SEPA Office of Water EPA 842-R-25-001
Washington, DC 20004
2020 National MPRSA Ocean Site Monitoring
Assessment Report
EPA Marine Protection Permitting Program
January 2024
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Executive Summary
The Marine Protection, Research, and Sanctuaries Act (MPRSA) regulates the transportation and
disposition (dumping) of any material into ocean waters. Underthe MPRSA, the U.S. Environmental
Protection Agency is responsible for designating and managing MPRSA ocean sites used for
permitted activities. The U.S. Army Corps of Engineers (USACE) is responsible for issuing MPRSA
permits for dredged material using the EPA's environmental criteria; MPRSA permits for ocean
dumping of dredged material are subject to the EPA's review and written concurrence. For all other
materials, the EPA is responsible for issuing MPRSA permits. The EPA, together with USACE,
develops site management and monitoring plans (SMMPs) for each MPRSA ocean site designated
for the ocean dumping of dredged material. The EPA's management and monitoring of these ocean
sites ensures that MPRSA permitted activities will not unreasonably degrade or endanger human
health or welfare, the marine environment, or economic potentialities.
In 2020, the EPA managed 99 MPRSA-designated ocean sites located off the U.S. Atlantic, Gulf of
Mexico, and Pacific coasts; and near the islands of Puerto Rico, Hawaii, Guam, and American
Samoa. This National MPRSA Ocean Site Monitoring Assessment Report provides a comprehensive
overview of the EPA's 2020 monitoring activities conducted at ten MPRSA-designated ocean sites
and one whale carcass disposal area in five of the EPA's coastal Regions:
• Western Long Island Sound Disposal Site, CT (Region 1)
• Historic Area Remediation Site (HARS), NJ and Whale Disposal Area (Region 2)
• Morehead City, NC Ocean Dredged Material Disposal Site (ODMDS )(Region 4)
• Wilmington, NC ODMDS (Region 4)
• Corpus Christi Ship Channel Maintenance, TX ODMDS (Region 6)
• Corpus Christi Ship Channel New Work/Construction, TX ODMDS (Region 6)
• Brazos Island Harbor Maintenance, TX ODMDS (Region 6)
• Brazos Island Harbor New Work/Construction, TX ODMDS (Region 6)
• Matagorda Ship Channel, TX ODMDS (Region 6)
• LA-2, CA ODM DS (Region 9)
Based on the results of these 2020 oceanographic surveys, the EPA determined that
environmentally acceptable conditions were met at each of the surveyed ocean sites and
permitted disposal of dredged material underthe MPRSA can continue at these sites.
Additionally, the EPA will use the data and information collected in 2020:
• to improve on the protocol followed to ensure whale carcasses disposed in ocean
waters off the coast of New Jersey sink to the whale carcass disposal area;
• to inform site management, including modification of five ODMDSs along the Gulf
coast of Texas, as well as future updates to each sites' MPRSA-required
management and monitoring plan;
• to inform future surveys at these sites, including where increased dredged material
disposal from deepening and navigation infrastructure projects is anticipated, to
ensure dumping will not unreasonably degrade orendanger human health orthe
environment; and
• to refine methodologies for collecting data from towed video (e.g., remotely
operated vehicle) to be able to collect comparable quantitative information via
imagery and video in rocky and hard bottom areas.
EPA Marine Protection Permitting Program
2
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Contents
Executive Summary 2
List of Figures 3
Acronyms and Abbreviations 5
1.0 Introduction 6
1.1 Ocean Site Monitoring 7
2.0 Report Objectives 8
3.0 Summary of Monitoring Surveys 9
3.1 Region 1 - Western Long Island Sound Disposal Site 10
3.1.1 Background 10
3.1.2 Survey Objectives, Activities, and Findings 11
3.1.3 Conclusions and Recommended Management Actions 14
3.2 Region 2 - Historic Area Remediation Site, NJ and Whale Carcass Disposal Area 15
3.2.1 Background 15
3.2.2 Survey Objectives, Activities, and Findings 16
3.2.3 Conclusions and Recommended Management Actions 21
3.3 Region 4- Morehead City, NC & Wilmington, NC Ocean Dredged Material Disposal Sites 21
3.3.1 Background 21
3.3.2 Survey Objectives, Activities, and Findings 22
3.3.3 Conclusions and Recommended Management Actions 31
3.4 Region 6 - Corpus Christi, Brazos Island Harbor, and Matagorda Ocean Dredged Material
Disposal Sites 32
3.4.1 Background 32
3.4.2 Survey Objectives, Activities, and Findings 33
3.4.3 Conclusions and Recommended Management Actions 42
3.9 Region 9 - LA-2 Ocean Dredged Material Disposal Site 43
3.9.1 Background 43
3.9.2 Survey Objectives, Activities, and Findings 44
3.9.3 Conclusions and Recommended Management Actions 48
4.0 Next Steps 48
5.0 Acknowledgements 49
6.0 References 49
List of Figures
Figure 1. Approximate locations of the ten ocean sites surveyed in 2020 9
Figure 2. Location of the Western Long Island Sound Disposal Site (WLDS) 11
Figure 3. Acoustic survey transects at the WLDS disposal site 12
Figure 4. Bathymetry of the WLDS study area 13
Figure 5. WLDS bathymetric elevation comparison (depth difference) 2020 vs 2014 14
Figure 6. 2020 Historic Area Remediation Site (HARS) studyarea 17
Figure 7. 2020 HARS survey transects 18
Figure8. Numberof image paris for each percent attached epifauna bin by transect at the HARS..19
EPA Marine Protection Permitting Program
3
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Figure 9. Number of image paris for each coral percent cover by transect at the HARS 20
Figure 10. Number of image pairs for each sponge percent cover bin by transect at the
HARS 20
Figure 11. Morehead City ODMDS and sampling stations 23
Figure 12. Grain size distribution at the Morehead City ODMDS 24
Figure 13. Taxa density (number of species (nos) per m2) at the Morehead City ODMDS 25
Figure 14. 2020 distribution of major taxonomic groups at the Morehead City ODMDS 26
Figure 15. Taxa richness at the Morehead City ODMDS 27
Figure 16. Wilmington ODMDS and sampling stations 28
Figure 17. Grain size distribution at the Wilmington ODMDS 29
Figure 18. Taxa density at the Wilmington ODMDS 30
Figure 19. 2020 distribution of major taxonomic groups at the Wilmington ODMDS 30
Figure 20. Taxa richness at the Wilmington ODMDS 31
Figure 21. Locations of the three study areas in the Gulf of Mexico along the Texas coast 32
Figure 22. Station locations for the Corpus Christi study area 34
Figure 23. Sediment data for the Corpus Christi study area by station, 2020 35
Figure 24. Distribution of major taxa for the Corpus Christi, Texas sampling stations, 2020 36
Figure 25. Taxa richness data for the Corpus Christi, Texas sampling stations, 2020 37
Figure 26. Density data for the Corpus Christi, Texas sampling stations, 2020 37
Figure 27. Sampling locations in and around the Brazos Island Harbor study area 38
Figure 28. Percent composition of substrate particles grouped by type for each station within the
Brazos Island Harbor study area 39
Figure 29. Range chart illustrating results for barium concentrations of the three samples in the
Brazos Island Harbor study area 40
Figure 30. Sampling centroids in and around the Matagorda study area 41
Figure 31. Percent composition of substrate particles grouped by type for each station
within the Matagorda study area 42
Figure 32. LA-2 ODMDS and study area offshore of Los Angeles-Long Beach, CA 44
Figure 33. LA-2 ODMDS study area and SPI-PVI target station locations 45
Figure 34. Predominant grain size by station in the LA-2 study area 46
Figure 35. Sediment type derived from PVI analysis denoting presence of gravels at the LA-2
study area 47
List of Tables
Table 1. Table of MPRSA-designated ocean sites surveyed in 2020. The five sites in Region 6
are located within three study areas: Corpus Christi, Brazos Island Harbor,
and the Matagorda Ship Channel 9
EPA Marine Protection Permitting Program 4
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Acronyms and Abbreviations
aRPD apparent redox potential discontinuity
BVA Barry Vittor and Associates
CFR Code of Federal Regulations
COC contaminant of concern
CTD conductivity, temperature and depth meter
DDT dichloro-diphenyl-trichloroethane
ER-L effects range-low
ER-M effects range-median
ft feet
F/V fishingvessel
HARS Historic Area Remediation Site
km kilometers
km2 square kilometers
m meter
m2 square meter
m3 cubic meter
MPRSA Marine Protection, Research and Sanctuaries Act
MRL minimum reporting limit
nmi nautical mile
nmi2 square nautical mile
NOAA National Oceanic and Atmospheric Administration
ODMDS ocean dredged material disposal site
PAH polycyclic aromatic hydrocarbon
PCB polychlorinated biphenyl
PRA priority remediation area
PVI plan view imaging/image
ROV remotely operated vehicle
R/V research vessel
SMMP site management and monitoring plan
SPI sediment profile imaging/image
SQG sediment quality guideline
SVOC semi-volatile organic compound
TOC total organic carbon
USACE U.S. Army Corps of Engineers
USC United States Code
WLDS Western Long Island Sound Disposal Site
y3 cubic yard
EPA Marine Protection Permitting Program
5
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
1.0 Introduction
The Marine Protection, Research, and Sanctuaries Act (MPRSA) regulates the dumping and
transportation for the purpose of dumping of any material into the ocean. The MPRSA defines
"dumping" broadly as a "disposition of material" which includes release for both disposal and non-
disposal purposes (33 U.S.C. Section 1402(f)).
The MPRSA prohibits or restricts (primarily in terms of material type, amount, and location) the
disposition of materials into the ocean that would adversely affect human health, welfare, or
amenities; the marine environment; ecological systems; or economic potentialities. Section 101 of
the MPRSA (33 U.S.C. 1411) generally prohibits the transportation of any material for the purpose of
dumping, except as authorized by a permit.
In the United States today, the primary material (in terms of volume) permitted under the MPRSA is
uncontaminated dredged material, which is sediment that is excavated or otherwise removed from
our nation's waterways. The removal of sediment supports a network of coastal ports and harbors
that are used for commercial, transportation, national defense, and recreational purposes. In
2019, this marine transportation network, partially facilitated by the dredging of waterways,
contributed more than $69 billion and 581,000 jobs to the U.S. economy (National Ocean
Economics Program). Other materials that are permitted under the MPRSA include fish wastes,
vessels, marine mammal carcasses, and human remains for burials at sea.
