Indus

Source and Upstream

The source of the river is at an altitude of about 5300 m ^[2] (5182 m according to the Geological Dictionary ^[3] and 5500 m according to Britannica ^[4] ) in the south-west of the Tibet Plateau, on the northern slope of Mount Kangrinboche (Kailash) , about 40 km to the north from Mapam Yumzo Lake . Under the name Sengge-Dzangbo ^[5] (Shitsuanhe ^[6] ) it flows to the confluence with the river Gar-Dzangbo ^[7] near the village of Langmar, where it is called Indus ^[3] .

Over 1000 km of Indus flows northwest through the Karakoram mountains, following a deep tectonic valley and forming numerous rocky gorges. The border between the Tibet Autonomous Region and the Indian state of Jammu and Kashmir Indus crosses at an altitude of 4572 m near the village of Demchok ^[4] . After a long mountain stretch, the river goes into the valley where the ancient city of Leh is located - the capital of the historical region of Ladakh . Not far from Leh, the Zaskar River flows into the Indus (on the left), after which, near the city of Thingmosgang, the river again goes into the gorge and flows to the border settlement Batalik .

After crossing the border between the state of Jammu and Kashmir and the Pakistani Northern Territories , the Shingo River flows into the Indus. After about 80 km, the Shayok River flows into the Indus on the right. At the Skardu (the main city of Baltistan ), the Shigar River flows into the Indus on the right, fed by the largest Biafo and Baltoro glaciers. The Indus reaches its northernmost point at the peak of Haramosh , after which it merges with the Gilgit River (also on the right) near the city of Boundji and turns to the south-west, breaking between the spurs of the Himalayas and Hindu Kush . From here on the banks of the Indus is the Karakorum highway . Almost immediately after the confluence with Gilgit, the Indus replenishes with the waters of the Astor River and flows at the foot of the Nanga-Parbat Mountain, which feeds the river with its glaciers. Then the Indus crosses the border of Kashmir and flows into the territory of Pakistan.

In the middle reaches it crosses the hilly lowlands where the Tarbela dam was built in 1977. After this, the Indus receives a large tributary of Kabul (the height of the confluence is about 610 m), flows along the Kalabag gorge between the spurs of the Suleyman mountains and the Salt Range, and then goes to the Indo-Gangetic Plain .

Plains

Having merged with the Soan River and stepped onto the plains of the Punjab near the city of Daud Hel , Indus is divided into several branches and a channel. The river and its accompanying canals flow through the cities of Mianvali and Dera-Ismail Khan . The town of Cote Addu built the Towns Dam. Having passed through Dera-Ghazi-Khan , the Indus receives the waters of the largest tributary of the Indus of the Panjnad River, after which the width of the river increases from 400-500 m to 1-2 km. At the city of Sukkur ( Sind region), the Nara arm separates from the Indus, but reaches the sea only in high water, although in antiquity, apparently, it served as the main channel. In the lower reaches, the Indus crosses the western edge of the Thar desert. Passing over a plain over 1800 km, it flows into the Arabian Sea .

The river carries a large amount of sediment , so its channel is elevated above the sandy plain. For a considerable extent, the riverbed is bunded to protect the adjacent territories from floods that sometimes occur. In 1947 and 1958, large areas were destroyed by the flood; the 2010 flood also caused great damage to the country. Sometimes severe floods cause the river to change its course.

Delta

Hyderabad , located 150 km from the sea, begins the Indus Delta , which has an area of ​​30 thousand km² (the seventh largest in the world ^[8] ) and a coastline of 250 km. The river is divided into 11 main branches, but the total number of channels in the Indus delta cannot be precisely determined, because each flood changes the entire pattern. Over the course of this century, and the main course has changed its place many times. Currently, the main riverbed is called Gajamro , flows into the sea at a point with coordinates 24 ° 6 's. w. and 67 ° 22 'in. The coastal strip with a depth of 8 to 32 km is poured at high tide. ^[four]

The Indus Delta formed during the Holocene ^[8] .

List of tributaries

The largest of the tributaries:

Water Mode

In the mountainous area, Indus feeds mainly due to the melting of snow and glaciers, where the runoff is about 220 km³ / year, with an average water flow rate of about 7000 m³ / s. ^[3] Consumption is minimal in the winter months (December-February), from March to June, water rises. In the lower part of the basin, the river is replenished with water from monsoon rains, which leads to spring-summer floods (March - September). During this period, water rises 10-15 m in the mountains, and 5-7 m in the flat part. In the period of high water (July-September), the river bed in floodplains reaches 5–7 km in width (in the region of the city of Dera-Ismail Khan, the width reaches 20–22 km)

The average water flow in Hyderabad is 3850 m³ / s, but in wet years this figure can reach 30 thousand m³ / s. After entering the plain, the Indus loses water through evaporation and seepage. In dry periods, the Indus in the lower reaches may dry out and not reach the Arabian Sea.

