Wave modelling framework to characterise surf break will be presented at Australasian Coasts & Ports 2019

Next week, MetOcean Solutions’ Senior Physical Oceanographer Simon Weppe will be presenting the numerical wave modelling methodology used to characterise surf break wave mechanics at Mangamaunu, a point break in Kaikōura, New Zealand at the Australasian Coasts & Ports 2019 conference in Hobart.

The investigation used the numerical model SWASH (Simulation WAves till SHore), a non-hydrostatic wave-flow model, to provide detailed characterisation of the existing surf break wave mechanics. The methodology was developed such that it can be applied for baseline characterisation of other surf breaks, as well as impact assessment for proposed coastal engineering projects.

Breaking waves (top) and full sea surface elevation field (bottom) predicted by SWASH, overlaid on a georeferenced image.

Breaking waves (top) and full sea surface elevation field (bottom) predicted by SWASH, overlaid on a georeferenced image.

“The SWASH wave model proved to be a useful tool to understand key features of the nearshore wave propagation, wave breaking and circulation in a surf break assessment context,” says Simon.

“High-quality surf breaks are rare assets with high amenity value for the community, and a prerequisite for ensuring appropriate protection is a robust understanding of the surf break wave mechanics.”

The Mangamaunu Point Break is a high-quality surf break that was recognised as one of the 17 “nationally-significant” surf breaks under New Zealand Coastal Policy Statement. However, the November 2016 earthquake (7.8 Mw) resulted in a dramatic uplift along the Kaikōura coastline and dynamics of the pre-quake, existing (i.e. post-quake) and post proposed development configurations were modelled to evaluate potential impacts on surf quality.

“The surf quality was assessed by examining changes in breaker position and the incident and reflected wave energy gradients,” explains Simon. “A robust understanding of the surf break wave mechanics provides the baseline to assess potential effects arising from future coastal modifications or environmental changes.”

Together with Simon, MetOcean Solutions’ consultancy team will also be represented at the conference by Dr Alexis Berthot, Dr Séverin Thiébaut and Remy Zyngfogel. Their work on statistical analysis of near-bed kinematics and hydrodynamic modelling in a micro-tidal salt wedge estuary will be published in the following weeks at www.metocean.co.nz/news.

The Australasian Coasts and Ports 2019 brings together engineers, planners, scientists and researchers to discuss multi-disciplinary issues related to coasts and ports. The 2019 Conference theme “Future directions from 40°S and beyond” reflects the increasing awareness about the need to find suitable means for adapting to change in the “right” direction. Visit coastsandports2019.com.au

Access full abstract here. For more information, contact us at enquires@metocean.co.nz