Backwater or brackish water-influenced Baltic Sea inflow
The backwater or brackish water-influenced Baltic Sea inflow (type 23) is a flowing water type (LAWA type) of the north German lowlands defined by the Federal / State Working Group on Water .
Water structure
The most important characteristic for the classification of a stretch of water in this type is the backwater of the water due to the scarcely existing gradient to the Baltic Sea as well as a regular reversal of the flow direction due to high water levels in the Baltic Sea. Therefore, brackish water flows into the river temporarily . The mineral beds of the rivers are often below today's sea level in the Baltic Sea and are filled with organic material such as peat or mud.
Flora and fauna
The creatures of these river sections have to be adapted to the temporary influence of brackish water. They differ greatly depending on the frequency and degree of salt exposure. Mosquitoes , mussels and various crustaceans as well as perch , eel and flounder occur among others . Migratory species such as sea trout are represented seasonally .
The plants that occur also have to cope with the temporarily increased salt content. Common species are the common pondweed and the marsh pond thread . In the bank zones there are often extensive reed beds and sedges . Plankton can also be present and then consists mainly of diatoms and green algae .
Examples
- Peene from the Kummerower See
- Lower Recknitz
- Warnow from Bützow (inflow of water from the Baltic Sea artificially prevented by Mühlendamm in Rostock )
swell
- Profile of the river type 23 on wasserblick.net (PDF file; 169 kB)