A Coastal Model Supporting Urban Catchment Management

This paper presents outcomes from the development of hydrodynamic model of Tallebudgera Creek, a small coastal creek in South-East Queensland, Australia. The entrance to Tallebudgera creek is situated on a coast which is subject to highly variable wave energy, including swell events derived from occasional tropical cyclones. A prevailing longshore sediment transport rate of approximately 500,000 m(3) yr(-1) is derived from an oblique wave approach due to the predominantly south-east wave direction. The entrance is subject to infilling by marine sands and is currently dredged annually to mitigate flooding impacts and to maintain water quality. The model is calibrated with water level and discharge data and describes the flow behaviour for this well-defined hydrodynamic system with the inclusion of wave-current interaction at the entrance. The model was developed in order to simulate and to test the impact of a range of potential future management schemes for the creek, such as modifications to the entrance or changes to the present maintenance dredging regime. The model was found to be sensitive to bed roughness at upstream locations more than at the downstream region. The presence of a weir-like structure upstream resulted in a modified tidal signal.