Trapping efficiencies calculated from the modelling display seasonal variability (Figure 7). Generally, trapping efficiencies at the locations of mixed flow and tidal flow regime are highest during the pre-monsoon and lowest during the dry season. At the locations of mixed flow and tide-dominated flow regime, trapping efficiency is high during monsoon season as well. However, at the location of river-dominated flow trapping efficiency is generally highest during monsoon and lowest during the pre-monsoon season. Trapping efficiency generally increases gradually along the gradient from river-dominated to tide-dominated flow regime during pre-monsoon when the mean tidal range is highest for all flow regimes and increases in a downstream direction (Figure 4). Maximum trapping efficiencies for unregulated flow are low: about 6% at the location of river-dominated, 10% at the location of mixed flow and 13% at the location of tide-dominated flow regime. Regulation of flow increases the trapping efficiency for all the regions and seasons (Figure 7). For the river-dominated flow regime regulation of flow into the re-opened polder during monsoon increases trapping efficiency by about 5 times when compared to unregulated flow. For tide-dominated and mixed flow regimes this increase is about 4 times. This demonstrates that the temporary trapping of the flood water within a beel by gate regulation indeed leads to a larger proportion of the sediment to settle.