United States .
Environmental Protection
Agency
Office of Water
(WH-556F)
EPA840-F-93-001b
July 1993
4>EPA The Problem of
Nonpoint Source Pollution
In the past twenty years, the Nation has
made great strides in improving the quality of
our waters. We can be proud that we are able to
swim and fish in waters that just two decades
ago were too polluted for these activities.
Improvements have come as a result of a
significant public and private investment to
control "point sources" of pollution, largely
from industry and municipalities.
Unfortunately, water quality problems
remain. Eight to 21 percent of our surface
waters still do not meet the uses for which the
states have designated them, e.g., fishing,
swimming, drinking. Another 19 to 25 percent
of these waters only partially support their
designated uses.
The states report to EPA every two
years on the quality of the Nation's waters.
These reports are compiled into the "National
Water Quality Inventory." The most recent
reports show that the leading cause of our water
quality problems is nonpoint source pollution.
Nonpoint source pollution, or polluted runoff,
is the result of many different human activities
that take place over a wide, geographic area. -
Pollutants from these activities are carried into
our surface and ground waters through rainfall,
thunderstorms and snow melt, as well as
through man-made runoff from irrigation and
drainage.
Runoff from agricultural lands is the
leading cause of nonpoint source pollution and
affects between 50 and 70 percent of our im-
paired surface waters. Impaired waters are
those that do not meet the uses for which the
states have designated them.
The primary agricultural nonpoint
source pollutants are sediments, nutrients
(nitrogen and phosphorus), animal wastes,
pesticides, and salts. Pollutants enter surface
water through direct surface runoff or through
seepage to ground water that discharges into
surface water.
Of the agricultural pollutants, siltation
is the most common cause of impaired streams
and rivers. Suspended solids result in turbidity,
reduce sunlight available to aquatic plants,
cover fish spawning areas and food supplies,
clog filter feeders, and harm fish gills. It is
caused by erosion from farm and grazing lands,
forested areas, development, and other sources.
Nutrients, from the runoff of excess
fertilizers and from animal wastes, are the
second most common cause for impairment.
Nutrients can stimulate the growth of algae,
using up oxygen in the water that would
otherwise be available for fish, plants, and other
aquatic life. Animal wastes also contribute
bacteria which can kill fish and threaten human
health. Some agricultural practices may also
result in the loss of wetlands and damage to
riparian areas, increasing the problems of
nonpoint source pollution because these areas
act as natural filters.
Non-agricultural sources of nonpoint
source pollution include runoff from construc-
tion, land development, forestry operations, and
abandoned mines, as well as
hydromodification.
Urban runoff contains pollutants
(sediments, road salts, oily residues, nutrients,
and toxics) from city streets, paved areas, and
lawns. Sediments constitute the largest mass of
pollutants from urban areas. Urban runoff
affects between five and 15 percent of surface
waters.
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The construction of highways, roads,
and land development projects produces
sediments and toxic materials that degrade
water quality and permanently modify fishery
and wildlife habitat.
Timber cutting and other forestry-
operations affect approximately five percent of
surface waters. Logging roads and deforested
lands produce large amounts of sediments that
eventually end up in streams, rivers, and lakes.
In addition, many types of plants and wildlife
can be affected by the loss of their habitat.
Hydromodification, a result of flood
control and stream channelization projects as
well as reservoirs and dams, affects runoff,
increases sediment deposits, and changes water
quality and fishery habitats. It also increases
treatment costs for water intended for human
consumption and industrial use.
Poor water quality costs us billions of
dollars annually. It increases our costs for the
treatment of drinking water, limits the produc-
tivity of our fisheries, and reduces our recre-
ational opportunities. In Iowa, sediments are
the leading pollutant in surface waters. Iowa's
Department of Natural Resources reports that
sediment problems alone cost lowans approxi-
mately $32 million every year in damages to
recreation, fish and wildlife resources, munici-
pal water supplies, transportation, and blocked
drainage on agricultural lands.
The remaining problems of water
quality will be addressed most effectively at the
state and local level. There are two and one-half
million farming operations alone in the country.
Cost-effective solutions can vary widely, and
may even vary from one section of a single farm
to another; solutions must be adaptable over
time to respond to changing physical, economic,
and social conditions at the local level.
Many members of Congress and
advocacy groups are concerned that the nation
has been too slow in dealing with polluted
runoff. We have known about the problem
since the earliest days of our water pollution
control efforts. Industry and municipalities are
also concerned that their substantial investment
in cleaner water is being jeopardized by the
problems of nonpoint source pollution. Many
industries are beginning to ask why more
stringent restrictions should be placed on their
effluent when the sources that are now respon-
sible for the majority of water quality impair-
ments have very few or no restrictions placed
on them.
One approach to solving the problem of
nonpoint source pollution can be found in the
Coastal Zone Act Reauthorization Amendments
of 1990. (See related fact sheet EPA 840-F-93-
OOlc) Through this law, Congress requires
states with coastal zone management programs
to adopt coastal nonpoint source programs.
These programs can be tailored to the particular
needs and problems within the state, but must
have "enforceable policies and mechanisms."
This is one of several approaches that are being
explored by members of Congress as they
consider how to improve our Nation's ability to
successfully address nonpoint source pollution.
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