The Ganges

Physical Geography

The Ganges flows 2,510 km from its source, at the terminus of the Gongotri glacier of Gomukh in the Himalaya mountains, to its mouth into the Indian Ocean through the Ganges delta. The catchment area covers a huge 1.73 million km² including the 4 nations of Tibet, Nepal, India and Bangladesh, with major geographical changes throughout this whole basin. As a result of the vast size of this region the physical setting of the Ganges will be broken down into 3 sections, the Upper-, Middle-, Lower-course including the delta that is present in this system.

Formation/Geology

The history of the Ganges begins approximately 75 million years ago with the the movement of the Indian tectonic plate, which at the time was a part of supercontinent Gondwana, north-eastwards across the then Indian ocean, for 50 million years, where it met the Eurasian plate subducting underneath it. As the Indian tectonic plate subducted under the eurasian plate it gave rise to the creation of the Himalayas. Over a long period of time alpine glaciers formed throughout the Himalayas creating the source of many asian rivers including the Ganges. 

The Ganges begins its journey in the Himalaya mountains where glacial melt water forms the Bhagirathi river, a clear stream that flows down the Himalayas where it confluences with the Alaknanda river. Once at the confluence of these two rivers the official course of the Ganges begins, the river basin itself is relatively large encompassing a total of 3 major river systems the Ganges, Brahmaputra and Meghna (GBM) collectively known as the GBM River Basin. The Ganges flows southwest as it flows 256.9 km through its narrow Himalayan valley emerging into the Gangetic Plain where a dam diverts some of the flow into the Ganges Canal, which is used for irrigation in northern India. The water that is not diverted into the Ganges Canal flows along the original course of the Ganges where the river begins to flow southeast along the plains of northern India. The river then flows for a 900 km stretch where it is joined by one of its key tributaries, the Ramganga. Further along the river course, the Ganges is met by the Yumuna and Saraswati where at this point the Ganges itself is smaller than the Yumuna. 

Following this confluence the Ganges begins to glow east where the Tons, Gomti and Ghaghara rivers join its course as they flow southwards from the Himalayas. As the Ganges continues to meander throughout India it is met by a further 3 rivers: the Son, Ganfaki and Kosi rivers. At this point the Ganges continues its journey throughout West Bengal, continuing along a south-southeast course where the first distributary of the Ganges is formed known as the Bhagirathi-Hooghly located close to the Bangladesh border. The water levels of this distributary are controlled before the border at the Farakka Barrage diverting some flow into a canal system influencing the natural function of the river.

The main branch of the Ganges continues to flow through West Bengal region until it enters Bangladesh where it is then known as the Padma river where it is joined by the Jumuna river, a branch of the Brahmaputra river, before it reaches a confluence with the Meghna river where the river then becomes known as the Meghna Estuary, emptying into the Bay of Bengal. As the Ganges enters the indian ocean at the Bay of Bengal the Ganges Delta is formed covering an area that lies between Bangladesh and West Bengal, India.

Climate

The Ganges brahmaputra river basin covers a large area of asia spanning from its source in Tibet through Nepal, India and Bangladesh as such there is a wide range in the climate across the basin from the cold frigid temperatures of the Himalayas to the much warmer monsoon climate of India and Bangladesh. The average temperature of the basin ranges from 30.3°C in the summer months to 21.1°C in the winter. Precipitation also ranges greatly across the basin as the lower course of the Ganges-Brahmaputra river basin is situated in a monsoon climate, as such the average annual precipitation varies from 760 mm in the western end of the basin while the eastern edge receives approximately 2,290 mm. The monsoon climate that is prevalent in the lower course of the Ganges is pivotal for the sustained flow of the river with approximately 80% of the total precipitation in india occurring during the monsoon period, as such water availability across the region is highly dependent on the monsoon itself in order to sustain the countries through the rest of the year.

Human Geography

The Ganges basin supports 10% of the global population that all in some way rely on the waters of the Ganges be that for economic reasons, water resources or religious practices. The Ganges provides many benefits for those along its banks with the river being used for transportation, freshwater resources, fishing, agriculture (irrigation), bathing and also a pathway for the removal of wastewater, oftentimes untreated. As such, the heavy reliance on the basin for the ever growing population in the region has put a stress on the basin itself. 

