The Assam Plain or Brahmaputra Plain


The Assam Plain or Brahmaputra Plain is one of the major geological territories of India. The Brahmaputra Plain is also known as the Brahmaputra Basin. In terms of yearly flow, the Brahmaputra is the fourth largest river in the world. The lower part of the Brahmaputra River valley is a devastatingly flood-prone region with severe outcomes to the economy, society, and public health. The details about precipitation and snowfall in the area are scarce.

The interannual precipitation variance is small and it is a poor indicator of the amount of rainfall in the Brahmaputra valley during the monsoon months. Powerful evidence is recorded, nevertheless, that most part of snow cover in the spring in the upper segment of the Brahmaputra valley is a reliable predictor of the level of inundation during monsoon. In spite of this fact, big events of inundation are a common occurrence in the state. The Brahmaputra Valley is habitat to approximately 300 million people.

Once the Brahmaputra River moves into Arunachal Pradesh, the name of the river is changed to Siang. The river subsequently increases the speed of its flow in comparison to its source in Tibet. The river ultimately penetrates into the plains and the river is named as the Dihang River. The Dihang River moves for approximately 35 km and is connected with two other rivers: Lohit and Dibang. From this area of confluence, the river gets broader and is named as Brahmaputra. The Jia Bhoreli River meets it in the Sonitpur District and is named as the Kameng River. The river then runs across Arunachal Pradesh and traverses the entire stretch of Assam. On certain occasions, the river is as broad as 10 km in Assam.

In the middle of Lakhimpur and Dibrugarh districts in Assam, the river splits into two separate watercourses - the northern Kherxhutia waterway and the southern Brahmaputra waterway. The two watercourses meet once more after traveling approximately 100 km downriver, creating the Majuli Island. Close to the prehistoric religious hub of Hajo in Guwahati, the Brahmaputra River runs across the rugged landscape of Shillong and is at its most tapered spot where the Battle of Saraighat took place. In April 1962, the Saraighat Bridge, which is the first rail-cum-road bridge over the Brahmaputra, was opened to the general public.

The ancient Sanskrit name of the Brahmaputra River is Lauhitya. Nevertheless, locally, the river is recognized as Luit in Assam. The indigenous clans of the Bodos name the river Bhullam-buthurm, which stands for “making a gurgling sound”. This nomenclature was subsequently transformed into Sankrit as Brahmaputra.

In comparison to other rivers, Brahmaputra River carries less pollution. The principal dilemma associated with the river is the wastes discharged by petroleum refineries into the river. These are the principal industries that make a significant contribution to polluting this river. There are also some small scale and medium scale industries that emit industrial wastes into this river. Constant deluges caused by this river are a significant issue that is plaguing the Government of Assam.

Inundations have been taking place more frequently over the past few years with removal of trees and other human actions being the principal reasons.

Major Rivers in Brahmaputra Plain



The major rivers in the Brahmaputra Plain are as follows:

  • Lohit River
  • Brahmaputra River
  • Dihing River
  • Burhidihing River
  • Manas River
  • Kameng River
  • Yamuna
  • Sankosh
  • Rangeet River
  • Teesta River
  • Lachung River
  • Lachen River
  • Jaldhaka River
  • Darla River

Physical Geography of the Assam Plain



The physical geography of the Assam plain is a domain of remarkable geologic foundation, geomorphic features, weather, wide biodiversity, and other elements.

Assam, stretching from 89° 42’E longitude to 96°E longitude and 24° 8’ N latitudes to 28° 2’ N latitudes in the graticule, is a northeastern state in India. It is situated at the heart of Northeast India. With an area of 78,438 km², Assam is approximately equal to the area of Austria or Ireland.

Geologic and geomorphic foundation



Geologically, according to plate tectonics, the state of Assam is the easternmost outcrop of the Indian plate, where it is shoving below the Eurasian Plate, forming a subduction zone. It is hypothesized that because of the shift of the Indian plate to the northeast, the deposit stratums of a prehistoric geoincline known as Tethys (in the middle of Eurasian and Indian Plates) have been thrust upward to create the Himalayan Mountain Ranges. It has been calculated that the elevation of the Himalayan Mountain Range is growing by 4 cm every year. Consequently, the Assam plain has a distinctive geomorphologic setting with valleys, dismembered mountains of the South Indian Plateau System and the Himalayan Mountain Ranges bordering its north, northeast, and eastern sides.

