel was esignated as a temporary ODM S (ODMDS-West) for shoal material that 

was not used beneficial! . The proposed permanent desi ation of the existing temporary ODMDSWest on would allow th continued disposal of drt:dged atetialremoved fi-om the bar channel of the 

federally-authorized an maintained project, Atchafalaya River and Bayous Chene, Boeuf, and Black, 

Louisiana. 

The proposed permane ODMDS-West will be a 16 mil long by 3 mile wide rectangul ar area similar 

to the existing temporar ODMDS-West, except that its ength would be shortened by 2 miles on the 

north end; that area is p oposed as a Bird Island Disposal Site Expansion. 

Threatened and Enda gered Species 

The proposed project w uld be located in an area where he threatened piping plover ( Charadrius 

melodus) may be prese t. The piping plover is a small ( inches long), pale, sand-colored shorebird 

that winters in Louisian and may be present for 8 to 1 0 onths annually. Piping plovers arrive from 
22 

their northern breeding grounds as early as late July and;emain until late March or April. They feed 

on polychaete marine onns, various crustaceans, insec s and their larvae, and bivalve mollusks that 

they peck from the top for just beneath the sand. Pi pi g plovers forage on intertidal beaches, 

mudflats, sand flats, at al flats, and wash-over passes th no or very sparse emergent vegetation. 

They roost in unvegeta ed or sparsely vegetated areas, hich may have debris, detritus, or microtopographic relief offe g refuge to plovers from high inds and cold weather. They also forage and 

roost in wrack (i.e., sea eed or other marine vegetation deposited on beaches. In most areas, 

wintering piping plove s are dependent on a mosaic of s tes distributed throughout the landscape, 

because the suitability f a particular site for foraging o roosting is dependent on local weather and 

tidal conditions. Plove move among sites as enviro tal conditions change, and studies have 

indicated that they gen rally remain withjn a 2-mile are . Major threats to this species include the loss 

and degradation ofhab tat due to development, disturba 'ce by humans and pets, and predation. 

On July 10, 2001 , the ervice designated critical habitat for wintering piping plovers (Federal Register 

Volume 66, No. 132); map of the seven critical habitat units in Louisiana can be found at 

ht ://criticalhabitat.fw . ov/crithab. Their designated c "tical habitat identifies specific areas that are 

essential to the conserv tion of the species. The prima constituent elements for piping plover 

wintering habitat are th se habitat components that sup rt foraging, roosting, and sheltering and the 

physical features neces for maintaining the natural p ocesses that support those habitat 

components. Constitu t elements are found in gcologi ally dynamic coastal areas that contain 

intertidal beaches and ats (between annual low tide an annual high tide), and associated dune 

systems and flats abov annual high tide. Important co ponents (or primary constituent elements) of 

intertidal flats include and and/or mud flats with no or ery sparse emergent vegetation. Adjacent 

unvegetated or sparse) vegetated sand, mud, or algal fl ts above high tide are also important, 

especially for roosting lovers. 

Construction activities g near the project area to be temporarily 

displaced to nearby are s containing foraging and loafin habitat. Piping plover designated critical 

habitat occurs on islan s immediately north of the prop ed work, but not directly within the dredging 

Jimjts or the disposal 

Federally listed as an et dangered species, the West lndi manatee (Trichechus manatus) may occur in 

the project area. West ndian manatees frequently enter akes Pontchartrain and Maurepas, and 

associated coastal wate s and streams duritig the summe months (i.e., June tltrough September). 

Manatee occurrences i Louisiana are increasing, and th y have been regl,llarly reported in the Amite, 

Blind, Tchefuncte, and ickfaw Rivers, and in canals wi bin the adjacent coastal marshes of 

southeastern Louisiana Manatees may also infrequent! be observed in the Mississippi River and 

coastal areas of southw stern Louisiana. Threats to this pecies include collisions with boats and 

barges, entrapment in ood control structures, poaching habitat loss, and pollution. Cold weather and 

outbreaks of red tide m y also adversely affect these ani aJs. 

The endangered pallid turgeon (Scaphirhynchu.s· a/bus) nay also occur in the project area. The pallid 

sturgeon is found in Lo isiana, in both the Mississippi a d Atchafalaya Rivers (with known 

concentrations in the vi inity of the Old River ControlS ucture Complex); it is possibly found in the 

Red River as well. Th pallid sturgeon is adapted to Jar e, fTee-flowing, turbid rivers with a diverse 

assemblage of physical characteristics that are in a cons t state of change. Detailed habitat 

requirements of this fis are not known, but it is believ to spawn in Louisiana. Habitat loss through 

river channelization an dams has adversely affected thi species throughout its range. Entrainment 

issues associated with redging operations in the Missis ippi and Atchafalaya Rivers and through 
23 

diversion structures o e Mississippi River are two po entia! effects that should be addressed in 

future planning studies nd/or in analyzing current proj c t effects. Juvenile pallid sturgeon appear to 

be at risk for entrainme tin hydraulic dredges, because ftheir benthic holding behavior and their 

relatively low burst sw' ing speed. The density of p lid sturgeon in the lower portion of the 

Atchafalaya River Delt is thought to be low; however, ere have been limited sampling efforts in that 

area. As river morpho! gy changes further downstream habitat suitability for this species is generally 

thought to also gradual y decrease towards the river mo th. Furthermore, the pallid sturgeon is 

believed to be a stricti freshwater fish, and is probably mpletely absent from the Atchafalaya River 

Delta during low river ows when more saline water fro Atchafalaya Bay intrudes upriver to a 

greater extent. 

