NATIONAL
ESTUARY
PROGRAM
NUTRIENT REDUCTION
Through the efforts of the Long Island Sound Study (LISS), measurable results are being achieved in reducing nitrogen discharges to the Long Island
Sound—a water body where sewage treatment plants discharge more than a billion gallons of nutrient-rich effluent. Large inputs of nutrients such as ni-
trogen have over-fertilized significant areas of the Sound, fueling the excessive growth of marine plants that deplete the water's oxygen. These low dis-
solved oxygen levels—a condition called hypoxia—degrade the habitat for fish and shellfish.
THE NATIONAL ESTUARY PROGRAM IN ACTION
Long Island Sound Study
To address the problem, LISS
provides progressive leadership
that has resulted in investments
to upgrade wastewater treat-
ment plants to treat nitrogen,
implement watershed protec-
tion measures aimed at reduc-
ing polluted runoff, and protect
and restore wetlands and other
natural habitats.
To gain a better understanding
of the relationship between ni-
trogen discharges to the Sound
and dissolved oxygen levels,
LISS supported research, moni-
toring, and the development of
mathematical water circulation
and water quality models that
helped provided a scientific ba-
sis for establishing a nitrogen
reduction target of 58.5 percent
for sources that include sew-
age treatment plants, storm-
water runoff, and atmospheric
deposition. Connecticut and
New York incorporated the tar-
get into a Total Maximum Daily
Load (TMDL) for nitrogen to help
meet water quality standards.
The states have also revised
their water quality standards
for dissolved oxygen in marine
waters to reflect EPA criteria for
protection of living resources in
marine waters and created new
provisions for pollutant trading
for cost-effective attainment of
water quality standards. Imple-
mentation of the TMDL is mov-
ing forward, with upgrades at
wastewater treatment plants
decreasing the amount of nitro-
gen discharged into Long Island
Sound by Connecticut and New
York's 106 sewage treatment
plants. By 2008, daily discharg-
es had decreased by 50,000
pounds compared to year 1994
baseline levels. These reduc-
tions are partly due to innovative
strategies. Connecticut's Nitro-
gen Credit Exchange program,
which won a 2007 EPA Blue
Ribbon Water Quality Trading
Award, sold $10.5 million worth
of credits in five years. In 2007,
34 percent of the 79 participat-
ing sewage treatment plants had
reduced nitrogen output below
EFFECTIVE
EFFICIENT
ADAPTIVE
COLLABORATIVE
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assigned permit limits, making
them eligible to sell a total of
$2.07 million in nitrogen credits.
This innovative program is ex-
pected to save the state between
$200 million and $400 million in
wastewater treatment construc-
tion costs over the next decade.
In New York, "bubble permits"
now provide flexibility to dis-
chargers on how to attain per-
mit limits. This concept allows
sewage treatment plants within
each management zone to meet
their "bubble" limit by upgrading
some, but not all, of the plants.
This approach is expected to
save New York City up to $660
million in sewage treatment plant
upgrade costs and is now being
applied in Westchester County.
Watershed management is an-
other valuable approach to re-
ducing nitrogen discharge. For
example, a stewardship action
plan, developed for the Nisse-
quogue River watershed in the
Town of Smithtown on Long
Island, New York, contains ob-
jectives such as reducing the
impacts of stormwater pollu-
tion, investigating groundwater
quality and tracking of potential
impacts of contaminants, and
reducing the impacts of nitrogen
overloading on water quality.
Local watershed associations
and municipalities throughout
the Sound are developing pro-
grams to reduce polluted runoff,
from educating homeowners
about ways to reduce the leach-
ing of nutrients into streams
from lawn fertilizer applications
to installing filters in coastal
storm drains to keep sediment,
debris, harmful bacteria, oil, and
toxic metals from entering the
Sound.
The states of Massachusetts,
Vermont, and New Hampshire
are also working with the Con-
necticut River Nitrogen Work
Group to discuss reducing ni-
trogen loading from the Con-
necticut River watershed to the
Long Island Sound. These states
are participating in the process
to revise the Long Island Sound
TMDL by evaluating options for
additional nitrogen reduction
scenarios.
Visit www.longislandsound-
study.net to learn more about
this and other LISS efforts.
EPA's National Estuary Program
(NEP) is a unique and successful
coastal watershed-based program
established in 1987 under the
Clean Water Act Amendments.
The NEP involves the public and
collaborates with partners to pro-
tect, restore, and maintain the wa-
ter quality and ecological integrity
of 28 estuaries of national signifi-
cance located in 18 coastal states
and Puerto Rico.
For more information about the
NEP go to www.epa.gov/owow/
estuaries.
The NEP: Implementing the Clean Water Act in ways that are Effective, Efficient, Adaptive, and Collaborative.
EPA-842F09001
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