Widespread encroachments and unregulated construction on floodplains made the devastating flashflood in Himachal Pradesh's Mandi district worse, according to a new study. The flood struck Thunag village in 2025, killing 15 people and leaving hundreds homeless.
Study reveals how encroachments worsened Mandi flashflood damage
The assessment comes from the Centre for Disaster Risk Reduction and Resilience at Himachal Pradesh University in Shimla. Deputy Director Mahesh Sharma led the research team, which combined field surveys with analysis of high-resolution satellite images.
The researchers found a clear pattern in the damage. According to the study, structures located immediately adjacent to the floodplains suffered disproportionately greater damage irrespective of their construction type. In contrast, buildings situated only a short distance uphill remained largely unaffected.
What the Mandi flashflood study means for floodplain construction
This finding points directly at human activity as a key factor in the disaster's severity. The study suggests that buildings built too close to drains and floodplains had no protection, no matter how strong they were built. The location mattered more than the materials used.
The research highlights a simple but critical lesson: where you build matters as much as how you build. Structures on floodplains faced the full force of the water, while those just a short distance uphill escaped the worst damage.
Our Take: A clear warning for flood-prone regions
In our view, this study delivers a blunt message that goes beyond Mandi. Encroachments along drains and floodplains are not just a legal problem — they are a life-and-death issue. The 15 lives lost in Thunag village are a direct consequence of allowing construction in places nature reclaims during extreme weather.
The finding that even well-built structures near floodplains suffered severe damage should worry every district in India's mountainous regions. It means no amount of engineering can fully protect a building placed in the wrong spot. The only real solution is to stop building on floodplains altogether and clear existing encroachments.
Authorities in Himachal Pradesh and other hill states should treat this study as an urgent call to enforce floodplain regulations. The next flashflood may not come with a warning, and the cost of ignoring this research could be measured in more lives lost.