Although paflid sturg n are unlikely to occur in the pro ect area, the Service offers the following 

recommendations. Th e are not requirements, but thei implementation may further reduce the 

unlikely chance of enc untering pallid sturgeons or othe fish species while conducting dredging 

activities. 

1. To the extent p ssible, schedule dredging activi sin the project area during low flow periods, 

when salt wate occurs on the channel bottom fu her upriver than during normal or high river 

flows. 

2. Consider imple enting special operating proced es for hydraulic dredges that were developed 

to protect sea les, and are required for those ecies in some dredging areas. Those 

procedures inc! de minimizing suction pump op ration while the draghead or cutterhead is 

suspended in th water column. 

3. If hopper dredg are utilized, explore t11e feasib lity of using a rigid sea turtle deflector, which 

is designed to p otect sea turtles by preventing t em from entering the draghead, and evaluate 

the;: t:ffectivene of that device for pallid sturgeo 1 and other fish species. 

Endangered and threat ned sea turtles forage in the nea hore waters, bays and sounds of Louisiana. 

The National Marine F sheries Service (NMFS) is respo sible for aquatic marine threatened or 

endangered species. Pease contact Eric Hawk (727/82 -5312) at the NMFS Regional Office in St. 

Petersburg, Florida, fo information concerning those s ·es in the aquatic environment. When sea 

turtles leave the aquati environment and come onshore o nest, however, the Service is responsible for 

consultation. Accordi gly, we recommend that you con ct this office if your activities would occur 

on beach areas during e sea turtle nesting season (dep nding on the species in question). 

Migratory Birds 

The proposed project ould be located in an area wh e colonial nesting waterbirds may be present. 

Colonies may be pres nt that are not currently listed in the database .maintained by the Louisiana 

Department of Wildli and Fisheries. That database s updated primarily by monitoring the colony 

sites that were previo ly surveyed during the 1980s. ntil a new, comprehensive coast-wide survey 

is conducted to dete ine the location of newly-estab ished nesting colonies, we recommend that a 

qualified biologist ins ect the proposed work site for e presence of undocumented nesting colonies 

during the nesting se on. For areas containing nesti g shorebird/seabird species (i.e., gulls, terns, 

plovers, and skimmers all activity occurring within 65 feet of a nesting colony should be restricted to 

the non-nesting perio , depending on the species pre ·ent, and no part of the project should occur 

outside those window . We recommend that on-site ntract personnel be infonned of the need to 
24 

identify colonial nesti g birds and their nests, and sho ld avoid affecting them during the breeding 

season (i.e., the time p riod outside the activity windo' ). A complete list of those species and their 

respective project activ ty windows is available upon re est. 

State Wildlife Manag ment Areas 

The proposed project is located immediately south ofth Louisiana Department of Wildlife and 

Fisheries' (LDWF) Ate afalaya Delta Wildlife Manage ent Area (Main Delta), in St. Mary Parish, 

Louisiana. That Wildli e Management Area (WMA) co sists of approximately 15,000 acres of fresh 

marsh and scrub-shrub, which provide habitat for numer us waterfowl, alligators, furbearers, and fish. 

Trapping for furbearers and commercial fishing are p itted. Numerous species of non-game 

amphibians, reptiles, bi ds, mammals, and invertebrates lso utilize the area. Recreational uses of the 

area include fishing, hu ting, birding, and camping. 

The proposed project is not expected to impact the WM , but because of the very near proximity of 

the project, all work pi s should be provided to the LD F for their review. 

Project Impacts 

The permanent ODMD -West would have the same typ of impact as the temporary site, but over a 

slightly smaller area. S me benthic organisms will be b ried and killed by dredged material, but they 

are expected to recolon ze from nearby populations. Th increase in turbidity expected during disposal 

operations would be te porary, and impacts to nekton w uld be minimal because animals in this area 

are adapted to the norm lly turbid conditions in the Atch falaya River Delta. 

Recommendations 

The Service recognizes he economic importance of com ercial navigation and thus the need for 

periodic dredging of se eral sections of the Atchafalaya iver navigation channel, including the 

ARBC, to maintain safi operating conditions for those v ssels. 

