Wednesday, October 28, 2009
MARSHES AND BOGS
MARSHES AND BOGS A bog is an area of wet, spongy ground, consistj.ng of decomposing moss and other vegetation, on the surface of a shallow pond or lake. Marshes and swamps are poorly drained, low-lying tracts of land that possess distinct flora. These are places where water stands at or close to the ground surface over a broad area. Some emerge by shifting of river channels on flood plains, while others emerge from the sea. Rushes, reeds and certain mosses are characteristic of marshland. A marsh may be drained to provide agricultural land as has occurred in the Fens of East Anglia.
SOME IMPORTANT LAKES IN INDIA
SOME IMPORTANT LAKES IN INDIA
Some of the important lakes in India are-Oal and Wular lakes in Jammu and Kashmir; Chllka lake in Orissa;Ohebar, Sambhar and Pushkar lakes in Rajasthan; Bhimtal, Satta or Satta I and Roop Kund in Uttarakhand; BhoJ wetland in Bhopal (M.P.); Chandratal, KhaJjlar, Nake, Renuka lakes in Himachal Pradesh; Pulicat lake on the Coromandel Coast on the Andhra Pradesh-Tamil Nadu border; Chembarambakkam. Kalivell and Veeranam lakes in Tamil Nadu; Hussain Sagar Himayat Sagar and Osman Sagar lakes in Hyderabad and Kolleru in Andhra Pradesh; Loktal (also called Floating Lake) in northeast India; Khecheopalrl and Tsongmo lakes in Sikkim; Vembanad, Vembanattu and Veeranpuzha lakes in Kerala.
Some of the important lakes in India are-Oal and Wular lakes in Jammu and Kashmir; Chllka lake in Orissa;Ohebar, Sambhar and Pushkar lakes in Rajasthan; Bhimtal, Satta or Satta I and Roop Kund in Uttarakhand; BhoJ wetland in Bhopal (M.P.); Chandratal, KhaJjlar, Nake, Renuka lakes in Himachal Pradesh; Pulicat lake on the Coromandel Coast on the Andhra Pradesh-Tamil Nadu border; Chembarambakkam. Kalivell and Veeranam lakes in Tamil Nadu; Hussain Sagar Himayat Sagar and Osman Sagar lakes in Hyderabad and Kolleru in Andhra Pradesh; Loktal (also called Floating Lake) in northeast India; Khecheopalrl and Tsongmo lakes in Sikkim; Vembanad, Vembanattu and Veeranpuzha lakes in Kerala.
LAKES
A lake is a body of water that lies in a hollow on. the earth's surface and is entirely surrounded by land. It is unconnected with the sea except by rivers. In arid and semiarid areas lakes may have no outlet to the sea and form the focus of an area of inland drainage. As a result the water of the lake becomes increasingly saline. Some inland seas are actually large lakes, e.g:, the Caspian Sea, Dead Sea artd Aral Sea.
CLASSIFICATION OF LAKES Though most lakes have been formed by the action of glaciers and icesheets, others have been formed by rivers, marine and wind action, by earth movement and vulcanicity, and a few lakes are also man-made. Some basic categories may be considered.
(i) Lakes produced by earth movements These are lakes formed by tectonic forces. They may be formed in two ways. (a) By crustal warping. These occupy basin-like depressions e.g., Caspian Sea, Lake Victoria (Africa), Lake Eyre (Australia). Lake Titicaca (Peru/Bolivia) is the highest tectonic lake in the world. (b) By faulting. These occur in rift valleys, e.g., Lake Nyasa (East Africa), the Dead Sea and Loch Ness (Scotland). These lakes are usually long, narrow and deep.
(ii) Lakes formed by erosion They may be of two types.
a) Both valley glaciers and ice sheets gouge out hollows and troughs on earth surface which later get filled with water to form lakes. These may be cirque lakes, forming in arm-chain-like depressions, also called tarns, found in mountain regions, or they may be trough lakes which occupy long hollows excavated in valley bottoms, also called ribbon lakes. They may also be rock basin lakes, formed by ice-scouring action of ice sheets resulting in formation of shallow hollows, as in Canada and Finland.
(b) Wind-eroded lakes: In the extensive depressions which are created by wind-erosion in the arid regions, if excavation is carried out below the water table, a lake may develop; e.g., the Qattara Depression in Egypt. Oases formed out of aquifers are more permanent lakes. Some desert lakes-palaya, for example-dry up because of excessive evaporation.