Geomorphic researches also come to a decision that the Brahmaputra is a river from the Paleolithic age, which is more aged than the Himalayas, which frequently traverses higher elevations in the Himalayas, wearing down at a higher speed than the rise in the elevation of the mountain range to keep up its discharge. The altitude of the bordering areas is still growing, creating precipitous canyons in the state of Arunachal Pradesh.

Physiography of Brahmaputra Plain



When the Brahmaputra River moves into the Assam plain, it becomes a braided river and together with its tributaries, forms the drainage area of the Brahmaputra Basin. The breadth of the Brahmaputra Basin in Assam is about 80 to 100 km and the length is approximately 1,000 km. The breadth of the Brahmaputra River is almost 16 km at various areas in the basin.

The hills of North Cachar and Karbi Anglong and those adjacent to Guwahati and North Guwahati (together with the Khasi and Garo Mountains) are essentially divisions of the South Indian Plateau System. These have worn down and dismembered by the various rivers in the area.

The mean elevation of these hills in Assam differs from 300 to 400 meters.

The southern portion of Barak Basin is split by the North Cachar and Karbi Anglong Hills from the Brahmaputra Basin in the state. The Barak rises from the Barail Range close to the boundaries of Assam, Manipur, and Nagaland and runs across the district of Cachar. The river meets the Brahmaputra River in Bangladesh. In Assam, Barak Basin is a tiny basin with a mean thickness and span of about 40 to 50 km.

Mineral Resources of Assam Plain



The Brahmaputra Plain is bequeathed with minerals like natural gas, petroleum, limestone, and coal. There are other insignificant minerals like kaolin, magnetic quartzite, clay, sillimanites, and feldspar. A small amount of iron ore is also found in West Assam.

The upper districts of Assam are the principal storages of petroleum and gas. Petroleum was first explored in Assam in 1889. It is calculated that Assam and bordering areas hold approximately 150 million tons of petroleum reserves. Currently, Assam ranks as the 3rd biggest crude petroleum and natural gas producer in India, representing 16% and 8% respectively of the overall production of these minerals in the nation.

A Tertiary coal belt is situated in Dibrugarh, Tinsukia, Karbi Anglong, Sivasagar, and North Cachar Hills districts and the area features an approximate reserve of 370 million tons. The coal of Assam is crumbly in nature and the sulphur content is quite significant. This coal is mostly used by steamers, hydroelectric power stations, and regional railways. Low humidity, low explosive cooking coal has been found in the Hallidayganj Singrimari region.

There are many limestone reserves in Assam. The principal limestone reserves are located in Karbi Anglong and North Cachar Hills districts. An overall limestone reserve of 97 million tons has already been established in these two districts and approximately 50% of the reserve is of cement form. In addition, there is a projected limestone reserve of 365 million tons close to Umrangshu in the North Cachar Hills district.

Among the insignificant minerals, there are kaolin reserves in Lakhimpur and Karbi Anglong districts, quartzite reserves in Nagaon district, and rocks with sillimanite content in Karbi Anglong district.

Weather features



Assam typically features a “Tropical Monsoon Rainforest Climate”. The Assam plain is a clement area and witnesses heavy precipitation and dampness. Winter remains from the latter part of October to the latter part of February. The lowest temperature is 6 to 8° C. Early mornings and nights are misty, and rainfall is sparse. Summer begins from the middle of May, together with high moisture and precipitation. The highest temperature is 35 to 38° Celsius, however, this is lessened by regular rainfalls. The maximum precipitation of the rainy season takes place during June. Cloudbursts named as Bordoicila are common during the afternoons. Autumn and Spring with modest temperatures and moderate precipitation are the calmest seasons.

Biodiversity of Brahmaputra Plain



The Biodiversity of the Assam Plain or the Brahmaputra Plain makes it one of the popular tourist spots for wildlife enthusiasts since it houses a wide variety of exotic flora and fauna. The remarkable achievement in the last few years is that the Kaziranga National Park has worked as a wonderful habitat for protecting the Indian Rhinoceros. Nevertheless, an abrupt growth in the number of people in Assam endangers various types of flora and fauna along with their natural environments.

