Lake is one form of terrestrial waters that is often
encountered. In simple terms, lakes can be interpreted as basins on the surface
of the Earth which are usually bowl-shaped naturally filled with a collection of
water (generally fresh water) in relatively large quantities. Most of the water
sources that fill and provide water supply to the lake come from rainwater and
river flow that empties into the lake. Springs and ground water can also fill
the lake. In such cases lakes are generally permanent, meaning they remain
filled with water throughout the year. Conversely, if the water source of the
lake fill is only one kind, such as from rain water, then generally the lake is
temporary or periodic. So, the lake can dry at certain times.
Based on the type of water, the lake can be divided
into two, namely as follows.
a. Saltwater Lake.
Generally saltwater lakes are located in semiarid or arid areas, where
evaporation occurs which is very strong and does not have an output stream. If
this kind of lake becomes dry, then the remaining layer of salt in the bottom
of the lake. Many temporary lakes are found in the arid region which has high
salinity. Examples of saltwater lakes are the Great Salt Lake in America and
the Dead Sea in Jordan.
Great Salt Lake
Object Source: https://www.youtube.com/watch?v=pIJvh8GiyKc
b.
Freshwater
lake. This lake is mainly located in humid (wet) areas that have high rainfall.
In general, these lakes get water from rainfall and always drain the water to
the sea. So this lake is an open lake. Almost all Indonesian lakes are
freshwater lakes.
According to the process of formation, the lake can
be divided into several types, namely as follows.
a. Tectonic Lake, which is
a lake formed by the presence of tectonic processes that cause dislocation of
rock layers, such as folds and faults. On the surface of the Earth that has
decreased is filled with enough water (rainwater, rivers, springs) so that a
lake is formed. Examples of tectonic lakes located in Indonesia are Lake Poso,
Singkarak, Tempe, and Tondano. An example of a tectonic lake outside Indonesia
is Lake Tanganyika in East Africa.
b.
Volcanic
Lake, which is a type of lake located on the former crater hole of a volcano,
so the lake is formed due to volcanic activity. In the former a volcanic
eruption there will be a basin called volcanic depression. If the bottom of the
basin is covered by water-resistant volcanic material, falling rainwater will
be accommodated and form a volcanic lake. The shape and extent of volcanic
lakes is influenced by the type of volcanic process that forms them. The type
of volcano maar will form a maar lake. In volcanoes with eruption of the
caldera, extensive caldera lakes will form. Examples of volcanic lakes are Lake
Kelimutu, Kerinci, Rinjani, Telaga Warna, and Lake Batur.
c. Lake Tecto-Volcanic,
which is a type of lake formed by a combination of tectonic and volcanic
processes, for example Lake Toba.
Lake Toba
Object Source: https://www.youtube.com/watch?v=-UNn0YKpdoU
d. Karst Lake (Dolina),
which is a lake that can be found in limestone / karst regions as a result of
the dissolution of limestone that forms water filled basins. Generally in the
form of small lakes that are temporary. If at the bottom and dolina cliffs
there is a clay material which is a waterproof material, then the falling
rainwater will be accommodated in dolina and cannot continue to enter the
limestone so that dolina lake is formed. Dolina lakeccan also occur due to the
presence of high water in limestone soils. Actually the limestone is not
translucent, but because it has regular gaps, the rainwater that falls still
enters and seeps down. If the soil layer below the limestone layer is a
waterproof layer and the rainfall in the area is large, then the water stored
in the limestone layer is high enough so that the bottom of dolina can be
inside the karst water surface.
e. Glasial Lake, which is
a type of lake formed by erosion by glaciers. Glacial lakes are found in
regions around the polar climate. After the ice age ended, the areas that the
glaciers had once passed through became dry and filled with water. If the
valley that contains water is not related to the sea, then the valley will
become a lake. Examples of glacial lakes are Lake Michigan, Lake Superior, and
Lake Ontario that are between Canada and the United States.
Lake Superior from above
Object Source: https://www.youtube.com/watch?v=Ekgic7aHc50
f. Cirques are lakes whose
water comes from melting ice. Cirques can be found in high mountain areas where
some of their bodies are covered in ice mass.
Cirques Lake in Callaghan National Park, Canada
Object Source: https://www.youtube.com/watch?v=5fN9Iu3aclM
g. Stoppable Lake, can be
formed when materials such as mountain debris or lava flows that stem the river
valley, so that the flow of water will be restrained and eventually form a
lake. Here also includes artificial lakes called Dams / Reservoirs, for example
Gajah Mungkur Reservoir in Wonogiri, Central Java and Jatiluhur Reservoir in
West Java.
Gajah Mungkur Reservoir
Object Source:
https://www.youtube.com/watch?v=7mKodBqJkl4
One pool of Gajah Mungkur Reservoirs
h. Lakes due to river
erosion, for example horseshoe lakes.
The process of forming horseshoe lakes
Object Source:
https://www.youtube.com/watch?v=4qKS_Nk7UmY
Presented by
(Benteng Terpadu Raya/Great Integrated Fortress)
Reference:
·
Wardiyatmoko,
K. 2004. Geografi SMA Jilid 1 untuk Kelas
X Kurikulum 2004 Berbasis Kompetensi. Jakarta: Erlangga.
·
Utoyo,
Bambang. 2009. Geografi 1 Membuka
Cakrawala Dunia untuk Kelas X Sekolah Menengah Atas/Madrasah Aliyah.
Jakarta: Pusat Perbukuan Departemen Pendidikan Nasional.
·
Soegimo,
Dibyo and Ruswanto. 2009. Geografi: untuk
SMA/MA Kelas X. Jakarta: Pusat Perbukuan Departemen Pendidikan Nasional.
·
Rahayu,
Saptanti and friends. 2009. Nuansa
Geografi 1: untuk SMA/MA Kelas X. Jakarta: Pusat Perbukuan Departemen
Pendidikan Nasional
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