New Delhi, July 20: The Yamuna River in Delhi has narrowed by nearly 68 per cent over the past two centuries, while its discharge has declined by around 89 per cent, significantly reducing its ability to cope with extreme flood events according to a new study by researchers from the University of Delhi and the Indian Institute of Science Education and Research (IISER), Bhopal.
Published in the Journal of the Geological Society of India, the study analysed historical maps and satellite imagery to examine hydrogeomorphic changes along the 50 kilometre stretch of the Yamuna flowing through Delhi between 1799 and 2026.
Researchers found that the river’s average bankfull width the width when the river is full but not overflowing declined from about 658 metres in 1799 to around 210 metres in 2024. During the same period, the river’s discharge dropped from approximately 30,000 cubic metres per second to about 3,900 cubic metres per second.
The study attributes these changes largely to extensive human intervention, including the construction of multiple barrages, embankments and rapid urban expansion in the national capital.
It also found that embankments built between 1912 and 2024 disconnected nearly one third of the Yamuna floodplains, cutting off around 45 square kilometres of natural floodplain from the river. While these embankments were designed to protect the city from flooding, researchers said the isolated floodplain areas have since been developed but continue to face inundation during high flow events.
According to the study, Delhi population grew from about 250,000 in the early 19th century to nearly 21.5 million in 2024, placing increasing pressure on the river system through urbanisation and infrastructure development.
The researchers warned that the combined effects of shrinking river width, reduced discharge and floodplain disconnection have weakened the Yamuna natural capacity to absorb and manage floods, making the river system less resilient to extreme weather events.