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Oder Water And Nutrient Discharge And Salinity Distribution In The Pomeranian
Bight During The Oder Flood
V. Mohrholz 1 , H.U. Lass 1 , W. Matthaus 1 & M. Pastuszak 2 .
1 Institut für Ostseeforschung
Scestrasse 15
18119 Rostock-Warnemünde
2 Sea Fisheries Institute
ul. Kollataja 1
81 332 Gdynia
Abstract
During July 1997 two strong rainfall events occured in the upper Oder catchment area. From
04. to 07. Juli and from 17. to 21. Juli up to 500 % of the long time mean precipitation was
observed.The extremly high precipitations caused a flood in the Oder area with river water
transports never observed before. The impact of high river discharge on the Oderhaff and Pomeranian
Bight was investigated by shipbome measurements and numerical modeling.
During the flood the Oder discharge was estimated by sea level differences between the Oderhaff
and the Pomeranian Bight employing a barotropic box model. The characteristically puls
like water exchange between the lagoon and the Baltic was into steady outflow during the
flood.
In contrast to the western part the eastern part of the lagoon was completly washed out in first
few days of the flood. Transport of nutrients from the lagoon into the Pomeranian Bight was
calculated and was comperable with spring situations.
Due to the westerly wind conditions at the end of July the lagoon water plume was transported
along the polish coast into the Bornholm Sea. In August the wind changed to easterly directions
and the lagoon water plume was distributed along the Usedom and Rügen coast towards
the Arkona Basin.
First results of the Oder flood simulation by a coupled circulation-biochemical model show that
the organic load of the flood was sedimented mainly in the western part of the Pomeranian
Bight and in a small strip off the polish coast.
