&EPA
United States
Environmental Protection
Agency
EPA841-F-05-001
Protecting Water Quality
AGRICULTURAL RUNOFF
I/
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, activities from working farms
and ranches can affect water quality.
In the 2000 National Water Quality
Inventory, states reported that agricul-
tural nonpoint source (NFS) pollution
is the leading source of water quality
impacts on surveyed rivers and lakes,
the second largest source of impair-
ments to wetlands, and a major
contributor to contamination of sur-
veyed 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 pesticides,
irrigation water, and fertilizer.
Pollutants that result from farming and
ranching include sediment, nutrients,
pathogens, pesticides, metals, and salts.
Impacts from agricultural activities on
surface water and ground water can
be minimized by using management
practices that are adapted to local
conditions. Many practices designed
What Is Nonpoint Source Pollution?
Nonpoint source (NPS) pollution, unlike pollution from point sources
such as industrial and sewage treatment plants, comes from many
diffuse sources. Polluted runoff is caused by rainfall or snowmelt
moving over and through the ground. As the runoff moves, it picks
up and carries away natural and human-made pollutants, finally
depositing them into watersheds through lakes, rivers, wetlands,
coastal waters, and even our underground sources of drinking water.
Did you knoiv that runoff from farms is the leading source of
impairments to surveyed rivers and lakes?
to reduce pollution also increase
productivity and save farmers and
ranchers money in the long run.
There are many government programs
available to help farmers and ranchers
design and pay for management
approaches to prevent and control
NPS pollution. For example, over 40
percent of section 319 Clean Water
Act grants have been used to control
NPS pollution from working farms
and ranches. Also, many programs
funded by the U.S. Department of
Agriculture and by states provide
cost-share, technical assistance, and
economic incentives to implement NPS
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
agricultural water pollution 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 most 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
Farmers apply nutrients such as
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, or are
applied just before it rains, nutrients
can wash into aquatic ecosystems.
There they can cause algae blooms,
which can ruin 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
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 working 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 such as 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. Farmers
and ranchers can limit discharges by storing
and managing facility wastewater and
runoff with appropriate waste management
systems.
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
of grazing on water quality, farmers and
ranchers can adjust grazing intensity, keep
livestock out of sensitive areas, provide
Related Publications and Web Sites
National Management Measures to Control Nonpoint
Source Pollution from Agriculture
epa.gov/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.
Agricultural Nonpoint Source Pollution Management
Web Site
epa.gov/nps/agriculture.html
This web site features a collection of links to helpful documents,
federal programs, partnerships and nongovernmental
orrganizations that convey advice and assistance to farmers and
ranchers for protecting water quality.
National Agriculture Compliance Assistance Center
epa.gov/agriculture or call toll-free: 1-888-663-2155
EPA's National Agriculture Compliance Assistance Center is the
"first stop" for information about environmental requirements that
affect the agricultural community.
Animal Feeding Operations (AFO) Web Sites
AFO Virtual Information Center: epa.gov/npdes/afovirtualcenter
Overview of regulations and helpful links: epa.gov/npdes/afo
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, farmers 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.
Farm Bill Conservation Funding
In May 2002 President Bush signed the
Farm Bill, providing up to $13 billion for
conservation programs for six years.
This Farm Bill represents an 80 percent
increase above current levels of funding
available for conservation programs
designed to prevent polluted runoff.
For more information, visit www.usda.
gov/farmbill.
Funding Sources
Searchable Catalog of Federal Funding Sources for
Watershed Protection
epa.gov/watershedfunding
Agricultural Management Assistance Database
www.nrcs.usda.gov/programs/ama
Clean Water Act Section 319(h) funding (epa.gov/nps/
319hfunds.html) is provided to designated state and tribal agencies
to implement approved nonpoint source management programs.
Environmental Quality Incentives Program (www.nrcs.usda.
gov/programs/eqip) 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 (www.fsa.usda.gov/dafp/cepd/default.
htm) implemented by the U.S. Department of Agriculture
provide financial incentives to encourage farmers and ranchers to
voluntarily protect soil, water, and wildlife resources.
For More Information
U.S. Environmental Protection Agency g
Nonpoint Source Control Branch (4503T) ^ cs
1200 Pennsylvania Avenue, NW £ y
Washington, DC 20460 |
epa.gov/nps
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