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
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.
Evidences supporting Palaeochannels
Hydrogeological evidences Lunkaransar, Didwana and Sambhar, the Ranns
of Jaisalmer, Pachpadra, etc. are a few of the notable lakes, formed as a result
of the changes; some of them are highly saline today, the only proof to their
freshwater descent being occurrences of gastropod shells in those lake beds. Mr.
Oldham accepted that there have been great changes in the hydrography of Punjab
and Sind within the recent period of geology. Wilson has mentioned about the
Sotar valley where “the soil is all rich alluvial clay such as is now being
annually deposited in the depressions which are specimens of those numerous
pools which have given the Saraswati its name, ‘The River of Pools’; and there
seems little doubt that the same action, as now goes on, has been going on for
Archaeological evidences Most of the archaeological sites of the-then
civilisation are located on the Saraswati river basin. There are four Harappan
and pre-Harappan sites in Punjab, in addition to the sites in Rajasthan and U.P.
These sites are located at Rupar (present Ropar), Nihang Khan, Bara and Sirsa
valley. Harappan culture flourished in the western part of Punjab around 2500
B.C. It is believed that the Harappans entered through the Indus Valley into
Kalibangan valley on the left bank of Ghaggar (erstwhile Saraswati) and spread
to Punjab along the Saraswati River. Carbon dating of the material at Kalibangan
suggests that Harappan culture flourished around 2500 B.C. in India and existed
for 1000 years. So the present day geomorphologic set up did not exist till 1500
B.C. and the Indus, the Sutlej and the Beas followed independent courses to the
Evidences from Remote Sensing and GIS A remote sensing study of the
Indian desert reveals numerous signatures of palaeochannels in the form of
curvilinear and meandering courses, which is identified by the tonal variations.
The Saraswati River could be traced through these palaeochannels as a migratory
river. Its initial course flowed close to the Aravalli ranges and the successive
six stages took west and northwesterly shifts till it coincides with the dry bed
of the Ghaggar River.
Yash Pal et al.
found that the course of the river Saraswati in the states of Punjab, Haryana
and Rajasthan is clearly highlighted in the LANDSAT imagery by the vegetation
cover thriving on the rich residual loamy soil along its earlier course. Digital
enhancement studies of IRS-1C data (1995), combined with RADAR imagery from
European Remote Sensing satellites ERS 1/2, identified subsurface features and
recognised the palaeochannels beneath the sands of the Thar Desert. A study of
NRSA, based on satellite derived data, has revealed no palaeochannel link
between the Indus and the Saraswati, confirming that the two were independent
rivers; also, the three palaeochannels, south of Ambala, seen to swerve
westwards to join the ancient bed of the Ghaggar, are inferred to be the
tributaries of Saraswati/Ghaggar, and one among them, probably Drishadvati.
Digital enhancement techniques using high resolution LISS-III data of IRS-1C
satellite, together with pyramidal processing, identified two palaeochannels
trending NE-SW in Jaisalmer district of Rajasthan, which are presumed to be the
lost river Saraswati. In a study, NRSA used Indian Remote Sensing Satellite
(IRS-P3) Wide Field Sensor (WiFS) data covering the Indus river system to study
the palaeodrainage in northwestern India. The image elements such as tone,
colour, texture, pattern, association of WiFS and SIR-C/X-SAR images helped to
derive information on current as well as palaeodrainage. WiFS image reveals very
faint trace of the river Saraswati/Ghaggar while in the SIR-C/X-SAR image, the
connectivity of the palaeochannel could be easily established due to the
presence of dark irregular shaped features associated with wetness.
Missing of a prominent river from the map is not a mystery; it is quite
natural as the natural phenomena evolve through environmental changes. A part of
the river Saraswati till now exists as Ghaggar in Haryana, the rest of it has
disappeared in the fringes of the Marusthali or the Thar Desert. Bhabha Atomic
Research Centre, Mumbai has made a breakthrough in its research for the
existence and probable location of the mythical Saraswati river. The Rajasthan
Ground Water Department undertook the task to ‘unearth’ the river with the
collaboration of BARC and Physical Research Laboratory, Ahmedabad (a wing of
ISRO) in 1998. If the effort is successful, the people living in the desert belt
of Rajasthan will be hopefully supplied more than 3500 year old water derived
from palaeo-channels, believed to be the mythical Saraswati.