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Here is a compilation of essays on ‘Lakes in India’ for class 6, 7, 8, 9, 10. Find paragraphs, long and short essays on ‘Lakes in India’ especially written for school students.
Essay on Lakes
- Essay on the Meaning of Lakes
- Essay on the Distribution of Lakes
- Essay on the Characteristic Features of Lakes
- Essay on the Classification of Lakes
- Essay on the Obliteration of Lakes
Essay # 1. Meaning of Lakes:
Lakes are those static bodies of water on the land surface which are surrounded by lands on all sides and are always located on the land surface. There is wide range of variation in the size of lakes. Some lakes are as small as ponds having a meagre areal extent of a few square metres while some lakes are as large as the Great Lakes (comprised of Superior, Michigan, Huron, Onatario and Erie Lakes) of North America.
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Lakes are also called as inland standing water but this is not always true as some lakes are also located along the sea coasts e.g. Chilka lake in Orissa. Lakes are not permanent features on the earth’s surface. Lakes are formed, developed and are ultimately obliterated due to siltation and upliftment of lake beds due to diastrophic movements, for example, several lakes have disappeared in the Kumaun region of Uttaranchal e.g. Sukha Tal (‘tal’ means lake or pond, Sukha Tal means dry lake) and Saria Tal (means rotten lake) around Nainital town. Lakes, thus, may be defined as non-permanent features of static waters on the land surface.
Essay # 2. Distribution of Lakes:
If we look at the distributional pattern of lakes over the globe it appears that they do not have any specific spatial pattern of their distribution. They are found over the mountains, plateaux, plains alike. The highest lake of the world, Tso Sekuru, is located at the height of 18,284 feet AMSL (Tibetan plateau). On the other hand. Dead Sea, the lowest lake of the world, is located 1300 feet below sea level.
Normally, lakes are found more in the following regions:
(i) Humid regions,
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(ii) Glaciated regions,
(iii) Flood plain areas,
(iv) Sea coastal areas, and
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(v) Rift valley zones etc.
Though lakes are found in all continents from equator to the poles including Antarctica continent and from humid through arid and semiarid regions to polar regions but lakes are more abundantly found in:
(i) The high latitude areas of North America,
(ii) South America,
(iii) Western Europe, and
(iv) Rift valley zones of east Africa.
The important lakes of the world include Caspian Sea, Chad Lake, Great Lakes of the USA and Canada (Superior, Michigan, Huron, Ontario and Erie lakes), Victoria lake, Aral Sea, Nyasa lake, Lake Baykal, Lake Tanganyika, Great Bear lake, Titicaca lake, Dead Sea, Crater Lake (USA) etc.The Himalayas are studded with numerous lakes.
In fact, Kumaun region of Uttaranchal may be called as Lake Region because of the presence of numerous lakes (e.g. Naini tal Lake, Bhimtal, Khurpatal, Sattal, Naukuchiatal, Sukhatal. Sariatal etc.). The highest glacial lake of India is Devtal which is located at the height of 17,745 feet AMSL in Garhwal Himalaya, Gaurikund is the second highest lake (height 18,200 feet AMSL) of the world.
Essay # 3. Characteristic Features of Lakes:
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It may be pointed out that each lake has its own characteristics and hence it becomes difficult to enumerate such characteristics which may be common to all lakes.
Inspite of this limitation some common characteristic features may be identified:
(1) Lakes are variables and change with time. Each lake has its own life history or life-cycle which includes origin, development and obliteration (extinction).
(2) Some lakes are found at higher heights (thousands of metres from sea level) of the mountains and plateaux for example, Tso Sekuru Lake of Tibetan plateau (at 18,284 feet AMSL), Devtal of Garhwal Himalaya (at 17,745 feet AMSL), Rakastal, Mansarovar Lake (Tibet) etc. whereas some lakes are found below sea level e.g. Dead Sea (1300 feet below sea level).
(3) Some lakes are characterized by greater depth e.g. Baykal Lake of Siberia (more than 1.6 km deep) whereas many of the lakes are very shallow which become almost dry during dry summer season and thus such lakes are also called seasonal lakes.
(4) Lakes range in areal extent from a tiny tarn glacial lake having an a real extent of a few square metres to very extensive lakes like Caspian Sea (area, 4,30,000 km2), Great Lakes of North America etc.
Two favourable conditions are required for the origin and development of lakes e.g.:
(i) Suitable places where water may collect and may remain stationary, basins or troughs or depressions are the most ideal places for the development of lakes,
(ii) There should be proper and regular supply of water. If the water table of groundwater is higher than the beds of the basins, there is sufficient supply of water from underground sources. Each lake is characterized by inlet and outlet.
