Evolution of mud in the Scheldt estuary
Wartel, S.; van Eck, G.Th.M.; van Maldegem, D.C. (2002). Evolution of mud in the Scheldt estuary, in: ECSA Local Meeting: ecological structures and functions in the Scheldt Estuary: from past to future, Antwerp, Belgium October 7-10, 2002: abstract book. pp. 17
In: (2002). ECSA Local Meeting: Ecological structures and functions in the Scheldt Estuary: from past to future, Antwerp, Belgium October 7-10, 2002: abstract book. University of Antwerp: Antwerp. 73 + 1 cd-rom pp., more
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| Keywords |
Aquatic organisms > Estuarine organisms
Biological phenomena > Evolution
Food
Pollution
Sedimentary structures > Bed forms > Banks (topography) > Mud banks
Sediments
Topographic features > Landforms > Coastal landforms > Tidal flats
Water bodies > Inland waters > Wetlands > Marshes > Salt marshes
Belgium, Schelde R. [Marine Regions]
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| Authors | | Top |
- Wartel, S., more
- van Eck, G.Th.M., more
- van Maldegem, D.C., more
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| Abstract |
For a sustained management of a man-made estuary like the Scheldt estuary knowledge of the behaviour of fine sediments and the mud balance is necessary because fine sediments determine habitats, provide food for organisms, transport contaminants, determine the pollution status of the bottom sediments and influence the access from the shipping channel to the harbour (docks). The determination and the monitoring of the mud balance of an estuary is however difficult to accomplish especially when anthropogenic influences are profound like in the Scheldt estuary. For some elements of the mud balance of the Scheldt estuary quite a lot knowledge has been obtained the last decade. The following elements of the mud balance will be discussed. 1. The occurrence of mud in the estuary. Mud occurs on the tidal flats near the salt marsh (mud flats), in harbours with a free opening to the river, and also, in the high turbidity zone of the Beneden ZeeScheldt (middle estuary) in the river channel. The sediments in this area are sandy muds and differ from the mud in the access channels mainly by the amount of sand. 2. The supply of fluvial mud to the estuary. This supply has been estimated with some degree of precision for the last 10 years. It decreased from 1992 till 1996 from 250 ktons to 95 ktons and from then on increased again to 350 ktons. 3. The evolution of the quantities (stock) of mud in the bottom sediments in the Beneden ZeeScheldt. With bottom maps, compiled by several authors between 1963 and 1999, the change in mud volume in the bottom sediments in the Beneden ZeeScheldt can be evaluated. Between 1964 and 1986 the mud volume increased with 2% per year. Between 1986-1999 a further increase of 0.7% per year, is observed. Most of this “new and polluted” mud has sedimented in the access channels to the sluices of Zandvliet, Berendrecht and Kallo and is removed from 1993 onwards, especially from the access to the Kallo sluice by a large scale operation. The 2.8 million tons of sediments removed are dumpted in a harbour dock on the left bank. From the data it can be concluded that during the post-1986 period the mud supply to the river bed has been reduced by approximately 50% compared to the previous period. |
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