-SEPA
United States
Environmental Protection
Agency
EPA841-F-03-004
Protecting Water Quality
The United.States has more than
330 million acres of agricultural
land that produce an abundant supply
of food and other products. Ameri-
can agriculture is noted worldwide
for its high productivity, quality,
and efficiency in delivering goods
to the consumer. When improperly
managed however, agricultural
activities can affect water quality.
In the 2000 National Water Quality
Inventory, states reported that agri-
cultural nonpoint source (NFS)
pollution is the leading source of
water quality impacts on surveyed
rivers and lakes, the second largest
source of impairments to wetlands,
and a major contributor to contami-
nation of surveyed estuaries and
ground water. Agricultural activities
that cause NFS pollution include
poorly located or managed animal
feeding operations; overgrazing;
plowing too often or at the wrong
time; and improper, excessive, or
poorly timed application of pesti-
cides, irrigation water, and fertilizer.
Agricultural pollutants that result
from these activities are sediment,
nutrients, pathogens, pesticides,
metals, and salts. Agricultural
impacts on surface water and ground
water can be minimized by using
management practices that are
[What Is Nonpoint Source pollution? __.
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DM you know that runoff from farms is the leading source of
impairments to surveyed rivers and lakes?
customized for local conditions.
Many practices designed to reduce
pollution also save producers money
in the long run.
There are many government pro-
grams available to help people design
and pay for management approaches
to prevent and control NFS pollution.
For example, over 40 percent of
section 319 Clean Water Act grants
have been used to control agricultural
NFS pollution. Also, many programs
funded by the U.S. Department
of Agriculture and states provide
cost-share, technical assistance, and
economic incentives to implement
NFS pollution management
practices. Many local organizations
and individuals have come together
to help create regional support
networks to adopt technologies and
practices to eliminate or reduce
water quality impacts caused by
agricultural activities.
Sedimentation
The most prevalent source of water
pollution caused by farming activities
is soil that is washed off fields. Rain
water carries soil particles (sediment)
and dumps them into nearby lakes
or streams. Too much sediment
can cloud the water, reducing the
amount of sunlight that reaches
aquatic plants. It can also clog the
gills offish or smother fish larvae.
In addition, other pollutants like
fertilizers, pesticides, and heavy
metals are often attached to the soil
particles and wash into the water
bodies, causing algal blooms and
depleted oxygen, which is deadly
to much aquatic life. Farmers and
ranchers can reduce erosion and
sedimentation by 20 to 90 percent by
applying management practices that
control the volume and flow rate of
runoff water, keep the soil in place,
and reduce soil transport.
Nutrients
Producers apply nutrients like
phosphorus, nitrogen, and potassium
in the form of chemical fertilizers,
manure, and sludge. They may also
grow legumes and leave crop residues
to enhance production. When these
sources exceed plant needs, nutrients
can wash into aquatic ecosystems.
There they can cause algae blooms,
which reduce swimming and boating
opportunities, create foul taste
and odor in drinking water, and
kill fish by removing oxygen from
the water. High concentrations of
nitrate in drinking water can cause
methemoglobinemia, a potentially
fatal disease in infants, also
known as blue baby syndrome. To
combat nutrient losses, farmers can
implement nutrient management
plans that help maintain high yields
and save money on fertilizers.
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Animal Feeding Operations
(AFOs)
By confining animals in small areas or lots,
farmers and ranchers can efficiently feed
and maintain livestock. But these confined
areas become major sources of animal waste.
An estimated 238,000 farms and ranches
in the United States are considered animal
feeding operations, generating about 500
million tons of manure each year. Runoff
from poorly managed facilities can carry
pathogens (bacteria and viruses), nutrients,
and oxygen-demanding organics and solids
that contaminate shellfishing areas and
cause other water quality problems. Ground
water can also be contaminated by waste
seepage. An operator can limit discharges
by storing and managing facility wastewater
and runoff with an appropriate waste
management system.
