PP Morphology and water movement processes

PP Morphology and water movement processes
Context PP Ontpoldering Perkpolder
Decompositie type IOR

Activity



The largest morphological change in the new Perkpolder area occurred during the first 1-2 months following the opening on June 25, 2015. The inlet eroded and this sediment dropt into the deep pond just inside Perkpolder area. Thereafter, the inlet was more or less in equilibrium and further sedimentation of Perkpolder was controlled be net sediment influx from outside, which is probably mainly muddy. Every tide about 1.7 million m3 water flows in and out. With a typical mud concentration of 50 mg/l, we can estimate the net sediment influx to be 60 x 103 tons/year. Assuming a dry bed density of 600 kg/m3, this implies that about 80% of the incoming sediment was trapped inside Perkpolder area between 30 July 2015 (T1) and April 2016 (T4). A 2DH Delft3D model was set up to simulate hydrodynamics, sediment dynamics and morphodynamics due to tidal forcing. The model reproduces the measured velocities and the inlet reasonably well, and was further calibrated on the estimated net sediment influx and the morphological changes between June 2015 and April 2016. Thereafter, the model was used to better understand how the new intertidal area develops. It was shown than a 50% volume reduction of creeks and pond hardly affects the sedimentation, which is also the case for a 50% change in inlet width. The latter does influence the more local sedimentation and erosion patterns, i.e. close to the inlet (Boersema et al. 2016, page 23-26). 




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Onderdeel van PP Monitoring the development of the low dynamic intertidal area at Perkpolder
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Bestaat uit Type
PP Changes in height Activity
PP Discharge inlet Condition
PP Morphological development Activity
PP Sedimentation balance Outcome

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HZ University of Applied Sciences
Rijkswaterstaat, Ministerie van Infrastructuur en Milieu
Projectbureau Zeeweringen
Waterschap Scheldestromen
Provincie Zeeland
Deltares