Fauna of the Brahmaputra Plain



Other than the Tiger and Rhinoceros, the following types of fauna are seen in the area:

  • The Swamp Deer or Dolhorina (Cervus duvauceli duvauceli)
  • Chital or Spotted Deer/Futukihorina (Axix axix)
  • The Hoolock Gibbon
  • The Clouded Leopard (Neofelis nebulosa)
  • The Wild Buffalo
  • Pigmy Hog or Nol-gahori (Sus salvanis)
  • The Golden Langur (Trachypithecus geei)
  • The Hispid Hare
  • The unusual Giant Civet
  • The Golden Cat
  • The Hog Badgers
  • The Binturong
  • The Civet cats
  • The Porcupines
  • Mongooses
  • Gangetic Dolphins
  • Pythons
  • Giant Squirrels

Avifauna

You will see the following varieties of birds in the area:
  • The White-winged Wood Duck or Deuhnah (Cairina scultulata)
  • Blue-throated Barbet or Hetuluka (Megalaima asiatica)
  • The Great Pied Hornbill or Rajdhonesh (Buceros bicornis homrai)
  • The Ring-tailed Fishing Eagle or Kuruwa (Haliaeetus leucorythus)
  • The Migratory Pelicans
  • The Himalayan Golden-backed Three-toed Wood-pecker or Barhoituka (Dinopium shorii shorii)

Assam is one of the most plentiful biodiversity areas in the world. There are many tropical rainforests situated in Assam. In addition, there are bamboo plantations, riverine plains, and various marshland bionetworks. Most of these regions have been looked after by famous reserved forests and national parks. The Manas and Kaziranga have been listed as two World Heritage Sites. The Manas is a tiger sanctuary and at the same time, Kaziranga houses the endangered Indian Rhinoceros.

The state of Assam is also famous for orchids and rare species of plants and commodities manufactured from timber.

Natural Calamities in Brahmaputra Plain



The Assam Plain is a natural calamity-prone area. Significant precipitation, cutting down of trees, and other elements have led to deluges on a yearly basis and created huge damages to life, property, and employment. The area is also earthquake prone. Gentle vibrations are common and powerful earthquakes are unusual. Three powerful earthquakes took place in the past:

In 1869
  • The riverbank of the Barak River went down by 15 feet
In 1897
  • It measured 8.1 on the Richter scale.
In 1950
  • It measured 8.6 on the Richter scale.

Tourist Attractions in Assam Plain



Given below are the names of the prominent tourist attractions in the Brahmaputra Plain:

  • Manas National Park
  • Kaziranga National Park
  • Dibru-Saikhowa National Park
  • Nameri National Park
  • Pobitora Wildlife Sanctuary
  • Orang National Park
  • Garampani Wildlife Sanctuary
  • Gibbon Wildlife Sanctuary
  • Burasapori Wildlife Sanctuary
  • Chakrashila Wildlife Sanctuary
  • Sonai-rupai Wildlife Sanctuary
  • Bornodi Wildlife Sanctuary
  • Laokhowa Wildlife Sanctuary
  • Nambor Wildlife Sanctuary
  • Podumani Bherjan Borajan Wildlife Sanctuary
  • Joydihing Rainforest
  • Deepor Beel Bird Sanctuary
  • Panidihing Bird Sanctuary
  • Sualkuchi
  • Majuli
  • Bogamati
  • Sarthebari
  • Ledo and Stilwell Road
  • Digboi oil town
  • Maibong
  • Haflong
  • Bongaigaon
  • Jatinga
  • Guwahati
  • Umrangshu hotwater spring
  • Madan Kamdev archaeological area
  • Hajo archaeological area
  • Charaideo
  • Sivasagar archaeological area
  • Tezpur archaeological area
  • Surya Pahar Goalpara archaeological area
  • Dhansiri/Dhonxiri Valley archaeological area
  • Kapili Valley archaeological area
  • Mayong
  • Karbi Anglong
  • Chapanalla Waterfall
  • Bordua
  • Dibrugarh

Tourist attractions in the Assam Plain include wildlife sanctuaries, national parks, bird sanctuaries, archeological regions, and heritage spots.

Last Updated on 02 February 2011