Climatic
change and neotectonic movements have led to migration and abandonment of
several rivers and drainage systems. Some of them are ‘lost’ because of the
overburden of silt. But several evidences left by them usually help in proving
the existence of a geomorphic feature in a particular location, which attract
the attention of the interested people to discover the past. In India, the river
Saraswati reflects such a fascinating history, supported by geological,
hydrological and archaeological evidences as well as the records of the most
modern tools, such as remote sensing and GIS. With the aid of remote sensing
through orbiting satellites, the mystery of the river is more or less solved.
History behind the mystery
The satellite
imagery of Saraswati river
Geological record indicates that
during the late Pleistocene glaciation, the water of the Himalayas was frozen
and that in the place of rivers, there were only glaciers, masses of solid ice.
When the climate became warmer, the glaciers began to break up and the frozen
water held by them surged forth in great floods, inundating the alluvial plains
in front of the mountains. The melting of glaciers has also been referred in Rig
Vedic literature, in mythological terms. It was the first interglacial period in
Holocene marking the break-up of glaciers and release of the pent-up waters that
flowed out in seven mighty river channels referred as the ‘Sapta Sindhu’ in the
Rig Veda, traced from east to west. The ‘Sapta Sindhu’ refers to the rivers
Saraswati, Satadru (Sutlej), Vipasa (Beas), Asikni (Chenab), Parosni (Ravi),
Vitasta (Jhelum) and Sindhu (Indus). Among these, the Saraswati and the Sindhu
were major rivers that flowed from the mountains right up to the sea. The hymns
in praise of the Saraswati are probably some of the oldest, composed more than
8000 years ago.
For 2000 years, between 6000 and 4000 B.C., the
Saraswati flowed as a great river. R. D. Oldham (1886) was the first geologist
who argued logically pointing to the great changes in the drainage pattern of
the rivers of Punjab and western Rajasthan converting a once fertile region into
a desert. According to geological and glaciological studies, the Saraswati was
supposed to have originated in Bandapunch massif (Saraswati-Rupin glacier
confluence at Naitwar in western Garhwal).
The river, which had
originated from Kapal tirith in the Himalayas in the west of Kailash, was
flowing southward to Mansarovar and then taking a turn towards west. Even today
the Saraswati flows from the south of Mana pass which meets river Alaknanda, 3
km away in the south of Mana village. Descending through Adibadri, Bhavanipur
and Balchapur in the foothills to the plains, the river took roughly a
southwesterly course, passing through the plains of Punjab, Haryana, Rajasthan,
Gujarat and finally it is believed to have debounched into the ancient Arabian
Sea at the Great Rann of Kutch. In this long journey, the Saraswati is believed
to have had three tributaries, Shatadru (Sutlej) originating from Mount Kailas,
Drishadvati from Siwalik Hills and the old Yamuna. They flowed together along a
channel, presently known as the Ghaggar River, which is known as Hakra River in
Rajasthan and Nara in Sindh. Some experts consider these two rivers as a single
river whereas others consider the upper course of the Saraswati as Ghaggar and
the lower course as the Hakra River, while some others call the Saraswati of the
weak and declining stage as the Ghaggar.
Ancient courses of
Saraswati river in Bahawalpur province (Cholistan desert)
The river was obliterated within a short span, in the
Quarternary period of the Cenozoic era, through a combination of destructive
catastrophic events. The decline of the river appears to have commenced between
5000 and 3000 B.C., probably precipitated by a major tectonic event in the
Siwalik Hills of Sirmur region. Geological studies reveal that the massive
landslides and avalanches were caused by destabilising tectonic events which
occurred around the beginning of Pleistocene, about 1.7 million years ago in the
entire Siwalik domain, extending from Potwar in Pakistan to Assam in India.
Those disturbances, linked to uplift of the Himalayas, continued intermittently.
Presumably, one of these events must have severed the glacier connection and cut
off the supply of melt water from the glacier to this river; as a result, the
Saraswati became non-perennial and dependent on monsoon rains. The diversion of
the river water through separation of its tributaries led to the conversion of
the river as disconnected lakes and pools; ultimately it was reduced to a dry
channel bed. Therefore, the river Saraswati has not disappeared but only dried
up in some stretches.