GWR 2024 Look Inside - Flipbook - Page 3
BLUE PLANET
INLAND WATERS
Air pocket
LONGEST RIVERS
The Nile flows north from
Burundi (its most southerly
source) in Central Africa to the
Mediterranean Sea, passing
through 10 other countries
along the way. It is not just
its continent’s longest river
but the world’s. Laid out in
a straight line, it could link
the cities of Paris and Delhi.
The Amazon is a close second
place; while just missing out
on the “longest” title, it does
claim a plethora of other
riverine records (see right).
Highest river
The Yarlung Tsangpo’s source lies 6,020 m (19,750 ft) above
sea level at the foot of the Angsi Glacier in Tibet, China.
The lowest is the Jordan River. Where it empties into the
Dead Sea (see below), it is 436 m (1,430 ft) below sea level.
Open
cenote
(mature)
Halocline
(where fresh
water meets
salt water)
Greatest river by discharge
South America’s Amazon outputs 200,000 m³ (7.1 million cu ft)
of fresh water into the ocean every second. That’s 17% of the
global total and enough to fill the Dead Sea in under a week!
This can rise to 340,000 m³ (12 million cu ft) in the wet season.
The Amazon is fed by the largest river basin, covering
7.04 million km² (2.72 million sq mi) across eight nations –
14 times the size of Spain. At its broadest (not in flood), the
Amazon spans 11 km (6.8 mi), also making it the widest river.
Africa: Nile – 6,695 km
South America: Amazon – 6,400 km
Asia: Chang (Yangtze) – 6,300 km
North America: Missouri – 3,767 km
Europe: Volga – 3,692 km
Oceania: Murray – 2,508 km
Antarctica: Onyx – 32 km
Largest freshwater lake
• By surface area: One of the five Great Lakes, Superior covers
82,414 km² (31,820 sq mi) of Canada and the USA.
• By volume: Lake Baikal in Siberia, Russia, has a capacity of
c. 23,615 km3 (5,666 cu mi). Dipping to 1,642 m (5,387 ft) in its
central basin, it’s the planet’s deepest lake too.
• In the tropics: The 59,947-km2 (23,146-sq-mi) Lake Victoria
(aka Nyanza, Nam Lolwe or Nalubaale) is Africa’s biggest lake
by area. It’s the primary reservoir of the River Nile (see left).
Semi-open
cenote
(young)
Sea
Cave
Porous
limestone
(karst)
Coastal
aquifer
Largest ephemeral lake
As the name suggests, ephemeral lakes come and go. Kati
Thanda (aka Lake Eyre) in South Australia, located in a
basin that forms the country’s lowest natural point, is the
largest such non-permanent body of water. When the dry
salt pan floods every eight years or so, Kati Thanda can
grow to 9,690 km2 (3,740 sq mi) – similar in size to the city
of Melbourne. Proliferations of algae and bacteria can
transform the water shades of pink and orange.
Cenotes
are the
visible part of an
“anchialine” syst
em:
one that seems
landlocked but is
linked to the
ocean.
Largest lake
The Caspian Sea is Earth’s biggest inland body of water, with
a surface area of 371,000 km² (143,244 sq mi). Bordered by
Kazakhstan, Russia, Azerbaijan, Iran and Turkmenistan, the
shoreline of this saltwater lake is c. 7,000 km (4,350 mi).
Tallest waterfall
Kerepakupai Merú (aka Salto Ángel, or Angel Falls) in eastern
Venezuela descends 979 m (3,212 ft) in total, with the longest
single drop being an uninterrupted 807-m (2,648-ft) cascade.
Largest tropical wetland
Approximately 0.03% of Earth’s fresh water is found in
swamps, bogs and marshes, of which the Pantanal in
South America is among the most significant. Located
principally in Brazil, but also Bolivia and Paraguay, this
160,000-km2 (61,780-sq-mi) wetland is a haven for flora
and fauna, including jaguars. In the rainy season (Dec–
May), some 70–80% of the Pantanal is flooded.
Deepest hypersaline lake
The Dead Sea on the Israel-Jordan border averages 120 m
(393 ft) deep, but bottoms out at c. 306 m (1,004 ft). Also
the lowest exposed body of water, it lies 436 m (1,430 ft)
beneath mean sea level. With a salinity almost 10 times
greater than that of seawater, salt-encrusted rocks are a
common sight along its shores.
Widest waterfall
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Raging around islets and over rocky crags, the Khône Falls on
the Mekong River in southern Laos have a total crest width of
10,783 m (35,377 ft) between the western and eastern banks.
This is four times the span of South America’s Iguazú Falls.
Although exceptional horizontally, this series of cascades and
rapids has a maximum vertical drop of just 21 m (69 ft).
SHOWER IN A WATERFALL
Follow in the soggy footsteps of millions who have been hopping on to boats to get soaked beneath
the roiling waters of Niagara Falls on the US-Canada border since 1846. You’ll be in good company:
with up to 22.5 million pilgrims heading here each year, it’s the most visited waterfall.
LONGEST FLOODED CAVE SYSTEM
From the surface, Mexico’s Yucatán Peninsula
appears fairly bereft of water, but looks can
be deceiving… Beneath the surface lies a
labyrinth of water-filled caverns and tunnels –
effectively an underground river network.
The most extensive contiguous section – the
Sac Actun System – measures at least 371.9 km
(231.1 mi) long, as of the most recent survey
conducted in 2019. It claimed the record in
2018, when it was confirmed that the Sac
Actun (“White Cave”) and Dos Ojos (“Two
Eyes”) cave networks were linked. This aquatic
maze has been carved out from the limestone
landscape over millennia via erosion from
both below (by the sea) and above (by rain);
see Yucatán’s karst topography in top corner.
Offering a glimpse into Sac Actun’s hidden
world are some 220 cenotes
– natural pools left exposed
by collapsed sinkholes. They
come in many shapes and
sizes, from the 40-m-deep
(131-ft) El Pit (main image) to
the shallower, jungle-edged
Nicte-Ha (inset).
Although the main rocky base of
El Pit visited by recreational divers
lies 40 m down, adjoining caverns
actually descend much farther, up
to 121 m (397 ft) underground.
From the Mayan, Nicte-Ha translates as
“Flower of the Water” – referring to the many
waterlilies that grow in this cenote.
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