The Nakdong Estuary, Korea, is a dramatic example of an Anthropocene estuary. Over the last century, the construction of two dams has divided the estuary into two discharge energy regimes with the East Nakdong Estuary receiving discharge and the West Nakdong Estuary receiving no discharge. The mean-flow sediment flux gradient during high discharge was the main mechanism for deposition in the East Nakdong Estuary. Because of limited observations, the sediment transport mechanisms for the entire estuary remained unclear. To complement previous observations that were limited to a high discharge event of the East Nakdong Estuary, this study aimed to better understand the spatiotemporal variation of sediment transport and the mechanisms of deposition throughout the Nakdong Estuary. Sediment fluxes and bed level changes were estimated by utilizing the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST). Results confirmed that the East and West Nakdong Estuaries had different depositional patterns. The East Nakdong Estuary was characterized as a river-dominated environment with a high influence of river discharge that experiences rapid deposition. The West Nakdong Estuary was characterized as an environment mainly influenced by tides and waves that contribute to gradual deposition throughout the year. The mean-flow sediment flux by river discharge was a main mechanism of deposition in the East Nakdong Estuary after the construction of dam. The continuous landward mean-flow flux by tides and waves through the inlets was the dominant mechanism for deposition in the West Nakdong Estuary. These model results suggest that the Nakdong Estuary may serve as an analogue for a microtidal estuary altered by an estuarine dam, particularly those for which there is a monsoonal climate or anthropogenically reduced river discharge.

韩国那洞河口是人类世河口的一个典型例子。在上个世纪，两个大坝的建设将河口分为两种排放能效形式，东洛东河口接收排水，西洛东河口不接收排水。高涌流时的平均流量泥沙通量梯度是东洛东河口沉积的主要机理。由于观测有限，整个河口的泥沙输送机制仍不清楚。为了补充以前仅限于东洛东河口大流量事件的观测结果，本研究旨在更好地了解整个洛东河口的沉积物运移的时空变化和沉积机理。沉积物通量和床位变化是通过利用海洋-大气-波-沉积物耦合传输（COAWST）估算的。结果证实，Nakdong东部和西部河口有不同的沉积模式。洛东河口的特征是河流为主的环境，对河流流量的影响很大，并且沉积迅速。西那洞河口的特点是主要受潮汐和波浪影响的环境，这些潮汐和波浪全年都在逐渐沉积。大坝建成后，河东河口的平均流量泥沙通量是东洛东河口沉积的主要机理。潮汐和波浪通过入口连续向陆上平均流动通量是西洛东河口沉积的主要机制。