|Analysis of multibeam echo sounding data on bed forms near the Walsoorden sandbar, a first phase in the subtidal habitat classification for the Western Scheldt|
Plancke, Y.M.G.; Vos, G.; Ysebaert, T.J. (2009). Analysis of multibeam echo sounding data on bed forms near the Walsoorden sandbar, a first phase in the subtidal habitat classification for the Western Scheldt, in: [s.d.] 6th Symposium on River, Coastal and Estuarine Morphodynamics, RCEM 2009, 21-25 September, 2009, Santa Fe City, Argentina.
In: (S.d.). 6th Symposium on River, Coastal and Estuarine Morphodynamics, RCEM 2009, 21-25 September, 2009, Santa Fe City, Argentina. [S.n.]: [s.l.]. , more
Bed forms; Disposal; Dredged materials; Echo sounding; Ecology; Habitat; River morphology; ANE, Netherlands, Westerschelde, Plaat van Walsoorden [Marine Regions]; Brackish water
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- Numerical research on the reshaped tip of the Walsoorden sandbar, more
Within the scope of the long term vision of the Scheldt estuary, a new disposal strategy was proposed by an international expert team appointed by the Antwerp Port Authority. After the feasibility study, two in situ disposal tests were carried out near the Walsoorden sandbar in the Western Scheldt. Both tests were thoroughly monitored, both morphological as ecological.A project was defined to investigate the impact of bed forms, hydrodynamics and sediment properties on the ecological value in the shallow water area near the Walsoorden sandbar. The goal of this project is to make a habitat classification for the Western Scheldt based on its ecological value, allowing to define which areas are best suited for disposal of dredged material and which areas should be avoided.In the first phase the multibeam echo sounding data were analysed in respect to the occurrence of bed forms. The analysis was executed in four steps, resulting in a limited number of classes.A large spatial variation was found for the analysed parameters. The average length of bed forms ranged from 5 m to 50 m, the average height from 0,10 m to almost 2,00 m, while, considering the asymmetry due to tidal currents, most of the sections were flood dominated.In a second phase the seasonal variation of the bed forms was investigated, analysing the multibeam echo sounding data of the summer condition (September 2007).In the third phase of the project the relation between the occurrence of bed forms and hydrodynamic parameters (using a validated numerical hydrodynamic model) was investigated. With the addition of sediment properties (grain sizes) a classification based on the physical parameters is made. These “physiotopes” were finally validated with the ecological data (i.e. Macrobenthos and fish), trying to make a classification in “ecotopes”.