The Service also suppo ts the beneficial use of dredged 1 at erial for fish and wildlife habitat creation 

and restoration. The S ice previously recommended i a July I, 201 I, letter that material dredged 

from the ARBC be use beneficially for habitat creation nd restoration. According to the Corps, the 

dredged material from t is part of the channel is typicall low in percent sand. and therefore has been 

deemed unsuitable for eating persistent subaerial land. However, the upper portion of the A RBC is 

likely to contain a high r percentage of sand, and the Co s has now determined that material fi·om that 

area may be suitable to creating bird island habitat. In July, 13, 2011 , Public Notice, the Corps 

proposed the designatio of the upper 2 miles of the exis ing temporary ODMDS-West as an 

expansion of the area a ailable to create islands for colo ·al nesting birds. The northern part of the 

proposed permanent 0 MDS-West.is also located near t at upper section of the ARBC. If more 

sections of the ARBC a e found to contain suitable mate ·al, the ODMDS-West should be considered 

for new expansion area for bird island creation in the fu ure. 

The Service offers the Bowing recommendations for ii orporation into project planning and 

implementation to help rotect and enhance fish and wil life resources: 
25 

1. Non-beneficial isposal of dredge material into t proposed ODMDS should be considered as 

a last resort, and conducted only when dredged m terial composition is such that beneficial use 

is impossible. 

2. The Corps sboul recheck the dredge material co position before each dredging event to 

determine if mo e sections of channel bottom rna rial could be used beneficially to create or 

restore habitat f r fish and wildlife resources. Th t information should be provided to the 

resource agenci prior to the development of dre ging plans and specifications. 

The Service looks forw d to continued coordination wi the EPA and the Corps during the 

preparation of the draft IS. We appreciate the opportun ty to review the public notice, and offer 

comments to further pr ect fish and wildlife resources. f you need further assistance or have 

questions regarding this letter, please contact David Cast llanos (337 /29 1-3112) of this office. 

~o_\0W 

h

radRieck 

Acting Field Supervisor 

ouisiana Ecological Services Office 

cc: USACE, New Orlea s District (Attn: Mr. John Fiore tino) 

EPA, Region 6, 144 Ross Avenue, Dallas, Texas 75 02-2733 (Attn: Ms. Jessica Franks, PhD) 

NMFS, Baton Roug , LA 

LDWF, Baton Rou , LA 

OCPR, Baton Roug , LA 

LDNR, CMD, Bato Rouge, LA 
26 

Fiorentino, John MVN 

From: 

Sent: 

To: 

Cc: 

Subject: 

Dr. Franks, 

Steven_M_Wright@nps.gov 

Wednesday, August 17, 2011 12:57 PM 

franks.jessica@epa.gov Fiorentino, John MVN; waso_eqd_extrev@nps.gov; shawn_alam@ios.doi.gov 

Notice of Intent, Prepare Environmental Impact Statement, Designation of an Ocean Dredged Material Disposal Site (ODMDS) in the Gulf of Mexico Off the Mouth of the Atchafalaya River; 

DOl (ER-11/0616) 

Notice of Intent to prepare an Environmental Impact Statement, Designation of an Ocean 

Dredged Material Disposal Site (ODMDS) in t he Gulf of Mexico off the mouth of the Atchafalaya 

River. 

Based on the information provided in t he subject Notice of Intent, the National Park 

Service has no comments at th.i!> time. 

We appreciate the opportunity to provide input regarding the resources and i ssues that 

will be evaluated. 

Steven M. Wri ght 

National Park Service 

Southeast Regional Office 

Planning & Compliance Division 

100 Alabama Street SW 

Atlanta, GA 30303 

(404) 507- 5710 
27 

NRCS Natural Resources Conservation Service 

3737 Government Street 

Alexandria, LA 71302 

September 20, 2011 

Joan Exnicios 

DOA 

P.O. Box 60267 

United States Departaoent of Agric•lture 

New Orleans, Louisiana 70160-0267. 

RE: Atchafalayi River Bar Chann~l ~~ea.~. Dredged ~ate al Site 

Dear Joan: 

(318) 473-ns1 

Fax: (318) 473-7626 

I have reviewed the above referenced project for potential requirements of the Farmland Protection Policy 

Act (FPPA) and potential impact to Natural Resource Conservation Service projects in the immediate 

vicinity. 

Projects are subject to FPPA requirements if they may irreversibly convert farmland (directly or indirectly) 

to nonagricultural use and are completed by a federal agency or with assistance from a federal agency. 

For the purpose of FPPA, farmland includes prime farmland, unique farmland, and land of statewide or 

local importance. Farmland subject to FPPA requirements can be forest land, pastureland, cropland, or 

other land, but not water or urban built-up land. 

The project map submitted with your request indicates that the proposed construction areas will not 

impact prime farmland and therefore is exempt from the rules and regulations of the Farmland Protection 

Policy Act (FPPA)-$ubtitle I of Title XV, Section 1539-1549. Furthermore, we do not predict impacts to 

NRCS work in the vicinity. 

