Travel writers often describe beautiful places as having “pristine”, “pure”, “crystal clear” waters. But which bodies of water are truly the cleanest and the clearest? Where in the world do breath-taking aesthetics reflect the science of “pristine”?
quality and water clarity are important technical considerations for
environmental scientists. Impacts on the quality and clarity of a body of water
can come from its source, its depth, the sun, natural phenomena (ranging from
weather incidents to volcanic activity) and the living organisms in and around
it (people included).
clear waters do exist throughout the world, if you know where to look. The
following are some of the most pristine bodies of water in the world.
Crater Lake, United States
1,943ft-deep Crater Lake, located in Oregon, was formed 7,700 years ago when
the volcano Mount Mazama collapsed after a huge eruption, and according
to the US National Park Service, it may be the cleanest large body of water
in the world. Crater Lake is so pristine because it is fed almost entirely by
snow and rain; there no rivers or streams flowing into it bringing nutrients,
sediment and/or contaminants. In addition, since Mazama is dormant today, no
gases or liquids affect the lake water, as is sometimes the case with other
vibrant colour is a strong indicator of its clarity. “Crater Lake is this
amazing blue that you really have to see to believe – it’s hard to even capture
it in a photograph,” said park ranger Dave Grimes. It appears this way to our
eyes because plain water molecules absorb the longer colour wavelengths of
green, yellow, orange and red and bounce back the shorter blue wavelengths,
Grimes described. If there were more particles in the lake, or less water, it
would appear less blue.
Lake Baikal, Siberia
southeastern Siberia, north of the Mongolian border and about 70m from the city
of Irkutsk, Lake Baikal holds one-fifth
of our planet’s fresh water. Baikal is the deepest lake in the world, its
waters plunging down about 1,700m.
you see all over the world”, explained Darran
Crabtree, director of conservation for the central and western New York
chapter of The Nature Conservancy, “is
that where you do have very deep bodies of water relative to the input area [the
watershed], you have a real fighting chance for having high water quality and
clarity.” Although Lake Baikal’s watershed – the area of land served by a body
of water – is fairly large, the lake has such incredible volume that most
pollutants get diluted deep into its waters.
Lake Vostok, Antarctica
historic culmination of a 30-year mission, Russian scientists finally
successfully penetrated a 20-million-year-old subglacial lake in Antarctica
earlier this year. Hidden under a sheet of ice that was two-and-a-half miles
thick, Lake Vostok had previously been untouched by the outside world, causing
researchers at the Russian
Arctic and Antarctic Research Institute to predict that it may be “the only
giant super-clean water system on the planet”. The largest in a network of
more than 200 subglacial lakes, Lake Vostok covers about 15,540sqkm – nearly the area of North America’s Lake
Ontario – and reaches a depth of 1,000m,
making it the third deepest lake in the world. (Lake Baikal is the deepest and Lake
Tanganyika in East Africa is the second deepest.)
A patch of the South Pacific Ocean
organisms and less organic matter generally leads to clearer waters. Scientists
from the University of the Mediterranean’s
Oceanography Centre of Marseille discovered that a
patch of ocean near Easter Island in the South Pacific Ocean is one
of the most lifeless systems on the planet. With waters as clear as some of
the purest fresh water, the researchers concluded in their study, it
may be the clearest section of ocean on earth.
Lake Malawi, East
life-poor patch of ocean in the South Pacific to a life-rich lake in the East
African Rift System, clear waters can be found in all different corners of the
world. Lake Malawi, also called Lake Nyasa, is the second deepest body of
freshwater in Africa and one of the deepest in the world, reaching a depth of 706
meters. Serving Malawi, Tanzania and Mozambique, the 579km-long lake is
accessible in Malawi via the towns of Mangochi or Monkey Bay in the south and via
Mzuzu, Karonga or Nkhata Bay in the north.
is classified as a Unesco
World Heritage site due to its diversity of endemic fish. Providing habitat to more
fish species than any other lake in the world, its cichlids
fish are considered as important for the study of evolution as Charles
Darwin’s finches in Ecuador’s Galapagos Islands. Its clarity remains
relatively high, though, largely because of its depth. These conditions make
Lake Malawi an extraordinary place for freshwater scuba
diving. In the lake, however, there is the risk of bilharzia, an infection by a
type of parasitic worm, so travellers who choose to swim or dive there often
stock up on the treatment, Praziquantel tablets.
Blue Lake, New Zealand
study by the Auckland-based National
Institute of Water and Atmospheric Research found some of the clearest
waters on record in the small Blue Lake, part of Nelson
Lakes National Park in New Zealand’s Southern Alps, accessible from the
village of Saint Arnaud. While relatively shallow (only seven meters deep), Blue
Lake’s horizontal visibility – the
measured length one can see underwater – can get up to about 80m. The lake is
spring-fed by neighbouring Lake Constance (a glacial lake), but most of the
water’s particles are filtered out when it passes a dam between the two lakes
formed by landslide debris, scientists from the institute found.
Hornindalsvatn Lake, Norway
Annecy has gained the reputation of being “Europe’s cleanest lake”, Norway is
home to freshwater bodies that are far deeper and less visited. Located near
the town of Grodas, Hornindalsvatn Lake, the deepest lake in Europe at about
514m, is surrounded by beautiful mountains, glaciers and fjords. Snowmelt is
responsible for much of the lake’s water, while run-off streams from glaciers
do not drain directly into the lake, according to Norway’s tourism board,
resulting in high levels of quality and clarity.
Travelwise is a BBC Travel column
that goes behind the travel stories to answer common questions, satisfy
uncommon curiosities and uncover some of the mystery surrounding travel. If you
have a burning travel question, contact Travelwise.