Fluvial, tidal, and combined hydro-morphodynamics interaction in a complex, seasonal, sediment transport regime has been the subject of extensive research. It becomes particularly challenging when there is limited data. The Ganges-Brahmaputra-Meghna (GBM) Delta is one example of a huge system lacking data. Bathymetric data simultaneously covering the rivers and estuaries is hardly present, let alone sequences of bathymetries or a system-wide sediment budget. Hence it is difficult to understand and predict future developments. This research aims to make a sediment budget for the GBM delta with a process-based model. It is a first-ever sediment budget simulation for the GBM system. A process-based morphological model, Delft3D, has been used to reproduce the bathymetric evolution over time and the associated sediment budget. This chapter demonstrates the possibilities for the application of a robust modeling system to assess the morphodynamic evolution and sediment budget and pathways. The Ganges and Jamuna rivers carry sediment load in the ranges of 216–1038 million tonnes/yr and 80–228 million tonnes/yr respectively. The total accumulation in the estuary system is 1150 million tonnes/yr, out of which more than eighty percent of sediment is in suspension. The model results show that about 22% of the total sediment coming into the system is deposited in the floodplains and tidal plains and causes river morphology changes. The rest of the sediment is lost to the pro-delta, to the deep ocean bed, or leaves the domain. The results also indicate that Padma, Gorai, Pussur-Sibsa, Bishkhali, Shahbajpur channel, Lower Meghna, Tentulia Channel, and Arial Khan rivers are mainly in the aggrading phase, whereas, the Ganges, Jamuna, and Baleshwar are in the degrading phase. This particular delta model offers many opportunities to compare with sediment data, where it deals with a poorly surveyed area.

复杂的季节性沉积物输送体系中的河流、潮汐和综合流体-地貌动力学相互作用已成为广泛研究的主题。当数据有限时，这变得特别具有挑战性。恒河-布拉马普特拉-梅格纳 (GBM) 三角洲就是一个缺乏数据的庞大系统的例子。同时覆盖河流和河口的测深数据几乎不存在，更不用说测深序列或系统范围的沉积物预算了。因此，很难理解和预测未来的发展。本研究旨在使用基于过程的模型为 GBM 三角洲制定沉积物预算。这是 GBM 系统的首次沉积物收支模拟。基于过程的形态学模型 Delft3D 已被用于重现随时间的测深演变和相关的沉积物预算。本章展示了应用强大的建模系统来评估形态动力学演化和​​沉积物收支和路径的可能性。恒河和贾木纳河的泥沙承载量分别为 216-10.38 亿吨/年和 80-2.28 亿吨/年。河口系统的总堆积量为 11.5 亿吨/年，其中 80% 以上的沉积物处于悬浮状态。模型结果表明，进入系统的泥沙总量中约有22%沉积在洪泛平原和潮汐平原，导致河流形态发生变化。其余的沉积物会流失到前三角洲、深海床或离开该区域。结果还表明，Padma、Gorai、Pussur-Sibsa、Bishkhali、Shahbajpur 海峡、Lower Meghna、Tentulia 海峡、阿里尔汗河和阿里尔汗河主要处于退化阶段，而恒河、贾木纳河和巴莱什瓦尔河处于退化阶段。这个特殊的三角洲模型提供了许多与沉积物数据进行比较的机会，在那里它处理的是调查不充分的区域。