首页> 外文期刊>Oceanographic Literature Review >Spatial and seasonal variability of sediment accumulation potential through controlled flooding of the beels located in the polders of the Ganges-Brahmaputra-Meghna delta of Southwest Bangladesh
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Spatial and seasonal variability of sediment accumulation potential through controlled flooding of the beels located in the polders of the Ganges-Brahmaputra-Meghna delta of Southwest Bangladesh

机译:通过位于孟加拉国恒河 - Brahmaputra-Meghna delta的膨胀架的塞尔斯受控灌浆灌浆的空间和季节变异潜力

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摘要

The Ganges-Brahmaputra-Meghna (GBM) delta plain within Bangladesh is one of the most vulnerable to relative sea level rise (RSLR) in the world especially under current anthropogeni-cally modified (i.e., embanked) conditions. Tidal river management (TRM) as practiced in coastal regions of Bangladesh may provide an opportunity to combat RSLR by raising the land level through controlled sedimentation inside beels (depression within embanked polders) with re-opening of polders. To date, TRM has been applied to tide-dominated coastal regions, but the potential applicability of TRM for the beels within the polders of river-dominated and mixed flow (MF) regimes remains to be assessed. We apply a calibrated 2D numerical hydromor-phodynamic model to quantify sediment deposition in a beel flooded through breaching of the polder dike under conditions of river-dominated, tide-dominated and MF regimes for different seasons and applying different regulation schemes for the flow into the beel. Simulation results show considerable seasonality in sediment deposition with largest deposition during the monsoon season. The potential of controlled flooding is highest in the tide-dominated region, where sediment accumulation can be up to 28 times higher than in the river-dominated region. Regulating flow into a beel increases trapping efficiency, but results in slightly lower total deposition than without regulation. We conclude that re-establishing flooding of the beel within the polder without regulating the flow into the beel through breaching of the polder dike is a promising strategy for the mixed and tide-dominated flow regions in the delta as the sediment accumulation can raise the land surface at a higher rate than RSLR and effective SLR (ESLR). In the more upstream river-dominated section of the delta, accumulation rates would be much lower, but the pressure of sea level rise on these areas is lower as well. Owing to the abundant availability of sediment, application of controlled flooding like TRM therefore provides an opportunity to counteract the impact of RSLR and ESLR by means of land raising, particularly along the tidal river reaches in the GBM delta.
机译:孟加拉国的Ganges-Brahmaputra-Meghna(GBM)三角洲平原是世界上最容易受到海平面上升(RSLR)之一,特别是在目前的人体化学修改(即,静止)条件下。孟加拉国沿海地区实践的潮汐河管理(TRM)可以通过将土地层面通过塞尔兹(堤防膨胀者内的萧条)的控制沉淀来筹集土地水平来提供机会。迄今为止,TRM已应用于潮汐主导的沿海地区,但TRM对河流主导的和混合流动(MF)制度的膨胀架内的BEELS的潜在适用性仍有待评估。我们应用校准的2D数值液压动力学模型,以通过违反河流主导的,潮汐和MF制度的条件,在不同季节的条件下违反圩区淹没的泥石沉积,并将流量的不同调节方案应用于流入Beel。仿真结果显示了季风季节最大沉积沉积物沉积的相当大季节性。潮汐占主导地区的受控洪水的潜力最高,其中沉积物积累可以高于河主导地区的28倍。调节流入BEEL增加诱捕效率,但导致总沉积总沉积略低于没有调节。我们得出结论,通过违反圩区违反平台堤防,在圩区内重新建立斗牛叶片的洪水,这是达到沉积物积累的混合和潮汐型流量区域的有希望的策略表面比RSLR和有效的SLR(ESLR)的表面更高。在三角洲的上游河主导部分中,积累率将低得多,但海平面上升的压力也较低。由于沉积物充足的可用性,因此控制洪水如TRM的应用,因此提供了抵消RSLR和ESLR的影响,通过陆地提高,特别是沿潮汐河流达到GBM DELTA。

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  • 来源
    《Oceanographic Literature Review》 |2021年第6期|1391-1391|共1页
  • 作者单位

    Copernicus Institute of Sustainable Development Utrecht University Utrecht Netherlands;

    Copernicus Institute of Sustainable Development Utrecht University Utrecht Netherlands;

    Copernicus Institute of Sustainable Development Utrecht University Utrecht Netherlands;

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