New research hopes to save lives by predicting landslide dams

Whataroa - New research aims to save lives in West Coast communities by predicting high-hazard zones where landslide dams may form, potentially resulting in major flooding.

Landslide dams form when debris from a landslide blocks a river channel. This creates a large dam that backfills into the upstream valley and eventually bursts. This is known as outburst flooding, and can have devastating impacts on communities, destroying homes and infrastructure.

As seen in the Kaikoura event, large numbers of landslides and landslide dams can form after a significant earthquake. Heavy rainfall can also cause landslide dams and increase the risk of the dam bursting.

University of Canterbury researcher Jane McMecking has created a model to assess where landslide dams and outburst flooding might occur on the West Coast as part of her masters thesis. 

She hopes her research will save lives in the event of an Alpine Fault earthquake and help councils and local Civil Defence with their evacuation plans. 

Landslide dams are likely to form along the mountainous regions of the West Coast during a large earthquake.

They are most hazardous when they are in areas near communities and lifelines, such as farming regions and State Highway 6.

For example, a landslide dam outburst flood in the Haast catchment could impact State Highway 6 for tens of kilometres, while the farming communities in the Hokitika and Whataroa catchments were also identified as high hazard.

Although the prospect of a landslide dam outburst flood sounds daunting, McMecking says being prepared is key.

McMecking’s research was recently recognised in the three minute thesis competition where university students summarised their work in a three-minute video without props or animations.

She was awarded first place in the masters category and represented the university in the national final in September 2022.

Toka Tū Ake EQC Head of Research Dr Natalie Balfour says that this kind of research is essential to understanding the impact of natural hazards on communities.

Toka Tū Ake EQC is a Crown Entity that operates under the Earthquake Commission Act 1993. We invest in natural hazard research and education to help communities to reduce their risks, and we provide natural hazard insurance cover for damage to residential properties caused by earthquakes.

Photo: Canterbury researcher Jane McMecking at Whataroa