Combining Infrastructure Improvements and Air
Quality Benefits: A Case Study of the New York/
New Jersey Harbor Deepening Project
This case study is an example of how a team of federal, state, and heal stakeholders in New York and
New Jersey worked together to cost-effectively and expediently offset emissions over the life of a harbor
deepening project. The resulting marine vessel engine upgrades ensured the project complied with the
Clean Air Act and provided lasting clean air benefits.
Efficiency improvements are increasingly important
for ports around the country as they strive to handle
growing container volumes, compete for inland
markets and cope with market uncertainties. But
ports are not the only player in a rapidly changing
industry. Ocean carriers have made their own efficiency
gains, rapidly increasing the size of their ships to take
advantage of economies of scale on the high seas. A
generation ago, the largest container ships could barely
hold 4,000 twenty-foot containers. Today ships are built
to hold five times that number.
The expansion of the Panama Canal, completed in
2016, provided an impetus for ports on the East and
Gulf Coasts to embark on major projects to cope with
these larger vessels by deepening navigation channels
United States
Environmental Protection
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and harbors. But dredging millions of cubic yards of
sediment is neither easy nor cheap, and carries with
it the potential to disrupt the environment. Many
deepening projects spark opposition from local
communities or environmental advocates, who viewed
this infrastructure development at odds with goals of
protecting human health and the environment.
This need not be the case. The New York/New Jersey
Harbor Deepening Project demonstrated how to
simultaneously protect air quality and modernize
critical infrastructure.The achievement was made
possible by a proactive collaboration between federal,
state and local agencies and the local port authority.
The benefits of the multi-agency collaboration
went further than the immediate project, helping to
position the agencies to meet federal environmental
requirements for future projects.
Office of Transportation and Air Quality
September 2021

The $2.1 billion New York/New Jersey Harbor
Deepening Project began construction in 2004.
Over the course of the subsequent 12 years, the US
Army Corps of Engineers (Army Corps) oversaw the
completion of 21 dredging contracts, removing more
than 40 million cubic yards of sediment to provide a 50-
foot depth for ships accessing the Port of New York and
New Jersey, the East Coast's largest port.
Before the project could proceed, the Army Corps
as the lead federal agency had to demonstrate
compliance with environmental requirements. To
meet Clean Water Act requirements, they committed
at the outset to construct 40 acres of wetlands at two
marsh restoration sites. Through the beneficial reuse
of dredged material, they were able to restore two
additional sites later in the project.
The Federal General Conformity provision under the
Clean Air Act requires federal agencies to ensure that
their activities do not interfere with state efforts to
attain the National Ambient Air Quality Standards
in areas that don't meet those standards. When a
new federally funded project exceeds an annual air
emissions threshold, the sponsor must offset all the air
emissions from the project.
For the Harbor Deepening Project, meeting the
Federal General Conformity obligations was not a
straightforward process. At the onset of the project,
there were significant uncertainties related to the
timing of construction work and emissions over the
lifetime of the project. Ultimately there were over
twenty separate dredging contracts for the various
phases of the project spanning over a decade. There
was no way prior to the start of construction to be
certain of the extent of offsets needed each year.
In addition, the types of offsets mattered. The air
regulators and affected communities expressed
concern that obtaining credits from stationary sources
shut down many years ago would not adequately
protect air quality and be consistent with state efforts
to achieve federal standards. They indicated a strong
preference for concurrent emission reduction projects
to achieve compliance with General Conformity.
The potential offsets, however, were also subject to a
large amount of uncertainty. Several different types
of offset projects - equipment electrification, engine
repowering and vehicle replacements for example -
were known to be effective emission reduction options,
however the cost and technical feasibility in the marine
sector were not well understood.
Lastly, the timing and magnitude of emissions and
offsets was also a major consideration. The initial
plan envisioned project emission spread relatively
evenly across the multiple years of the project, never
exceeding 500 tons per year. However the project
partners recognized that conditions might change
which they did. At peak construction, dredging
operations resulted in approximately 1,000 tons of
nitrogen oxides (NOx) that would need to be offset.