Under the MPRSA, the U.S. Environmental Protection Agency establishes marine protection criteria
forthe evaluation of all MPRSA permit applications. Underthe MPRSA, the EPA is the permitting
authority for all materials other than dredged material. In the case of dredged material, the U.S.
Army Corps of Engineers (USACE) issues MPRSA permits (or, in the case of federal navigation
projects, directly authorizes activities underthe MPRSA) using the EPA's marine protection criteria
(40 CFR 227 and 228). All MPRSA permits and federal projects involving the disposition of dredged
material into the ocean are subject to the EPA's review and written concurrence.
Dredged material that is proposed for permitting under the MPRSA is evaluated and tested to
ensure that the material will not adversely affect human health and the marine environment. The
sediments dredged from our nation's waterways sometimes are contaminated by historical
pollution. If biologically available, contaminants may be ingested or absorbed by marine
organisms, resulting in toxicity or bioaccumulation (accumulation of pollutants in the organism's
tissues), which, in turn, exposes other organisms in the food web, potentially including humans.
The Evaluation of Dredged Material Proposed for Ocean Disposal, commonly known as the Green
Book (EPA 503/8-91/001), contains technical guidance for determining the suitability of dredged
material for ocean disposal through chemical, physical, and biological evaluations. Only dredged
material found suitable for permitting under the MPRSA using the procedures in the Green Book
can be released in an MPRSA ocean site.
The EPA establishes the criteria forthe designation of MPRSA ocean sites and is responsible for
designating these sites underthe MPRSA. To minimize the adverse impacts of MPRSA-permitted
activities on human health and the marine environment, the EPA designates sites based on
environmental studies of the proposed site and the regions adjacent to the proposed site, and
historical knowledge of the impact of dumping on areas with similar physical, chemical, and
biological characteristics. The EPA analyzes these impacts through environmental assessments or
environmental impact statements. In general, the EPA designates sites only in areas where MPRSA-
EPA Marine Protection Permitting Program
6
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
permitted activities will not have a significant impact on various amenities, such as fisheries, coral
reefs, and endangered species.
The EPA is also responsible for managing all ocean sites designated under the MPRSA. Managing
MPRSA ocean sites involves:
• regulating the times, quantity, and characteristics of the material released at the site;
• establishing release controls, conditions, and requirements to minimize potential impacts
to the marine environment; and
• monitoring the site and surrounding environment to verify that unanticipated orsignificant
adverse effects are not occurring from historical or continued use of the site and that terms
of the MPRSA permit are met.
All designated MPRSA ocean sites are required to have a site management and monitoring plan
(SMMP). The EPA, in conjunction with the USACE, develops an SMMPfor each site. Each SMMP
includes, but is not limited to:
• a baseline assessment of site conditions;
• a monitoring program for the site;
• special management conditions or practices to be implemented at the site that are
necessary for protection of the environment;
• consideration of the quantity of material and the presence, nature, and bioavailability of the
contaminants in the material;
• consideration of the anticipated long-term use of the site; and
• a schedule for review and revision of the SMMP.
1.1 Ocean Site Monitoring
In 2020, the EPA managed 99 MPRSA-designated ocean sites located off the U.S. Atlantic, Gulf of
Mexico, and Pacific coast; and near Puerto Rico, Hawaii, Guam, and American Samoa.
The EPA monitors environmental conditions in and around ocean sites as part of its
implementation of the MPRSA. Underthe MPRSAand its implementing regulations, the EPA uses
monitoring data to:
• Evaluate potential ocean sites and designate ocean sites (MPRSA 102(c)(1); 40 CFR
228.4(b), 40 CFR 228.6(a));
• Assess trends in environmental impact (40 CFR 228.9(a)(1));
• Evaluate impacts after site use (40 CFR 228.10(a) and (b));
• Modify site use (40 CFR 228.11 (a) and (d));
• Prohibit activities where necessary (MPRSA 102(c)(2)); and
• Develop an SMMPfor each site, which must be reviewed and revised at least every 10 years
(MPRSA 102(c)(3)).
The EPA's Regional MPRSA Coordinators and Chief Scientists plan and conduct oceanographic
surveys to assess the physical, biological and chemical conditions at ocean sites and the
surrounding marine environment. The EPA typically evaluates environmental impact at a site by
comparing current conditions to those at the time of designation (baseline conditions) along with
any other historical survey data. For example, the EPA may use monitoring information to evaluate
movement and deposition of the permitted material to determine whether or how to modify site
use. Ocean areas near the MPRSA ocean site which are not affected by permitted activities are
used for comparisons to assess the impact from site use. The quantity and distribution of samples
EPA Marine Protection Permitting Program
7
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
collected in each monitoring survey are determined based on survey- and site-specific factors. The
information collected from these site assessments inform the EPA's ongoing planning and
decision-making regarding the management and monitoring of ocean sites.
As part of oceanographic surveys of the sites, the EPA may collect a variety of data to ensure that
permitted dredged material is being adequately tested and that there are no unexpected adverse
impacts at and around the sites. Sediment samples, water samples, organisms from benthic
trawls, sediment plan view images (PVI) (photographs of the surface of the seafloor), and/or
sediment profile images (SPI) (photographs of a cross-section of the upper 15-20 cm of the
sediment-water interface) may be collected to evaluate the physical and biological state of the
benthic environment in and around the ocean site and at reference areas. Parameters used to
evaluate benthic habitat or benthic habitat quality include, but are not limited to: sediment grain
size, depth of oxygenated sediment, depth of the apparent redox potential discontinuity (aRPD)
(which indicates habitat quality by measuring interactions between sediment chemistry and
biological activity within sediment), and sediment penetrability (Rhoads and Germano, 1982).
Benthic community health can be classified using defined successional stages and species
diversity. Successional stages at a site can range from stage zero (recently disturbed) to stage
three (mature). Species diversity is a metric which combines species richness (the number of
different species) and evenness (the relative abundance of species) to provide an overall indication
of community structure.
The EPA may also analyze sediment samples for contaminants of concern (COCs) including
metals, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), persistent
pesticides, semi-volatile organic compounds (SVOCs), organotins, and/or dioxins. To evaluate the
extent to which MPRSA-permitted dredged material may impact benthic communities at or near
sites, the EPA commonly compares contaminant concentrations in sediments collected at and
around ocean sites to sediment quality guidelines (SQGs), which are informal benchmarks used to
relate chemical concentrations in sediments to the potential toxicity to benthic or aquatic
organisms. Many EPA Regions rely on effects range low (ER-L) and effects range median (ER-M),
national SQGs which are developed by the National Oceanic and Atmospheric Administration
(NOAA) (NOAA, 1999). Chemical concentrations below the ER-L are not likely to cause adverse
effects, while chemical concentrations above the ER-M are likely to cause adverse effects.
2.0 Report Objectives
In 2020, the EPA's Chief Scientists conducted oceanographic surveys at ten MPRSA ocean sites as
well as one whale carcass disposal area (Table 1, Figure 1) to inform planning and ongoing
decision-making with respect to the management and monitoring of these sites. This national
report serves as a comprehensive summary of these monitoring efforts which were conducted in
five of the seven EPA coastal Regions.
EPA Marine Protection Permitting Program
8
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Table 1. Table of MPRSA-designated ocean sites surveyed in 2020, The five sites in Region 6 are located
within three study areas: Corpus Christi, Brazos Island Harbor, and the Matagorda Ship Channel.
EPA
Region
MPRSA Ocean Site
Area (nmi2)
Depth (ft)
1
Western Long Island Sound, CT (WLDS)
2
75-115
2
Historic Area Remediation Site and whale carcass disposal, NJ
15,7
40-138
4
Morehead City, NC
8
50*
4
Wilmington, NC
9,4
35-52
6
Corpus Christi Ship Channel Maintenance, TX
0,61
35-50
6
Corpus Christi Ship Channel New Work/Construction, TX
1,4
46-53
6
Brazos Island Harbor Maintenance, TX
0.42
43-65
6
Brazos Island Harbor New Work/Construction, TX
0.42
60-67
6
Matagorda Ship Channel, TX
0.54
25-40
9
Los Angeles/Long Beach (LA-2), CA
0.77
360-1,050
* Depth reported as a site average
10
8
Western Long
« Island Sound
~ Historic Area
Remediation Site
~ Los Angeles/Long Beach (LA-2)
& More head City
~ Wilmington
+ Matagorda Ship Channel
~ Corpus Christi New Work &
Corpus Christi Maitenance
~ Brazos Island Harbor New Work &
Brazos Island Harbor Maintenance
fan. DeLorme, NaJtiraVue. Esri.
Figure 1. Approximate locations of the ten ocean sites surveyed in 2020. Numbers indicate EPA Regions,
3.0 Summary of Monitoring Surveys
A summary of 2020 survey objectives, activities, and results, as well as conclusions and
recommended management actions resulting from these surveys, is presented below,
EPA Marine Protection Permitting Program
9
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
3.1 Region 1 - Western Long Island Sound Disposal Site
3.1.1 Background
The Western Long Island Sound Disposal Site (WLDS) lies approximately 3.1 miles (5.0 km) south of
the Connecticut coastline in the western portion of the Long Island Sound and is surrounded by
three historical disposal sites (Figure 2). The WLDS covers an area approximately 2 square nautical
miles (nmi2) (6.9 km2) in size. Water depths at the WLDS vary across the site, sloping from 75 ft (23
m) at the shallowest point along the northwestern boundary to 115 ft (35 m) in the central portion of
the site.
The EPAdesignated the WLDS underthe MPRSAin 2016, howeverthe general vicinity of the WLDS
has likely been used for disposal operations for more than a century. Since the beginning of record
keeping in 1982, approximately 1.5 million cubic yards (y3; 1.15 million cubic meters, m3) of
dredged material has been disposed at the WLDS. Approximately 124,000 y3 (94,805 m3) of dredged
material has been disposed at a single location at the southern-most of two mounds in the North-
East corner of the site since the previous bathymetric survey in 2018.
EPA Marine Protection Permitting Program
10
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
73'WO-W
Figure 2. Location of the Western Long Island Sound Disposal Site (WLDS), depicted as the green square. The
red squares are reference areas, which are sampling locations used for comparison when evaluating WLDS
conditions.