The inlet allows influx of water in the lake through those rivers which debouch into the lake, while the outlet allows exit of lake water through streams and ‘nalas’ which emerge or take their sources from the lake. The volume of water depends on the ratio between the input and output of water.
The level of a lake is determined by the level of outlet of that lake as there may not be any water above the level of outlet because in such case water would flow out of the lake through streams and ‘nalas’ which emerge from the lake.
The main sources of lake water are:
(i) Seepage water from groundwater reservoirs,
(ii) Direct rainwater,
(iii) Water brought by the rivers which debouch in the lakes, and
(iv) Melt-Water (through melting of glaciers, ice, ice caps etc.) etc.
Evaporation largely affects the volume of water in the lakes. The volume of lake water is remarkably reduced in the arid and semi-arid regions mainly during summer season because of loss of water due to excessive evaporation.
The nature of lake water also gives definite status to a particular lake. Salinity is a significant characteristic feature of lakes. Salts are taken out from the rocks and are brought to the lakes through surface runoff, rivers, seepage of groundwater etc. Salts are, thus, gradually and gradually accumulated in the lakes which in due course of time become saline. Some of the lakes, having greater proportion of salinity, have been named as Salt Lakes.
The salinity varies from one lake to another. In fact, salinity of lakes depends on the climate of the concerned place, the nature of inlets and outlets and fluctuating trends of water during various seasons of the year. Marked reduction in the volume of lake water in the hot desert areas due to excessive evaporation causes high salinity.
Lakes are divided into two broad categories on the basis of presence or absence of salt in the lake water e.g.:
(i) Saline lakes, and
(ii) Freshwater lakes.
Essay # 4. Classification of Lakes:
1. On the basis of salinity:
(1) Freshwater lakes,
(2) Saline lakes,
(i) Alkali lakes (having sodium and potassium carbonates),
(ii) Bitter lakes (having sodium sulphate),
(iii) Borax lakes, and
(iv) Mixed lakes (having several types of salts).
2. On the basis of mode of origin:
(3) Glacial lakes
(i) Lakes formed due to glacial deposits
(a) Ground moraine lakes
(b) Terminal moraine lakes
(c) Lateral maraine lakes
(ii) Lakes formed due to glacial erosion
(a) Cirque lakes or tarn lakes
(b) Rock-basin lakes
(c) Cock lakes
(d) Clint lakes
(4) Fluvially originated lakes
(i) Plunge basin lakes
(ii) Oxbow lakes
(iii) Raft-dammed lakes
(iv) Delta lakes
(v) Alluvial fans lakes
(5) Aeolian lakes
(i) Sand dune lakes
(ii) Blowout lakes
(6) Volcanic lakes
(i) Lava dam lakes
(ii) Crater lakes
(7) Diastrophic lakes
(i) Relic lakes
(ii) Synclinal lakes
(iii) Fault lakes
(a) Normal fault lakes
(b) Rift Valley lakes
(8) Lakes formed due to mass-translocation
(i) Landslide basin lakes
(ii) Mudflow basin lakes
(iii) Slump basin lakes
(iv) Solution basin lakes
(9) Lakes formed by groundwater
(i) Cave lakes
(ii) Karst lakes
(10) Periglacial lakes
(i) Thermokarst lakes
(ii) Cauldron subsidence lakes
(11) Anthropogenic lakes
(i) Reservoir lakes
i. Glacial Lakes:
Several lakes are formed due to glacial erosion and deposition. Morainic deposits sometimes dam the flow of rivers and glaciers and thus form morainic lakes. It may be pointed out that there are largest number of glacial lakes in the world. The regions which were affected by Pleistocene glaciation are studded with numerous lakes of varying dimensions and are called gardens of lakes.
Such lake gardens are abudnantly found in Canada, Norway, Sweden and Finland. Though most of the glacially originated lakes are small in size but the Great Lakes of North America, the result of Pleistocene glaciation, denote the fact that glacial action can form even one of the most extensive lakes of the globe.
Ground moraine lakes are formed due to collection of water in the irregular smaller depressions formed due to deposition of moraines in the bed of the glacial valleys when either the ice sheets retreat or glaciers are ablated (melted). The depressions receive either the melt-water or seepage water coming as springs.
These lakes are called ground moraine lakes because of the fact that these are formed in the depressions which are created due to irregular deposits of moraine in the beds of the glacial valleys. Generally, ground moraine lakes are enclosed lakes as they do not have any outlet. Such lakes are of small size and shallow depth. They range in area from a few acres to several square kilometres (20 to 30 square kilometres). Thousands of such lakes are found in the areas glaciated during Pleistocene ice age.