For specific information about the soils found in the project area, please visit our Web Soil Survey at the 

following location: 

http:l/websoilsurvey.nrcs.usda.gov/ 

Please direct all future correspondence to me at the address shown above. · 

Respectfully, 

3::1.~ Acting State Conservationist ~~ 
28 

BOBBY JINDAL 

GOVERNOR 

October 11, 2011 

~tate .of 1fl.ouisia:na: 

DEPARTMENT OF WILDLIFE AND FISHERIES 

OFFICE OF WILDLIFE 

United States Army Corps of Engineers 

New Orleans District 

Regional Planning and Environment Division South 

Attn: Mr. John Fiorentino 

P. 0. Box 60267 

New Orleans. LA 70160-0267 

RE: Application Number: Atchafalaya River bar channel (ARBC), ODMDS-West 

ROBERT J . BARHAM 

SECRETARY 

JIMMY L . ANTHONY 

ASSISTANT SECRETARY 

Applicant: U.S. Army Corps of Engineers, N.O. District & U.S. Environmental Protection Agency 

Notice Date: September 15, 2011 

Dear Mr. Fiorentino: 

The professional staff of the Louisiana Department of Wildlife and Fisheries (LDWF) has reviewed the above 

referenced notice. Based upon this review, the following has been determined: 

LDWF suppons the permanent designation of the ODMDS as long as it can be modified as needed. Since the 

bar channel is part of a prograding delta system that is very dynamic, ODMDS may not be the only option for 

future maintenance dredging in this area_ LDWF' supports the ability to use alternative techniques for 

disposal in this area if deemed appropriate. 

LDWF does not oppose a permanent designation of an ODMDS site in the bar channel. However, LDWF 

recommends more beneficial use of dredge material such as the creation of bird nesting islands and marsh 

nourishment within the boundary of the Atchafalaya Delta Wildlife Management Area. The proper use of 

dredge material will provide improved habitat conditions for wildlife and Jishery resources. 

The Louisiana Department of Wildlife and Fisheries submits these recommendalions to the U.S. Army Corps of 

Engineers in accordance with provisions of the Fish and Wildlife Coordination Act (16 U.S.C. 661 et seq.). 

Please do nol hesitate to contact Habitat Section biologist Chris Davis at 225-765-2642 sbould you need further 

assistance. 

Sincerely, 

~~:~--------~ Biologist Program Manager 

cd/rb/cl 

P 0. BOX Q8000 • BA-roN ROU<;E. LOUISIANA 70898.0000 • PHONE l l' 2!51 7e5·2800 

AN EOVAI. Of'POR"I\JNrTY EMPLOYER 
29 

BOBBY JINDAL 

GOVER."'OR 

August 22, 2011 

Jessica Franks, PhD 

U.S. EPA, Region 6 

~tate of JLouisiana 

DEPARTMENT OF NATURAL RESOURCES 

OFFICE OF COASTAL MANAGEMENT 

1445 Ross A venue 

Dallas, Texas 75202-2733 

SCOTT A. ANGELLE 

SECRETARY 

RE: C20110326- Comments on the Notice to Prepare an Environrnentiu Impact Statement 

(EIS) for the Designation of an Ocean Dredged Material Disposal Site (ODMDS) in the 

Gulf of Mexico off the Mouth of the Atchafalaya River, St. Mary Parish 

Dear Dr. Franks: 

The Louisiana Department of Natural Resources, Office of Coastal Management (OCM), has 

been invited to provide comments in response to the above referenc.ed notice to prepare an EIS 

for the designation of a permanent ODMDS on the west side (right-descending bank) off the 

mouth of the Atchafalaya River. As the agency responsible for administering the federallyapproved Louisiana Coastal Resources Program (LCRP), we look forward to being in receipt of 

your consistency determination for this activity, as required by the Coastal Zone Management 

Act of 1972, as amended. We will also appreciate the opportunity to review the Draft EIS when 

it is completed, and offer these preliminary remarks. 

This open water site has been in use since 2002, when it was approved as a temporary disposal 

area for material dredged from the Atchafalaya River and Atchafalaya River Bar Channel 

(ARBC) during periodic maintenance. OCM recognizes the importance of maintaining 

navigation to Louisiana's ports, and fully understands the need for appropriate disposal sites for 

dredged matelial; however, OCM can not endorse a disposal site which does not result in the 

beneficial use of that material for wetland creation, restoration and/or protection. The LCRP 

requires beneficial use of all dredged material, to the maximum extent practicable, in order to 

help slow the cb:amatic loss of coastal wetlands our state is experiencing. Our concern is that by 

awarding this site a permanent designation, the U. S. Army Corps of Engineers-New Orleans 

District is provided with a non-beneficial and less costly alternative to beneficial use of this 

dredged material. 

The long-term indirect impacts of creating a pennanent ODMDS is not complementary to the 

mission of this Office. Louisiana's coastal communities and infrastructure are becoming 

increasingly vulnerable to the harmful effects of tropical storms as om coastal wetlands continue · 

Post Office Box 44487 • Baton Rouge, Louisiana 70804-4487 

617 North Third Street • 10th Floor • Suite 1078 • Baton Rouge, Louisiana 70802 

--------('225)-342,...759'1--- Fax-(225)?42=9459-- http:-f/www:dndouisiaoa:go·u------------

An Equal Opportunity Employer 
30 

·to decline. OCM is cognizant that valuable sediment recovered during maintenance dredging 

operations in the ARBC and other navigation channels should be beneficially utilized to reduce 

this wetland loss; however, the material is routinely wasted in ocean disposal. The Corps has 

long maintained that the cost of pumping dredged material from the ARBC to a suitable 

beneficial use site is prohibitively expensive, exceeding their Federal Standard, and this rationale 

has been used as a justification to avoid so doing. At this time OCM can not fully support the 

designation of a permanent ODMDS on the west side of the ARBC. OCM strongly encourages 

EPA to fully evaluate these indirect effects of this action on the natural and human environment 

of Louisiana. 

