Nonpoint source pollution is
pollution that is caused by diffuse sources and can negatively
affect waterways such as rivers, lakes, wetlands, and estuaries.
Nonpoint source (NPS) pollution is the leading cause of water
quality problems and is occurs when rainfall or snowmelt picks up
pollutants as it moves over land or through the ground and then
deposits then in water sources. Nonpoint source pollution can occur
in an urban or a rural setting and each area presents its own
unique circumstances. A mitigation plan for nonpoint source
pollution would need to address the specifics in each setting.
Unlike point source pollution, the
direct cause of nonpoint source pollution cannot be identified in
terms of the pollution coming from one distinct source. The diffuse
sources, depending on location, may include pollutants such as
excess herbicides, insecticides, and fertilizers, sediment, salt,
bacteria and nutrients, oil, grease, and toxic chemicals. The
result of these pollutants being deposited into various water
sources can be beach closures, the destruction of habitat, fish
kills, and unsafe drinking water, among other things. The most
common pollutants in terms of nonpoint source pollution are
sediment and nutrients (EPA, 2009).
Because NPS pollution is the
leading cause of water quality problems, the United States
Environmental Protection Agency has conducted extensive studies to
quantify the NPS problem. Approximately 40% of the surveyed
estuaries, lakes, and streams were determined to be not fit to meet
even the most basic of uses such as fishing and swimming. Of the
surveyed estuaries, urban runoff was determined to be the largest
source of water quality problems. Urban runoff often includes oils,
grease, and toxic chemicals that are washed from impervious
surfaces such as roads into the waterways and on to the receiving
waterbodies. Agricultural runoff is determined to be the cause of
pollution in 60% of the surveyed river miles that are classified as
impaired and in 50% of the impaired lake acreage. In addition to
the fertilizers and chemicals that are applied to agricultural
lands, soil erosion also contributes to the pollution problem
because of the increase in sediment load (EPA, 2009).
Residential areas present their own
form of problems with NPS pollution. Septic tanks that are not
properly functioning can contribute to the addition of bacteria and
nutrients. Also, fertilizers and pesticides that are not applied in
the proper manner can result in excess product reaching receiving
waterbodies as well. In addition, the improper use, storage, and
disposal of household chemicals can contribute to water pollution.
One of the major challenges with addressing NPS pollution is
determining what potential sources are contributing to the problem
(EPA, 2009).
NPS pollution is a problem that can
be addressed on many levels. On the federal level, programs such as
the Nonpoint Source Pollution Management Program are meant to
address the NPS pollution problem. This act was established in 1987
by the Clean Water Act Amendments. The Coastal Nonpoint Source
Pollution Program was established in 1990 by the Coastal Zone Act
Reauthorizing Amendments. Other ways the federal government can
take responsibility for NPS pollution is to ensure that federal
lands are managed for soil erosion, logging, and pesticide
application (EPA, 2009).
States can take responsibility for
NPS pollution by enacting legislation that enforces the use of best
management practices in industries such as mining and logging to
reduce the impact of those industries on the water resources.
Locally, ordinances can be passed for zoning as well as erosion
control. Individuals can also be responsible for their part in NPS
pollution by practicing conservation and by changing some habits
regarding landscaping and the use of household chemicals.
On the east coast of the United
States, an estimated 285 million pounds of nitrogen reach the
Chesapeake Bay each year. Excess nitrogen can lead to problems such
as algal blooms. When algae decompose, they deplete the water body
of oxygen and can result in 'dead zones' that disrupt the aquatic
food web. In 2002, the states that contribute to Chesapeake Bay
sought federal support to reduce the amount of nitrogen that was
reaching this important estuary. The states asked for $20 million
to test four new farm practices that could reduce the runoff from
agricultural lands by 50%. The anticipated reduction in nitrogen
loading would be about 6 million pounds per year. One of the
programs suggested by the states was to pay farmers to use fewer
nutrients on their crops and to plant cover crops to reduce soil
erosion (Blankenship, 2002).
In 2008, Virginia and Maryland
introduced another program aimed at reducing runoff from
agricultural land. This came as a result of a study that estimated
that 42% of the nitrogen, 46% of the phosphorus, and 72% of the
sediment that was reaching Chesapeake Bay came from agricultural
lands. Virginia proposed spending $20 million to implement best
management practices aimed at improving water quality. The main
components of the plan included building buffers around
agricultural fields, keeping cattle out of creeks and rivers, and
coming up with improved methods of fertilizer storage. In Maryland,
state officials proposed the Cover Crop Program to reduce sediment
loading from soil erosion as one of their strategies. Chicken farms
are a large business in Maryland and presents unique problems. A
manure management plan was proposed as well, but the enforcement of
manure management remains a problem (Kelleher, 2008).
