Delhi flood risk
Delhi's flood risk is barrage-release-driven with a 36-72 hour fuse: water released at Hathnikund (Haryana) takes two to three days to reach the Old Railway Bridge gauge, where 204.50 m means warning, 205.33 m danger, and 206.00 m evacuation. Only ~7% of the floodplain length is embanked, and the 2018 Drainage Master Plan that was meant to fix internal drainage remains largely on paper.
The first flood warning is issued when Hathnikund barrage discharge crosses ~1,00,000 cusecs (Flood Control Order 2026). The July 2023 record showed the thresholds can fail conservative: the river hit 208.66 m - 1.17 m above the 1978 record - at releases the CWC's own post-mortem called moderate, with the ITO barrage's jammed gates deepening the flooding in central Delhi.
Recent flood events - 7
A July-2023-like flood spell repeated within two years - evacuations along the floodplain and renewed questions about why 2023's lessons had not changed outcomes (SANDRP's analysis is the sharpest public account).
SANDRP - Sept 2025 repeat flood analysis →Yamuna peaked at 208.66 m on 13 July - highest since records began in 1963, breaking 1978's 207.49 m. Ring Road, Civil Lines, ITO and Rajghat inundated; ~27,000 evacuated. CWC's case study is the official post-mortem.
CWC - Delhi Floods 2023 case study →207.32 m at the Old Railway Bridge - the highest level between 1978 and 2023 (the comparison every 2023 report reached for). Floodplain settlements evacuated; an early-monsoon warning the 2023 post-mortems would cite.
The Tribune (2023 all-time-high report with historical levels) →Annual peak discharge ~3,466 cumecs at the Delhi Railway Bridge (the CWC's model-calibration flood). The river flooded the low floodplain beside the Games-readied embankments, putting the Games Village's floodplain siting into the national argument it has stayed in since.
CWC case study (annual peak-discharge table; 2010 calibration event) →Annual peak discharge ~7,028 cumecs - the largest flow between 1978 and 2023 in the CWC's series. Trans-Yamuna colonies flooded; with 1988 it pushed the embankment-extension debate.
CWC case study (annual peak-discharge table) →Annual peak discharge ~5,642 cumecs; large evacuations from the floodplain and trans-Yamuna. With 1995 it defines the high-flow band the river revisited for three decades before 2023 broke the level record outright.
CWC case study (annual peak-discharge table) →The benchmark flood: 207.49 m at the Old Railway Bridge, a record that stood 45 years until 2023. Model city planning still references the 1978 flood line.
CWC case study (historical benchmark section) →External monitoring sources - 3
We don't republish these; tracking dam-gauge live state lives elsewhere. These are the operational portals to use during a flood event.
India's oldest flood-forecast station (operating since 1958). Live levels + forecasts during monsoon; the single best public flood signal for Delhi.
Delhi Disaster Management Authority's flood page: thresholds, helpline (1077), and seasonal orders. No machine-readable feed.
The 153-page plan for Delhi's 3,737 km of drains across 11 agencies - the reference document for internal (rainfall) flooding, still largely unimplemented.
What we don't have (Delhi)
- No public real-time Hathnikund release feed - the 36-72 h lead-time signal exists only in news reports and alerts (highest-leverage RTI target)
- No public flood model or inundation forecast for Delhi (no iFLOWS/CFM-DSS equivalent)
- No public hotspot inventory with geometry; NRSC's 2023 satellite inundation maps sit behind a NICNET-only portal
- The internal-drainage story (waterlogging) has no live data: 11 agencies, no unified drain-condition feed
Chennai's flood-risk page renders modeled hazard zones, 2015/2020 hotspots, drainage and sewerage overlays - none of which exist publicly for this city. This page surfaces what's actually available rather than papering over the gap with synthetic data.