As part of her Master of Science thesis, University of British Colombia student Rose Beagley is studying the model to learn more about the river’s alluvial fan and gravel bed system in an effort to come up with ways of protecting the Franz Josef township from flooding.
“The Waiho River has been rapidly aggrading for years, and large floods could spill over the existing stopbanks,” she says.
“There is a proposal to realign the stopbanks to widen the river in order to reduce the rate of aggradation, thereby reducing the severity of the flood risk to Franz Josef. This would also make the township more resilient to the effects of earthquakes and landslides on the river.
“The aim of my project is to investigate the long-term effects of different stopbank alignments and come up with an alternative stopbank location.”
Lincoln University GIS senior lecturer Crile Doscher says Lincoln has a long history of using physical models to study gravel bed river systems.
“For this latest model, we are using a laser to capture river elevations. The early Weta Workshop used technology like this in the Lord of the Rings movies to scan in models of things like cave orcs and then animate them.”
He says the model of the Waiho River allows for experimentation within a wide range of different configurations without spending much money or time.
“To get the braiding effects we see on gravel bed river systems, we let sediment-laden water run out over a sloped surface and braiding naturally occurs over time.
“Water and sediment are mixed together at the top of the model and then flow downslope within the confines of the polystyrene walls, which simulate the natural landform boundaries of the floodplain.”
PHOTO: Rose Beagley studies the physical microscale model of the Waiho River at Lincoln University's water lab.