We thank you for the opportunity to comment. If you have any questions or wish to discuss this 

further, please call JeffHarris ofthe Consistency Section at (225) 342-7949. 

Sincerely, 

Keith Lovell 

Administrator 

Interagency Affairs/Field Services Division 

KL/JDH/cmc 

cc: John Fiorentino, COE-NOD 

Dave Butler, LDWF 
31 

Fiorentino, J lhn MVN 

From: 

Sent: 

To: 

Subject: 

September 23, 2011 

Beth Altazan-Dixon (Beth.Dixon@LA.GOV] 

Friday, September 23, 2011 11:17 AM 

Fiorentino, John MVN 

DEQ SOV 110920/27 40 USACE-Atchafalaya River Bar Channel 

Joan M. Exnic os, Chief 

USACE Environ Planning Branch 

P.O. Box 6026 

New Orleans, A 70160-0267 

RE: 110920/27 0 

USACE-Atchafa aya River Bar Channel 

Ocean D edged Material Disposal Site 

St. Mar Parish 

Dear Ms. Exni ios: 

The Departmen of Environmental Quality (LDEQ), Business and Community Outreach Division has 

received your request for comments on the above referenced project. 

After reviewi g your request, the Department has no objections based on the information 

provided in y ur submittal. However, for your information, the following general comments 

have been inc uded. Please be advised that if you should encounter a problem during the 

implementatio of this project, you should immediately notify LDEQ's Single-Point-of-contact 

(SPOC) at (22 ) 219-3640. 

se take any necessary steps to obtain and/or update all necessary approvals and 

environmental regarding this proposed project. 

* If you project results in a discharge to waters of the state, submittal of a Louisiana 

Pollutant Dis harge Elimination System (LPDES) application may be necessary. 
32 

* If the roject results in a discharge of wastewater to an existing wastewater treatment 

system, that astewater treatment system may need to modify its LPDES permit before accepting 

the additiona wastewater. 

* All pre~autions should be observed to control nonpoint source pollution from 

construction ~ctivities. LDEQ has stormwater general permits for construction areas equal to 

or greater th~n one acre. It is recommended that you contact the LDEQ Water Permits Division 

at (225) 219-, 181 to determine if your proposed project requires a permit. 

If our project will include a sanitary wastewater treatment f acility, a Sewage 

Sludge and Bi solids Use or Disposal Permit appli cation or Notice of Intent must be submitted no later than June 1, 2011. Additional informat ion may be obtained on the LDEQ website at 

htt :I /www. de .louisiana . ov orta1Lta!2.!f!D.£~_6LQ~f..l!!!)..L.._d;&.?i 

<htt : www . d q . louisiana .gov/portal/tabiQL£.2!-l.f>{DPf.~u.Lr_._~I?.!\ > or by contacting the LDEQ 

Water Permits Division at (225) 219- 3181. 

* If any ·f the proposed work is located in wetlands or other areas subject to the 

jurisdiction of the U.S. Army Corps of Engineers, you should contact the Corps directly 

regarding per~itting issues. If a Corps permit is required, part of the application process 

may involve a !water quality certification from LDEQ. * All pre autions should be observed to protect the groundwater of the region. 

* Please be advised that water softeners generate wastewaters that may require special 

limitations dJpending on local water quality considerations. Therefore if your water system 

improvements nclude water softeners, you are advised to contact the LDEQ Wat er Permits to 

determine if special water quality-based limitations will be necessary. 

* Any renJvation or remodeling must comply with LAC 33:III.Chapter 28, Lead-Based Paint 

Activitiesj L~C 33:III.Chapter 27, Asbestos-Containing Materials in Schools and State 

Buildings (inGludes all training and accreditation)j and LAC 33:III.5151, Emission Standard 

for Asbestos ~or any renovations or demolitions. 

* If any solid or hazardous wastes, or soils and/or groundwater contaminated with 

hazardous con~tituents are encountered during the project, notification to LDEQ's SinglePoint-of-Cont ~ct (SPOC) at (225) 219-3640 is required. Additionally, precautions should be 

Ldken to pr·ot ct workers from these hazardous constituents. 

Currently, St. Mary Parish is classified as attainment with the National Ambient Air Quality 

St andards and has no general conformity determination obligations. 

Please send a 1 future requests to my attention. If you have any questions, please feel free 

to contact me at (225) 219-3958 or by email at P_<.?.t.ll.:..f.1~ Q.D..@lg:KQY !!Ei!l:J.J:.Q.:!?.~.th ... !H!<..Q!l@~ ~Q~> . 