Project Details
Early on, the Army Corps and Port Authority of New
York and New Jersey recognized the need for close
coordination with federal and state partners. A full
five years before construction began, the agencies
formed a Regional Air Team, lovingly referred to as
the RAT, to ensure open communication and develop
a coordinated plan. Agencies involved in the RAT
include the Army Corps of Engineers New York District,
Port Authority of New York and New Jersey, New York
State Department of Environmental Conservation,
New Jersey Department of Environmental Protection,
New York City Department of Transportation, and U.S.
Environmental Protection Agency - Region 2.
Specifically, the RAT was charged with the following:
Provide a mechanism by which the final decisions
could be agreed upon and signed, ensuring that
General Conformity requirements would be met
prior to the start of construction while the design
phase moved forward and the start date could
remain unchanged;
Provide a determination of the federal action's
potential emissions impact;
Identify emission reduction strategies and
Develop an implementable mitigation plan to bring
the project into conformity with the Clean Air Act;
Develop monitoring and recordkeeping procedures
to track emissions and reductions during the life of
the project to ensure compliance.
Two major milestones prior to breaking ground
were the conditional Statement of Conformity and
the Harbor Air Management Plan. A Statement of

Conformity is a determination by the federal sponsor
that the project meets its General Conformity
obligations. The determination was conditional
because rather than specifying the precise mix of
credits and mitigation projects that would be used
to offset the Harbor Deepening Project emissions,
the conditional Statement of Conformity described
a process to arrive at the preferred offsets. This
was combined with a commitment not to begin
construction until the offset plan was in place.
The Harbor Air Management Plan laid out this offset
strategy. The RAT evaluated a total of 19 categories
of offsets and prioritized them based on timing, cost
effectiveness and risk.
In 2004 the plan was finalized, with a commitment to
review the plan annually and adjust as needed. The mix
of offsets envisioned in 2004 included aftertreatment
controls on a Staten Island Ferry, upgrading engines
on eight diesel tugboats, and using purchased offset
credits during the first two years of the project to allow
enough time to fully implement the plan.
To ensure that enough offsets were in place for each
year of the project, the RAT established a tracking
and reporting process. Prior to the bidding out of
contracts, the Army Corps refined emissions estimates
based on the type of dredging operations, the amount
of material, and the anticipated equipment. They
included requirements in the contracts with dredging
companies capping emissions and requiring that
companies report on engine characteristics and activity
on a monthly basis in order to confirm the caps on
emissions were not exceeded. The contracts specified
that if these caps were exceeded, the dredging
company would be required to obtain additional air
emission offsets at its own expense.
After the first years of construction, the RAT quickly
realized that the initial plan for offsets needed
significant adjustment. The RAT's analysis pointed to
the strategy of repowering even more marine engines
as the most cost-effective option for reducing NO;<. The
Port Authority of New York and New Jersey funded two
rounds of vessel repowers, providing funding for vessel
owners to replace aging marine engines with new
equipment meeting the cleanest standard available
at the time. In addition, New York City Department
of Transportation retrofitted or replaced engines on
its entire Staten Island Ferry fleet. All told, the project
partners funded engine repowers or aftertreatment
controls on three dozen tugs and ferries operating in
the harbor.
As an oversight mechanism, the owners who received
funding for repowers were obligated to keep their
vessels operating in the nonattainment area and report
on activity on an annual basis.
Through this process, the project sponsors were
able to ensure compliance with General Conformity
requirements - no easy feat for large, complex projects
such as harbor deepenings. Any ambiguity as to
compliance with these federal rules would leave the
project open to lawsuits, which in the worst case could
shut down construction.
