River Saraswati is considered as one of the most sacred and mighty rivers of India. Several verses in the Rig Veda described this river as a mighty one and provided some crucial geographical details of its tributaries as well as the terrain, the river system drained. The Mahabharata, on the other hand, mentioned Saraswati as a river that disappeared in sand.
Such geographical details evoked high interest of modern scientific communities on the river, notably since the 19th Century. Asiatic Society, the oldest (founded in 1784) and a highly reputed academic institution of the Indian sub-continent, played a pivotal role in acquiring and dissemination of knowledge on this legendary river, especially during the early years. Indian National Science Academy (INSA), which had its birth at the Asiatic Society, also took initiatives in this knowledge dissemination through holding academic discourses.
Considering the continued interest of the scientific communities in India on this lost river and keeping in view the explosion of new knowledge on this river system since the 1970s, the Asiatic Society and INSA organised a joint one-day seminar on “The lost river Saraswati: Geodynamic context” on October 12, 2017 in Kolkata.
The seminar was convened jointly by Dr SK Acharyya, former Director General of the Geological Survey of India, and Professor Kunal Ghosh, Fellow of both INSA and the Asiatic Society. It was held at the historical Vidyasagar Hall of Asiatic Society and attended by about 200 learned knowledge-seekers. The short inaugural session was presided over by Professor Isha Mahammad, President of the Asiatic Society while the Chief Guest was Professor D Mukhopadhyay, a senior distinguished Earth Scientist. Professor KS Valdiya, another senior distinguished Earth Scientist from Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, delivered the key-note address. The Welcome address and the Vote of thanks were moved by Dr Satyabrata Chakrabarti and Dr Sujit Kumar Das, Secretary and Treasurer of the Asiatic Society, respectively. This was followed by regular sessions where the speakers were: Professor Rajiv Sinha (Indian Institute of Technology, Kanpur), Dr Amal Kar (formerly of Central Arid Zone Research Institute, Jodhpur), Dr Anil K Gupta (formerly of Regional Remote Sensing Service Centre, Jodhpur) and Professor Michel Danino (Indian Institute of Technology, Gandhinagar). The valedictory session was presided by Professor Valdiya and all the speakers participated in it.
Professor D Mukhopadhyay, in his address as the Chief Guest, stated that the subject is truly interdisciplinary and this Seminar is focused to look at the problem from a geodynamic point of view. As far as the location of the old Saraswati is concerned there have been two contrasting views. In one view, Saraswati must lie between the Yamuna and the Sutlej. The present day seasonal stream Ghaggar-Hakra with its tributaries flows in this region. The other view is that Saraswati is to be equated with the ancient river Harakhwati in the Helmand River basin in Afghanistan. The first hypothesis received a boost when Landsat imagery analysis revealed the location of paleochannels. Geological history of the Sutlej-Yamuna interfluve suggests that Ghaggar has a wide channel but what is remarkable is the lack of incision in the river channels in this region. Study of subsurface deposits has led to identification of ancient channels. Provenance studies of the channel sediments along with the paleochannels in imageries, suggests that the old river which flowed along the Ghaggar channel was fed by old Sutlej from the north and the old Yamuna from the east. The cumulative evidence suggests the presence of an ancient river in the Ghaggar-Hakra region, though more detailed work is necessary. There were drastic changes in the river system in this region in the past, but these were pre-Harappan, possibly in Pleistocene. The river was in a declining stage during the acme of the Harappa civilization.”
Professor KS Valdiya, in his keynote address, provided an overview of recent research on the Saraswati and re-confirmed the existence of the Saraswati, as mentioned in the ancient Indian literature, and its demise. He explained through numerous illustrations how systematic scientific research since the late-1970s, involving remote sensing and field- and laboratory-based investigations on the geomorphic, geophysical, structural, sedimentological and isotopic properties of the landscape elements re-confirmed the existence of the ‘lost’ Saraswati, and also described the river’s broad evolutionary stages as well as its contribution to the evolution of human settlements and culture in the basin area. According to him, the enormous sediment volume laid down in the reaches of the present-day Ghaggar River in the Himalayan foothills to the deltaic part of the Nara River in Sind and Great Rann of Kachchh represent the work of two large Himalayan rivers, Tons in the east and the Sutlej in the west. Repeated tectonic activities since then led to the shifting away of these two rivers from the Ghaggar River valley, i.e., Tons to meet Yamuna in the east and Sutlej to meet Indus in the west, causing the Ghaggar to dry out. Late Quaternary changes in climate also had a role to play in the demise of the river and subsequent migration to more hospitable environment.