In Florida where the water table
tends to be high and canals and ditches are common, nonpoint source
pollution is a serious problem for the state's waterways. In an
effort to reduce the standing water that serves as a habitat for
mosquitoes and to provide more land for development, areas in
Florida have been ditched to drain the water quickly from inland
areas. While this serves its purpose to prevent flooding and reduce
the mosquito population, it also serves as a conduit for nonpoint
source pollution to reach important estuaries and other waterways.
The EPA originally set a deadline of 2004 for Florida to establish
limits on the amount of nutrients that reach these waterways.
Florida essentially disregarded the order, though many local
governments have enacted their own local ordinances to combat the
nutrient problem (Earthjustice, 2009).
Fertilizer ordinances such as those
in Sarasota County, Florida are designed to prevent excess
nutrients from residential application of fertilizer from reaching
the coastal waters. To do this, residents are not allowed to apply
fertilizer to their lawns from June 1st to September 30th. This is
Florida's rainy season when almost daily rainfall would wash many
of the nutrients out to receiving water bodies. Fertilizer-free
zones were established within 10 feet of water bodies. For those
who violate the ordinance, the first offense is a warning followed
by a $500 penalty for repeat offenders. The ordinance also
established a voluntary 'low-maintenance' zone within 6 feet of
water bodies and it recommended the use of slow-release fertilizers
(Whittle, 2007). The state has looked at statewide legislation
similar to Sarasota County's ordinance, but has been met with some
resistance from fertilizer companies. The phosphate industry is a
large component of the Florida economy and there is concern that
restrictions on fertilizer use would impact this market.
The high water table in Florida
also presents problems with the use of septic tanks. When properly
installed and maintained, septic tanks provide residential waste
water treatment. When they malfunction or are installed in a place
that does not allow them to function as they should, they can
contribute nutrients and bacteria to the NPS pollution problem.
Communities across the state are taking actions to replace septic
tanks with central sewer in areas where the septic tanks are
thought to be contributing to the nutrient loading that causes
algal blooms and bacteria that can result in beach closings. Marco
Island is one place that has taken steps to increase their central
sewer system to reduce the nutrient loading (SFWMD, 2008). The
problem with this course of action is that it is often cost
prohibitive. There is a cost to the utility for extending the sewer
lines and often a cost to homeowners to hook up to the system. In
addition, some homeowners are resistant to the idea of paying for
central sewer when with septic tank they had no monthly charges.
Local ordinances requiring central sewer are one solution to
voluntary hook ups that may not have the same participation
rate.
The mitigation strategy for NPS
pollution would have to have many layers. Beginning at the local
level, ordinances could be passed to address the problem. Among the
possible local strategies are: requiring new development to have a
higher percentage of pervious surfaces to reduce runoff volume;
enact fertilizer ordinances to reduce the amount of available
nutrients in runoff; require new developments to hook up to central
sewer and start septic tank replacement programs; institute public
education on the use, storage, and disposal of household chemicals;
and, improve stormwater management systems that would lengthen
retention time of stormwater runoff and allow removal of some
components of NPS pollution.
At the state level, a mitigation
plan would include: legislation regarding the use of fertilizers;
requirements for buffer zones around agricultural areas;
legislation for the storage and disposal of animal waste; grants
for homeowners who replace their septic tanks with central sewer
connections; and, to provide funding to support local initiatives
to reduce urban runoff. At the federal level, support would come in
the form of funding to investigate which strategies would work best
in certain areas, develop new best management practices, and to
provide subsidies for farmers who implement the best management
practices.
As with any strategy, the problem
with legislation at the local or state level is enforcement.
Enacting laws to restrict the use of fertilizers is only the first
step to addressing the problem. Finding and penalizing those who
ignore the law presents a greater challenge, especially in
communities where funds are sometimes in short supply. The benefits
of this multi-layered mitigation strategy is the reduction of
nonpoint source pollution reaching and harming our water bodies.
This protects habitat, areas used for drinking water supply and
recreation, and improves the quality of life. Challenges to the
plan would come from industries who may be impacted by the
reduction of sales in certain products, though the strategy may
encourage them to develop products that are more environmentally
friendly. The other challenges may come from homeowners who are
impacted financially if they are required to replace their septic
tanks with central sewer and from homeowners who are resistant to
the idea of a government entity telling them when and how much
fertilizer they can apply to their lawns.
Whatever the approach, it is
obvious that nonpoint source pollution is a serious problem in both
rural and urban areas. The pollution can kill fish, destroy
important habitat, impact fishing and recreational opportunities,
and present a threat to human health. The reduction of runoff, both
from urban areas and agricultural lands, will only improve the
health of the world's water resources. The mitigation strategies
are something that must be pursued in order to stop any further
degradation from occurring and before the water resources reach a
point where they are permanently impacted.