Physical controls and a priori estimation of raising land surface elevation across the southwestern Bangladesh delta using tidal river management
article
The Ganges–Brahmaputra–Meghna delta in Bangladesh is one of the largest and most densely popu lated deltas in the world and is threatened by relative sea level rise (RSLR). Renewed sediment deposition through tidal river management (TRM), a controlled flooding with dike breach, inside the lowest parts of the delta polders (so called beels) can potentially counterbalance the RSLR. The potential of TRM application in different beels across south western Bangladesh has been estimated previously but re quires further exploration. Neither the seasonal and spatial variations in physical drivers nor the non-linear character of physical drivers and several sensitive parameters for sedi ment deposition have been taken into account so far. We used a 2D morphodynamic model to explore the physical controls of the following five parameters on the total sediment deposi tion inside the beels during TRM: river tidal range (TR), river suspended sediment concentration (SSC), inundation depth (ID), width of the inlet (IW), and surface area of the beel (BA). Our model results indicate that these five parameters and their interactions are significant for sediment deposition per day (SPD), where SSC and BA have a high impact, TR and ID have a moderate impact, and IW has a low impact on sediment deposition. Non-linear regression models (NLMs) were developed using the results of 2D models to quantify how sediment deposition inside the beels depends on these parameters. The NLMs have an average coefficient of deter mination of 0.74 to 0.77. Application of the NLMs to 234 beels in southwestern Bangladesh indicates that TRM oper ation in beels located closer to the sea will retain more sed.
Topics
TNO Identifier
967509
ISSN
10275606
Source
Hydrology and Earth System Sciences, 26(4), pp. 903-921.
Publisher
Copernicus GmbH
Pages
903-921