Ganga Basin

Overview of the Basin

• In total, Ganga has 11 basin states - Uttar Pradesh, Madhya Pradesh, Rajasthan, Bihar, West Bengal, Uttarakhand, Jharkhand, Haryana, Chhattisgarh, Himachal Pradesh and Delhi.
• It is the biggest river basin in the country draining an araea of 8,61,452 sq.km. which is slightly more than one fourth (26.3%) of the total geographical area of the country.
• Ganga basin is bounded by the Himalayas on the north, by the Aravalli on the west, by the Vindhyas and Chottanagpur plateau on the south and by the Brahmaputra Ridge on the east.
• The delta of the greater Ganga basin is one of the largest in the world and is known by the name Sundarbans after the Sundari trees covering an area of 60,000 sq.km.
• The hydroelectric potential of the Ganga basin has been assessed 20711 MW.
• Ganga drains a basin of extraordinary variation in altitude,climate, land use, flora & fauna, social and cultural life.Ganga has been a cradle of human civilization since time immemorial.
• Predominant soil types found in the basin are sand, loam, clay and their combinations, such as sandy loam, loam, silty clay loam and loamy sand soils.
• On an average, each square km of the Ganga basin receives a million cubic meter (MCM) of water as rainfall. 30% of this is lost as evaporation, 20% seeps to the subsurface and the remaining 50% is available as surface runoff. The deep channel of the river bounded by high banks facilitates the passage of ground water as base flow. Annual flooding is the characteristic of all rivers in the Ganga basin. The Ganga rises during the monsoon but the high banks restrict the flood water from spreading. The flood plain is usually 0.5 to 2 km wide. This active flood plain is flooded every year. In addition to this the existing structures on the Ganga Basin also affect its discharge.

Ganga River

• The Bhagirathi River rises from the Gangotri glacier near Gomukh at an elevation of about 7,010m above sea level in Uttarkashi district of Uttarakhand is considered as the source of River Ganga.
• Ganga gets its name at Dev Prayagi Uttarakhand at the confluence of Rivers Bhagirathi and Alaknanda.
• Flowing downhill from Gangotri Glacier at Gomukh, Ganga is joined by a number of streams, such as Mandakini, Dhuli Ganga and Pindar.
• The Ganga is the 20th longest river in Asia and the 41st longest in the world. The total length of the Ganga River is 2,525 km. and the navigable length is 631 km.
• From a hydrological point of view, the entire length of Ganga can be divided in three stretches - the Upper Ganga reach that extends from the origin to Narora Barrage in Bulandshahar district of Uttar Pradesh: the Middle Ganga reach from Narora Barrage to Ballia distrrict in Uttar Pradesh, and the lower Ganga reach from Ballia to its delta.
• The principal tributaries of Ganga are Yamuna, Son, Ramganga, Ghaghara, Gandak, Kosi and Mahananda. Chambal and Betwa are the two important sub - tributaries.
• Ganga has been a cradle of human civilization since time immemorial. It is one of the most sacred rivers in the world and is deeply revered by the people of this country.
• Ganga sustains a rich biodiversity that includes River Dolphins, Turtles, Mugger Crocodiles, Smooth Coated Otter etc.
• Ganga is habitat for 143 different freshwater fish species.
• Rapidly increasing population, rising standards of living and exponential growth of industrialisation and urbanisation have exposed water resources, in general, and rivers, in particular, to various forms of degradation. The mighty Ganga is no exception. The deterioration in the water quality impacts the people immediately. Ganga, in some stretches, particularly during lean seasons has become unfit even for bathing. The threat of global climate change, the effect of glacial melt on Ganga flow and the impacts of infrastructural projects in the upper reaches of the river, raise issues that need a comprehensive response.

Major Projects

Tehri dam (260.5 m) in Uttarakhand is the highest dam on Ganga while Nanak Sagar dam situated in Udham Singh Nagar district of Uttarakhand state is the longest dam (19.2 km) on Ganga.

Ganga River Basin Management Plan

Ganga River Basin Management Plan (GRBMP) was prepared by consortium of 7 IITs in 2010. The plan is being implemented by National Mission for Clean Ganga (NMCG) under Namami Gange Programme. NMCG has sanctioned a total of 254 projects worth Rs.24,672 crore in accordance to the 7 thrust areas viz. Nirmal Dhara (Clean river), Aviral Dhara (Wholesome river), River Front Development (Swach Kinara), Capacity Building, Research & Monitoring, Conservation of bio-diversity and Awareness creation, specified in the GRBMP plan.

Under Namami Gange Programme, variety of coordinated activities meant for cleaning of river Ganga including treatment of municipal sewage, treatment of industrial effluent, drain bio-remediation, river surface cleaning, rural sanitation, river front development, construction of ghats and crematoria, afforestation & biodiversity conservation, public outreach program etc have been taken up.

Sources:

1. Hydrology and Water Resources Information System for India
2. National Mission for Clean Ganga