Clues to ancient Kosi superflood say it could happen again today 

Clues to ancient Kosi superflood say it could happen again today 

Subject: Geography

Section: Places in news

Context: A study led by an IIT Kanpur scientist has found that an ‘extreme monsoon event’ occurred around 11,000 years ago.

More about the news:

• A team of geologists, including researchers from IIT Kanpur and the Universities of Edinburgh and Glasgow, has undertaken a study to reconstruct ancient river floods in the Gangetic plain dating back 23 to 5 million years ago during the Miocene era.
• They utilized sedimentary cores from beneath the Karnali, Ganga, and Kosi rivers to examine changes in sediment composition over time.
• Surprisingly, they discovered that climate change-related events and seismic activities occurring today could result in super-floods that pose a severe threat to the population in the Gangetic plain.
• This revelation underscores the need for an immediate overhaul of India’s disaster management strategy to account for “cascading hazards,” which refer to natural disasters triggered by other disasters.
• The study’s origins lay in an unusual observation that older sedimentary layers contained large particles downstream from the usual gravel-sand transition point.
• Investigating this anomaly led the researchers to the Mohand anticline in Uttarakhand, where they analyzed sediment layers to estimate deposition times.
• Their findings suggested that an “extreme monsoon event” occurring every 200-1,000 years, combined with hyperconcentrated flows caused by triggers like landslides, could result in catastrophic floods.
• The increased likelihood of extreme monsoons and landslides due to climate change poses a growing risk to regions prone to such events.
• The study advocates for an integrated disaster management approach that considers the interconnectedness of earthquakes, landslides, and floods to better mitigate these complex cascading effects.