(iii) Lakes produced by deposition These may be of the following kinds. (a) River deposits: Ox-bow lakes _are cutoffs of mature rivers, made in flood plains, which eventually get separated from the river. They are common in lower valleys of the Mississippi. Deposits of alluvium in deltas may isolate a distributary, thus producing a delta lake, e.g., Etang de Vaccares in the Rhone Delta.
(b) Lakes produced by glacial deposits: Moraine-dammed lakes are caused by the deposition of terminal moraine across a valley, e.g., in the Lake District (England). Lake Grade (Italy) was formed like this. Depressions in boulder clay result in lake formation, such as the lakes in Northern Ireland.
(c) Marine deposits can form lakes: They are called Haffs. These lakes have been formed by sand bars extending along a coast and cutting off indentations in the coast, thus producing lagoons. These are found in southern coast of Baltic Sea and along Les Landes coast of south-west France.
(iv) Lakes produced by vulcanicity
(a) Crater and caldera lakes: Craters are formed when the top of a volcano gets blown off in a violent eruption. A caldera is formed if a crater gets enlarged by subsidence. Examples are Crater Lake in Oregon (USA), Lake Toba in north Sumatra and Lake Knebel in Iceland.
(b) Lava-blocked lakes: River valleys get blocked by lava to form a lake; the Sea of Galilee was formed by lava-flow blocking Jordan valley.
(c) Lavasubsidence lakes: These are caused by depressions caused by collapse of the lava crust, e.g., Myvatn, in Iceland.
(v) Other Types
(a) Solution lakes: Some rocks are dissolved and removed by rain water. This produces underground caverns. Limestone caverns collapse to expose lakes which are usually long and narrow, e.g., Lac de Chailexon in Jura Mountain. Sometimes, solution, aided by subsidence, produces large depressions called polje. Rock salt has been removed by solution in Cheshire (England) and the depressions have formed containing lakes, called 'flashes'.
(b) Barrier lakes: These are temporary lakes formed by ice, lava, moraine damming a valley, or damming by landslides, avalanches or screes.
(c) Beaver lakes: These are created by some animals like beavers which build dams across the streams to form lakes, e.g., Beaver lake in Yellow Stone National Park (USA).
(d) Mining ponds: These are caused by open cast mining, e.g., by tin mining in West Malaysia. (e) Man-made lakes: These are artificial lakes made by building dams across rivers.
Importance and Use Lakes play an important role. They are used for communication as natural routes; for hydro-electric power development; for regulating the flow of rivers; as a source for fishery; for water storage; for providing irrigating water. They also moderate the climate.
CLASSIFICATION OF LAKES Though most lakes have been formed by the action of glaciers and icesheets, others have been formed by rivers, marine and wind action, by earth movement and vulcanicity, and a few lakes are also man-made. Some basic categories may be considered.
(i) Lakes produced by earth movements These are lakes formed by tectonic forces. They may be formed in two ways. (a) By crustal warping. These occupy basin-like depressions e.g., Caspian Sea, Lake Victoria (Africa), Lake Eyre (Australia). Lake Titicaca (Peru/Bolivia) is the highest tectonic lake in the world. (b) By faulting. These occur in rift valleys, e.g., Lake Nyasa (East Africa), the Dead Sea and Loch Ness (Scotland). These lakes are usually long, narrow and deep.
(ii) Lakes formed by erosion They may be of two types.
a) Both valley glaciers and ice sheets gouge out hollows and troughs on earth surface which later get filled with water to form lakes. These may be cirque lakes, forming in arm-chain-like depressions, also called tarns, found in mountain regions, or they may be trough lakes which occupy long hollows excavated in valley bottoms, also called ribbon lakes. They may also be rock basin lakes, formed by ice-scouring action of ice sheets resulting in formation of shallow hollows, as in Canada and Finland.
(b) Wind-eroded lakes: In the extensive depressions which are created by wind-erosion in the arid regions, if excavation is carried out below the water table, a lake may develop; e.g., the Qattara Depression in Egypt. Oases formed out of aquifers are more permanent lakes. Some desert lakes-palaya, for example-dry up because of excessive evaporation.
(iii) Lakes produced by deposition These may be of the following kinds. (a) River deposits: Ox-bow lakes _are cutoffs of mature rivers, made in flood plains, which eventually get separated from the river. They are common in lower valleys of the Mississippi. Deposits of alluvium in deltas may isolate a distributary, thus producing a delta lake, e.g., Etang de Vaccares in the Rhone Delta.
