Study:
Half of lakes in peril
Great
Lakes also feared endangered by airborne toxins By
Lee Bowman /
Article courtesy of Scripps Howard News Service
November 14, 2001 SHIGA, Japan
-- More than half the world's 5 million lakes are being
dried up or polluted to the point of ecological collapse,
according to experts meeting at an international conference
on lake conservation this week.
Lakes hold nearly 90 percent of all surface
freshwater, yet they are "among the most vulnerable and
difficult to restore of all natural ecological systems.
They have been widely ignored, even as they have deteriorated,"
said Masahisa Nakamura, director of the Lake Biwa Research
Institute in Shiga, Japan, where the ninth International
Conference on the Conservation and Management of Lakes is
being held.
The conference is part of a series of
meetings being held in advance of a World Water Forum in
2003.
The amount of water in freshwater lakes
is 35 times more than what's found in rivers, yet they can
quickly vanish. For instance, 543 significant lakes in China
disappeared when their water was diverted for irrigation
between 1950 and 1980.
In industrialized countries, shallow lakes
are the most endangered, especially in areas of intensive
farming or population growth. The most dramatic example
of this in the United States is Lake Okeechobee in Florida,
half the size of Rhode Island, but with an average depth
of 10 feet. Controlling and tapping its flow has drawn down
much of the lake and adversely affected the Everglades.
The Aral Sea between Kazakstan and Uzbekistan
has dropped from being the world's fourth largest lake to
eighth largest because of heavy withdrawals for irrigation.
Even the Great Lakes of North America
remain at risk because of to airborne toxins, invasive species
and periodic proposals to divert water from them, although
direct water pollution from the United States and Canada
has been markedly reduced in recent decades.
William Cosgrove, vice-president of the
World Water Council, which is sponsoring the meetings, said
successful lake recoveries can only take place "if citizens
who are affected get involved. They need to understand that
what they do in a lake's basin, the runoff from their lands
and activities, determines the health of that lake."
While people from the developing world
are more directly dependent on lakes than residents of industrialized
countries, Cosgrove notes that most campaigns to rescue
lakes have been in wealthier nations that have the resources
to build wastewater treatment plants and carry out restoration
efforts.
Once a lake becomes degraded, it can take
decades to restore water quality.
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