Sincerely, 

Beth Altazan- ixon 

Performance M nagement 

LDEQ/Business and Community Outreach Division 

Office of the Secretary 

2 
33
34 

Choctaw Nation of Oklahoma 

P.O. Box 1210 • Durant, OK 74702- 12 10 • (580)924-8280 

October 20, 20 11 

U.S. Army Corps of Engineers 

New Orleans District 

Regional Planning and Environment Division South 

Attn: Mr. John Fiorentino (CEMVN-PDC-CEO) 

P.O. Box 60267 

New Orleans, Louisiana 70160-0267 

Dear John Fiorentino: 

Gregory E. Pyle 

Chief 

CAry B:~tton 

Assistant Chief 

We have reviewed the following proposed project (s) as to its effect regarding religious and/or cultural 

significance to historic properties that may be affected by an undertaking of the projects area of potential 

effect. 

Project: Atchafalaya River Bar Channel- Ocean Dredge Material Disposal Site 

Project Location: Atcllafalaya River and Bayous Cltene, Boeuf, and Black, Louisiana 

Comments: The Choctaw Nation of Oklahoma has reviewed project (s) and based on the 

information provided to the best of our knowledge it will have no adverse effect on any historic 

properties in the project's area of potential effect. However, should construction expose buried 

archaeological or building materials such as chipped stone, tools, pottery, bone, historic 

crockery, glass or metal items, or should it uncover evidence of buried historic building materials 

such as rock foundations, brick, or hand poured concrete, this office should be contacted 

immediately @ 1-800-522-6170 ext. 2137. 

Sincerely, 

Ian Thompson Ph.D, RPA 

Director Historic Preservation Department 

Tribal Archaeologist, NAGPRA Specialist 

Choctaw Nation of Oklahoma 

By~Caren ::--:::;.....o:*::7T"='-""'- . -­ A 

IT/cj 

Clioctaws ... growina witli y riae. ftoy e ana success! 
35 

ALABAMA-COU~HATTA TRIB€ OF T€XA~ b71 State Pork Rood 56 • Livingston. lcxos 7/351 • (936) 563-1100 

October 12,2011 

U.S. Army Corps of Engineers 

New Orleans District 

Attn: CEMVN-PDC-CEC (Fiorentino) 

P.O. Box 60267 

New Orleans, LA 70160-0267 

Dear Mr. Fiorentino: 

On behalf ofMikko Oscola Clayton Sylestine and the Alabama-Coushatta Tribe, our 

appreciation is expressed on your efforts to consult us regarding the Atchafalaya River 

Ocean Dredged Material Disposal Site proposal in St. Mary Parish. 

Our Tribe maintains ancestral associations throughout the state of Louisiana despite the 

absence of written records to completely identifY Tribal activities, villages, trails, or 

grave sites. However, it is our objective to ensure significances of Native American 

ancestry, especially of the Alabama-Coushatta Tribe, are administered with the utmost 

attention. 

Upon review of your September 15, 2011 submission, St. Mary Parish exists beyond our 

scope of interest for the state ofLouisiana. Therefore, no impacts to cultural assets of the 

Alabama-Coushatta Tribe of Texas will occur in conjunction with this proposal. 

Should you require further assistance, please do not hesitate to contact us. 

Respectfully submitted, 

Historic 

B~~ Preservation Officer 

Telephone: 936 - 563- 1181 celestine.bryant@acrribe.org rax: 936 - 563 1183 
36 

Jessica Franks, PhD 

U.S. Environmental Protection Agency, Region 6 

1445 Ross A venue 

Dallas, Texas 75202-2733 

Franks.jessica@epa.gov 

Dear Dr. Franks, 

William A. Fontenot 

632 Drehr Ave. 

Baton Rouge, LA 70806 

225-383-5673 

wafont@cox.net 

August 16, 2011 

Thank you so much for providing me with information on the plans by the U.S. 

EPA to prepare an Environmental Impact Statement (EIS) on the dredging by the U.S. 

Army Corps of Engineers in Atchafalaya Bay and the placement of the dredged material 

on the west side of the navigation channel. The document linked to the public notice is 

titled, "US Army Corps of Engineers Request for MPRSA Section 102 (c) Designation of 

ODMDS-West for Continued Placement of Maintenance-Dredged Material from the 

Atchafalaya River Bar Channel." Please accept the following as my comments on this 

document. 

On page nine of this document there is a list of Wildlife Management Areas that 

are described as being eight and 29 miles from the areas where dredging and spoil 

disposal are planned. This is not a correct description of the area where the U.S. Army 

Corps of Engineers has been dredging and dumping spoil for many years. The 

Atchafalaya River shipping channel and the spoil disposal areas are located in the middle 

of the Atchafalaya Delta Wildlife Management Area. This is one of the largest state 

Wildlife Management Areas and includes the two emerging bird-foot deltas at the mouth 

of the Atchafalaya River and W~x Lake Outlet as they empty into Atchafalaya Bay. This 

250,000 acre Wildlife Management Area was created many years ago when J. Burton 

Angelle was the secretary of the Louisiana Department ofWildlife and Fisheries and 

Sandra Thompson was the Secretary of the Department of Culture recreation and 

Tourism. For the EPA to put out a public document without recognizing the importance 

of this Wildlife Management Area is troubling and I hope does not indicate a lack of 

attention to this sensitive location. 