Lateral moraine lakes are formed in two ways e.g.:
(i) Due to damming of the mouths of tributary glacial valleys by the accumulation of lateral moraines and filling of these tributary valleys by water. Such lakes are purely temporary because these are drained out when the morainic dams are breached due to accumulation of huge volume of water,
(ii) Due to accumulation of water between the walls of glacial valleys and the lateral moraines parallel to the valleys.
Terminal moraine lakes are formed when the glaciers are ablated. In fact, several successive morainic ridges parallel to each other are formed due to recession of ice sheets during great ice ages. The water, when located between two morainic ridges, forms such lakes. Grand Lake of the state of Colorado (USA) is an example of such lakes. Several terminal moraine lakes are found in Wisconcin and Minnesota states of the USA where these lakes were formed during the recession of ice sheets at the time of Pleistocene glaciation of North America.
Rock basin lakes (fig 14.1) are formed due to filling of depressions and hollows, formed by glacial erosion in the beds of glacial valleys, with water. The water collecting in cirques forms cirque or tarn lakes. Naina or Nainital lake of India (in Kumaun region of Uttaranchal) is considered as an example of corrie or cirque lake but many geologists refute this hypothesis and consider Naina lake as the result of tectonic movements.
ii. Fluvial Lakes:
Like glaciers, rivers also form several types of lakes through their erosional and depositional works. It may be pointed out that rivers are generally destroyers of lakes rather than creaters of lakes. Lakes are often obliterated due to filling of sediments and head-ward erosion by rivers. Fluvially originated lakes are generally temporary and are soon obliterated. Fluvially originated lakes include plunge pool lakes, structural lakes, oxbow lakes, alluvial fan lakes, delta lakes, flood plain lakes, and raft-dammed lakes.
Plunge pool lakes are formed in the plungs pools which are formed at the bases of major waterfalls. Such lakes are formed in the beds of river valleys due to recession of waterfalls. Structural lakes are those which are formed due to damming of river water because of major obstructions caused by the exposure of resistant rock beds across the river channels. These lakes are drained out as the resistant rock beds are eroded away.
Oxbow lakes are more frequently found with the alluvial rivers. These lakes are formed when a meandering river straightens its course and the acute meander loops are left out. These left-out or separated meander loops become oxbow lakes (fig. 14.1). Such lakes are abundantly found in the Ganga plains wherein nearly all the major rivers like the Ganga, the Rapti, the Gomti, the Gandak, the Ghaghra, the Kosi, the Hoogly etc., are associated with numerous oxbow lakes. The situation of oxbow lakes quite away from the rivers gives clues for the palaeochannels of the river concerned. Wular lake of Kashmir is considered to be an ox-bow lake.
Alluvial fan lakes are formed due to obstruction of free flow of the rivers offered by the alluvial fans developed at the foothill zones of the mountains. Such smaller lakes have been formed in fan areas all along the foothill zones of the Sivalik Ranges of the Himalaya. Delta lakes are formed due to collection of water in the low-lying areas between two distributaries of the main river draining the delta.
Such delta lakes are more frequently formed in bird-foot deltas because the seaward projecting narrow branches of delta are bent by sea and tidal waves and thus water is locked between the branches of delta and lakes of smaller sizes are formed. Colair lakes of Godawari delta have been formed between two deltas. Such lakes in the Ganga delta are called beels. Ponchastrian lakes of Mississippi in Luisiana state are fine examples of delta lakes. Mayeh Lake of Nile delta and Marigot Lake of Niger delta are other significant examples of delta lakes.
Flood plain lakes are small and temporary lakes which are formed due to collection of water in the depressions formed during the uneven deposition of alluvia at the time of floods. Raft lakes are formed when several larger wooden logs and rafts obstruct the free flow of water as they form temporary dams across the river channels. Such lakes become hazardous when the dams formed by wooden rafts are breached and lake water gushes downstream with very high velocity causing severe flash floods.
iii. Volcanic Lakes:
Volcanic lakes include lava-dammed lakes and crater lakes. The outflow of enormous volume of lavas during fissure flow of volcanic eruption blocks the free flow of the rivers as lavas after being solidified due to rapid cooling form dams across the river valleys and thus the waters are obstructed and blocked upstream from the lava dams to form lava dammed lakes.
Lake Tine of Abyssina and Lake Nicaragua of Middle America are examples of lava- dammed lakes. Crater lakes are very common types of lakes which are associated with most of the volcanic craters. Crater lakes are formed when the craters and calderas are filled with water. Crater Lake of the state of Oregon (USA) is the best example of this category. This lake has a diameter of 10.2 km with a depth of 3,975 feet.
iv. Diastrophic Lakes:
Diastrophic movements caused by endogenetic forces are perhaps the most potent factors for the origin of many of the lakes all over the world. The synclinal lakes are formed when some of the depressions are filled with water. Edward and George lakes of South Africa are the examples of synclinal lakes. Anticlinal lakes are formed due to damming of river flow when the anticlines are formed across the rivers.