There is physiographic and historical evidence proving that, at least from the time of the culture of Mohenjo-Daro Indus, several times changed the position of his channel below the southern Punjab. In the area of ​​the cities of Rohri and Sukkur, the river is sandwiched between limestone cliffs, and to the south the river bed has moved to the west, especially its delta. Over the past 7 centuries, in the upper part of Sinda Indus has moved 15-30 km to the west. ^[four]

The Indus basin area is 970 thousand square kilometers, which makes it the twelfth in the world in this indicator ^[8] .

The climate of the region is arid and semi-arid. Precipitation is seasonal, in the lower part of the Indus their value is small, while more than half of the precipitation comes from the Southwest monsoon (in the period July-September). On the plain, the average annual rainfall is less than 100 mm, but as it rises upstream, this figure increases, reaching 500 mm in Lahore and 2000 mm in the Himalayas. Arid climate causes strong evaporation from the surface of the water, especially in the lower Indus, where the evaporation can reach 2000 mm per year ^[8] .

The main nutritious areas of the Indus are western Tibet , the Karakorum mountain system, and the Indus-Yarlung suture zone (suture is the junction of various tectonic parts along the fault ). The influence of tributaries from the Hindustan plate is very insignificant ^[9] .

The appearance of the river is attributed to the period after the collision of the Hindustan plate with Asia (according to various estimates, the collision occurred from 55 ^[10] to 35 million ^[11] years ago in the Eocene era of the Cenozoic era ). Thus, Indus can be considered one of the oldest rivers in the world, it is older than the Himalayas, which reached their final height when the Indus already existed ^[8] . During the existence of the Indus, significant deformations of the earth's surface occurred, in particular, significant uplifts, but they did not entail significant movements of the channel. Research data show that, in ancient times, Indus was a drain from the Lhasa Plate ( Eng. Lhasa Plate ), and its Indus occurred in the interaction of the collision of the Hindustan Plate with Asia and the raising of parts of the Lhasa Plate ^[9] .

Indus played an important role in shaping the surface of the region. The stability of its position for several tens of millions of years since the time of the Ypresian layer has led to the fact that the Indus waters took an active part in erosion processes. Sedimentary rocks from the Himalayas were carried by the Proto-Indus into the Arabian Sea from the middle of the Eocene , increasing the erosion of the rising Karakoram and the Lhasa Plate. While many rivers of East Asia were closed during mountain building during their history, the Indus, which flows along the seam formed during the collision of plates, has shifted only 100 kilometers to the east over millions of years (this was caused by the rise of the Suleiman Mountains and their pressure on Indus Valley East). The removal by the Indus of sedimentary rocks also influenced the formation of Mekran , before the raising of the Marri Range from the Arabian Basin was carried out, one of the reasons for which was also the active supply of sediment. In addition to a hundred-kilometer shift of the Indus channel to the east, the river delta also moved southward. The reason for this was the natural process of promoting deltas of water flows into the seas, caused by the removal of particles, as well as tectonic compression processes in this place of the sea.

The completion of the rise of Tibet and a decrease in active sedimentation 8.5 million years ago occurred simultaneously with the emergence of the South Asian monsoon ^[9] .

With the exception of the Pakistan mountain range, the Indus Valley lies in the driest part of the Indian subcontinent . The average annual rainfall over the entire length of the Indus varies from 125 to 500 mm. In addition to the Himalayan glaciers, the Indus is fueled by monsoon rains from July to September.

In the northern part of the Indus basin, the January temperature drops below zero, and in July it reaches 38 ° C. The river does not freeze. One of the hottest places on Earth - the city of Jacobabad is located west of the Indus in the upper Sindh - the temperature there rises to 49 ° C. ^[four]

Estimates of the Indus Valley from the time of Alexander the Great indicate the dense forests that covered this region in the past. However, at present, these forests have decreased significantly. The founder of the Mughal state, Babur, in his memoirs, Babur-nama wrote about rhinos found on the banks of the river. Intensive deforestation and the human impact on the ecological situation in Sivalik led to a severe deterioration in growing conditions. The Indus Valley is an arid region with few vegetation. Agriculture is supported mainly by irrigation .