(b) Lakes produced by glacial deposits: Moraine-dammed lakes are caused by the deposition of terminal moraine across a valley, e.g., in the Lake District (England). Lake Grade (Italy) was formed like this. Depressions in boulder clay result in lake formation, such as the lakes in Northern Ireland.
(c) Marine deposits can form lakes: They are called Haffs. These lakes have been formed by sand bars extending along a coast and cutting off indentations in the coast, thus producing lagoons. These are found in southern coast of Baltic Sea and along Les Landes coast of south-west France.
(iv) Lakes produced by vulcanicity
(a) Crater and caldera lakes: Craters are formed when the top of a volcano gets blown off in a violent eruption. A caldera is formed if a crater gets enlarged by subsidence. Examples are Crater Lake in Oregon (USA), Lake Toba in north Sumatra and Lake Knebel in Iceland.
(b) Lava-blocked lakes: River valleys get blocked by lava to form a lake; the Sea of Galilee was formed by lava-flow blocking Jordan valley.
(c) Lavasubsidence lakes: These are caused by depressions caused by collapse of the lava crust, e.g., Myvatn, in Iceland.
(v) Other Types
(a) Solution lakes: Some rocks are dissolved and removed by rain water. This produces underground caverns. Limestone caverns collapse to expose lakes which are usually long and narrow, e.g., Lac de Chailexon in Jura Mountain. Sometimes, solution, aided by subsidence, produces large depressions called polje. Rock salt has been removed by solution in Cheshire (England) and the depressions have formed containing lakes, called 'flashes'.
(b) Barrier lakes: These are temporary lakes formed by ice, lava, moraine damming a valley, or damming by landslides, avalanches or screes.
(c) Beaver lakes: These are created by some animals like beavers which build dams across the streams to form lakes, e.g., Beaver lake in Yellow Stone National Park (USA).
(d) Mining ponds: These are caused by open cast mining, e.g., by tin mining in West Malaysia. (e) Man-made lakes: These are artificial lakes made by building dams across rivers.
Importance and Use Lakes play an important role. They are used for communication as natural routes; for hydro-electric power development; for regulating the flow of rivers; as a source for fishery; for water storage; for providing irrigating water. They also moderate the climate.
DIFFERENCES BETWEEN HIMALAYAN AND PENINSULAR RIVERS
Himalayan Rivers
Nature of flow Perennial as dependent Seasonal dependent on rainfall as well as snow melt rainfall alone
Catchment areaVery large basins
ErosionDeep valleys and gorges in the Himalaya due to intensive erosion
Nature of the course Meandering course and shifting beds in the Great plains
Other featuresV-shaped valleys, high waterfalls and huge delta.
Penisular Rivers
Nature of flowSeasonal dependent on rainfall alone
Catchment area Erosion Shallow graded valleys with little erosion
Nature of the course Straight and linear course.
Other features Shallow valleys, small waterfalls, delta and estuaries.
Nature of flow Perennial as dependent Seasonal dependent on rainfall as well as snow melt rainfall alone
Catchment areaVery large basins
ErosionDeep valleys and gorges in the Himalaya due to intensive erosion
Nature of the course Meandering course and shifting beds in the Great plains
Other featuresV-shaped valleys, high waterfalls and huge delta.
Penisular Rivers
Nature of flowSeasonal dependent on rainfall alone
Catchment area Erosion Shallow graded valleys with little erosion
Nature of the course Straight and linear course.
Other features Shallow valleys, small waterfalls, delta and estuaries.
