Tide dominated deltas are not studied so extensively as river-dominated and wave-dominated deltas. Although, a huge amount of sediments supplied by major rivers, is stored in tide dominated deltas. Through modeling of a tide dominated delta, insight will be achieved about the inf
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Tide dominated deltas are not studied so extensively as river-dominated and wave-dominated deltas. Although, a huge amount of sediments supplied by major rivers, is stored in tide dominated deltas. Through modeling of a tide dominated delta, insight will be achieved about the influences of tidal and fluvial processes on sediment transport and deposition in these tide dominated environments. Process based modeling of tide dominated deposits makes it possible to distinguish the controls of tidal depositional processes on the depositional architecture in terms of reservoir properties. Due to the fact that tide-dominated deposits are very heterogeneous, process based modeling of these deposits could support high resolution correlation and delineation of reservoir flow units.
The purpose of this research was to study the process based sedimentation model for tidal influenced deltaic deposits when considering variable sediment load and river discharges. The objective was to model the sediment storage in the tide dominated delta and to study morphological changes in the delta at annual conditions and due to variable river discharge and sediment load.
The research method involves process based modeling with the Delft3D modeling software. Here several scenarios have been executed while varying parameters, which control river and tidal influences. The simulation results were used to study the sedimentation pattern development and morphological changes within a tide dominated delta. This research uses the Fly delta, in Papua New Guinea as case study area, with the focus on the area between the apex and the mouth of the delta.
Depth average velocity and yearly sedimentation rates were used as criteria to select the most suitable scaled sediment load scenario for the simulations.
Bed level study shows that the sedimentation rates varies within the delta, with highest sedimentation in the mid-delta area, and lowest at the channel mouth.
The morphological development shows that changes around a specific island has resulted scouring of the channel bottom at tidal conditions and deposition of coarse grained sediments along the sides of the channel. Further it was distinguished that the highest sand accumulation has been occurred at the upstream part of the island and the highest clay sedimentation at the downstream part of the island. This characterize an important difference between more fluvial-dominated deltas and tide-dominated deltas
The main problem during modeling was related to the scaling of the model according to the Fly delta geometry and flow conditions. This was caused by the Delft3D model limitations, for size and resolution of the model grid.
Overall we conclude that longer-term simulations create the possibility to study the morphological development within the delta in more detail.