Ms Nina Keath1, Mr Salvador Juardo
1City Of Onkaparinga, Noarlunga, Australia
City of Onkapringa is home to 31kms of coastline, much of which is comprised of highly erodible soft sedimentary cliff-faces. With roads, infrastructure and housing at risk, council has recognised the need to actively monitor coastal erosion and work with local communities to identify appropriate responses.
In 2015, City of Onkaparinga used aerial photography and photogrammetric modelling (the science of making measurements from photographs) to create a high-resolution, 3D computer model of the entire coastline. Local company, Aerometrex, used a helicopter to capture 25,000 photographs and added 125 ground control points to generate a detailed 3D mesh accurate to 50 millimetres. Each photograph represents 36 million data points, so 25,000 photographs creates trillions of data points.
As the first ever application of this technology to the problem of coastal erosion, it has proved to be highly effective for:
– establishing an accurate baseline of the coast,
– monitoring erosion over time (a follow up hot-spot scan in 2018 revealed a quantifiable rate of erosion),
– modelling sea-level rise and future development,
– safely and efficiently collecting the data required for designing coastal infrastructure, and
– effectively presenting reliable and compelling information to local communities.
The success of this approach has resulted in councils across Australia and the world adopting this method.
Watch 3D modelling of the Onkaparinga cliffs at: https://www.youtube.com/watch?v=2M4gw4LlHH4
Nina Keath is a Senior Strategic Planner at City of Onkaparinga.
Salvador Juardo is a Coastal Planner at City of Onkaparinga