3.1.2 Survey Objectives, Activities, and Findings
The objectives of the 2020 investigation were to characterize the seafloor topography and surface
features of the site and surrounding area to confirm compliance with permits for dredged material
disposal activities, confirm the stability of older dredged material deposits, and evaluate reference
areas associated with the site. The acoustic survey, which consisted of bathymetric, backscatter,
and side-scan sonar data, was conducted within the full WLDS footprint as well as an extended
EPA Marine Protection Permitting Program
11
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
area to the south to further evaluate conditions in and around the existing three reference areas
established for WLDS (Battelle 2020). The survey was conducted aboard the 39 ft (12 m) F/V
Jeanette ffrom October 14 to 16, 2020, prior to the start of any seasonal disposal activities at the
WLDS.
The bathymetric data provided measurements of water depth that, when processed, were used to
map the seafloor topography. Backscatter and side-scan sonar data provided images that
supported characterization of surface sediment texture and roughness. Side-scan sonar data allow
qualitative characterization of features that are not depicted by backscatter or bathymetric data.
Each of these acoustic data types were used to assess dredged material disposal footprint and
surface sediment features.
Acoustic data were collected using an R2Sonic 2022 broadband multibeam echo sounder (MBES).
The total survey covered a rectangular area approximately 1.5x1.9 mile (2.4 x 3.1 km) in size
(Figure 3).
1) Survey conducted 10/14-16/2020.
2) Grid CT State Plane NAD 83 Meters
Figure 3, Acoustic survey transects at the WLDS disposal site. Survey lines are 148 ft (45 m) apart with
crosslines spaced 1,312 ft (400 m) apart, with a total length of 123.4 miles (198.6 km).
EPA Marine Protection Permitting Program
12
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Bathymetric data did not suggest the presence of new disposal features or noteworthy seabed
features (Figure 4).
X Obstruction -
Wreck
Designated Survey Area
Site Boundary
NOTES:
1) Survey conducted 10/14-16/2020.
2) Grid CT Stale Plane NAD 83 Meters
Metiers
2&D 400
Figure 4. Bathymetry of the study area, including the WLDS, as measured during the 2020 survey.
The bathymetric elevation comparison between 2014 and 2020 (Figure 5) suggests accumulation of
approximately 20 ft (6 m) of material in the larger (southern) of the two northeastern mounds, while
the northern mound appears to have compacted by approximately 3.3 ft (1 m), as is generally
observed once disposal operations over an area are terminated.
EPA Marine Protection Permitting Program
13
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
<$>
~T~
24L50O
Site Boundary
Designated Survey Area
~r
242000
NOTES:
1) Positive differences indicate elevatkia increases.
Negative differences indicate cocnpactlcxii and/or evasion.
2) Grid CT Stale Plane NAD 83 Meters
Figure 5. WLDS bathymetric elevation comparison (depth difference) 2020 vs 2014. Positive differences
between surveys suggest deposition/accretion since 2014 (indicated in yellow, orange, and red); negative
differences suggest compaction/erosion since 2014 (indicated in green).
The results from the acoustic backscatter identified a few fine-scale coarse disposal features in
the northern portion of the site that were not observed in 2014 data. It is possible that some of the
finer differences in backscatter between these surveys are associated with differences in acoustic
discrimination capability between multibeam echosounder systems rather than changes in bottom
texture.
3.1.3 Conclusions and Recommended Management Actions
The 2020 WLDS survey objectives were fully met. Region 1 concluded that the disposal of
approximately 124,255 y3 (95,000 m3) of dredged material since the previous survey in 2018 has
increased the size/height of the most recent mound formed in the northeastern portion of the site,
but the deposits formed by the disposal have not dispersed outside of the site. Given the current
EPA Marine Protection Permitting Program
14
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
height and footprint of the active disposal mound in the northeast portion of the site, EPA Region 1
suggests that dredged material disposal at this northeast location should be terminated, and a new
disposal target should be established.
The lack of change in bathymetry across the full site (other than the active area of disposal) when
compared to the 2014 survey further supports the use of the WLDS with confidence in the stability
of deposits formed by the disposal of dredged material. The high-resolution acoustic data
collected to the south of the WLDS will provide additional insight in locating the collection of
reference samples for comparison when evaluating the WLDS site conditions.
The EPA recommends that future monitoring of the WLDS should be conducted following the
disposal a cumulative total of greater than 130,795 y3 (100,000 m3) of dredged material or
sooner if disposal activities are not in compliance with MPRSA federal authorizations and
dredged material permit conditions (e.g., off target disposal).
3.2 Region 2 - Historic Area Remediation Site, NJ and Whale Carcass Disposal Area
3.2.1 Background
Historic Area Remediation Site
The Historic Area Remediation Site (HARS) is located in the New York Bight Apex, approximately 3.5
nautical miles (nmi) east of Highlands, New Jersey, and 7.7 nmi south of Rockaway, New York.
Since the 1800s, the New York Bight Apex has been used for disposal of dredged material and a
variety of other wastes including municipal garbage, building materials, sewage sludge, and
industrial waste. The HARS, which is 15.7 nmi2 in area and an average of 89 ft (27 m) in depth,
encompasses several of these historical disposal sites, including the former New York Bight
dredged material disposal site known as the Mud Dump Site.
The Mud Dump Site was closed in 1996 after surveys revealed dioxin and PCB accumulation in
benthic invertebrates within and around the site. The EPA designated the HARS in 1997 for
placement of dredged material. The management priority for the HARS is to reduce the impacts
from previous disposals to return environmental conditions to acceptable levels, as defined in the
HARS-specific guidance, by covering the surface of the site with uncontaminated dredged
sediments. As such, the EPA designated the HARS as an ocean remediation site, restricting
dumping in the area solely to remediation material (a significant portion of the material placed at
the HARS is rocky and glacial till material from various deepening and widening projects in New
York and New Jersey harbors). The placement of such remediation material renders toxic
sediments unavailable to marine organisms and prevents further exposure to contaminated
sediments. The area targeted for remediation within the HARS is comprised of nine individual
priority remediation areas (PRAs) measuring approximately 1 nmi2 in size (Figure 7). The HARS is
jointly managed by EPA and USACE, and multiple stakeholders and government agencies
collaborate on this effort including state and federal agencies, port authorities, non-governmental
organizations, and academics.
Whale Carcass Disposal Area
Under the MPRSA, the EPA authorizes the ocean disposal of marine mammal carcasses when
there is not another viable option for carcass disposal other than disposal in ocean waters. A
floating carcass near shore (e.g., in a harbor) may pose a risk to public safety before making
EPA Marine Protection Permitting Program
15
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
landfall to the extent it might attract predators (e.g., sharks) to a recreation area in nearby waters or
pose a hazard to navigation.
When a marine mammal carcass is found floating in the NY/NJ Harbor area and there is no viable
option for land-based disposal, the EPA and USACE, in coordination with the NOAA Stranding
Network, tow the carcass to an ocean disposal area located approximately 28 nmi (51.9 km) off the
coast of NJ. Typically, chains and cement blocks are used to sink and anchor the carcass in place
on the seafloor, preventing it from floating back into the harbor area and becoming a hazard to
navigation and/or floating onto a nearby beach. To date, five whale carcasses have been disposed
of in the whale carcass disposal area.
3.2.2 Survey Objectives, Activities, and Findings
Prior to 2020, the most recent EPA survey at the HARS was conducted in 2018 and consisted of
chemistry, physical, and toxicity analyses. The primary objective of the 2020 survey was to use a
remotely operated vehicle (ROV) to survey a rocky hard-bottom area within the HARS and adjacent
sediment types to gather information about how to manage the rock area for successful
colonization by encrusting organisms. A secondary objective of this 2020 survey was to use the
ROV to search for and examine the remains of five whale carcasses disposed in the whale carcass
disposal area and confirm that there are no lasting ecological impacts of several large carcasses
decaying in one location on the seafloor. The survey took place from November 10-17, 2020,
aboard the R/V Hugh R. Sharp.
Historic Area Remediation Site
Most of the 2020 survey time was spent within the HARS in the western regions of PRAs 1, 2, and 3
(Figure 6). Rocky material placed at the western boundary of the HARS in PRAs 1 and 2 originated
from federal deepening projects that occurred from 2001 to 2014. The material placed along the
western margin was Pleistocene glacial till including boulders, rocks, and cobble. No disposal
activity has occurred in PRAs 1-3 since 2014.
EPA Marine Protection Permitting Program
16
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Data: 2020 Bathymetric depth | | PRA
data over acoustic relief model 0 2,500 5,000
5x vertical exaggeration | 1 Western Region ^ iMpfpr
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
73*59'Q"W 73"58'0"W 73 "57tJ"W 73"5$XTW 73'55-O'W 73"54m/V TyWCTW 73'52'0*W 73*81 WIT 73"50'0'W 73'49X>"W
2020 ROV Dive Transect
~ Priority Remediation Area (PRA)
3Nautical Miles
INSPIRE
* s##vMK5*n(»*rAt
Background, NOAA Nautical Chart (Sounding in Feet)
3 Kilometers
0 1
Coordinate System NAD 1 SB3
Os-cument Narrw: HARS_TDls_2020J^GV_Overview Projected Coordinate System NAD 1983 NY Sluts Plane Long Island F*Ht! Date 7 .'28/2021
Figure 7. 2020 HARS survey transects (nine within PRAs 1 -3 and two outside of the HARS) marked in red.
To identify and map out sediment type transitions along the rock boundary area (shown as the red
rectangle in Figure 6), ROV transects were completed throughout PRAs 1 -3 (Figure 7). Along these
transects, forward-facing HD screen grabs and downward-facing plan view digital stills were
collected every two minutes.
The video and images were analyzed for sediment type and percent cover of encrusting organisms,
image pairs of screen grabs and plan view digital still images (images taken less than 30 seconds
apart) from the rock transects were analyzed for substrate type and percent coverage of fauna
identified, image pairs were also analyzed for presence/absence of red clay.
EPA Marine Protection Permitting Program
18
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Initial observations found that levels of rock colonization varied but many rocks (including some in
all transects) had abundant encrusting growth including corals, barnacles, and sponges. No clear
pattern in rock colonization levels was apparent. Larger areas of clay than expected were observed,
including several large clay mounds that were previously thought to be rock piles. These clay areas
did not appear to support many benthic organisms, though some burrows were observed.
In some areas, sediment adjacent to rock was predominantly gravel (>80% gravel cover) or gravel
mixes (30-80% gravel cover). Images from transects in PRA 3 generally had higher occurrences of
sand (<5% gravel cover), gravelly (5-30% gravel cover), and gravel mixes compared to images from
transects in PRAs 1 and 2 where gravel cover tended to be higher. For the artificial reef area outside
of the HARS, image analysis found adjacent sediment type to be predominantly gravel. For the
natural reef area outside of the HARS, image analysis found sediment type to be generally gravelly
with some instances of gravel mixes. Overall, in the western boundary rock area within the HARS,
larger gravel types (boulder and cobble) were observed more often in PRAs 1 and 2. Transects
within PRA 3 contained a wider variety of substrate subgroups, and muddy sandy gravel was most
frequently observed.
