Physical controls and a priori estimation of raising land surface elevation across the southwestern Bangladesh delta using tidal river management

Abstract. The Ganges–Brahmaputra–Meghna delta in Bangladesh is one of the largest and most densely populated deltas world threatened by relative sea level rise (RSLR). Renewed sediment deposition through tidal river management (TRM), a controlled flooding with dike breach, inside lowest parts polders (so-called beels) can potentially counterbalance RSLR. potential TRM application different beels across southwestern has been estimated previously but requires further exploration. Neither seasonal spatial variations physical drivers nor non-linear character several sensitive parameters for have taken into account so far. We used 2D morphodynamic model to explore controls following five on total during TRM: range (TR), suspended concentration (SSC), inundation depth (ID), width inlet (IW), surface area beel (BA). Our results indicate that these their interactions are significant per day (SPD), where SSC BA high impact, TR ID moderate IW low impact deposition. Non-linear regression models (NLMs) were developed using quantify how depends parameters. NLMs an average coefficient determination 0.74 0.77. Application 234 indicates operation located closer will retain more as result decreasing inland. Lower land elevation reasons western part sediment. Smaller higher raise due increase (SPD) area. Compartmentalization larger may elevation. Thus, length time cyclic order need vary from 1 multiple years RSLR, depending current local accumulation rates. found operating only monsoon season sufficient 96 % 80 all than 3 5 times yearly respectively. Applying seasonally offers huge advantages keeping available agriculture rest year. methodology presented here, applying based modeling, be low-lying sinking around provide priori estimation