CSIR-NGRI study unravels 45-km long buried river in Ganga-Yamuna region

The river falls within a region where a lost mythological river ‘Saraswati’ was believed to be flowing in the past, says the CSIR-NGRI study

A high resolution airborne electromagnetic study in the Ganga-Yamuna region, supplemented with drilling and logging data to address the groundwater crisis, by scientists of the CSIR-National Geophysical Research Institute (NGRI), has unravelled an exhaustive aquifer information with discovery of a 45-km long buried river equal to these two rivers.

Principal aquifer

This ancient river, likely to be extending towards the Himalayas, is characterised by porous and permeable structures and is hydro-geologically linked with Ganga and Yamuna through an underlying principal aquifer, which could help in replenishing groundwater resources in the region.

The river falls within a region where a lost mythological river ‘Saraswati’ was believed to be flowing in the past, says the CSIR-NGRI study titled “Airborne Electromagnetic Signatures of an Ancient River in the Water – Stressed Ganga Plain, Prayagraj, India: A Potential Groundwater Repository”. The findings were published in the latest ‘American Geophysical Union – Advancing Earth & Space Science’.

“The results add a new dimension to this mythological belief and offer a new possibility for management of the dwindling groundwater in the Ganga-Yamuna doab (area between the two rivers),” said CSIR-NGRI director V.M. Tiwari, who did the seminal work along with his colleagues Subash Chandra, M. Vidyasagar, K.B. Raju, Joy Choudhury, K. Lohithkumar, E. Nagaiah, Sateesh C, Shakeel Ahmed and Saurabh K. Verma.

Previous studies in the Ganga basin have revealed migratory behaviour of the rivers due to tectonic activity and climate change, leaving their remanence as a paleochannels of mostly sandy loam soil with high porosity and permeability.

Airborne investigations show the signature of a buried paleochannel in an active foreland basin of the Ganga river constituting the central part of the largest alluvial tract in the world formed by Indus, Ganga and Brahmaputra rivers.

The topography above and below the Ganga and the paleoriver shows evidence of tectonic disturbances suggesting the buried river was an independent entity and not a paleo course of Ganga. Conclusive proof in this regard can be obtained after determining the ages of sediments associated with the two rivers.

The study indicates that the aquifer systems of Ganga-Yamuna and their hydrogeological connectivity possibly facilitates exchange of polluted water between these two and also the paleoriver providing corridors for groundwater movement connecting aquifers.

Hence, the study can also be used for Ganga cleaning programmes. “We can locate potential sites for groundwater recharge and ensure supply of good quality water at Sangam, Prayagraj,” he added.

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