Colonization of rocks by encrusting organisms was found to be generally high throughout the
western boundary rock area, where most image pairs from all three PRAs were categorized as
having dense or moderate percent cover of attached epifauna, similar to artificial reef outside of
the HARS (Figure 8). Image analysis of the natural reef area outside of the HARS found a wider
range of epifauna cover, ranging from sparse to dense.
Attached Epifauna
Percent Cover
S
Complete (90-100%)
Dense (70 to <90%)
Moderate (30 to <70%)
Sparse (1 to <30%)
Trace (<1%)
None
PRA 1
North
Figure 8. Number of image pairs for each percent attached epifauna bin by transect at the HARS (INSPIRE
2021). Image pairs are screen grabs from videos and plan view digital still images (images taken less than 30
seconds apart) from the rock transects.
The image analysis found that in PRAs 1 -3 and in the two reference areas outside of the HARS, the
largest size rocks (boulders) had the highest levels of faunal percent cover.
The northern star coral (Astrangia poculata) and sponges (e.g., Clionia) were documented in all
transects in PRAs 1, 2, and 3. The northern star coral occurred in more image pairs and at higher
percent cover values in PRAs 1 and 2 compared to those in PRA 3 (Figure 9). The opposite pattern
EPA Marine Protection Permitting Program
19
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
was observed for sponges, with sponges occurring at highest percent cover values in images from
transects in PRA 3 (Figure 10).
- 10
CD
3 5
CO
CO
CT>
CM
00
CO
CNI
CO
00
o
CO
CO
CO
CO
CO
h-
CM
CO
PRA 1
North
PRA 2
PRA 3
-> South
00
CO
co
tj- in
co co
oo co
REF
Northern Star Coral
Percent Cover
i
30 to <40%
20 to <30%
10 to <20%
1 to <10%
<1%
None
IND
Figure 9. Number of image pairs for each coral percent cover bin by transect at the HARS (INSPIRE 2021).
Image pairs are screen grabs from videos and plan view digital still images (images taken less than 30
seconds apart) from the rock transects.
20
% 15
0.
o>
cn
TO
— 10
CD
.Q
E
=!
I
I
t-mpv-CDCMOCOh-COTj-LO
COCNCOCOCOCOCOCSICOCOCO
COCOOOOOOOCOCDCOCOOOOO
PRA 1
North
PRA 2
PRA 3
South
REF
Sponge
Percent Cover
I
50 to <60%
40 to <50%
30 to <40%
20 to <30%
10 to <20%
1 to <10%
<1%
None
IND
Figure 6. Number of image pairs for each sponge percent cover bin by transect at the HARS (INSPIRE 2021).
Image pairs are screen grabs from videos and plan view digital still images (images taken less than 30
seconds apart) from the rock transects.
In PRAs 1 and 2, northern star coral percent cover was generally higher than sponge cover, and in
PRA 3 and both reference transects, sponge percent cover was generally higher than northern star
coral percent cover. Northern star coral and sponges were found at similar densities in image pairs
from the two transects outside of the HARS.
EPA Marine Protection Permitting Program
20
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Whale Carcass Disposal Area
During the ROV survey of the whale carcass disposal area, Region 2 located bones and sinking
blocks from only one whale carcass. Neither the bones nor sinking blocks from the other four
whales disposed in the area were found within the study area. The remains that were located were
from a humpback whale that had been disposed of six months prior to this survey. Monitoring
results revealed that the carcass was reduced to whale bones with minimal whale tissue remaining
within six months, and Region 2 found no measurable impact on sediment quality parameters
(including total organic carbon, grain size, and polychlorinated biphenyl concentration) from
carcass decomposition.
Follow up discussions between EPA Region 2 and USACE suggested that the most likely reason the
remains of the other four whales were not located in the whale disposal area is either that the tow
vessel or carcass drifted off the disposal area while sinking was in process.
3.2.3 Conclusions and Recommended Management Actions
The survey objectives were accomplished, and environmentally acceptable conditions are being
met at the HARS. The ROV footage of the western boundary rock area shows that deepening
material made primarily of large rocks has been successful at creating artificial reef habitat with
high levels of encrusting organism colonization in the HARS regardless of adjacent sediment type.
Based on observations of red clay mounds having little visible colonization by benthic organisms,
an SPI survey was subsequently conducted to delineate the areas of red clay within the HARS and
to assess the level of colonization by benthic organisms. The Region plans to have further
discussions with the federal and local partners and stakeholders about management of existing
clay areas within the HARS and future placement of clay material. Additionally, Region 2 will
consider the results of the 2020 survey when updating the SM MP for the HARS.
Recommended management actions for future whale carcass disposals in the NY/NJ Harbor area
include using an improved sinking protocol where the EPA and USACE will release trapped gasses
within the carcass with a blade before sinking to reduce buoyancy and increase sinking speed. In
addition to using chains and cement blocks to weigh down the carcass, releasing trapped gasses
should help ensure the carcass ends up within the whale carcass disposal area coordinates.
3.3 Region 4- Morehead City, NC & Wilmington, NC Ocean Dredged Material Disposal
Sites
3.3.1 Background
Morehead City ODMDS
Designated by the EPA in 1987, the Morehead City ODMDS is located approximately 3 nmi (5.6 km)
south of Atlantic Beach, near Cape Lookout, North Carolina (Figure 11). The site is 8 nmi2 (27.4 km2)
in size and averages approximately 50 ft (15 m) in depth. Material at the site consists primarily of
fine sand from the Morehead City Harbor and entrance channel. The last status and trends survey
at the Morehead City ODMDS was completed in September 2011. In the last fifteen years, the site
has received a yearly average of 485,207 y3 (370,967 m3) of material.
Wilmington ODMDS
The EPA designated the Wilmington ODMDS in 2002. The site is located approximately 5 nmi (9.7
km) offshore Bald Head Island, North Carolina. The Wilmington ODMDS has an area of about 9.4
EPA Marine Protection Permitting Program
21
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
nmi2 (27.4 km2) (Figure 16). Depths within the ODMDS range from approximately 35 to 52 ft (9 to 11
m). On average, approximately 1.5 million y3 (1.15 million m3) of dredged material is disposed
annually. The ODMDS is used for the disposal of new work and maintenance material from the
Wilmington Harbor Civil Works Navigation Project, and channels and berthing areas maintained for
the Military Ocean Terminal, Sunny Point. An SMMP was developed for the site at designation and
reviewed and revised in 2012. The EPA last conducted a trend assessment survey at the
Wilmington ODMDS in May 2010.
Because of the proximity of these MPRSA-designated ocean sites to each other, oceanographic
monitoring was conducted at both site during the same survey.
3.3.2 Survey Objectives, Activities, and Findings
The primary objective for this survey was to collect sediment, water, and benthic biota samples
from each site to conduct a routine trend assessment ensuring the sites were meeting
environmental goals. The purpose of a trend assessment survey is to determine the physical,
chemical, and biological structure of a disposal site and assess how those parameters change over
time. The information collected during trend assessment surveys are also used to evaluate the
efficacy of the current SMMP. The survey was conducted aboard the University of Georgia's R/V
Savannah from February 7-12, 2020.
During this survey, Region 4 collected benthic (sediment and biological) samples and assessed the
water column at each site. Region 4 collected sediment and macroinvertebrate samples using a
double 0.04m2 Young Grab (two 0.04m2 grabs in one frame). The sediment samples were
processed on board and sent to a laboratory to be analyzed for grain size distribution and
concentrations of PCBs, pesticides, semi-volatile organics (SVOAs), metals, total organic carbon
(TOO), total solids and butyl-tins. Macrofauna samples were also processed on board and sent to a
laboratory to be analyzed for benthic community parameters including density, diversity, evenness,
and richness. Additionally, Region 4 collected physiochemical data from the water column at the
center of each site. The vessel's conductivity, temperature, and depth (CTD) probe was used to
measure dissolved oxygen, salinity and temperature throughout the water column at that station.
Region 4 scientists compared the physical, chemical and biological results among stations within
the ODMDSs and to stations outside of the ODMDSs. They also compared sediment chemistry
results against historical concentrations at the ODMDSs.
EPA Marine Protection Permitting Program
22
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
chemistry and macroinvertebrates, six of which were outside the ODMDS (MH14-MH19).
Morehead City ODMDS
Results from the sediment grain size analysis showed that sediment grain sizes were fairly uniform
within and outside of the Morehead City ODMDS and consisted largely of fine sand (Figure 12).
Fines (silts and clays) at stations inside and outside the ODMDS ranged from a minimum of 2,4% to
a maximum of 9.7% of the sediment composition. The similarities in sediment texture measured
inside and outside of the ODMDS suggest that conditions across the study area are relatively
consistent and that disposal activities are not altering the grain size conditions within the site
compared to conditions in the surrounding area where no dredged material has been disposed.
EPA Marine Protection Permitting Program
23
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Morehead City, NC ODMDS Grain Size Distribution
w 1 f i i i r i m s 11 n 11 pi 111
90
80
70
60
as 50
40
30
20
10
01 j . y 111 iiiiiiii 11 i.i i ¦
MH01 MH02 MH03 MH04 MH04D MH05 MH06 MH07 MH08 MH09 MH10 MH11 MH12 MH13 MH14 MH15 MH16 MH17 MH18 MH19
Inside Stations Outside Stations
¦ Gravel ¦ Coarse Sand ¦ Medium Sand ¦ Fine Sand ¦ Fines
Figure 8. Grain size distribution at the Morehead City ODMDS. All stations were predominantly sand with
variable amounts of fines.
Results from Region 4's sediment chemistry analyses showed that, with the exception of four
metals (arsenic, chromium, iron, and lead), the concentration of all contaminants (PCBs,
pesticides, SVGAs, metals, TOC, total solids, and butyl-tins) was at or below the minimum
reporting limit (MRL), The concentrations of the aresenic, chromium, iron, and lead that were
detected above the MRL were below levels of concern. There were no significant differences in
metals concentrations inside versus outside the ODMDS.
