Clean
freshwater resources are essential for drinking, bathing, cooking, irrigation,
industry, and for plant and animal survival. Unfortunately, the global supply of
freshwater is distributed unevenly. Chronic water shortages exist in most of
Africa and drought is common over much of the globe. The sources of most
freshwater supplies¡X groundwater
(water located below the soil surface), reservoirs, and rivers¡Xare under
severe and increasing environmental stress because of overuse, water
pollution, and ecosystem degradation. Over 95 percent of urban sewage in
developing countries is discharged untreated into surface waters such as rivers
and harbors.
Polluted
River
The pollution of rivers and
streams with chemical contaminants has become one of the most critical
environmental problems of the century. Chemical pollution entering rivers and
streams can be classified according to the nature of its sources: point
pollution and nonpoint pollution. Point pollution involves pollution from a
single concentrated source that can be identified, such as an outfall pipe
from a factory or refinery. Nonpoint pollution involves pollution from
dispersed sources that cannot be precisely identified, such as runoff from
agricultural or mining operations or seepage from septic tanks or sewage drain
fields.
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Industrial
Water Pollution
Industrial pollutants that run
into streams, rivers, or lakes can have serious effects on wildlife, plants,
and humans. In the United States there are strict rules for the amount and
composition of substances that factories can release into bodies of water.
These rules are not always enforced, and much industrial water pollution comes
from accidental chemical or oil spills.
About
65 percent of the global freshwater supply is used in agriculture and 25 percent
is used in industry. Freshwater conservation therefore requires a reduction in
wasteful practices like inefficient irrigation, reforms in agriculture and
industry, and strict pollution controls worldwide.
In
addition, water supplies can be increased through effective management of watersheds
(areas that drain into one shared waterway). By restoring natural vegetation to
forests or fields, communities can increase the storage and filtering capacity
of these watersheds and minimize wasteful flooding and erosion. Restoration and
protection of wetlands is crucial to water conservation. Like giant sponges,
wetlands stabilize groundwater supplies by holding rainfall and discharging the
water slowly, acting as natural flood-control reservoirs.
