The results of the different model scenarios are compared for the total
sediment accumulation over the seasons and for the trapping efficiency.
The results demonstrate that estimated total sediment deposition over
the season inside the beel of the re-opened polder varies per season for
all flow regimes (Figure 6). At all locations, total sediment
accumulation over the seasons is highest during the monsoon season
(Figure 6). For the tide-dominated regime, seasonal variation in
sediment accumulation is smaller than for the river-dominated and mixed
flow regimes. The sediment deposition during monsoon is almost 50%
higher than during the dry season for the tide-dominated flow regime,
whereas it is ten times higher for the river-dominated regime, and
almost 40 times higher for the mixed flow regime (Figure 6).
Along the gradient from river-dominated to tide-dominated flow regime,
the calculated total sediment deposition for all three seasons increases
substantially. During monsoon, total sediment deposition with
unregulated flow is about 4,600 tons at the location of river-dominated
flow, about 100,200 tons at the location of mixed flow and about 129,800
tons at the location of tide-dominated flow regime. The total sediment
deposition at the location of tide-dominated regime is highest among the
flow regimes for all seasons, and almost 28 times higher than at the
location of the river-dominated flow regime during monsoon season
(Figure 6).
Regulation of flow into the re-opened polder affects sediment deposition
within the polder. Model simulations show for the location of
river-dominated flow regime that using successive gate operation results
in about 18% more sediment deposition during the monsoon period.
Conversely, for the location of the tide-dominated and mixed flow
regimes unregulated flow into the re-opened polder results in higher
sediment deposition (Figure 6). During monsoon, unregulated flow into
the re-opened polder results in about 19% more deposition than
regulated flow with successive gates at the location of the mixed flow
regime, and about 45% more for tide-dominated flow regime.