Benthic infaunal (sediment-dwelling) communities can be used as indicators of the ecosystem
health at the seafloor. Region 4 used macroinvertebrate data to compare community parameters
between stations inside the site versus outside the site. Results from the 2020 survey showed that
the only statistically significant difference in macrofauna was that the density of macrofauna
collected from outside of the site was greater than the density of macrofauna collected from inside
of the site (Barry Vittor and Associates (BVA) 2020A, Figure 13). Densities inside the ODMDS ranged
from 1,200 organisms/m2 at Station MH3 to 3,525 organisms/m2 at Station MH11, with an average
of 2,189 organisms/m2. Densities outside the ODMDS ranged from 988 organisms/m2 at Station
MH19 to 4,825 organisms/m2 at Station MIH14, with an average of 3,435 organisms/m2 (BVA 2020A).
EPA Marine Protection Permitting Program
24
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
5000
4000
3000
0
3
I'
1
a
| 2000
H
1000
•— C-J
h
H h
Liside
Station On Ride
Figure 9. Taxa density (number of species (nos) per m2) at the Morehead City ODMDS. Density was
significantly higher at stations outside the ODMDS when compared to stations inside the ODMDS.
Stations inside the Morehead City ODMDS were either dominated by annelids (MH1, MH2, MH5,
MH6, MH8-MH13}, arthropods (MH4 and MH7), or by other taxa (MH3). Stations outside the
ODMDS had similar patterns in that annelids dominated MH14, MH15.MH17, andMH18,
arthropods dominated MH16, and othertaxa dominated MH19 (BVA 2020A, Figure 14).
EPA Marine Protection Permitting Program
25
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
70
MH1 MH? MH3 MH4 MH5 MH6 MH7 MH8 MH9 MH10 MH11 MH1? MH13
Inside Stations
¦ Annelida ¦ Mollusca BArthropoda Other Taxa
MH14 MH1S MH16 MH17 MH18 MH19
Outside Stations
Figure 10. 2020 distribution of major taxonomic groups at the Morehead City ODMDS.
Taxa diversity inside the Morehead City ODMDS ranged from 2.59 at Station MH3 to 3.50 at Station
MH9 (average = 3.18}. Taxa diversity outside the ODMDS ranged from 1.93 at Station MH19 to 3.55
at Station MH14 (average = 3.11). The high taxa diversity both inside and outside the site reflects a
species-rich assemblage at all stations associated with the Morehead City ODMDS (BVA2020A).
Taxa evenness inside and outside the Morehead City ODMDS ranged from 0.76 to 0.91 and 0.71 to
0.87, respectively. Taxa richness inside the ODMDS ranged from 30 to 61 and outside the ODMDS
ranged from15 to 66 (Figure 15). Taxa diversity, richness, and evenness all showed no significant
differences between stations inside the site versus outside the site (BVA 2020A).
EPA Marine Protection Permitting Program
26
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
70
65
60
55
50
Figure 11. Taxa richness at the Morehead City ODMDS. Taxa richness averaged 44.5 for stations inside the
ODMDS and 51.5 for stations outside the ODMDS.
Region 4 compared the data collected from the 2020 survey to data from the survey conducted iri
2011. Overall, there were no significant differences in the benthic macroinvertebrate community
from 2011 to 2020 (BVA 2020A). Taxa richness was 2.8x and 3.Ox higher in 2020 inside and outside
the ODMDS when compared to 2011. Densities were also 2.8x and 3.3x higher inside and outside
the ODMDS when compared to 2011. However, there was no statistically significant difference
found for richness or density between 2011 and 2020 (BVA 2020A).
Results from Region 4's CTD cast showed that dissolved oxygen, salinity, and temperature were
similar throughout the water column. These in-situ water column profiles can be used to describe
the physical characteristics of the water and serve as a foundation for understanding the local
marine environment. By looking at the physiochemical properties of the water column profile,
Region 4 can identify anomalies indicative of impacts from dredged material disposal activities.
The parameters Region 4 measured at the Morehead City ODMDS were within expected values for
this nearshore, shallow environment indicating no lasting impacts from dredged material disposal
were present in the water column.
EPA Marine Protection Permitting Program
27
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
"^7
\y
s."
Wilmington, NC OD1MDS Stations
February7, 2020
i '»
i
i
1 Oc H'J j
A
Pilot Boarding Area
45 ^4
r! Z
%> v,
fl'/V *cn *
Mo (A)
' WHIS
f?AGON ( ¦ ¦)
A!$
46
4?
SB
V:i?
34
X/
\ 47
%
\
\
>s
&
vvu 17
/
,47
I
£ urns
/" .
f Du,r:p-zf&
r (Jre-'jge-J
I far:* nil*': 5}
j Deotns from Sursey of 20Cf7
W12
f MSA
W01
3c
W02 W03
WJ F!H4n
42'OOJji
4£5V16
W15
s
4a
¦ Nautical Miles
0 0.25 0.5
1.5
~
CTD Cast
43
•
Wilmington Sediin ent Stations
4'
50
I 47
f
Figure 12. Wilmington ODMDS and sampling stations. Sixteen stations were sampled for sediment chemistry
and macroinvertebrates, eight of which were outside the ODMDS (W09-W16).
Wilmington ODMDS
Results from the sediment grain size analysis showed that sediment grain sizes were fairly uniform
within and outside of the Wilmington ODMDS, inside the site boundaries, all but two stations
consisted of >92% sand. Stations outside of the site all consisted of greater than 94% sand (BVA
202QB, Figure 17). The similarities in sediment texture measured inside and outside of the ODMDS
suggest that conditions across the study area are relatively consistent and that disposal activities
are not altering the grain size conditions within the site compared to conditions in the surrounding
area where no dredged material has been disposed.
EPA Marine Protection Permitting Program
28
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
WILMINGTON, NC ODMDS, (20-0149)
GRAIN SIZE DISTRIBUTION, FEB. 2020
Inside Stations Outside Stations
¦ Fines F Sand iMSaac lCSand ¦ Gravel
Figure 13. Grain size distribution at the Wilmington ODMDS. Sediment grain sizes were similar at stations
both inside and outside the ODMDS.
Results from Region 4's sediment chemistry analyses showed that the concentration of five metals
were at or below the MRL. Seven metals (aluminum, arsenic, chromium, lead, nickel, and zinc)
were measured in concentrations above the MRL, however, their concentrations were below levels
of concern. Results from sed sediments that were tested for PCBs, pesticides, SVOAs, metals,
TOC, total solids, and butyl-tins were all at or below the minimum reporting limit MRL. There were
no significant differences iri metals concentrations inside versus outside the ODMDS.
Results from the macrofaunal analyses showed that macrofaunal densities inside the ODMDS
ranged from 425 organisms/m2 at Station W02 to 1,638 organisms/m2 at Station W07 (BVA 2020B,
Figure 18). Densities outside the ODMDS ranged from 938 organisms/m2 at Station W09 to 4,113
organisms/m2 at Station W14. There was no significant difference in density between stations
inside and outside the ODMDS. Additionally, benthic organism densities at stations both inside and
outside the ODMDS were not significantly different in 2020 when compared to results from the
survey conducted in 2010.
EPA Marine Protection Permitting Program
29
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
£
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
0
Wilmington. NC ODMDS (20-0149)
Taxa Density (Taxa/m2) (February. 2020)
. . -=\
l.llllll ll
a=i+
n
WM W02 W03 W04 W05 W06 W07 W0S
Inside Stations
W09 W10 Wll W12 W13 W14 W15 W16
Outside Stations
Figure 14. Taxa density at the Wilmington ODMDS. Densities averaged 1,000.0 organisms/m2 inside the
ODMDS and 1,698.4 organisms/m2 outside the ODMDS.
In 2020, taxa diversity was high both inside (2.80) and outside (3.03) the Wilmington ODMDS,
reflecting a species-rich assemblage at all stations associated with the Wilmington ODMDS site.
There was no significant difference in diversity between stations inside and outside the ODMDS.
Taxa diversity at stations both inside and outside the ODMDS was not significantly different in 2020
when compared to 2010 (BVA2020B). The stations inside the ODMDS were dominated by a mixed
assemblage of annelids, mollusks (bivalves), and arthropods (amphipods). The stations outside the
ODMDS were dominated by annelids and mollusks (Figure 19).
Annelida t-v-M Molhisca
Artkropoda I I Other Taxa
3
P
|I|A
1
Figure 19. 2020 distribution of major taxonomic groups at the Wilmington ODMDS.
EPA Marine Protection Permitting Program
30
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Taxa richness inside the ODMDS ranged from 18 taxa at Stations W02 and W04 to 44 taxa at Station
W07. Taxa richness outside the ODMDS ranged from 28 taxa at Station W16 to 44 taxa at Stations
W10 and W14 (Figure 20). In 2020, taxa richness was significantly higher at stations outside the
ODMDS when compared to stations inside the ODMDS. There was no significant difference in taxa
richness inside and outside the ODMDS between 2010 and 2020 (BVA 2020B).
Wilmington. NC ODMDS (20-0149)
Taxa Richness (February, 2020)
50
45
40
W01 W02 WQ3 W04 W05 W06 W07 W08 W09 W10 Wll W12 T.VI3 W14 WI5 W16
Inside Stations Outside Stations
Figure 15. Taxa richness at the Wilmington ODMDS averaged 26.1 for stations inside the ODMDS and 36.9 for
stations outside the ODMDS.
Taxa evenness inside the ODMDS ranged from 0.76 at Station W06 to 0.94 at Station W02. Taxa
evenness outside the ODMDS ranged from 0.64 at Station W14 to 0.93 at Station W09 (BVA2020B).
Results from Region 4's CTD cast showed that dissolved oxygen, salinity, and temperature were
similar throughout the water column. These measurements were within expected values for this
nearshore, shallow environment and indicated that no lasting impacts from dredged material
disposal were present in the water column.
3.3.3 Conclusions and Recommended Management Actions
The data and information collected from this survey show that ongoing dredged material disposal
activities have resulted in little change to the physical, chemical, and biological characteristics of
both the Morehead City and Wilmington ODMDSs and surrounding areas. The results from the 2020
survey confirm that environmentally acceptable conditions, as outlined in the SMMP, are being met
at the Morehead City ODMDS and at the Wilmington ODMDS and that pre-disposal testing and
evaluation of dredged material has been effective at preventing any contaminated material from
being disposed of at the ocean sites. While this information will be incorporated into the next
SMMP update for each ofthese MPRSA ocean sites, no immediate site management modifications
are necessary at this time.
Region 4 intends to continue to routinely monitorthe chemical, physical, and biological
parameters inside and surrounding both ODMDSs to document any changes to the area, ensure
that short-term anticipated impacts stay within the boundaries of the ODMDSs, and thatdisposal
activities are not causing lasting adverse impacts.
