The inner part of a tide-dominated estuary is often typified by a tight meander bend, where bedload transport from both upstream by river flows and downstream by flood tidal currents merges to establish a bedload convergence (BLC) with the weakest energy condition in the estuary. Despite the potential significance in evaluating relative importance between tidal and river processes, the morphodynamics of the inner estuary remains relatively unexplored in terms of their response to governing processes. This study, based on satellite imagery and field observation, demonstrates that the inner part of the Sittaung River estuary in Myanmar has evolved via active morphodynamics over various temporal scales ranging from monthly to centennial cycles. Channels, including swatchways and flood barbs, migrate rapidly in response to mutually evasive tidal currents on monthly time scales, leading to an increase in the channel sinuosity. Annually, seasonal river floods accelerate channel migration, causing a tight meander bend. A chute cutoff of the point bar at the tight meander bend occurs during the river floods every 6 to 9 years, triggering substantial down-estuary changes in the position of the main channel, bars, tidal flats, and saltmarshes. Over centennial time scales, the main channel formed a large-scale, tight meander bend with a sinuosity exceeding 5, near the downstream end of the inner estuary, which corresponds to the BLC of the estuary. A chute cutoff of the large-scale tight meander bend during the high river flows resulted in the morphologic changes throughout the fluvial-marine transition zone of the Sittaung River estuary: widening of the main channel and the estuary via accelerated channel migration to accommodate an increase in river flows and tidal prism caused by an increase in the hydraulic gradient due to the shortening of the channel length. The tight meander bend has migrated seaward at centennial time scales, suggesting that the river influence has increased over the time, and the estuary is in the progradational phase to become a sediment-exporting delta. The recurrence of the bend tightening after the chute cutoff, however, indicates that flood-tidal currents drive the morphodynamic evolution of the estuary, and the gradual transition from an estuary to a delta is unlikely. Rapid channel migration with bar growth, frequent cutoff, and subsequent infilling of the abandoned channels over various temporal scales all typify the tide-dominated estuary is charged with high sediment loads imported from both rivers and offshore. Despite the construction of dams and reservoirs that reduced sediment supply into the estuary, other anthropogenic activities such as mining activities and deforestation appear to drive an increase in sediment loads, promoting the morphodynamics of the inner part of the Sittaung River estuary.

潮汐河口的内部通常以曲折弯弯曲为典型特征，在河床中上游的河水和下游的洪水潮汐流共同进行河床负荷输送，以建立河床能量条件最弱的河床收敛（BLC）。 。尽管在评估潮汐和河流过程之间的相对重要性方面具有潜在的重要性，但就其对治理过程的响应而言，内河河口的形态动力学仍然相对未被研究。这项基于卫星图像和野外观测的研究表明，缅甸西贡河河口的内部区域已经通过活跃的形态动力学在各个时间尺度上（从每月到百年周期）演变。渠道，包括样板路和洪水倒钩，在每月的时间尺度上，由于相互逃避的潮流而迅速迁移，导致通道弯曲度增加。每年，季节性的河道洪水会加速河道的迁移，导致弯道弯曲。每6到9年一次河水泛滥期间，在弯弯曲曲的弯道上，点状条会发生斜槽切断，从而触发主要河道，条状，潮滩和盐沼​​的下游河口变化。在百年时间尺度上，主河道在内河口的下游端附近形成了一条曲率超过5的大尺度，紧密的曲折弯，与河口的BLC相对应。在河水流量大的时候，大范围的曲折弯的溜槽截断导致了整个始发河河口河-海过渡带的形态变化：通过加速河道迁移扩大主河道和河口，以适应因河道长度缩短而引起的水力梯度增加而引起的河流流量和潮汐棱镜的增加。弯曲的弯曲弯道已在百年时间尺度上向海迁移，这表明河流的影响随着时间的推移而增加，河口处于发育阶段，成为沉积物输出三角洲。但是，滑道切断后弯头收紧的再次出现表明潮汐流驱动着河口的形态动力演化，并且不太可能从河口逐渐过渡到三角洲。快速通道迁移，带材增长，频繁切断，随后在各个时间尺度上对废弃河道进行充填，都代表着以潮汐为主的河口充斥着从河流和近海进口的高泥沙量。尽管修建了大坝和水库，减少了河口的泥沙供应，但其他人为活动，例如采矿活动和森林砍伐，似乎推动了泥沙负荷的增加，促进了西贡河河口内部的形态动力。