Yamuna in Delhi has narrowed 68%, lost 89% of its flow since 1799: Study
A first-of-its-kind study has used an archival map from 1799 to trace how the Yamuna has changed over more than 200 years, showing that the
A first-of-its-kind study has used an archival map from 1799 to trace how the Yamuna has changed over more than 200 years, showing that the river flowing through Delhi has become far narrower and carries much less water than it once did. Researchers found that the river has narrowed by about 68 per cent and that its discharge, or the volume of water flowing through it, has dropped by around 89 per cent since the late 18th century. Read Full Story The study, carried out by researchers from the Department of Geology at the University of Delhi and the Indian Institute of Science Education and Research, Bhopal, says human intervention and urbanisation have sharply altered the river. It found that barrages, canals, embankments and development on the floodplains have changed the Yamuna from a wider, freer river into a more constrained one that is less able to cope with floods. The findings, accessed by PTI, have been published in the paper, "Two Centuries of Hydrogeomorphic Changes: Width-Discharge Dynamics of the Urbanised Yamuna River in Delhi". To reconstruct the river's past, the researchers used an archival map prepared by Upjohn in 1799 and preserved in the Archives of India, along with historical maps and modern satellite images. "People have talked about changes in the Yamuna river in the Delhi stretch, but no one has talked about the changes in its discharge in the stretch on this timescale," Professor Vimal Singh, one of the researchers, said.
The researchers said the 1799 map showed the Yamuna before any barrages were built across it, offering a rare view of its natural state. They found that the river's average bankfull width, or the width when it is full but not overflowing its banks, reduced from about 658 metres in 1799 to around 210 metres in 2024. Using this width, they estimated that the river's discharge fell from about 30,000 cubic metres per second in 1799 to roughly 3,900 cubic metres per second in 2024. The study said these changes took place as Delhi's population rose from around 2.5 lakh in the early 19th century to nearly 2.15 crore in 2024. Drawing on historical records, census data and population projections, it said Delhi had a population of around 1.5 lakh in 1630 during the reign of Mughal emperor Shah Jahan. The city's population stood at around four lakh in 1901, rose to about 9.2 lakh by the 1940s and jumped to 17.44 lakh in the 1950s following Independence and Partition. The researchers also noted that Delhi occupies just 0.05 per cent of India's land area but is home to nearly 1.5 per cent of the country's population, putting heavy pressure on the river. According to the study, the first major intervention came with the British-built Tajewala barrage in 1873, followed by the Okhla barrage in 1874, the Wazirabad barrage in 1959 and the ITO Barrage in 1966-67.
The BriefWire