Lost courses of legendary Saraswati river, which flowed from north-east to south-west in millennium, have been traced by satellite imagery in Jaisalmer district, reports a study. Recently, interpretation of landsat-imagery of the western part of Rajasthan revealed buried courses of the river running between the two ends of north-east to south-west, nuclear scientists of the Bhabha Atomic Research Centre (BARC) in the January issue of "Current Science" journal said. Dr S. M. Rao and Dr K. M. Kulkarni of the isotope division of the BARC had undertaken isotope hydrology studies on groundwater in 1995 and analysed samples for hydrogen, oxygen and carbon isotopes.
The Saraswati river has been described as a mighty Himalayan river in the ancient Indian literature (Rig Veda) and several myths have been woven around its existence and disappearance. The present study confirms this course has links with the dry bed of Ghaggar river in the north-east (Ganganagar district) while in the south-west it met or cut across surviving courses of the Hakra and Nara rivers in Pakistan, the paper said.
The study shows that the area through which the river bed it traced supports vegetation even during summer. This shown that these courses still maintain their head water connection and form potential groundwater sanctuaries for exploitation. In the north-western part of Jaisalmer district, in spite of very low rainfall (less that 150 mm) and extreme weather conditions, groundwater is available at a depth of about 50-60 metres along the course of the defunct river and wells in the vicinity do not dry up throughout the year, the paper said.
The groundwater in
the area is rich in stable isotope content as compared to other Himalayan
rivers. Groundwater samples exhibit negligible tritium content indicating
absence of modern recharge. Radiocarbon data suggest the groundwater is
a few thousand years old. The levels of carbon-14 isotope decrease along
the suspected river course downstream indicating hydraulic continuity of
the Saraswati buried channel from Kuria Beri to Ghantiyalji. A groundwater
velocity of 20 metres per year has been estimated from the isotopic analysis.
Two senior scientists at the Bhabha Atomic Research Centre, Dr S M Rao and Dr K M Kulkarni, claim to have traced the course of the River Saraswati, which, according to legend, was lost in the Thar desert of Rajasthan.
According to Rao and Kulkarni, the river, originating from the same source as the Sutlej, flows underground through northern Rajasthan, Bhawalpur, and Sind in Pakistan till it empties out in the Rann of Kutch.
The duo, working in tandem with the Ground Water Department of Rajasthan and the Central Arid Zone Research Institute, have traced the course of the river using Landsat imagery and isotope-tracing techniques.
"We discovered many underground fresh-water channels with low levels of tritium, a naturally occurring radioactive isotope, which helps to establish the age of the water," said Rao, who heads the isotope division at BARC, Mumbai.
In the case of the channels Rao and Kulkarni studied at Ghantiali, Kuriaberi and Nathurakuan in Jaisalmer district, the water was found to be more than 8,000 years old. "This was a pluvial episode with plenty of rainfall in this area. The episodes of aridity began much later," says Rao.
This is borne out by ancient accounts of the river. The Saraswati is mentioned in the Vedas as a mighty river, originating in the Himalayas and flowing westwards through Rajasthan. But the Mahabharata, which was written much later (around 1,000 BC), reports a once-mighty river that was drying up.
In Rajasthan, the Saraswati is more than a water source - the river is revered as Vanaspati Devi. The search for the lost river has drawn scholars and royal patronage for centuries. "Our study will have an emotional as well as historic significance for Rajasthanis," says Rao.
But Rao and his colleagues will have to hurry up as work on the second phase of the Indira Gandhi Canal has begun and infusion of fresh water is likely to disturb the underground channels.
Rao's work has also
been made more difficult by the fact that the Saraswati has changed her
course to the west at least five times. An earlier study linked the ancient
Saraswati to the present-day Ghaggar river while other scholars have suggested
that the Sutlej at one point flowed into the Saraswati, later shifting
westwards to join the Indus system.
Another hypothesis suggests that the
Indus itself could at one point have been a tributary of this mighty river,
which, according to Vedic sources, was bigger than the Ganga.
The old underground channels of the Yamuna have also been traced to Saraswati's system. The Yamuna probably flowed into the Saraswati before joining the Ganga through the Chambal.
The channel of the Saraswati, with a constant width of six to eight metres, is traceable through Shtarana in Punjab, up to Marot in Pakistan, through northern Rajasthan, and is likely to have extended to the Hakra-Nara bed around the Rann of Kutch, which then emptied out into the Rann.
Rao's research is supported by Landsat images which show a narrow strip of vegetation along the course supported by groundwater while the surrounding areas continue to be dry.
The research has
practical use for the parched state. "The freshwater channels can be tapped
for domestic use, reducing the hardship faced by the people during dry
months," says Rao. The water channels pass right through the heart of the
Rajasthani desert.
Forest scientists from the University of Melbourne and the Indian Council of Forestry Research and Education (ICFRE) have joined forces to tackle the growing salinity of productive land along the Rajasthan Canal in north-west India.
The project, funded by AusAID, has established a strong collaboration between forest scientists at the ICFRE in Jodhpur, the School of Forestry and the CSIRO Tree Seed Centre in Canberra.
The Rajasthan Canal constructed in the 1960s, carries precious water from the Ganges River into the great Indian Thar Desert for the irrigation of agricultural crops. Cracks in the canal have allowed water to seep on to adjacent land, causing water logging and salinity problems in other productive land.
It has been established that trees will intercept water seepage, thus reducing the problem. The aim of the collaboration is to trial species from the Australian flora which can be added to the list of species currently grown along the canal. Dr Chris Weston from the School of Forestry has visited Rajasthan twice to establish a trial of selected Eucalypts, Acacias and Casuarinas near Phalodi in Rajasthan.
"This collaborative project will help to solve a potentially disastrous environmental problem in Rajasthan," he said.
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