Professor Rajiv Sinha, in his presentation on “The lost Saraswati: River morphodynamics as an alternative model for development of ancient urban settlements in NW India” showed through an analysis of numerous deep sedimentary sections across the dry valley of the Ghaggar River and across some palaeochannels of the Sutlej, the reconstructed palaeo-valleys of the erstwhile Sutlej over time. The old channels, dated between ~4 thousand years before present (ka BP) and ~80 ka BP, when stacked over time and the sediments analysed in terms of river dynamics, revealed a typical episodic and abrupt migratory behaviour of alluvial streams, called ‘avulsion’, which typically take place at century to millennial time-scale and leads to diversion of river flow into new or abandoned channels. Based on a knowledge of the wide swinging behaviour of the present-day Kosi River during avulsion, computer simulation modelling of the fluvial processes leading to avulsion, and optical simulation dating of the sedimentary sequences in the Ghaggar valley, he suggested that the Sutlej’s flow through the Ghaggar valley terminated considerably before the discovered pre-Harappan and Harappan settlements (~4.8 – ~3.9 ka BP) and that the diversion to Sutlej’s present course was completed shortly after ~8 ka. He argued that the early settlements discovered along the dry valley of the Ghaggar were established along a relict valley rather than on an active Himalayan river like the Sutlej, mainly to avoid the risk of large damages due to unpredicted avulsion and flooding, and at the same time to derive benefits of its water sources. Confinement of the Sutlej to its present incised course since the shifting away from the Ghaggar valley likely reduced its propensity to re-route frequently into the abandoned channels, thus enabling long-term stability to the early settlements along the Ghaggar valley.
Dr Amal Kar spoke about “Research paradigms on the mapping and understanding of Saraswati River system”. Citing old map records he informed that James Rennell (1788) and his Survey of India (SoI) team should get the credit for first unambiguous mapping of the remnants of a large Himalayan river flowing independent of the Indus to the sea, which was marked by them in the sub-Himalayan plains as the Sursooty, the Caggar and the Kenkar, and then as a dotted line through Cholistan and Sind. Over the next one century SoI accurately mapped the abandoned streams in the area and the dry valley of the Ghaggar. CF Oldham (1874) named the Ghaggar-Hakra-Nara as the “Saraswati”, and argued that its survival depended on the supply from the Sutlej. This Rennell-Oldham discovery provided the foundation for future studies on civilization and environmental changes in the region, especially along the dry valley of the Ghaggar. Recent provenance studies through zircon dating and isotopic composition pattern of sediments reveal overwhelming contribution of the Sutlej River in the alluviation process. The first satellite-based discovery of some buried courses of the Saraswati and one of its tributaries, the Drishadvati, in the Punjab Plains and in the Thar Desert was made by Ghose, Kar & Husain (1979) and Kar & Ghose (1984). This work was followed in the desert by linking of the findings with a shallow aquifer in the desert tract of Jaisalmer by Kar and Shukla (1993, 2000) which extended the scope of Saraswati research into the desert proper, with emphasis on groundwater management, placer deposits, etc., along the palaeochannels.
Dr Anil K Gupta spoke on “Course of river Saraswati satellite-based studies findings and implications”, and narrated the studies carried out by ISRO in Haryana, Punjab, Rajasthan and Gujarat, especially to rediscover the buried channels of the river and explore their economic and archaeological potential. Using data from old maps, archaeological records, landform features, sediment characteristics, stream flow, groundwater, etc., the marked courses were validated. Based on the findings, Haryana Government embarked on a plan of revival of Saraswati in the state through Haryana Saraswati Heritage Board.
Professor Michel Danino, in his paper on “The Saraswati river: Issues and debates”, argued that the existence of the mighty Saraswati was proven in the studies carried out in the Nineteenth Century while the archaeological discoveries along this lost river further strengthened the earlier findings. Since the last three decades, several new geo-scientific investigations in the river’s basin area have brought out many intricate details of the river’s fate with time, including its expanse, condition during the Mature Harappan period, and ultimate disappearance. In view of the large body of scientific evidence gathered so far, the questioning of the river’s identification in some quarters was uncalled for. At the concluding session, it was unanimously decided that a befitting publication in this area is to be brought out by the Asiatic Society.