The Ganga River Basin The Ganga basin covers over 12,500 sq. kilometers in northern India and ranks among the largest in the world in drainage basin area and length. Flowing across the great alluvial Indo-Gangetic plains, the Ganga is bordered by the Himalayas to the north and the Vindhya-Satpura ranges to the south. The river has two main headwaters in the Himalayas--the Bhagirathi and the Alaknanda and others for each of its other tributaries. The Bhagirathi flows from the Gangotri glacier at Gomukh and the latter from a glacier near Alkapuri. Farther downstream, the river is joined by a number of other Himalayan rivers, the Yamuna, Ghaghara, Gomti, Gandak and Kosi. However, the Ganga and its major tributaries, the Yamuna, Ram Ganga, and Ghaghara are the only Himalayan rivers that have significant base and flood flows.
According to scientific theory, the level of pollution in a river depends upon the concentration of pollutants and the discharge of the river. Both concentration and discharge are affected by hydrologic, geomorphologic, topographic and cultural factors. The rivers of the Ganga basin drain the southern slopes of the Great Himalaya and carry one of the largest sediment loads on earth. Deglaciation at the headwaters of tributaries that form the Ganga, human-instigated forms of erosion such as tree felling, farming, and construction of settlements all contribute to the river's discharge and concentrations of pollution.
At Haridwar, where the plains meet the foothills of the Himalayas, a significant portion of the main stream of the Ganga is diverted into the Upper Ganga Canal. This is an irrigation channel that feeds the alluvial tract lying between the Ganga and Yamuna rivers. The Upper Ganga Canal flows into the Lower Ganga Canal near Aligarh and flows to Kanpur before returning to the parent stream. Scientists argue that the reach of the river from Kannauj to Allahabad is particularly vulnerable to human induced pollution. Beyond this reach, the Ganga gains additional waters from the Yamuna river at Allahabad and from the Ghaghra, Kosi and Gandak rivers farther downstream
. Today, over 45 million people reside in the Ganga basin. The Ganga passes alongside 29 cities with populations above 100,000, 23 cities with populations between 50,000 and 100,000, and 48 towns less than 50,000. The Central Pollution Control Board estimates that the main sources of pollution along the reach of the river are urban liquid waste (sewage/sullage), industrial liquid waste, large scale bathing of cattle, throwing of dead bodies in the river, surface run-off from solid waste landfills and dumpsites, and surface runoff from industrial solid waste landfills or dumpsites. The Central Pollution Control Board reports that three-fourths of the pollution of the river comes from the discharge of untreated municipal sewage, of which 88% is created in Class-I cities (cities with populations above 100,000). Without more specific data on discharge amounts, however, the Central Pollution Control Board can only provide estimates that are tallied from the estimates of wastewater flows generated in each of the cities through which the Ganga passes.
Industrial wastewater is discharged by a number of industries situated in this riparian zone. In 1995, the Central Pollution Control Board listed 191 grossly polluting industries in the state of Uttar Pradesh, 6 in the state of Bihar, and 67 in the state of West Bengal. These industries were discharging toxic substances into effluent flows with BOD concentrations of more than 100 mg per liter and each unit was generating over one million liters of wastewater per day. The industries represented in this river basin are sugar and paper mills, cloth, woolen, cotton and rayon mills, tanneries, ordinance factories, battery industries, thermal power houses, chemical plants, metal and steel factories, distilleries, and fertiliser corporations. Heavy metals such as cadmium, zinc, nickel, lead, chromium and copper are concentrated in the river water and the sediments. The Central Pollution Control Board reports high levels of zinc and nickel in the sediment of the Yamuna river downstream from the capital city of Delhi.
The Ganga river basin is fed by many tributaries that drain the Himalayas and the Vindhya Satpura ranges. These paths of drainage also carry run-off from point and nonpoint sources of pollution and from agricultural fields, making the river a receptacle for the flow of many different liquid and solid elements. This drainage gives Ganga power pollution and power. She gains toxins and bacteria harmful to humans but also takes in the discharge. Generally, scientists cite the loss of discharge as the more serious factor contributing to the rise in levels of pollution since without adequate flow, toxins and bacteria cannot be flushed and degraded.
The Ganga basin is the cradle of Hindu and Buddhist pilgrimage culture. Some of the most important centers of spiritual learning and healing have thrived for centuries along her banks and those of her tributaries. At the headwaters of the Ganga in the Himalayas, sacred shrines at Tapavan, Gomukh, Bhojbasa, and Gangotri mark the sources of her power. The shrines of Kedarnath and Badrinath also celebrate their position in the upper reaches of the watershed. Farther downstream in the Himalayas are Uttarkashi and Rishikesh and along the plains lie Haridwar, Allahabad (Prayag), Banaras, Vindhyachal, Nadia and Kalighat. Along the river Yamuna, we find the sacred complexes of Mathura and Vrindavan and inland within the Ganga basin, the Hindu center of Vindyachal and the Buddhist sites of Gaya, Rajgir and Nalanda. In these pilgrimage centers and in countless other smaller sacred spots along her great traverse, pilgrims worship the Ganga and carry away her pure water for worship and purification.