Rivers

Our waters are used in a variety of ways, these influence their status. The results of the monitoring of the EC Water Framework Directive show it needs forceful measures in the whole catchment and at the rivers to meet the good status.

Table of Contents

 

Hydrography (facts and figures)

Rivers are subdivided into six river systems as well as the coastal areas of the North and Baltic Seas. The rivers are the  Rhine, Ems, Weser and Elbe, which flow into the North Sea, the Odra, which flows to the Baltic Sea, and the Danube, whose tributaries empty into the Black Sea. The river systems are interconnected by a number of canals.

Future management of waters in accordance with the new European Water Framework Directive will classify the fluvial and coastal areas of Germany into the following river basin districts : Danube, Maas, Rhine, Ems, Weser, Elbe, Odra, Eider, Schlei/ Trave, and Warnow/ Peene.

 

Nutrients in watercourses

Evaluation of nutrient data is based on a chemical water quality classification developed by Working Group of the Federal States on Water Issues (LAWA). In 2011, the monitoring sites within the LAWA network of monitoring sites for watercourses registered quality class II and better: at 33 % of 255 monitoring sites for total phosphorus; at 15 % of 257 monitoring sites for nitrate nitrogen; at 82 % of 257 monitoring sites for ammonia nitrogen. The greatest emissions for phosphorus owes to eroded soil material from land used for agricultural purposes, and for nitrogen, from inputs into groundwater from the agricultural sector. These two areas also have the greatest potential to make reductions.

Long-term statistical series (1955-2011) from the Bimmen/Lobith monitoring station on the Rhine (German-Dutch border) exist on contents of orthophosphate-phosphorus, ammonia nitrogen and nitrate nitrogen. Annual mean values for 1955-1975 show that average concentrations of orthophosphate initially increased sharply from about 0.05 to 0.4 mg P/l, and to some 2.5 mg N/l for ammonia. Average concentrations nitrate rose from roughly 2 to 4 mg N/l between 1955 and 1985. Since mid-1970s average concentrations of ammonia nitrogen decreased and are now at 0.05 mg N/l, average concentrations of orthophosphate phosphorus decreased since mid-1980s and are now at 0.06 mg P/l, the average concentrations of nitrate nitrogen are since 2000 in the middle at 2.6 mg N/l.

Monitoring data on the Danube, Rhine, Weser, Elbe and Oder demonstrates a decline in concentrations of phosphorus and ammonia, although a decline in concentrations of the Elbe and Oder begins in 1991 only. A slight downturn in nitrate concentrations has been registered in recent years. A comparison of the mean of the 90-percentile (LAWA monitoring sites) for the periods 1991-2000 and 2001-2010 attests to a slight drop in nitrate, a somewhat higher decline in total phosphorus, and a steep drop in ammonia (Change in concentration of nutrients).

More information of the change of concentration of nitrate shows the report of the nitrate directive .

 

Heavy metals and metalloids in watercourses

The assessment of metals is based on the EU-wide Environmental quality standards (chemical status) for lead (dissolved: 7,2 µg/l), cadmium (dissolved: 0,08 µg/l (class 1 of water hardness)), nickel (dissolved: 20 µg/l) and mercury (dissolved: 0,05 µg/l) and on the national EQS to determine ecological status for arsenic (suspended solids: 40 mg/kg), chromium (suspended solids: 640 mg/kg), copper (suspended solids: 160 mg/kg), zinc (suspended solids: 800 mg/kg), selenium (dissolved: 3 µg/l), (silver(dissolved: 0,02 µg/l) and thallium(dissolved: 0,2 µg/l).

In 2009-2011, the EQS for suspended solids were exceeded in the case of arsenic, chromium, copper and zinc. The EQS for dissolved concentration levels were exceeded in the case of cadmium, selenium and silver.

Graphs show the development of concentration in suspended particles of lead, cadmium, chromium, copper, nickel, mercury, and zinc along Danube, Rhine, Weser, Oder and Elbe in between 1990-2011.

Diffuse sources are responsible for a high share of total inputs of heavy metals.