The potential response of shoreface depositional environments to sea level rise over the present century and beyond remains poorly understood. The shoreface is shaped by wave action across a sedimentary seabed and may aggrade or deflate depending on the balance between time-averaged wave energy and the availability and character of sediment, within the context of the inherited geological control. For embayed and accommodation-dominated coastal settings, where shoreline change is particularly sensitive to cross-shore sediment transport, whether the shoreface is a source or sink for coastal sediment during rising sea level may be a crucial determinant of future shoreline change. While simple equilibrium-based models (e.g. the Bruun Rule) are widely used in coastal risk planning practice to predict shoreline change due to sea level rise, the relevance of fundamental model assumptions to the shoreface depositional setting is often overlooked due to limited knowledge about the geomorphology of the nearshore seabed. We present high-resolution mapping of the shoreface-inner shelf in southeastern Australia from airborne lidar and vessel-based multibeam echosounder surveys, which reveals a more complex seabed than was previously known. The mapping data are used to interpret the extent, depositional character and morphodynamic state of the shoreface, by comparing the observed geomorphology to theoretical predictions from wave-driven sediment transport theory. The benefits of high-resolution seabed mapping for improving shoreline change predictions in practice are explored by comparing idealised shoreline change modelling based on our understanding of shoreface geomorphology and morphodynamics before and after the mapping exercise.

在本世纪及以后的时间里，人们对海岸面沉积环境对海平面上升的潜在反应仍然知之甚少。沿沉积海床的波浪作用来塑造海岸面，并在继承的地质控制范围内，取决于时均波浪能与沉积物的可利用性和特征之间的平衡，其可能发生侵蚀或收缩。对于以河床和居所为主的沿海环境，海岸线变化对跨岸沉积物运输特别敏感，在海平面上升期间，岸面是沿海沉积物的源头还是汇点，可能是未来海岸线变化的关键决定因素。虽然简单的基于均衡的模型（例如Bruun法则）已广泛用于沿海风险规划实践中，以预测由于海平面上升而引起的海岸线变化，由于对近海海床地貌的了解有限，因此常常忽略了基本模型假设与岸面沉积环境的相关性。我们通过机载激光雷达和基于船只的多波束echosounder调查，提供了澳大利亚东南部海岸-内陆架的高分辨率地图，该地图揭示了比以前已知的更为复杂的海床。通过将观测到的地貌学与波浪驱动的泥沙运移理论的理论预测相比较，利用测绘数据来解释海岸面的范围，沉积特征和形态动力学状态。