The Ganges itself is considered sacred by those of the Hindu faith believed to be the embodiment of the goddess Ganga with the waters of the Ganges being seen as holy water purifying those who wash within it. With the Ganges and its main tributary the Yamuna river recently being granted the same legal rights as human beings meaning that polluting or damaging the river is considered legally equivalent to harming a human.

Pollution

The Ganges is one of the most polluted rivers in the world sourcing its pollution from domestic sources, industry, agriculture, untreated wastewater, littering and religious practices. Domestic sources of pollution range from wastewater to littering. With approximately 500 million people living within the basin in over 200 cities and towns of varying size a lot of domestic wastewater is produced, however, much of this wastewater is discharged directly into the Ganges without being treated leading to a high level of organic material within the river. This not only poses a threat to the environmental health of the river but also Human health throughout the basin as there is an increase in the potential for the contamination of drinking water resources as well as through direct exposure to the material as a result of bathing customs in the country. There is also a greater risk of the spread of diseases such as cholera with bacteria thriving in the conditions that are present within the Ganges. 

Pollution sourced from industry have many sources throughout the basin with the discharge of untreated effluent and chemicals used throughout the many industries including tanneries, textile mills, power plants, chemical plants and abertois to name a few (Hammer, 2007). As a result of poor regulations many industries take shortcuts to dispose of products that are no longer of use to the company directly discharging untreated products into the river. Many of these products are rich in hazardous metals and chemicals that have the potential to bioaccumulate within both the ecology of the ganges but also the humans living within the basin. These hazardous materials include Arsenic, lead, Cadmium, mercury Sulfuric acid and many more substances that have a major detrimental impact on health (Hammer, 2007). Other industries such as Agriculture throughout the basin also pose a major threat to the environmental health of the Ganges with water being removed from the basin at a faster rate than it is being replenished, increasing the concentration of the pollutants within the Ganges.

15% of the pollution of the ganges Originates from floral products used in religious ceremonies and therefore cannot be put into landfills as such many of the people dump them into the ganges itself, introducing pesticides and fertilisers that were sprayed onto these flowers during the growing process straight into the ganges itself. Other religious practices within the Ganges basin also have a harmful impact, with pollution originating from the offering of food and other items that are disposed of in the Ganges as a result of Hindu offerings, leading to an increase in both the organic material in river but also an increased concentration of microplastics within the river (Hammer, 2007).

Climate Change

Climate change poses a major threat to the Ganges, with changes in precipitation patterns and increased temperatures greatly impacting the flow of the river and its many tributaries. Increasing temperatures as a result of climate change has led to a reduction in the size of the glaciers that support the Ganges throughout its upper course, with the recession of glaciers throughout the Himalayas being a pivotal issue that has come about as a result of climate change. This reduction in the natural resources available within the GBM catchment is severely endangering the sustained health of the Ganges, with the Gangotri Glacier glacier receding at a rate of 22 m/year. As such this is chief concern for sustained flow of the Ganges with 70% of the Ganges water originating from this icemass. The issue of recession in the Gangotri glacier is further exacerbated by changing precipitation patterns with a reduction in the amount of snowfall that occurs annually, reducing the ability of the glacier to replenish its resources. 

The flow of the Ganges is also highly dependent on the monsoon climate of the region as well as glacial meltwater in order to sustain the flow of the river. Changing precipitation patterns for the monsoon climate of the basin also creates a potential for a reduction in the natural water resources of the river reducing the flow of the Ganges. Anthropogenic actions have exacerbated the change in climate across the region increasing the prevalence of extreme events including both flood events and droughts. This is a major issue for those situated within the GBM basin as there is a heavy reliance on the monsoon climate of the region to sustain water resources throughout the year. 

Rising sea-levels pose a major threat for much of the GBM basin with Bangladesh, a country with ⅔ of its total area situated within the basin, being prone to flooding events with two thirds of the land area being less than 5m above sea level (Becker et al. 2020). This not only increases the risk of inundation along the low lying regions of the basin but also poses a major threat to both the health of the basin’s inhabitants and the environment, with the potential for the spread of polluted river water flooding the area. As such, there would be a greater exposure to not only the harmful pollutants but also waterborne diseases such as cholera.