£1m project aims to forecast long-term effects of debris transported by natural disasters

The SUPERSLUG initiative will assess how sediment moved by landslides, avalanches and other extreme events can impact river systems and the landscapes and communities near them.

Landslides, avalanches and glacial floods can have an immediate and devastating effect on anything in their path.

However, a £1million research project is now going to explore their potential to impact communities often located hundreds of kilometres away and many years after an event has originally taken place.

Centred on the headwaters of the Ganges River in the Himalayas, the SUPERSLUG initiative is named after the huge masses of debris created by such natural disasters, sometimes described as sediment slugs when they travel down rivers.

Using a range of novel monitoring technologies and sensors, scientists will develop and test numerical models to provide the most comprehensive predictions yet of where, when and how the long-term impacts of recent and future extreme events might be felt.

The three-year project is being supported with a grant of almost £840,000 from the Natural Environment Research Council, part of UK Research and Innovation.

Researchers from the University of Hull will provide expertise in catchment modelling for the project, which will be led by the University of Plymouth, with colleagues from the universities of Exeter, Leeds, Newcastle and Staffordshire. The project will also harness the expertise of academics at the University of Calgary, Indian Institute of Technology Roorkee and the Wadia Institute of Himalayan Geology.

Professor Tom Coulthard, Professor of Physical Geography at the University of Hull said: “The initial effects of the Chamoli disaster were catastrophic and that, understandably drew the initial focus of the scientific response. However, the volume of sediment that was unleashed during that event will continue to travel through the catchment area over a period of years, decades or even centuries."

Dr Matt Westoby, Associate Professor of Physical Geography at the University of Plymouth, is the project’s lead. He said: “High mountain regions such as the Himalayas and the Andes are among the most active – and most hazardous – on the planet. The effects of a changing global climate are only going to exacerbate that hazard, with more intense monsoons leading to increased landslide activity, and the retreat of glacial ice cover causing landscape instability and triggering far-reaching floods.”

The project will focus on a 150 km stretch of the Ganges River impacted by the 2021 Chamoli disaster. Initially triggered by a rock and ice avalanche, a fast-moving, debris-laden flood killed more than 200 people with extensive and severe damage being caused across the region, including to valuable hydropower and transport infrastructure.

In the immediate aftermath, scientists from across the world – including many of those involved in the SUPERSLUG project – came together to understand the processes that led to the initial disaster.

Over the last two years, funding from UK Research and Innovation enabled pilot work in collaboration with in-country partners to better understand the short-term legacy of the disaster, pump-priming the more ambitious SUPERSLUG project.

The new research will use the data gathered during that time, as well as using drones and satellite imagery to monitor changes in the landscape and river system over the space of several years.

It will also employ seismic sensors and wireless ‘smart cobbles’ alongside other complementary techniques, including automatic water level monitoring, to explore how sediment is transported during normal and flood conditions.

This and other information will be used to develop a large-scale digital twin of the river system, which will be used to explore catchment management decisions.

Importantly, the project team will engage directly with communities and authorities in the Ganges region, to ensure their findings are accessible and useful to disaster management professionals, hydropower operators and the wider international academic community.

Professor Coulthard said, “Often it’s the rocks, house sized boulders and sheer volume of sediment moved rather than flood water that causes the most damage in these cascading multi-hazard events. The combination of remote sensing data with information gathered from sensors placed in the heart of the sediment slug will bring new understanding of how long the wave sticks around. This is fundamental for managing these events and predicting their impacts.”

All images credit: Matt Westoby

To find out more about the SUPERSLUG project, visit the case study page.