Ganges Basin

Ganges-Brahmaputra-Meghna basins

The Ganges basin is a part of the Ganges-Brahmaputra basin draining 1,086,000 square kilometres in Tibet, Nepal, India and Bangladesh. To the north, the Himalaya or lower parallel ranges beyond form the Ganges-Brahmaputra divide. On the west the Ganges Basin borders the Indus basin and then the Aravalli ridge. Southern limits are the Vindhyas and Chota Nagpur Plateau. On the east the Ganges merges with the Brahmaputra through a complex system of common distributaries into the Bay of Bengal. Its catchment lies in the states of Uttar Pradesh (294,364 km²), Madhya Pradesh (198,962 km²), Bihar (143,961 km²), Rajasthan (112,490 km²), West Bengal (71,485 km²), Haryana (34,341 km²), Himachal Pradesh (317 km²) and Delhi (1,484 km²), the whole of Bangladesh, Nepal and Bhutan. Several tributaries rise inside Tibet before flowing south through Nepal. The basin has a population of more than 500 million, making it the most populated river basin in the world.

Description

The basin comprises semi-arid valleys in the rain shadow north of the Himalaya, densely forested mountains south of the highest ranges, the scrubby Shiwalik foothills and the fertile Gangetic Plains. Central highlands south of the Gangetic Plain have plateaus, hills and mountains intersected by valleys and river plains. The important soil types found in the basin are sand, loam, clay and their combinations such as sandy loam, silty clay etc.

The annual surface water potential of the basin has been assessed as 525 km³ in India, out of which 250 km³ is utilisable water. There is about 580,000 km² of arable land; 29.5% of the cultivable area of India.

Water-related issues of the basin are due to both high and low flows. In India, the states of Uttar Pradesh, Bihar and West Bengal are affected by floods. Bangladesh – at the confluence of Brahmaputra River and Ganges River – suffers from severe floods almost every year. Northern Ganges tributaries such as Kosi, Gandak and Mahananda are the most flood-prone, but southern tributaries also contribute. Low flows are caused by scarcity of rainfall outside the summer Monsoon, and sometimes by failure of this monsoon to develop to its normal extent. The Gangea is joined by Kosi, Ghaghra, Gandak from the Himalayas and by Chambal, Betwa, Son from the peninsular region.

See also

The Indian Ganga River Basin {IGRB} is one of the most fertile and densely populated river basins in the world. IGRB is facing cascading effects of human interference and climatic change. Aridity as measured by aridity index (AI) is projected to increase over land under climate change. Aridity has adversely affected the vegetation. For example Anogeissus Pendula forest in Jaipur has been adversely affected by aridity. Only few of the trees in this forest are left. Long term change in inherent and dynamic qualities of soil has accelerated the land degradation in many regions throughout IGRB. Construction of dams and canals around IGRB has also resulted in diminishing soil fertility in IGRB. Soil salinity has also increased. The present analysis clearly elucidated an alarming increase in aridity that could cause other cascading impacts in future thereby making it unfit for human use.

References

    Coordinates: 25°42′N 84°54′E / 25.7°N 84.9°E / 25.7; 84.9

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