Faulting and fracturing very often form lakes of various dimensions. San Andreas Lake and Crystal Spring Lake are the examples of fault lakes. Many of the lakes in the East African rift valley zone are the result of faulting events e.g. Lake Tanganyika, Lake Victoria, Lake Nyasa, Lake Albert, Lake Rudolf etc. Dead Sea, Jordan Valley etc. are also the examples of rift valley lakes. Several lakes have been formed in the 8-km wide Rocky Mountain Trench.
Mass-translocation of rock-wastes includes landslides, rockslides, rock-falls, debris slides, debris fall, mudflow etc. Temporary lakes are formed due to damming of the rivers caused by accumulation of huge volume of debris coming down from the nearby hills due to major landslides.
These lakes are drained out when the dams created by landslide are breached due to accumulation of excessive volume of water upstream from the dams. Such temporary and ephemeral lakes are very often formed in the Himalayas where landslides and mudflow are of very common occurrence. Lake San Cristobal of south western Colorado state was formed by Slumgullion Mudflow. The catastrophic landslides of October 1968 in Darjeeling formed two lakes through the damming of Tantakhola, a tributary of Jaldhaka River.
v. Freshwater Lakes:
Freshwater lakes are characterized by very low amount of salt in the water and high rate of influx (inflow) and outflow of water. Freshwater lakes receive water from direct rainfall, surface runoff and water springs in humid regions and from melt-water in glaciated regions.
The inflow of water in the lakes is of high order, so several streams and nalas emerge from these lakes, and thus salt contents are also drained out with outflowing streams. So there is no regular accumulation of salt in freshwater lakes. Most of the lakes of Kumaun region of Uttaranchal are freshwater lakes. Dal and Wular lakes of Kashmir are freshwater lakes.
Baikal lake is the largest fresh water lake as it contains 20 percent of total 23 billion tonnes of freshwater of the world. This lake was formed about 25-30 million years ago but could not disappear by now because of the fact that lake shores expand by 2 cm per year due to splitting of the continent (Asia) along the shores. Infact, Baikal Lake is tectonically formed and this activity still continues. The lake water is constantly clean because endemic epichura crestaceans constantly filter the lake water.
vi. Saline Lakes:
The lakes having relatively larger proportion of salt content say salinity are called salt lakes or saline lakes. Generally, salt lakes are found in semi-arid and arid regions of warm climate where the rate of evaporation is very high.
On the basis of variations of types and contents of salt, saline lakes are divided into four types e.g.:
(i) Alkali lakes having the dominance of salts of sodium and potassium carborates
(ii) Bitter lakes contain salts of sodium sulphate,
(iii) Borax lakes having high proportion of borax and
(iv) Mixed lakes having mixture of different salts.
Sambhar and Panchbhadra lakes of Rajasthan, Salt lakes of Lingtzi Tang of Kashmir etc. are the examples of salt lakes of India. Chilka Lake of Orissa is also a saline lake. Saline lakes are abundantly found in the western arid and semi-arid regions of the USA, Chile, Peru, Sahara and arid and semi-arid regions of Asia.
Most of the present day salt lakes are, infact, the remnants of older freshwater lakes, for example Great Salt Lake of the state of Utah (USA) is the remnant of Bonneville Lake which was a freshwater lake. Similarly, saline lakes of western Nevada (USA) such as Curson, Pyramid, Winnimuca, Walkar and Honey lakes are the remnants of earlier freshwater lakes. Lakes Lahontan, Caspian Sea, Dead Sea, Aral Sea etc. are the examples of salt lakes.
Essay # 5. Obliteration of Lakes:
Each lake has its own life history or life cycle including its origin, development and obliteration (extinction). These successive and sequential changes pass through three stages of youth, mature and old. It may be pointed out that it is not necessary that all the lakes should pass through all the three stages of their evolution.
It is believed that except flood plain lakes and delta lakes almost all the lakes of the world are in youthful stage of their evolution because most of them were formed during and after Pleistocene glaciation. Lakes are generally obliterated because of deposition of sediments by the rivers. It is believed that the Great Lakes (Superior, Michigan, Huron, Erie and Ontario) of the USA and Canada would be obliterated due to sedimentation in the coming 45,000 years.
Lakes are obliterated because of:
(i) Lowering of outlet,
(ii) Sedimentation and siltation, and
(iii) Diastrophic movements.