Silchar: Intense bursts of rain in Nagaland and Arunachal Pradesh — not the Brahmaputra — triggered Assam’s devastating July floods, a study has found.The report, Assam Floods 2026: Comprehensive Situation Assessment and Pathways for Resilient Recovery, was released by Assam University researchers and collaborators on Tuesday.The floods, among upper Assam’s worst in recent decades, killed more than 100 people, displaced around 2.12 lakh and inundated nearly 21,000 hectares of farmland, the report said.Despite the devastation, Assam recorded a 29% rainfall deficit between June 1 and July 29, receiving 594.4mm against the normal 839.6mm. However, Nagaland recorded 181% excess rainfall on July 19, while Mokokchung district received 493% above normal.The deluge rushed down the hills into Assam’s south-bank tributaries, including the Dikhow, Disang, Jhanji and Dhansiri. The rivers crossed danger levels and breached ageing, vulnerable embankments at several locations.Severe flooding had already hit several tributaries before the Brahmaputra’s main channel peaked, the study noted. Water released from Nagaland’s Doyang reservoir after storage levels rose further worsened flooding in the Dhansiri basin.Researchers attributed the disaster to multiple factors, including reduced soil absorption, landslides in Nagaland’s Mon district, reservoir releases, silt accumulation, ageing embankments and disappearing wetlands.The report called for a region-specific early warning system using satellite imagery and geographic information technology. Besides forecasting river levels, the system should identify areas likely to be inundated and estimate the population at risk.It also recommended separate flood-management strategies for Assam’s five geographical regions, recognising riverbank erosion as a disaster, relief and compensation for char residents, wetland restoration, embankment modernisation and satellite-based post-monsoon damage assessments.
