The morphology and surf conditions of Aramoana Beach, Otago: A surf break of national significance

Aramoana Beach is a recognised surf break of regional and national significance and is protected under the New Zealand Coastal Policy Statement (2010). Until recently, little baseline data on the break had been collected. The objective of this thesis was to gain an understanding of how the morphological and surfing parameters vary and interact with each other and with the forcing wave climate. Ultimately, the baseline data gathered from this work will help inform and support the NZCPS (2010) in protecting Aramoana Beach and other surf breaks around New Zealand. The state, morphology and in turn the surfing parameters of Aramoana Beach are correlated and are a function of the forcing wave climate present at any given time, which is observed to have seasonal and annual variations. The morphological parameters of interest are the sand-bar orientations and sand-bar lengths, whilst the surfing parameters of interest are the peel angles and the ride lengths. Two cameras were set up overlooking Aramoana Beach to record known favourable surfing locations. The two locations were separated by 300 m. The results indicated that, at the camera one area of interest, El Niño phases as well as the forcing wave climate associated with autumn and winter, increased the sand-bar orientation, relative to true north (0 ), to face north-east and decreased the sand-bar lengths, whilst the state of Aramoana Beach became more dissipative in nature. During El Niño phases, as well as autumn and winter, south-east swell waves were dominant, and the significant wave height increased. In contrast, La Niña phases, as well as the forcing wave climate associated with summer and spring, decreased the sand-bar orientations, relative to true north, to face north-north-east and increased the sand-bar lengths, whilst the state of Aramoana Beach became more reflective in nature. During La Niña phases, as well as spring and summer, north-east swell waves were dominant and the significant wave heights were smaller, relative to El Niño. The peel angles and ride lengths of the breaking waves were more favourable in El Niño years and during autumn and winter compared to during La Niña years and during spring and summer at the camera one area of interest. At the camera two area of interest, the El Niño phase decreased the sand-bar orientations, relative to true north to face north (opposite to the camera one area of interest) and decreased the sand-bar lengths. In contrast, the La Niña phase increased the sand-bar orientations, relative to true north to face north-north-east and increased sand-bar lengths. The seasonal trends at the camera two area of interest were likely inaccurate due to the paucity of data. Surfing conditions at the camera two area of interest were more favourable during La Niña phases compared to El Niño phases, which was opposite to the camera one area of interest. The findings of this study add weight to the importance of protecting the swell corridors that contain the pre-conditioning features that are essential to producing the world-class surfing waves observed at Aramoana Beach