Water is responsible for some of the most amazing
scenery on the planet: great rivers and wetlands, giant waterfalls and
canyons. And many man-made waterworks are also amazing. Everybody knows
about the big dams, so we thought wed choose some others for our
list of the seven greatest water wonders on Earth.
Which is your favourite?
They look like a staircase for giants. But
these stone-walled steps down a mountainside in the Philippines are actually
narrow fields where farmers grow rice. And each step is kept watered by
a complicated network of channels that takes water on to each terrace,
starting from a spring near the top. This brilliant engineering
seen here at Banaue where the terraces have been declared a World Heritage
Site creates fertile land out of steep slopes. The first terraces
were built on Luzon by the Ifugao people around 2 000 years ago.
That was when the Romans were building their water aqueducts in Europe.
But, unlike Roman waterworks, the terraces remain in use, constantly maintained
and extended by the Ifugao farmers of today.
Want to see the power of rivers to eat away the land? Or just visit one of the most dramatic places on Earth? Go to the Grand Canyon in the United States. Here, over millions of years, the waters of the Colorado River have cut a canyon more than a kilometre deep in the plateau of northern Arizona. The canyon is 400 kilometres long and up to 25 kilometres wide. Peer over the rim and you look down past layer after layer of ancient rocks. The ones at the bottom are 1.7 billion years old.
PHOTO: DAVID ERIC/UNEP/B
In the deserts of Iran, they find water by digging tunnels deep into the hillsides. The tunnels, called qanats, tap water that collects underground after the regions occasional rains. In some places, the Iranians have dug them for more than 40 kilometres into the hillsides before finding water. The Iranians have been digging qanats for 2 000 years. There are around 40 000 of them, enough to circle the Earth 20 times. In some places, they have been replaced by modern pumps. But elsewhere their waters still irrigate fields and orchards and sometimes supply whole towns.
PHOTO: IRAN RIVERS.COM
Lake Baikal, in the middle of Siberia, is
the oldest and largest body of freshwater on the planet. It is 25 million
years old, over 600 kilometres long and in places 1.6 kilometres deep
almost as deep as the oceans. The lake contains a fifth of all
the liquid freshwater on the planet. It would take all the rivers of the
world a year to fill it. And the lake, a World Heritage Site, is home
to an amazing 1 200 species of plants, animals and fish found nowhere
else on Earth, including its own unique seal.
The Sahara may be a desert today, but once
it was wet. And underneath it still lie huge amounts of water. Most of
it is 30 000 years old. For the last 10 years, Libya has been pumping
this water up from hundreds of wells sunk into the desert sands, and sending
it in huge pipes to farms on the distant coast. The pipes are so big you
could drive a truck through them. And they carry as much water as a river
like the Mersey in England or the Rio Grande in America. In fact, this
is Libyas only river.
Jimmy Angel found the Angel Falls deep in the Devils
Canyon in the rainforests of Venezuela back in 1933. He was looking for
gold, but instead found the worlds tallest waterfall. It is almost
a kilometre high, falling straight off Auyan Tepui mountain into the jungle
below. Of course the local Indians, the Pemones people, knew about the
falls long before Jimmy Angel flew his bush plane down the canyon and
saw it. They called it the Churún Merú. But Jimmy told the
rest of the world so it bears his name.
The Sudd marshes are the biggest inland wetland
in the world. Their lakes and swaying papyrus cover an area bigger than
England and are home to elephants, hippos, crocodiles, giraffes, antelope
and millions of birds. The marshes get their water from the Nile, the
worlds longest river. In fact, more than half the rivers water
evaporates during its journey through the marshes. People downstream think
that is a waste of water. Egypt and Sudan had a plan to dig a canal round
the edge of Sudd, so the Nile could bypass the marshes. That way more
water would be left to irrigate fields and fill taps. A civil war in Sudan
stopped the canal when it was half-dug. But if it is ever completed, the
great Sudd marshes would dry up.
Our Planet 1996 Water Issue Our Planet 1998 Freshwater Issue
AAAS: Freshwater AAAS: Freshwater wetlands AAAS Mangroves and Estuaries
World Heritage sites - UNESCO Iran Rivers Courtney Milne Man Made River Project PDF Version