Comparing Methodologies to Analyse Seiche in Prototype and Model Harbours in NSW.

Coastal harbours are often subject to periodic surface water level and current speed oscillations ('seiche') of the order of 1 minute and longer. These oscillations can impede harbour operations by causing vessels to surge and sway at their berth; strain or break mooring lines; or cause other damage through overtopping or scour. Harbours known to seiche typically require investigations utilising both physical and numerical models to minimise or mitigate adverse impacts by any proposed development that may alter the resonant characteristics of the harbour or its response to incident forcing functions. This paper compares the use of wavelets, Fourier analysis and white noise simulation in a Coffs Harbour physical model and prototype harbours at Coffs, Crowdy Head, Port Kembla, Ulladulla and Eden Harbours. The paper will discuss some of the limitations and advantages of these methodologies to inform proposed development such as the boat ramp in Coffs Harbour and the proposed development at the ports of Coffs and Ulladulla. The paper will also present some of the successes and difficulties encountered by the authors in measuring and analysing seiching in NSW harbours resulting from a meteotsunami recorded in January 2022. [ABSTRACT FROM AUTHOR]