EPA Marine Protection Permitting Program
31
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
3.4 Region 6-Corpus Christi, Brazos Island Harbor, and Matagorda Ocean Dredged
Material Disposal Sites
3.4.1 Background
In February 2020, the EPA monitored five ODMDSs in the Gulf of Mexico: (1) Matagorda Ship
Channel, (2) Corpus Christi New Work, (3) Corpus Christi Ship Channel Maintenance, (4) Brazos
Island Harbor, (5) Brazos Island Harbor 42-Foot Project (New Work). The EPA anticipates increased
use of the five ODMDSs, which has prompted the need to consider site expansions to meet
anticipated site capacity needs. These five ODMDSs are located within three study areas (Figure
21).
Corpus Christi
Corpus Christi
Bay
Texas
Legend
I Survey Area
/i lie
c
Matagorda
Bay
Matagorda
Corpus Christi)
Brazos Island
Harbor
Gulf
of
Mexico
-i *
J
25
50
Coordinate System: GCS North American 1983
Depth in (Units)
100 Kilometers
—I
o
Figure 16. Locations of the three study areas in the Gulf of Mexico along the Texas coast.
EPA Marine Protection Permitting Program
32
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Matagorda Ship Channel ODMDS
The EPA designated the Matagorda Ship Channel ODMDS on September 10,1990. The Matagorda
Ship Channel ODMDS is a rectangular site occupying an area of approximately 0.5 nmi2 (1.9 km2)
with depths ranging from 25 to 40 ft (7.6 to 12.2 m). The USACE conducts regular operation and
maintenance dredging activities of the Matagorda Ship Channel removing an average of 2 million y3
(1.53 million m3) of dredged material annually. The study area monitored during this survey extends
3 nmi2 (10.3 km2) and includes the designated ocean site, an area being considered for site
expansion, and the surrounding marine environment.
Corpus Christi ODMDSs
EPA designated the Corpus Christi Ship Channel New Work ODMDS (formerly Homeport Project,
Port Arkansas, Texas) on August 31,1988. The Corpus Christi Ship Channel New Work ODMDS is
rectangular in shape and covers 1.4 nmi2 (4.8 km2) of the sea floor in water depths naturally ranging
from approximately 46 to 53 ft (14 to 16 m). The site is located approximately 3.3 nmi (6.1 km)
offshore.
The Corpus Christi Ship Channel Maintenance ODMDS was designated by the EPA on July 11,1989.
The site is rectangular in shape and covers 0.6 nmi2 (2.1 km2) of the sea floor in water depths
naturally ranging from approximately 35 to 50 ft (10.7 to 15.2 m). The Corpus Christi Ship Channel
Maintenance ODMDS is located approximately 1.7 nmi (3.1 km) offshore. The highest shoaling
sections of the Entrance Channel are dredged approximately every two years, and this
maintenance dredged material is disposed at the Corpus Christi Ship Channel Maintenance
ODMDS. Since the 1989 designation, approximately 9.5 million y3 (7.26 million m3) of dredged
material, primarily from the Entrance and Jetty Channels, have been disposed at the Corpus Christi
Ship Channel Maintenance ODMDS.
Brazos Island Harbor ODMDSs
The EPA designated the Brazos Island ODMDS on September 11,1990. Since then, approximately
3.6 million y3 (2.75 million m3) of dredged material from the Entrance and Jetty Channels have been
disposed there. The site is located approximately 1.6 nmi (3.0 km) offshore with water depths
ranging from 43 to 65 ft (13.1 to 19.8 m).
A second site, the Brazos Island 42-Foot Project (New Work) ODMDS, was designated by the EPA
on January 17,1992, for the disposal of construction dredged material from channel improvement
projects in Brazos Island Harbor. The site is located approximately 3.8 nmi (7.0 km) offshore with
water depths ranging from 60 to 67 ft (18.2 to 20.4 m). Approximately 575,000 y3 (439,620 m3) of
new work material from the widening and deepening of the Brazos Island Harbor Entrance and Jetty
Channels was placed at the Brazos Island Harbor NewWork ODMDS from February 20,1992, to
April 14,1992. This has been the only disposal to occur at the site.
The Brazos Island Harbor study area monitored during this survey extends 5.4 nmi2 (18.5 km2) and
includes both of the MPRSA-designated ocean sites each with an area of 0.42 nmi2 (1.4 km2), the
area being considered for expanding the sites, and the surrounding marine environment.
3.4.2 Survey Objectives, Activities, and Findings
The purpose of conducting monitoring in these three study areas was to collect sediment and
benthic macroinfaunal samples to 1) characterize the current physical, chemical, and biological
benthic conditions, 2) conduct a routine trend assessment ensuring the sites were meeting
environmental goals, and 3) collect data to from areas surrounding the site to inform site
EPA Marine Protection Permitting Program
33
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
expansions iri each area. Depending on the type of substrate material encountered, one of two
grab samplers were used, a Van Veen or a Smith-Mclntyre from the 135-ft (41-meter) Louisiana
Universities Marine Consortium (LUMCON) R/V Point Sur.
During this 2020 survey, Region 6 collected benthic (sediment and biological) samples from each
of the three study areas. The sediment samples were processed on board and sent to a laboratory
to be analyzed for the numerous contaminants of concern and conventional parameters including
grain size distribution, total organic carbon, metals, phenols, hydrocarbons, PCBs, and pesticides.
The full list of contaminants of concern and conventional parameters can be found in EPA Region
6's Regional implementation Agreement (USACE and USEPA, 2003) for ocean dredged material
disposal projects in Louisiana and Texas. Macrofauna samples were also processed on board and
sent to a laboratory to be analyzed for benthic community parameters including density, diversity,
evenness, and richness. Region 6 scientists compared the physical, chemical and biological
results among stations within the ODMDSs and to stations in the surrounding marine environment.
Matagorda
TX rjy
Corpus *
I
:os\
nd i
Brazos,
Island
Gulf of
M e x ic o
Si
8 Kilometers
H
2 4
h 1 1 ( v
Coordinate System: NAD 1983 StatePlane Texas South FIPS 4205 Feet
Depth in Meters
Legend
ft Sediment Grab Sample
I I Sampling Location
I I Current ODMDS Boundary
e /v
Texas
Figure 17. Station locations for the Corpus Christi study area. Twelve benthic monitoring stations were
located within the disposal areas and 18 stations were located outside of the ODMDS and in the potential
expansion area.
Corpus Christi ODMDSs
Results from the sediment grain size analysis showed that sediments throughout the Corpus
Christi study area varied. Sediments ranged from >80% sand at 20 stations to approximately 90%
silty-clay at three stations. A significant percentage of silty-clay fractions (>30%) was also found at
six stations, and some percent gravel fraction (shell hash) was found at four stations (BVA 2020C,
Figure 23).
EPA Marine Protection Permitting Program
34
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
%GraveI ~ %Sand
%Silt+Clay HI] %Moisture
%Solids
Percent
Figure 18. Sediment data for the Corpus Christi study area by station, 2020.
Results from Region 6's sediment chemistry analyses of samples collected from the Corpus Christi
study area showed that no trends were apparent, and all contaminants were found in very low
concentrations. Three metals, barium, manganese and nickel exceeded screening levels and
concentrations were higher in areas with higher proportions of silt and clay. Even though the
concentrations of these metals exceeded screening levels, they were found at very low levels
lacking risk potential and indicating no issues of concern.
Overall, the macroinfaunal assemblages inside the existing Corpus Christi ODMDSs were similar to
those outside of the ODMDSs, in terms of species abundance and composition of major taxonomic
groups (Annelida, Mollusca, and Arthropoda). Inside the ODMDS sites, all but two stations located
in the southeastern portion of the Corpus Christi study area were dominated (>50% assemblage
composition) by annelids; Station CC-025 was dominated by polychaetes, mollusks, and
arthropods, while Station CC-027 was co-dominated by polychaetes and arthropods. Outside the
ODMDS sites, all but six stations were dominated by polychaetes (Figure 24). The average total
biomass at the 12 stations inside the ODMDS sites was 1.67 g, and the average total biomass at the
18 stations outside the ODMDSs was 0.92 g (BVA 2020C).
EPA Marine Protection Permitting Program
35
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
100
90
so
70
60
50
40
30
20
10
I I Annelida 1 I Molhisca Arthropoda I I Other Taxa
3
E
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Inside
H I-
Outside
Station
Figure 20. Taxa richness data for the Corpus Christi, Texas sampling stations, 2020.
4500'
4000-
/
3500-
a
i
3000-
s
r—
2500'
2000-
1500-
1000 ¦
500'
ol
H H
Inside
Station
Outside
Figure 21. Density data for the Corpus Christi, Texas sampling stations, 2020.
EPA Marine Protection Permitting Program
37
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Taxa diversity at the stations inside and outside the ODMDSs averaged 2.48 and 2.62, respectively.
Taxa evenness inside and outside the ODMDS sites ranged from 0.62 to 0.91 and 0.60 to 0.90,
respectively (BVA 2020C).
Figure 27. Sampling locations in and around the Brazos Island Harbor study area.
Matagorda <
TX .
Corpus
Gulf of
Mexico
w
\A
Brazos\ J Area Shown |
Jsland \
Legend
• Sediment Grab Sample
~ Sampling Location
I I Current ODMDS Boundary
>S
XV
1 2
1 1 1 1 1
Coordinate System NAD 1983 StatePlane Texas South FIPS 4205 Feet
Depth in Meters
Brazos Island Harbor ODMDSs
Results from the sediment grain size analyses showed that sediments across the Brazos Island
Harbor study area were predominately sand, ranging from 90 to 95% with an average of 92% (Figure
28, Tetra Tech, Inc. 2020A) at all stations sampled.
EPA Marine Protection Permitting Program
38
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Substrate Type
I Clay
Gravel
Sand
Silt
001 002 003
Centroid 1
004 005 006
Centroid 2
007 008 009
Centroid 3
010 011 012
Centroid 4
013 014 015
Centroid 5
016 017 018
Centroid 6
019 020 021
Centroid 7
022 023 024
Centroid 8
025 026 027 028 029 030
Centroid 9 Centroid 10
SitelD
Figure 28. Percent composition of substrate particles grouped by type for each station within the Brazos
Island Harbor study area.
Results from Region 6's sediment chemistry analyses of the Brazos Island Harbor study area
showed that no trends were apparent, and all contaminants were in very low concentrations.
