Timescales of inlet morphodynamic forced by tides and waves

Abstract

<span style="font-size:11.0pt;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";mso-bidi-font-family:mangal;="" mso-ansi-language:en-in;mso-fareast-language:en-us;mso-bidi-language:hi"="">The time scale at which an inlet responds to changes of wave height, freshwater inflow or sediment supply is called the morphological timescale, <i style="mso-bidi-font-style:normal">T_morph</i>. To determine the morphological time scale, one usually analyses survey data of the inlet throat area or the volume of flood/ebb tidal deltas, but such data are costly and therefore rare. This paper analyses tidal records using a 24.5 hour moving window approach to find <i style="mso-bidi-font-style:normal">T_morph</i> and provides relationships between <i style="mso-bidi-font-style:normal">T_morph</i> and the external forcing from waves and tides for different coastal inlets in New South Wales, Australia. Response to extreme changes in forcing depends strongly on bay/inlet size; from small inlets which open and close several times every year to larger systems where the effect of even the most severe weather events is not- or is barely measurable via changes to the inlets hydraulic performance. Outcome can be used in coastal inlet management without extensive river flow and bathymetry data. </span>