The innovations in the Harbor Deepening Project
went well beyond compliance. The air quality benefits
arising from the project were significant and lasting. In
putting into place enough offsets to cover the highest
year of project emissions, the measures resulted in
a surplus of emission reduction offsets during other
years. All told, the project partners not only offset the
5,000 tons of nitrogen oxide project emissions but
eliminated more than 2,000 tons over and above that
figure. Furthermore, the repowered marine engines
will continue to provide a benefit for the lifetime of the
vessels, well beyond the end of the Deepening Project.
The added benefit to the environment allows the
project partners to showcase improvements in air
quality to concerned communities that were impacted
Photo Courtesy of New York City Department of Transportation (

by construction activity. It also puts agencies in a
stronger position for future projects.
It did not take long for these future projects to
materialize. In the years after 2012's Superstorm Sandy,
Congress authorized the Army Corps of Engineers to
conduct an extensive series of beach renourishment
projects along the New York and New Jersey coastline.
The Army Corps needed to move quickly to provide
storm protection while also meeting their General
Conformity requirements.
The vessel repowers completed for the Harbor
Deepening Project were continuing to provide an
emissions benefit that could be applied to these
beach renourishment projects as well as others that
emerged in the future. The RAT put together a protocol
that detailed how the offsets would be counted,
tracked and distributed among project partners.The
process culminated in a letter of concurrence signed
by all the partner agency executives, recognizing
that the protocol provided a mechanism to meet the
requirements of an Early Emission Reduction Credit
program under EPA's General Conformity regulations.
Lessons Learned
Building in flexibility is critical as changes to
project schedules and vessel activity can have a
significant impact on the timing and quantity of
offsets needed. General Conformity requirements
typically apply on an annual basis. A critical way
in which the RAT dealt with unexpected increases
in project emissions or decreases in offsets was by
building in contingency factors. The RAT applied a 10
percent buffer for both the project emissions estimates
and offset estimates. Building in this buffer proved
necessary as invariably towards the end of the year
some surprises occurred - a ferry vessel operated
less than expected or additional work on a dredging
contract was needed.
Additionally, despite the best efforts of the partners,
additional emissions credits twice needed to be
purchased from the states'offset registries. Monthly
meetings where year-to-date emissions were
monitored helped to ensure the scheduled offset
projects were sufficient. However, when necessary, the
group took additional steps to ensure the project was
always in compliance with the federal requirements.
The key to project success was a high level of
coordination between federal, state and local
agencies, and the non-federal partner (Port
Authority of New York and New Jersey). This
coordination began well before a dredge scooped the
first shovel-full of sediment and continued throughout
the entire span of the project. A written record of
the meetings, emissions tracking, and key decision
documents helped to bring new personnel up-to-date
on the background and current status of the project.
The technical work done by the RAT helped
develop a better understanding of marine vessel
sector emissions and identify the most cost
effective NOxemissions reduction strategies. The
program provided real world confirmation of the cost
effectiveness of reducing NOx emissions via marine
engine repowers. The average cost per ton of NOx
reduced from the marine repower projects was $2,078,
a figure that compares favorably with most other
emission reduction projects in the region.
A number of emerging technologies were evaluated,
including retrofitting a Staten Island Ferry with a
Selective Catalytic Reduction unit. The RAT also worked
with dredge operators to log engine data to have a
better understanding of the emissions profile in this
sector. Lastly, an emissions inventory of marine vessels
in the harbor at both the start and end of the project
added to an understanding of the potential for further
emissions reductions from this sector.
Next Steps
While the Harbor Deepening Project is over, the
Regional AirTeam remains active.The group is
continuing to track the offsets from the Harbor
Deepening and their application to meet General
Conformity requirements on other projects. The
process put in place has successfully been applied to
more than 10 projects subsequently.
The Army Corps of Engineers is in the process of setting
up a marine engine replacement program, using the
lessons learned from the Harbor Deepening Project,
to meet General Conformity obligations for additional
upcoming projects.
Additional Resources
Harbor Air Management Plan
Surplus NO Emissions Offset Protocol that includes
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sample contract language with emissions reporting