Sample location 6 (outside the ODMDSs) indicates slightly higher levels for several metals;
however, barium is the only measured constituent to exceed a screening threshold (Figure 29, Tetra
Tech, Inc. 2020A). Application of the threshold screening values resulted in exceedances for one
contaminant, barium. Though limited variation in substrate characteristics seems to be associated
with low concentrations of contaminants, there are no aspects of the sediment chemistry
indicating issues of concern.
EPA Marine Protection Permitting Program
39
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Baiiurii
50-
40-
1 I
.(O^ k <8^
G® G® G® G® G® G® G® G®^0^°
Figure 29. Range chart illustrating results for barium concentrations of the three samples in the Brazos
Island Harbor study area.
Macrofaunal data across the Brazos Island Harbor study area showed that most stations inside of
the site and all the stations outside the ODMDSs were dominated by polychaetes. Taxa richness
averaged 32 taxa/station inside the ODMDSs and 24 taxa/station at stations outside the ODMDSs.
Densities at stations inside the ODMDSs averaged 931.9 organisms/m2 and densities at stations
outside the ODMDSs averaged 526.0 organisms/m2. The macroinfaunal assemblages found at
stations both inside and outside the Brazos Island Harbor ODMDSs are adapted to a fluctuating
environment and are typical of those found in nearshore, shallow water benthic habitats (Felder
and Kemp, 2009).
EPA Marine Protection Permitting Program
40
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Legend
«¦ Sediment Grab Sample
~ Sampling Location
Current ODMDS Boundary
Gulf of
M o * ;c o
80*100**
4 Kilometers
1 2
1 . 1 . i
Caofdirate System NAD 19S1 StafePtane Texas South FIPS 4255 Feet
Oepst ir Meters
¦»e a"
Figure 22. Sampling centroids in and around the Matagorda study area.
Matagorda Ship Channel ODMDS
Results from the sediment grain size analyses showed that sediments throughout the Matagorda
study area followed a general trend where the percentage of sand in sediment samples decreased
further from shore. Sediments from stations closer into shore (1 -4} were predominantly sand
(more than 95%). Sand percentages decreased to approximately 60% at locations 5 and 6, and
samples collected from locations 9 and 10, farther from shore, had smaller percentages of sand
(Figure 31, Tetra Tech, Inc. 2020B).
EPA Marine Protection Permitting Program
41
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
i i i i i
001002 003 00* 006 006
-i—i—r
007 006 009
-i—i—I- -i—i—i— ~i—i—r -i—i—r~
010011012 013 014 015 016 017 016 019 020021
022 023 024
Ce-ntroid 8
-i—i—r -i—i—i-
025 026 027 028029 030
Substrate Type
| Gravel
Sand
Silt
Clay
SitelD
Figure 23. Percent composition of substrate particles grouped by type for each station within the Matagorda
study area.
Results from Region 6's sediment chemistry analyses of the Matagorda study area showed a
general trend of contaminants increasing with increased distances from shore. Six metals and one
pesticide: aluminum, arsenic, barium, colbalt, and manganese and gamma-BHC exceeded
screening levels. Although the concentration of these metals and pesticide exceeded the threshold
value, the concentrations measured were below the level of concern. The general trend of
increasing concentrations of contaminants with increased distance from shore is likely due to the
shift in predominant sediment grain sizes in present the area. Finer particle sizes (e.g., silts and
clays) tend to have higher concentrations of various contaminants than larger particle sizes (e.g.,
sand) and in the Matagorda study area, EPA Region 6 found that predominant grain size decreased
with increasing distance from shore.
Macrofaunal data across the Matagorda study area showed that the macroinfaunal assemblages
present were correlated with sediment grain size. The stations with predominantly sandy
sediments had macroinfaunal assemblages typical of sandy sediment habitats (e.g., abundance of
the chordate, Branchiostoma, haustorid amphipods, the polychaete, Polygordius), while
opportunistic polychaetes (e.g., Mediomastus, Magelona)were most abundant in stations with
higher percentages of silty-clay sediments. The macroinfaunal assemblages found at stations both
inside and outside the Matagorda ODMDS are adapted to a fluctuating environment and are typical
of those found in nearshore, shallow water benthic habitats (Felderand Kemp, 2009).
3.4.3 Conclusions and Recommended Management Actions
The data and information collected from this survey confirmed that environmentally acceptable
conditions, as defined in the sites site management and monitoring plans, are being met at the
Corpus Christi, Matagorda, and Brazos Island Harbor ODMDSs and that that pre-disposal testing
and evaluation of dredged material has been effective at preventing any contaminated material
from being disposed of at the sites. Region 6 intends to continue to routinely monitor the chemical,
EPA Marine Protection Permitting Program
42
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
physical, and biological parameters inside and surrounding the ODMDS to identify any changes,
ensure that short-term anticipated impacts stay within the boundaries of the ODMDSs, and that
disposal activities are not causing lasting adverse impacts.
Region 6 will also utilize the data collected during this survey to inform any modification of these
ODMDSs that may be needed to increase the capacity for disposal at MPRSA ocean sites of
dredged material generated from port, harbor, and channel maintenance and new work navigation
projects along the Gulf coast of Texas.
3.9 Region 9 - LA-2 Ocean Dredged Material Disposal Site
3.9.1 Background
The LA-2 ODMDS was first used as an interim1 MPRSA ocean site in the mid-1970s and was
subsequently designated as a permanent MPRSA ocean disposal site in 1992. It is located on the
outer continental shelf margin, at the upper southern wall of the San Pedro Sea Valley,
approximately seven nmi (13 km) offshore of the entrance to the Los Angeles/ Long Beach Harbor
(Figure 35). The site ranges in depth from 361 to 1,050 ft (110 to 320 m). It is a circular site, with a
radius of 3,000 ft (915 m); however, disposal must occur in the surface disposal zone, which has a
radius of 1,000 ft (305 m). The LA-2 ocean disposal site has received approximately 7.3 million y3
(5.58 million m3) of dredged material since its first use in 1976, including approximately 4.73 million
y3 (3.62 million m3) since designation in 1991.
The overall study area also considered far-field impact sources such as the Los Angeles County
water treatment system outfall and an Area of Potential Legacy Short Dumps (referred to herein as
the Legacy Area). "Short dumps" referto events where dredged materials were dumped before
reaching the MPRSA-designated ocean site. The Legacy Area extends from the entrance channels
of the Port of Los Angeles and Port of Long Beach and is the area within which most vessels would
pass through when approaching the designated LA-2 ODMDS.
1 Interim MPRSA ocean disposal sites are no longer available for use. Amendments enacted in 1992 under the
MPRSA require that no MPRSA permits shall be issued for an EPA-established ocean site after January 1,1997,
unless the site has received a final designation. In 2008, the EPA repealed expired, and therefore obsolete,
provisions regarding interim ocean disposal sites.
EPA Marine Protection Permitting Program
43
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Area of Potentially
Identifiable Legacy
(Historical) Short
Dumps Mounds
White Point Outfall
Operated by Los
Angeles County
LA-2 Study Area (2020)
Potential Point Source
or Impacted Areas
Proposed Study
Area: approx
7 nmi by 6 nmi;
maximum extent
for MBES survey;
SPI-PVP and grab
sampling in smaller
overall area or
targeted
yiiU
MHIIliU
Figure 24. LA-2 ODMDS and study area offshore of Los Angeles-Long Beach, CA.
3.9.2 Survey Objectives, Activities, and Findings
The EPA conducted a two-part oceanographic monitoring survey of the LA-2 ODMDS in the fall of
2020 aboard the MA/ Bold Horizon. During the first portion of the survey, the EPA conducted a
multi-beam echosounder (MBES) survey to characterize the seafloor of the overall LA-2 ODMDS
study area and identify any seafloor features that could affect the sediment sampling, The MBES
survey covered an area of 7 nmi by 6 nmi, extending beyond the designated disposal site in all
directions (Figure 33). The survey provided high-resolution bathymetry of the study areas, and the
results were used to inform the selection of sediment grab stations for chemical and benthic
community sampling.
During the second portion of the survey, the objectives were to: 1) collect sediment profile images
(SPI) and plan view images (PVI) to evaluate the extent and characteristics of the dredged material
footprint and any potential impacts of the dredged material disposal on the benthic environment;
2) collect sediment grain size and chemistry samples to determine whether analyte concentrations
are within the range of the material approved for disposal, and how the concentrations compare to
areas immediately outside of the site and further geographically removed; and 3) collect benthic
community samples to evaluate the recovery of the benthic community following dredged material
disposal and determine whether there are any impacts from dredged material disposal to the
benthic community outside the ocean disposal site.
SPI-PVI imaging is a monitoring technique used to provide data on the physical characteristics of
the seafloor and the status of the benthic biological community. SPI-PVI imaging has been shown
to be a powerful reconnaissance tool that can efficiently map gradients in sediment type, biological
communities, and disturbances from physical forces, anthropogenic input, or organic enrichment.
SPI and PVI were collected in a radial sampling design, allowing for sampling to occur both within
and outside of each disposal site, and encompassing most of the same area as the MBES survey.
EPA Marine Protection Permitting Program
44
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Stations were located within the LA-2 ODMDS boundary and along eleven radial transects, spaced
approximately 2,130 ft (650 m) apart and extending up to 4.5 miles (7.2 km) from the LA-2 ODMDS
center. In total, the EPA collected and analyzed SPI and PVI from 99 stations and sediment and
biological samples from 30 stations.
Depth (ft)
• 2020 SPI/PV Target Station
| 1 Area of Potentially Identifiable Legacy
I 1 (Historical) Short Dumps Mounds
| Proposed Study Area
| White Point Outfall
( *) LA-2 ODMDS
N 0
2
A
* 0
1 2
Bathymetry: MLWW (ft) - 40 ft res. - 1x VE
Document Name: LA2_2020_5PIPV_Targets Coordinate System MAD 19S5 State Plane California V FIPS 6405 Peel Date: 4/16,'202o
Figure 25. LA-2 ODMDS study area and SPI-PVI target station locations. The boundary of the ODMDS is
depicted in orange.
Sediment and benthic community samples were collected using a 0.1 m2 Van Veen Grab sampler.
The sediment samples were analyzed for grain size, TOO, metals, dioxins and furans, pesticides
(DDTs), organotins, PAHs, and PCBs. Chemistry of sediment samples within the dredged material
footprint was analyzed to determine whether the analyte concentrations correspond to levels
expected from pre-disposal dredged material testing. Sediment chemistry samples inside the
dredged material footprint was compared to samples collected outside of the dredged material
footprint.