In theory, the use of sandy spoil to build Bird Island East and Bird Island West 

with sand-rich spoil is a good idea. However, the document lacks any information 

regarding what efforts will be exerted to maintain these "bird islands" and for how long. 

The document also lacks an answer to whether or not the Corps of Engineers has any 

plans to "improve" these sandy islands with appropriate native marine and terrestrial 

vegetation that would help to provide stability and durability for these sandy islands. 

1 
37 

Other government agencies, such as the U.S. Fish and Wildlife Service, the U.S. 

Department of Forestry, the Louisiana Department of Wildlife and Fisheries, the 

Louisiana Department of Natural Resources and the Louisiana Department of Agriculture 

and Forestry should work with the Corps of Engineers and the EPA to develop plans for 

making these islands more stable and attractive for birds and aquatic species. There 

might also be some resources-other than the budget of the Corps ofEngineersavailable to improve and stabilize these new islands. 

The draft EIS should evaluate the design of these islands so they will be more 

likely to last in the dynamic waters of the Gulf of Mexico. I have visited many banier 

islands and none of the natural islands around the world are in the shape of squares or 

rectangles. The only barrier island I am aware of which is a square is the man-made 

disposal island in Minarnata Bay, Japan where massive quantities of hazardous waste, 

like mercury-contaminated sediment, was buried. 

The public notice made no mention that just last week the Corps of Engineers 

ended public comment on their plans to expand the size ofBird Island West. The EPA 

and Corps of Engineers must provide the public with information on all of the permits for 

dredging and filling that are connected with or in the general vicinity of the Atcbafalaya 

Bar Channel in order for the public to be properly informed. 

The EPA and Corps of Engineers need to provide more information in the draft 

EISon all other projects and developments that are directly or indirectly connected with 

the Atchafalaya Bar Channel and Spoil Disposal Area and any of their potential or real 

cumulative impacts. For instance, the 18-mile Atchafalaya Bar Channel and spoil 

disposal areas are identified by the EPA as part of the larger project called the Bayous 

Chene, Boeuf, Black and Atchafalaya River Project, which is more than 53 miles long. If 

the Atchafalaya Bar Channel did not exist then the Chene, Boeuf and Black project and 

most of the development related to the oil and gas industry from Intracoastal City in the 

western end of Vermillion Bay to Port Fourchom, just west of Grand Isle, would not exist 

today. 

These navigation projects, and especially the Chene, Boeuf, Black and 

Atchafalaya River Navigation Project are intimately connected together as the primary 

pathway for the massive offshore drilling rigs that are built at Amelia and moved down 

the Atchafalaya Bar Channel to the deeper waters of the Gulf of Mexico. Without the 

deeper Atchafalaya Bar Channel none of the massive rigs would have been built at the 

complex of construction sites in Amelia. Probably most of the support facilities along the 

Intracoastal Navigation Canal from Grand Isle to Intracoastal City would also not have 

been built without the Atchafalaya Bay Bar Canal. 

The EIS being developed by the EPA and Corps of Engineers should provide the 

information on the cumulative and comprehensive impacts to coastal resources, including 

water, wetlands and especially fish and wildlife and their habitat from all related projects 

and development as a result of the Atchafalaya Bar Channel. Adverse impacts have 

2 
38 

happened from the deepening of navigation channels, such as from the many tons oftoxic 

and hazardous waste dumped and buried at dozens of locations as well as many hundreds 

of acres of highly-productive wetlands and coastal waters that have been filled in or 

dramatically altered. No comprehensive assessments of all of these coastal-altering 

activities have been pulled together before now and no effort has been made to determine 

the cumulative adverse impacts from navigation and mineral exploration, drilling and 

development on water quality, wetlands, fish and wildlife resources as well as their 

habitat. 

Federal laws and court rulings have given us some excellent examples of how 

and why comprehensive and cumulative impacts need to be identified and evaluated 

when projects like dredging and the placement of spoil is being considered. Federal laws 

like the National Environmental Policy Act, the Clean water Act and the National 

Marine Policy Act provide opportunities for federal officials to insure that their work will 

not only improve the productivity of agencies and projects but help to protect our natural 

resources for present and future generations. Over the last eighty years Louisiana has lost 

more than one million acres of coastal land and wetlands. Most of these losses are the 

direct result of failure of officials on projects-like the Bayous Chene, Boeuf and Black 

and the Atchafalaya River navigation channel-to consider or evaluate land losses from 

dredging and filling of waters and the failure to provide for bank stabilization. 

Since this project is on state land, the bed of Atchafalaya Bay, and since this bay 

is under the jurisdiction of the State Land Office and the Louisiana Department of 

Wildlife and Fisheries, I expect both the EPA and the Corps of Engineers to develop a 

close working relationship with officials in these and other relevant state agencies. 

