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Yamuna's Shrinking Secret: Delhi River a Mere Fraction
17 Jul
Summary
- Yamuna's width decreased by 68% over two centuries.
- River discharge dropped by 89% since the late 18th century.
- Urbanization and barrages drastically altered the river's flow.
A study by Delhi University and IISER Bhopal geologists indicates the Yamuna River's width has shrunk by approximately 68%, with its discharge dropping by 89% since the late 18th century. This significant alteration is linked to extensive urban development and the construction of numerous barrages and embankments, beginning with British-era projects in the 1870s. These interventions have disrupted the river's natural seasonal flow.
Researchers used historical maps from 1799, surveys, and satellite imagery to reconstruct changes along the 50-km Delhi stretch. They observed the average width decreased from about 658 meters to 210 meters, and discharge fell from nearly 30,000 cubic meters per second to about 3,900 cubic meters per second. Approximately one-third of Delhi's floodplains have become disconnected due to embankments and urban expansion.
The study highlights how these changes reduce the Yamuna's capacity to absorb floods. Recent flood events, like the 2023 flooding, saw record water levels despite lower peak discharge compared to earlier floods. Authors suggest that embankments and encroachment confined floodwaters, raising water levels within the narrowed river corridor, transforming the Yamuna into a 'lower flow' regime primarily due to human intervention rather than climate shifts.
