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Technical
Resources >> Water Sources
>> Surface Water
Surface water, a term typically
used to refer to non-saline water that is naturally exposed to the
atmosphere, is the least abundant type of available freshwater.
It makes up roughly 2% of the freshwater which is available for
human use. Precipitation is the primary source of surface water.
Common types of surface water include streams, water runoff, rivers,
lakes, and ponds.
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| Surface water is much
more readily available for human use than other water sources such
as ground water or glacial ice. This is due to the higher accessibility
and abundance of surface water in many areas. This accessibility,
however, does not make this form of freshwater the most optimal for
human use. Surface water frequently has contaminants that require
more robust and complete treatment than groundwater, which is often
used without treatment. |
| In order to make use of surface water,
issues of chemical and bacteriological contaminants must be handled.
The properties of surface water are in constant flux. This creates
a situation where it becomes difficult to treat surface water, whereas
groundwater is comparatively stable. |
| The contaminants of surface water
are primarily affected by human and animal activity. Since a major
source of recharge for surface water systems is through runoff, surface
water may become contaminated by the pollutants associated with runoff.
These pollutants include human, agricultural, and industrial wastes.
An example is the process of heavy metal loading, which may occur
as a direct result of dumping industrial waste. |
| The contaminants of surface water
are primarily affected by human activity. Since a major source of
recharge for surface water systems is through runoff, surface water
may become contaminated by the pollutants associated with runoff.
These pollutants include agricultural and industrial pollutants. An
example is the process of heavy metal loading, which may occur as
a direct result of dumping industrial waste. Heavy metals as well
as toxic compounds, such as acids, further pollute the water. This
often helps to suppress the biological processes which act to purify
a river or stream. |
| Bacteriological concerns are, in
large, associated with surface water storage. Both bacteria and parasites
are provided with the nutrients to grow and populate in this environment.
It is common for Municipal water systems to treat this problem through
chlorination, coagulation, sedimentation and filtration of surface
waters. |
| For the most part, groundwater and
surface water are distinguished by location and time. A continuous
process of exchange occurs between the two types of freshwater. For
example, an effluent stream is one which receives water from groundwater.
An influent stream is on that supplies water to groundwater. Groundwater
moves at a much slower rate than surface water. This can cause contamination
which may emerge from groundwater years after the injection. Thus,
another source of contamination is groundwater discharge to lakes
or streams. |
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