Sediment grain size was generally related to water depth across the surveyed area. The shallower
stations located on the continental shelf were predominantly composed of fine sand, while
stations located within the deeper areas along the continental slope and within the San Pedro Sea
Valley were composed of either very fine sand or silt/clay (Figure 34). Gravels, including cobble and
boulder on soft sediment, were uncommon across the surveyed area; only 8 stations had
documented gravels (Figure 35). Overall, the stations inside the dredged material footprint were
predominantly sand (average of 62.6%), followed by silt (24.6%), and clay (12.4%). Similarly, the
predominant grain size of stations outside the site, not including the outfall, was also sand
(average of 57,8%), followed by silt (27.5%) and clay (14.42%),
EPA Marine Protection Permitting Program
45
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Figure 26. Predominant grain size by station in the LA-2 study area. Most stations are characterized by soft
sediments.
Predominant Grain Size Major Mode (phi)
• Medium pebble (-3 to -4)
6 Medium sand (2 to 1)
'face Layer Fine sand (3 to 2)
Very fine sand (4 to 3)
Silt/clay (>4)
Buried Layer
Silt/clay and fine sand mix
(>4 + 3 to 2)
&> Indeterminate
~ Area of Potentially Identifiable Legacy
(Historical) Short Dumps Mounds
~ Proposed Study Area
| White Point Outfall
C ^ LA-2 ODMDS
ML.Wft •„ VE "
Dredged material was observed at all stations within the LA-2 ODMDS boundary and at several
stations outside the disposal site, generally at stations in the vicinity of the LA-2 ODMDS and within
the Legacy Area. Dredged material was identified in SPI by the presence of features visually distinct
from native sediments, including patches of light gray or dark brown clay, disordered mixtures of
coarse and fine material, and distinct surficial layers of pale gray very fine sand and deep layers of
dark black silt/clay. In addition to the dredged material within the LA-2 ODMDS, there were several
stations nearthe LA-2 ODMDS boundary where trace dredged material was documented as
indicated by small amounts of light gray clay or small inclusions of dark brownish black sediment.
Often in these replicate images, there was evidence that the sediments had been reworked by
infauna and were beginning to resemble background sediments.
EPA Marine Protection Permitting Program
46
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Sediment Type (PV)
• Boulder
• Cobble
• Sandy Cobble
• Sandy Gravel
+ Gravelly Sand
© Sand
| | Area of Potentially Identifiable Legacy
I 1 (Historical) Short Dumps Mounds
| Proposed Study Area
~ White Point Outfall
~ LA-2 ODMDS
3 Kilometers
W, n-nf
Slope
067 066 065 064 063 001
Figure 27. Sediment type derived from PVI analysis denoting presence of gravels at the LA-2 study area.
Region 9 compared their sediment chemistry results to effects range low (ER-L) and effects range
median (ER-M) thresholds, which are measures of toxicity in marine sediments. Adverse effects are
rarely seen in sediments with chemical concentrations below the ER-L. Adverse effects are
generally observed in sediments with chemical concentrations above the ER-M. Most analytes
measured at stations within the dredged material footprint were below the ER-L, with the exception
of nickel, which slightly exceeded the ER-L at two stations, and arsenic, copper, mercury, and zinc,
which each only slightly exceeded the ER-L at Station 001. DDTs exceeded the ER-L at Station 064.
All analytes within the dredged material footprint were well below the ER-M.
Overall, the area within the dredged material footprint of the LA-2 ODMDS displayed less elevated
chemical concentrations than all other surrounding areas. Apart from values for zinc and lead, the
average concentrations of analytes inside the disposal site were all below those in the "outside
area" (i.e., the areas outside the dredged material footprint, but not including the White Point
Outfall nor the Legacy Area). However, average values for both zinc and lead inside the ODMDS
were well below the ER-L.
When measurable, each of the overall areas (i.e., the LA-2 ODMDS, the White Point outfall, the
Legacy Area, and other stations removed from the LA-2 ODMDS) had average apparent redox
potential discontinuity (aRPD) values above 1.0 cm, indicating that the areas are not considered
impaired. Additionally, there was no evidence of sedimentary methane nor of low dissolved oxygen
conditions in the water column nor at the benthic boundary layer in any of the SPI analyzed.
There were 15,407 organisms captured in the collected benthic community samples. Throughout
the study area, density ranged from a low of 980 animals per square meter (station 012; in the
Legacy Area), to a high of 21,120 (station 047) inside the LA-2 ODMDS. Throughout the study area,
EPA Marine Protection Permitting Program
47
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
there were 422 unique invertebrate taxonomic identifications (taxa richness). Within the LA-2
ODMDS, the taxa richness ranged from a low of 17 (station 001) to a high of 79 (station 047). Taxa
richness outside of the LA-2 ODMDS ranged from a low of 24 (station 078) to a high of 115 (station
085). The mean diversity and mean evenness inside the LA-2 ODMDS were both lower than those
same indices for the Legacy Area and the remaining areas outside of the LA-2 ODMDS. Overall, the
LA-2 ODMDS displayed higher mean abundance and density than the areas outside of the ODMDS
and the Legacy Area. This suggests that disposal activities are not causing lasting impacts to the
benthic community.
3.9.3 Conclusions and Recommended Management Actions
Results from the 2020 survey confirm that environmentally acceptable conditions, as defined in the
site management and monitoring plan, are being met at the LA-2 ODMDS and that pre-disposal
testing and evaluation of dredged material has been effective at preventing any contaminated
material from being disposed of at the site. The bulk of the dredged material disposed in the last
decade or more appears to have been deposited properly within the site boundaries. There are
minor and localized physical impacts from dredged material disposal, as expected, but no
significant adverse impacts are apparent to the benthic environment outside of site boundaries.
EPA Region 9 recommends that the LA-2 ODMDS can continue to be used under an updated
SMMP.
Region 9 intends to continue to routinely monitor the chemical, physical, and biological
parameters inside and surrounding the LA-2 ODMDS to document any changes to the area, ensure
that short-term anticipated impacts stay within the boundaries of the ODMDS, and that disposal
activities are not causing lasting adverse impacts.
4.0 Next Steps
The EPA conducts oceanographic surveys to monitor the impacts of regulated dumping at ocean
disposal sites and to inform management and monitoring decisions in accordance with the EPA
roles and responsibilities under the MPRSA and ocean dumping regulations. The EPA monitors to
ensure that dumping will not unreasonably degrade or endanger human health or the environment,
to verify that unanticipated adverse effects are not occurring from past or continued use of the site,
and to ensure that terms of MPRSA permits and MPRSA federal project authorizations are met.
Based on the results of these 2020 oceanographic surveys, the EPA determined that
environmentally acceptable conditions were met at each of the surveyed ocean sites and
permitted disposal of dredged material under the MPRSA can continue at these sites.
Additionally, the EPA will use the data and information collected in 2020:
• to improve on the protocol followed to ensure whale carcasses disposed in ocean
waters off the coast of New Jersey sink to the whale carcass disposal area;
• to inform site management, including modification of five ODMDSs along the Gulf
coast of Texas, as well as future updates to each sites' MPRSA-required
management and monitoring plan;
• to inform future surveys at these sites, including where increased dredged material
disposal volumes from deepening and navigation infrastructure projects are
anticipated, to ensure dumping will not unreasonably degrade or endanger human
health or the environment; and
EPA Marine Protection Permitting Program
48
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
• to refine methodologies for collecting data from towed video (e.g., remotely
operated vehicle) to be able to collect comparable quantitative information via
imagery and video in rocky and hard bottom areas.
5.0 Acknowledgements
This report is based on the monitoring surveys conducted, analyses performed, and conclusions
drawn by the EPA's Regional offices 1, 2, 4, 6, and 9 during 2020. This report was developed with
the support of Marine Protection Permitting Program staff from EPA Headquarters and all coastal
Regional offices.
6.0 References
Barry Vittor and Associates (BVA). 2020A. Morehead City, North Carolina Ocean Dredged Material
Disposal Site Trend Assessment Survey - Benthic Community Assessment. March 2020.
BVA. 2020B. Wilmington, North Carolina Ocean Dredged Material Disposal Site Trend Assessment
Survey- Benthic Community Assessment. April 2020.
BVA. 2020C. Corpus Christi, Texas Ocean Dredged Material Disposal Site 2020 Benthic Community
Assessment for the 2020 Monitoring of Region 6 Ocean Dredged Material Disposal Sites
and Potential Expansion Areas. July 2020.
Battelle. 2020. FY2020 Western Long Island Sound Disposal Site Survey Plan.
Attachment 1 - Standard Operating Procedures for Acoustic Surveys.
Felder, D.L and D.K Kemp. 2009. Gulf of Mexico Origin, Waters, and Biota. Volume 1,
Biodiversity. Texas A&M Press, College Station, Texas.
Inspire. 2021. Image Analysis Results for the 2020 Historic Area Remediation Site (HARS) ROV
Survey. TSAWP II Multiple-Award Contract EP-C-17-045. Technical Direction 8. July 2021.
National Ocean Economics Program. Market Data.
http://www.oceaneconomics.org/Market/ocean/oceanEcon.asp
NOAA. 1999. Sediment Quality Guidelines Developed for the National Status and Trends Program.
http://www.coastalscience.noaa.gov/publications/handler.aspx?key=1527
O'Donnell, J. 2020. Region 6 ODMDS Surveys - Corpus Christi ODMDS Chemical and Physical Data
Quality Assessment - February 2020. Memo to G. Townsend, June 15, 2020. Tetra Tech,
Inc., 10306 Eaton Place, Suite 340, Fairfax, VA 22030.
Rhoads, D. C. and J. D. Germano. 1982. Characterization of organism-sediment relations using
sediment profile imaging: an efficient method of remote ecological monitoring of the
seafloor (Remots™ System). Marine Ecology Progress Series. 8:115-128.
Tetra Tech, Inc. 2020A. Physical and Chemical Analysis of Bottom Sediments from Ocean Dredged
Material Disposal Sites in the Brazos Island Harbor (Texas, US) Survey Area. July 2020.
EPA Marine Protection Permitting Program
49
-------
2020 National MPRSA Ocean Site Monitoring Assessment Report
Tetra Tech, Inc. 2020B. Physical and Chemical Analysis of Bottom Sediments from Ocean Dredged
Material Disposal Sites in the Matagorda (Texas, US) Survey Area. July 2020.
USACEand USEPA, 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.
https://www.epa.gov/sites/default/files/2017-02/documents/r6ria.pdf
EPA Marine Protection Permitting Program
50
------- |