Major Rivers of India
Name of River Origin Destination Length Basin Area Average annual discharge
1. Ganga Gangotri Glacier, Uttar Kashi Bay of Bengal 2,525 8,61,404 4,93,400
2. Indus Mansarovar Lake, Tibet Arabian Sea 1,270 3,21,290 41,955
3. Godavari Nasik, Maharashtra Bay of Bengal 1 ,465 3,12,812 1,05,000
4. Krishna Mahabaleshwar, Maharashtra Bay of Bengal 1,400 2,58,948 67,675
5. Brahmaputra Kailash Range, China Bay of Bengal 720 1,87,110 5,10,450
6. Mahanadi Raipur (Chhattisgarh) Bay of Bengal 857 1,41,600 66,640
7. Narmada Amarkantak, Madhya Pradesh Arabian Sea 1,312 98,796 40,705
8. Cauvery Kodagu (Brahmagiri Hills), Karnataka Bay of Bengal 800 87,900 20,950
9. Tapi Betul, Madhya Pradesh Gulf of Khambhat 724 65,145 17,982
10. Pennar Chennakesva Hills (Kolar) Karnataka Bay of Bengal 597 55,213 3,238
11. Brahmni Ranchi, Jharkhand Bay of Bengal 800 39,033 18,310
12. Mahi Ratlam (Gwalior), Madhya Pradesh Gulf of Khambhat 533 34,842 8,500
13. Sabarmati Aravalli Hills (Gujarat) Gulf of Khambhat 300 21,674 3,200
Annual Discharge in million cubic metre
Peninsular Component
1. Mahanadi. Burhabalang
2. Mahanadi. Godavari
3. Indravati. Wainganga
4. Wainganga. Krishna
5. Krishna (Srisailam) . Pennar (Prodattur)
6. Pennar (Gandikotta) . Palar - Cauvery
7. Cauvery. Vaigai
8. Godavari (Ichampalli) . Krishna (Nagarjunasagar)
9. Krishna (Nagarjunasagar) . Pennar (Somasila)
9A.Krishna (Almatti) . Pennar
10. Pennar (Somasila) . Palar. Cauvery (Coleroon)
11. Godavari (Ichampalli) . Krishna (Pulichintala)
12.Godavari (Polavaram). Krishna (Vijayawada)
13. Par. Tapi . Narmada
14. Damanganga . Tansal Pinjal
15. West flowing rivers of Kerala and Kamataka
(West. East link)
(i). Beoti. Varda
(ii). Netravati . Hemavati
(iu).Pamba. Achankovil. Vaippar
16.Ken. Betwa
17. Parbati - Kalisindh . Chambal
2. Mahanadi. Godavari
3. Indravati. Wainganga
4. Wainganga. Krishna
5. Krishna (Srisailam) . Pennar (Prodattur)
6. Pennar (Gandikotta) . Palar - Cauvery
7. Cauvery. Vaigai
8. Godavari (Ichampalli) . Krishna (Nagarjunasagar)
9. Krishna (Nagarjunasagar) . Pennar (Somasila)
9A.Krishna (Almatti) . Pennar
10. Pennar (Somasila) . Palar. Cauvery (Coleroon)
11. Godavari (Ichampalli) . Krishna (Pulichintala)
12.Godavari (Polavaram). Krishna (Vijayawada)
13. Par. Tapi . Narmada
14. Damanganga . Tansal Pinjal
15. West flowing rivers of Kerala and Kamataka
(West. East link)
(i). Beoti. Varda
(ii). Netravati . Hemavati
(iu).Pamba. Achankovil. Vaippar
16.Ken. Betwa
17. Parbati - Kalisindh . Chambal
All River Systems
Indus System
@Indus
@ Jhelum
@ Chenab
@ Ravi
@ Satluj
@ Beas
Ganaa System
@ Ganga
@ Yamuna
@ Ramganga
@ Ghaghra
@ Gandak
@ Burhi Gandak
@ Baghmati
@ Kosi
@ Chambal
@ Kali Sindh
@ Betwa
@ Son
@ Rihand
@ Damodar
@ Banas
@ Luni
@ Sabarmati
@ Mahi
@ Narmada
@ Tapti .
@ Subarnarekha
@ South KoellBrahmani/Mahanadi
@Mahanadi
Godavari System
@ Godavari
@ penganga
@ Manjara
@) Wardha
@ Waiganga
@ Indravati
Krishna System
@ Krishna
@ Bhima
@ Tungabhadra
@North Pennar
@ South Pennar
@ Cauvery
@ Waigai
@Brahmaputra
@Indus
@ Jhelum
@ Chenab
@ Ravi
@ Satluj
@ Beas
Ganaa System
@ Ganga
@ Yamuna
@ Ramganga
@ Ghaghra
@ Gandak
@ Burhi Gandak
@ Baghmati
@ Kosi
@ Chambal
@ Kali Sindh
@ Betwa
@ Son
@ Rihand
@ Damodar
@ Banas
@ Luni
@ Sabarmati
@ Mahi
@ Narmada
@ Tapti .
@ Subarnarekha
@ South KoellBrahmani/Mahanadi
@Mahanadi
Godavari System
@ Godavari
@ penganga
@ Manjara
@) Wardha
@ Waiganga
@ Indravati
Krishna System
@ Krishna
@ Bhima
@ Tungabhadra
@North Pennar
@ South Pennar
@ Cauvery
@ Waigai
@Brahmaputra
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