Field measurement for Investigating the dynamics of Currumbin creek tidal inlet entrance

Abstract

Currumbin Creek is a small tidal inlet in south-eastern Queensland, Australia. There is a long history of morphological changes, entrance stabilization works and maintenance dredging activities. Despite these activities an effective longterm management plan is yet to be implemented. A key component of the development of such a plan is a model of morphological change, and this paper addresses an investigation of the dynamics of the whole system. A field campaign carried out in March, 2011 and included measurement of nearshore wave regimes, tidal levels and currents inside the creek, and also drogue tracking in the inlet entrance. Wave data was collected over six weeks by ADCPs in water depth of about 7-8 m. Tidal current discharges were also measured by an ADCP over two tidal cycles of 14.4 (spring) and 15 (neap) hours. Water levels were recorded using a Valeport Water Level Recorder during the whole measuring period. The investigations show that the creek is mixed, but mostly flood dominated and therefore, there is a reasonable potential for sediment to rapidly infill the entrance and for the entrance to be dominated by natural bypassing. This study is part of a broader research project aiming to maintain longer, more durable and stable tidal-inlet entrance channels in Currumbin Creek. These findings will contribute to the design of alternative entrance geometry or maintenance strategies in the next phase.