Ryan Lowe – Calculating coastal interactions to protect our land girt by sea, UWA

Professor Ryan Lowe focuses on understanding and predicting coastal processes.  By defining the physics of ocean waves and currents and how they interact with complex coastlines, his work has applications ranging from predicting beach erosion and coastal flooding to mapping nutrient flows or pollution spread in the environment.

About Professor Ryan Lowe

Ryan studied mechanical engineering at the University of California, but quickly discovered an interest in physical oceanography and ocean science more generally, completing a PhD in Civil and Environmental Engineering at Stanford University.  His early research focused on understanding how coastal water flows driven by waves interact on local scales with the roughness of many coastlines, like coral reefs, seagrass meadows or mangrove forests.  Since commencing at the University of Western Australia in 2007, his research has increasingly focused on improving predictions of wave-driven processes and hazards in coastal environments.  As part of this work, Ryan also identifies strategies to protect coastlines from flooding and erosion by incorporating both natural features of ecosystems and coastal engineering structures.

What drew him to science?

“I grew up on the beach,” admits Ryan.  “The ocean was a part of everything I did growing up.”  Enjoying science and mathematics in school, Ryan gravitated to engineering, and his interest in environmental flows and fluid mechanics steered him into physical oceanography.  “I wanted to understand the physics of the ocean.”

Research with supercomputers          

Water motion in the ocean occurs over a vast range of scales – from large-scale currents in ocean basins, to coastal current systems, down to the small-scales of ocean wind-waves and turbulence,” explains Ryan.  “So, understanding transport and mixing processes in the ocean requires models that can capturing ocean physics over a range of spatial and temporal scales that vary by application.  That range of spatial and temporal scales makes predicting ocean flows inherently challenging.  It’s not practical to measure everything out in the field, so we often create large numerical models using supercomputers that are usually supported by field or laboratory measurements of ocean flows.”

Experimental measurements of local interactions in the coastal zone, whether on a beach or in a wave tank, allow Ryan to develop methods to parameterise small-scale hydrodynamic processes that can then be incorporated into larger scale ocean models.  Equally, the numerical models are often used to improve the field work: by running models before heading to the coast, Ryan can gain insight into likely ocean conditions and plan the optimal places and frequencies to take useful measurements.

Real world solutions

Ryan’s work is allowing coastal ocean models to more accurately account for how coastal topography and habitats modify the coastal environment, and affect processes like beach erosion and coastal flooding.  Accurate models are also allowing better predictions of future coastal hazards, incorporating climate change effects such as sea level rise and the changing frequency and intensity of storms.

“Coastal flooding is a worldwide threat that is growing with climate change,” notes Ryan, “and 85 per cent of Australia’s population lives near the coast.  ‘Hard’ engineering flood defences such as seawalls and breakwaters work but come at significant cost, including to coastal ecosystems and general coastal amenity.  We can’t build them everywhere.”

Ryan’s predictive modelling is showing how ecosystem features such as seagrass meadows, coral reefs and mangroves can provide effective coastal protection by dissipating wave energy and reducing extreme water levels at the coastline.  This is leading to practical guidelines and proposals to preserve and restore these valuable ecosystems in place of conventional engineering structures to protect coastlines.

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