Whenever our various public officials can work together they are usually more 

productive. 

I look forward to working with the staff of the EPA and the Corps of Engineers on 

the proposed Environmental Impact Statement for the maintenance dredging and 

placement of dredged material in the Gulf of Mexico waters of Atchafalaya Bay. 

Sincerely yours, 

William A. Fontenot 

cc: John F. Fiorentino 

U.S. Army Corps of Engineers 

Coastal Environmental Compliance Section 

P.O. Box 60267 

New Orleans, LA 70160-0267 

john.fiorentino@usace.army.mil 

3 
39 

Jessica Franks, PhD 

William A. Fontenot 

Conservation Chair, Delta Chapter of the Sierra Club 

632 Drehr Ave. 

Baton Rouge, LA 70806 

225-383-5673 

wafont@cox.nct 

November 8, 2011 

U.S. Environmental Protection Agency, Region 6 

1445 Ross A venue 

Dallas, Texas 75202-2733 

Franks.jessica@epa.gov 

RE: Support for the proposed Environmental Impact Statement on dredging activities in Atchafalaya 

Bay, Louisiana 

Dear Dr. Franks, 

The EPA and Corps of Engineers have sent out a number of public notices on the plans by these 

agencies to declare the spoil disposal area on the west side of the Atchafalaya Bay Navigational 

Channel as a permanent disposal area. 

The Sierra Club offers the two suggestions below: 

I -After reading the many documents which are available to us, the Executive Committee of the 

Delta Chapter of the Sierra Club believes that the Environmental Protection Agency and the Corps 

of Engineers were correct in their determination that an Environmental Impact Statement should 

be prepared on the disposal of dredged material in Atchafalaya Bay. 

Clearly, the dredging of a navigational channel for approximately 18 miles in Atchafalaya Bay, 

which is part of the much larger Atchafalaya, Chene, Boeuf and Black Navigation Project, is a 

major federal action which we believe requires an Environmental Impact Statement. 

We also believe that these two federal agencies should, in the near future, prepare a 

comprehensive Environmental Impact Statement for the entire 70 mile project known as the 

Atchafalaya, Chene, Boeuf and Black Navigation Project rather than just the smaller proposed 

EIS for the very limited 18 mile section of the larger 70 plus mile navigation project. 

The primary reason for this extensive navigation project in south central Louisiana is to facilitate 

the movement of the massive oil well drilling structures which are built at the various 

construction sites along the Intracoastal Waterway near Amelia, Louisiana and then transported 

on the project known as the Atchafalaya, Chene, Boeuf and Black navigation project to their 

drilling locations in the Gulf of Mexico. 

While some environmental assessments have been developed by the EPA and Corps of 

Engineers in previous decades there is a real need for a comprehensive Environmental Impact 
40 

statement on the alterations an impacts which have occurred over the last 80 years in the waters, 

wetlands and shores of the Intracoastal Waterway and other waters in and near this very 

productive industrial construction area which is located in one of the most dynamic coastal 

environmental areas in the USA. 

Over the last eighty years Louisiana has lost more than a million acres of coastal lands and 

wetlands. A considerable amount of this loss of critical habitat for fish and wildlife resources and 

for the areas needed to buffer Louisiana from hurricanes has happened in the Morgan City area. 

The EPA and Corps of Engineers have never developed a comprehensive enviromnental impact 

statement which has considered all of the adverse impacts to fish and wildlife resources, their 

habitat, water and air quality, waters and wetlands and human health in the Morgan City area of 

Louisiana. 

Over the last eighty years our Sierra Club members have visited, photographed and evaluated 

hundreds of fish and wildlife areas, construction sites, waste storage and disposal areas and 

alterations for navigation, flood protection and the movement and storage of water. None of our 

federal and state agencies have considered all of the activities like flood control, navigation and 

waste disposal and how these thousands of activities have dramatically impacted human health 

and the environment. 

2 - Inasmuch as Jean Lafitte National Historical Park is one of many interests which has been 

notified of the draft EJS, so should the Atchafalaya National Heritage Area, also a program of the 

Department of the Interior/National Park Service. In 2006 the U.S. Congress passed legislation 

which created the Atchafalaya National Heritage Area which includes more than 10 million acres 

in fourteen parishes, including the Atchafalaya Floodway, Atchafalaya River Basin and the 

Atchafalaya Bay. All of these wetlands are part of this dramatic heritage area .. 

The state staff for the Atchafalaya National Heritage Area is located in the office of the 

Lieutenant Governor. The Program Director is Debra Credeur, 1051 North Third St., P .0. Box 

44243, Baton Rouge, LA 70804-4243, 

The Delta Chapter of the Sierra Club looks forward to working with the U.S. Environmental 

Protection Agency and the U.S. Army Corps of Engineers in updating all of the environmental 

considerations for dredging and spoil placement in Atchafalaya Bay which is part of the 

Atchafalaya, Chene, Boeuf and Black Navigation Project. 

William A. Fontenot