Livestock Grazing
Overgrazing exposes soils, increases
erosion, encourages invasion by undesirable
plants, destroys fish habitat, and may
destroy streambanks and floodplain
vegetation necessary for habitat and water
quality filtration. To reduce the impacts
ofgrazing on water quality, farmers and
ranchers can adjust grazing intensity, keep
livestock out of sensitive areas, provide
alternative sources of water and shade, and
promote revegetation of ranges, pastures,
and riparian zones.
irrigation
Irrigation water is applied to supplement
natural precipitation or to protect crops
against freezing or wilting. Inefficient
irrigation can cause water quality problems.
In arid areas, for example, where rainwater
does not carry minerals deep into the
soil, evaporation of irrigation water can
concentrate salts. Excessive irrigation can
affect water quality by causing erosion,
transporting nutrients, pesticides, and
heavy metals, or decreasing the amount
of water that flows naturally in streams
and rivers. It can also cause a buildup of
selenium, a toxic metal that can harm
waterfowl reproduction. Farmers can
reduce NFS pollution from irrigation by
improving water use efficiency. They can
measure actual crop needs and apply only
the amount of water required. Farmers may
also choose to convert irrigation systems to
higher efficiency equipment.
Pesticides
Insecticides, herbicides, and fungicides
are used to kill agricultural pests. These
chemicals can enter and contaminate water
through direct application, runoff, and
atmospheric deposition. They can poison
fish and wildlife, contaminate food sources,
and destroy the habitat that animals use for
protective cover. To reduce contamination
from pesticides, producers should use
Integrated Pest Management (IPM) tech-
niques based on the specific soils, climate,
pest history, and crop conditions for a
particular field. IPM encourages natural
barriers and limits pesticide use and
manages necessary applications to minimize
pesticide movement from the field.
Related Publications
Turn Your Home into a Storm Water Pollution Solution!
www.epa.gov/nps
This web site links to an EPA homeowner's guide to healthy
habits for clean water that provides tips for better vehicle and
garage care, lawn and garden techniques, home improvement,
pet care, and more.
National Management Measures to Control Nonpoint
Source Pollution from Agriculture
www.epa.gov/owow/nps/agmm
This technical guidance and reference document is for use
by state, local, and tribal managers in the implementation of
nonpoint source pollution management programs. It contains
information on effective, readily available, and economically
achievable means of reducing pollution of surface and ground
water from agriculture.
Nonpoint Source News-Notes
www.epa.gov/owow/info/NewsNotes
News-Notes is a periodic newsletter that reports local, state, and
national news on managing NPS pollution.
National Water Quality Inventory Report to Congress
(305(b) report)
www.epa.gov/owow/30Sb
EPA prepares this biennial report to inform the public about
general water quality conditions in the United States. The
document summarizes water quality data provided by states,
territories, tribes, and others.
Funding Sources
Clean Water Act Section 319(h) funding is provided to
designated state and tribal agencies to implement approved
nonpoint source management programs.
Clean Water State Revolving Fund provides funding for
the construction of municipal wastewater facilities and
implementation of NPS pollution management programs and
estuary protection projects.
Environmental Quality Incentives Program offers financial,
technical, and educational assistance to install or implement
structural, vegetative, and management practices designed to
conserve soil and other natural resources.
Conservation Reserve and Conservation Reserve
Enhancement Programs implemented by the U.S. Department of
Agriculture provide financial incentives to encourage farmers and
ranchers to voluntarily protect soil, water, and wildlife resources.
:. In May 2002 President Bush signed the Farm Bill, providing
up'to'l 13 "BimorTior' conservatTorTprograrns 'for s Ixyea rs~
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This Farm Bill represents an 80 percent increase above
:^^ current levels of funding available for conservation
$:;progfSrri'g designed to prevent polluted runoff. For more
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For More Information
U.S. Environmental Protection Agency
Nonpoint Source Control Branch (4503T)
1200 Pennsylvania Avenue, NW
Washington, DC 20460
www.epa.gov/nps
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