The Red River sediment dispersal system has been increasingly altered by human activities, but the resultant morphodynamic change and sediment budget in the Red River Delta (RRD) has been little studied in a holistic perspective. In this study, time-series analysis of river water and sediment discharges from 1960 to 2010 was carried out to trace human interferences on sediment routing processes, and historical charts from 1930 to 2008 were digitized to reconstruct the Digital Elevation Models for investigating spatiotemporal variations in the RRD morphology and calculating their depositional and erosional fluxes. The results show that sediment reduction by 61.3% in the Red River is mainly induced by constructing the Hoa Binh Dam at the lower reach of the Da river, and deforestation and other land-use change have recently increased significantly the sediment loads in the Thao and Lo rivers. Intertidal and subtidal morphological changes in the RRD are highly site-specific in response to natural and anthropogenic drivers. Rapid intertidal accretion majorly occurs near the distributary mouths because of abundant sediment supply and artificially promoted siltation by land reclamation projects, but severe coastal erosion may occur secularly after the distributary outlet shifting or temporarily by storm events. The subaqueous RRD is generally featured by the contour-parallel zonation of erosion and accretion determined by strong longshore currents associated with monsoon winds. Net accretion was observed in the tide-dominated northern subaqueous RRD and has recently changed into a slight erosion due to reduced sediment input in the last two decades, while net erosion was monitored in the southern subaqueous RRD predominated by wave and longshore currents and has recently entered into a slight accretion phase in response to the distributary outlet shifting and secular morphodynamic adjustment. The study RRD region received on average 41.1 Mt./yr (Mt = 10⁶ t) of suspended sediments, and 14.2 Mt./yr and 28.6 Mt./yr were estimated to accumulate on the intertidal flats and in the northern subaqueous RRD, respectively. However, erosion in the southern subaqueous RRD could contribute 42.9 Mt./yr of sediment to the system. Therefore, 41.2 Mt./yr of suspended sediment was indicated to escape from the study RRD region and transport further southward by longshore current to form the distal muddy clinoform along the inner Vietnam shelf. This sediment budget estimation should bear a significant uncertainty, but provides important information for multi-decadal sediment dispersal in a mega-delta system and coastal management.

由于人类活动，红河沉积物的分散系统已日渐改变，但对红河三角洲（RRD）的形态动力学变化和沉积物收支状况却缺乏全面的研究。在这项研究中，对1960年至2010年的河流水和沉积物排放量进行了时间序列分析，以追踪人为对沉积物路由过程的干扰，并对1930年至2008年的历史图表进行数字化处理，以重建用于调查沙特阿拉伯时空变化的数字高程模型。 RRD形态并计算其沉积和侵蚀通量。结果表明，红河沉积物减少61.3％的主要原因是在达河下游建造了Hoa Binh大坝，最近，森林砍伐和其他土地利用变化大大增加了邵河和洛河的泥沙负荷。在响应自然和人为驱动因素时，RRD的潮间带和潮下带形态变化具有很高的位点特异性。由于大量的泥沙供应和土地开垦项目人为地促进了淤积，潮间带快速增生主要发生在分流口附近，但是在分流口转移或暂时由于风暴事件而长期发生的严重海岸侵蚀可能会发生。水下RRD的特征通常是侵蚀和积聚的轮廓平行区域，该区域由与季风相关的强的近岸海流确定。在潮汐主导的北部水下RRD中观察到净增生，最近由于近二十年来沉积物输入减少而变为轻度侵蚀，而在南部波浪中RRD监测到的净侵蚀以波浪和长岸流为主，最近进入轻微的增生阶段，以响应分配出口的移动和长期的形态动力学调整。研究RRD地区平均每年收到41.1吨（Mt = 10⁶  t）的悬浮沉积物，分别估计在潮间带和北部水下RRD上堆积了14.2 Mt./yr和28.6 Mt./yr。但是，南部水下RRD的侵蚀每年可为该系统贡献42.9吨/年的沉积物。因此，表明有41.2 Mt./yr的悬浮沉积物从研究的RRD区域逸出，并被近岸海流进一步向南输送，形成沿越南内陆大陆架的远端泥质斜面形。沉积物预算估算应具有很大的不确定性，但可为大型三角洲系统中的数十年沉积物扩散和海岸管理提供重要信息。