“Ganges – A River of No Return?” by Gyan Marwah
Marwah, G. “Ganges – A River of No Return?” The South Asian. August 2004.
Ganges – A River of No Return?
By Gyan Marwah
The Gangotri glacier, source of the river Ganges, has been receding at such an alarming rate that environmentalists fear that if urgent measures are not undertaken, a time may come when Ganges may just disappear.
If environmentalists are to be believed, a dip in the holy Ganges for future generation of Indians could well become a thing of the past. The Gangotri glacier, source of the Ganges, is receding alarmingly and in a few hundred years will dry up considerably.
A recent study by the Geological Survey of India has confirmed the bad news. But the study adds that besides the receding glacier, it is also the flow of industrial toxics, dumping of solid wastes and dead bodies floating in the river that have all made the Ganges the most polluted water source of the subcontinent.
But what is of great concern is the fact that the Gangotri glacier, situated in the Uttarkashi District of Garhwal Himalaya, has been receding at the rate of 10-30 metres per year over the second half of this century. While the rate of retreat was nominal between 1935 and 1956, it started to increase rapidly after that.
In terms of the total area, the retreat was 2,530 square metres between 1935 and 1956. It increased by around two and a half times during 1956 and 1962 and five times from 1962 to 1971. The last survey carried out a couple of years ago showed that the recession has increased over ten times from its original readings.
Gangotri Glacier – 29 kilometres long, and two to six kilometres wide – sweeps like a gigantic highway through the heart of the mountains. It is the longest glacier in the Central Himalayas, with its snout just to the north of the Great Himalayan Range.
In the last 13 years, the glacial channel feeding the Ganges river has shifted 20 metres and has now changed track and the volume of water too is shrinking rapidly. Similarly, many parts of the ridge formed by rocks and debris over centuries have completely disappeared.
Largest Himalayan Glacier
One of the largest glaciers in the Himalayas, Gangotri originates at 7,100 metres above sea level and descends to a height of 4,000 metres, covering around 143 square kilometers in northern and eastern India. Its estimated volume is 27.75 cubic kilometres.
However, the length and volume of glaciers are not stable. They are dependent on mass balance, and therefore, on climate. Periods of positive mass balance result in glacier growth, periods of negative mass balance result in recession.
The Gangotri glacier originates from snowfields where the ice is white with a bluish tinge. Towards the lower end, it takes the appearance of a mud stream, due to the rocks and debris which flow down with the glacier and get buried in the snowfields.
Over the years these rocks and debris, called moraines, have risen to become high natural walls on the sides of the glacier valley through which the river carves out deep gorges. Most of these moraines were deposited when the glacier had reached its prime in the Pleistocene period.
Owing to the recent recession, the sidewalls have developed inner exposed surfaces and an outer surface in many parts has been pressed towards the side of the valley wall. They are overgrown with shrubby rhododendron or juniper. Due to the decrease in the volume of glacier ice during the recent period, crevices have appeared on the exposed inner surface.
The natural side walls have been subjected to heavy erosion and geologists fear that at the rapid rate the recession is taking place the glacier will be left without any support and will therefore disintegrate very soon in different directions.
The reasons for this erosion and recession are many. Scientists say that global warming, increasing population and mass scale deforestation are some of the main reasons leading to the recession in the glacial flow of the Gangotri.
The natural sidewalls hold more water in their soil and are therefore more heavily tree-lined than the surrounding area. It is these trees that are being felled at an alarming rate without any ostensible check by the state government of Uttaranchal. With such a bleak scenario there seems no solution in the immediate future and one has to wait and watch if nature takes its own course and helps itself.
However, there is a ray of hope. Experts at the government-aided, Geological Survey of India (GSI) are of the opinion that the situation may not be as alarming as some geologists are making it out to be. That’s because glaciers like the Gangotri are passing though a normal recessionary trend.
“There are two phases of a glacier,” explains Dr. Amber P. Tewari, a retired GSI official who has studied the glacier for over three decades. “The first is the glacial period, and the second is the recessionary period. Gangotri is passing through the second phase and this phase will continue for a couple of hundred years now.”
Though this may be a normal cyclic phase of Gangotri, the main concern of geologists is the rampant deforestation around the area and also the global warming. Both put together will not just make the recessionary period of Gangotri that much longer but would considerably reduce its flow and also fritter away parts of the valuable water into rivulets as the natural walls get eroded because of widespread felling of trees around its course.
In the past some of the great Himalayan glaciers have either disappeared or have eroded considerably. In the Saraswati valley, north of Badrinath, the transverse glacier Ratakona lies very near to the Mana Pass and is on the verge of drying up due to deforestation. In the Dhauli Ganga valley this glacier has totally disappeared. Similarly, the Pindari and Milan glaciers are also gradually receding.
“If there is recession and melting largely due to global warming, there is also a reduction in the amount of snowfall that the area receives annually due to deforestation. Let us hope that nature strikes a balance and glacial activity resumes over the next few decades,” says Dr. Tewari.
Environmentalists feel this can happen only if the state government, with the active support from the Centre, puts a total ban on felling of trees at least on the path of the Gangotri and also sets up a high level technical team to monitor the activity of the glacier.
But there seems no urgency on either side to look into the problem that threatens to become so severe in the coming decades that it could dry up the source of India’s holiest river.