“Every Kolkatan has a flood story. The Hooghly remembers all of them.”
Kolkata Water & Flooding
Hooghly River gauge levels, monsoon flooding, and waterlogging trends
The Hooghly is measured at Garden Reach, where the warning level is 5.18 metres and the danger level 5.45. In a typical year the river spends 9.6 days above warning and 1.9 days above danger. The highest reading in the record is 5.72 metres, in September 2020.
What turns a high river into a flooded city is timing. Kolkata sits largely below high-tide level and drains by gravity — when heavy rain coincides with a high tide and an upstream release, the water has nowhere to go.
About this data
What this page shows
Annual peak gauge levels from 2015 to 2025, the monthly pattern through the monsoon, monsoon rainfall plotted against peak river level, waterlogging incident counts, and a table of major flood events. September is consistently the peak month, averaging 5.14 metres. The 2025 peak was 5.08 metres.
Where the data comes from
Central Water Commission flood forecast bulletins for the Garden Reach station on the Hooghly, combined with IMD rainfall records.
Limitations worth knowing
The CWC publishes these bulletins as PDFs that are not machine-readable, and the source itself notes that the values assembled here are representative rather than a complete gauge-by-gauge transcription. Treat the annual peaks and day-counts as a reliable picture of pattern and magnitude, not as an official hydrological record — for that, cite CWC directly. Levels are measured above station datum, so they are not comparable to gauges elsewhere on the river. A single station also cannot describe flooding across the city: Kolkata's worst waterlogging is frequently caused by intense local rainfall with the river well below warning level.
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