The Indus basin and the river itself are characterized by biological diversity . The region is home to about 25 species of amphibians and 147 species of fish, of which 22 are found only in the Indus ^[12] .

Mammals

The Indian river dolphin ( English Indus river dolphin ) ( Platanista gangetica minor or Platanista indi ) is a species of dolphin that lives only in the Indus, mostly in the provinces of Sindh and Punjab ^[13] . In the past, it also appeared in tributaries of the river. According to the World Wildlife Fund, the Indian river dolphin is in first place among endangered cetaceans . Presumably, only about a thousand dolphin individuals remain ^[14] , a significant part of which lives on a short stretch of the river 130 kilometers long between the Sukkur and Guddu dams in Sindh. Dolphin is almost completely blind and guided by echolocation.

Ichthyofauna

Fishes are represented by families of cyprinids ( Indian cheshones , zebrafish , barbos , marinkas , etc.), loach ( boats , etc.), bagaris , catfish , macropods ( colises , etc.), snakeheads ( snakeheads , etc.) and others ^{[ 15]} . A popular gastronomic fish is the Ilish fish from the herring family.

The size of fish stocks in the river is quite large, and the cities of Sukkur , Tatta and Kotri are large fish centers. But the abstraction of water for irrigation needs and the construction of dams forced to implement special measures to maintain the number of fish.

In the middle of the III millennium BC. e. in the Indus Valley, one of the oldest civilizations has developed. Later, the Great Silk Road passed through the Indus Valley and its tributaries.

During the Arab conquests by the Arabs, the lower reaches of the Indus were captured.

• Hydroelectric potential of Indus is estimated at 20 million kW. ^[2] Built 14 large dams, including the Sukkur Dam . The size of sediment runoff on average is about 450 million tons per year.

The problem of using the water resources of the rivers of the Indus basin has repeatedly caused conflicts between India and Pakistan, as well as between individual states. The Indus Waters Treaty , concluded in 1960, regulates the distribution of the waters of the five Punjab rivers.

Irrigation

In the lower part of the Indus basin, about 12 million hectares of land are irrigated (mainly in the Punjab and in the delta), less than half of the river flow reaches the mouth. The total length of irrigation canals is approximately 65 thousand km, with the help of irrigation facilities irrigated over 1.7 million hectares.

Shipping

Navigation in the Indus is usually carried out from the mouth to the city of Deraismailhan (about 1200 km). Even higher, to the city of Attok , at the mouth of the Kabul River, small flat-bottomed vessels can rise.

Waterworks

The main dams and dams on the Indus ^[8] :

Since the beginning of the twentieth century, the Indus has undergone tremendous changes, which negatively affected almost all the wildlife associated with the river ^[13] . The construction of dams and dams led to a record reduction in water discharge in the Indus delta and the volume of incoming sediment. During the second half of the twentieth century, consumption fell by an order of magnitude ^[8] . Significantly reduced shipping lanes from the delta inland. Fresh water practically does not reach the delta, only occasionally during the monsoon period. The size of the delta, due to the fact that the sediment practically ceased to flow, has significantly decreased (from about 6,200 to 1,200 square kilometers). The flow of sea water into the river is observed, salt water passes up to 75 kilometers upstream. The lack of fresh water and the supply of sea led to the destruction of large areas of agricultural land, several settlements off the coast ceased to exist, several hundred thousand people were forced to change their place of residence. The strong wave energy inherent in the waters of the Indus delta, coupled with the cessation of sediment supply, causes desertification and deformation of the coastline ^[8] .

Lake Manchar plays a significant ecological role in the functioning of the Indus basin.

The Vedas (Rig Veda) admire Indus, the cradle of India . Sindhu (Indus) is one of the main rivers of the Seven Rivers (Saptasindhu). “Indus surpasses all current flows ... Its hum rises from earth to heaven, it creates infinite power in flashes of light ... Just like cows with milk lead calves, other rivers rattle in Indus. As the warrior king leads the warriors, so the Indus leads other rivers ... Rich in good horses, rich in gold, of noble appearance, rich in wealth of health. ” In this hymn, Indus is a "male" river. In other hymns, heavenly sages descend from heaven in Indus. The Vedas appeal to the Ganges twice, and to the Indus more than 30 times. Indus gave the province of Pakistan Sind his name.

Alisher Navoi mentions Indus ( Sind ) in his poem about Iskander 's journey to India. The river from the north borders the magical Nigar forest with sandalwood, olives and plane trees. From the sugarcane growing in it, the water in the river was sweet ^[16] .

• WWF Global 200 Ecoregions - Indus River Delta .