Selection of Appropriate Shifting of Tidal River Management

A perennial waterlogging situation has emerged in the polders of the southwest (SW) coastal part of Bangladesh over the last few decades. The earthen embankments delinked the huge natural floodplains and restricted the gradual process of natural deposition inside the polders. At the same time, they accelerated riverbed siltation outside the polders and even closed the exits of the sluiced gates. As a result, tidal rivers are unable to drain the nearby lands and polders anymore. Temporary de-poldering in order to allow tidal movement in a selected tidal basin, popularly known as tidal river management (TRM), is one of the most effective measures to address this issue. To solve the problem in the long-run, such operations are to be shifted effectively in different beels (large depressions). This study attempts to investigate the shifting of TRMs considering two virtual cases in a small stretch of Hari river: (1) from downstream (d/s) to upstream (u/s) and (2) from u/s to d/s. From the perspective of the indicator taken in the study as total sediment deposition, it is found that shifting the TRMs from d/s to u/s produced a slightly better result. The effective shifting of TRMs is thus necessary for sustainable operation of TRMs.