Freshwater - State and impacts (Germany)
Material pollution of watercourses
Monitoring carried out by the German Working Group on Water Issues (LAWA, Länderarbeitsgemeinschaft Wasser) show that water pollution by substances such as organic environmental chemicals, heavy metals and nutrients has fallen by varying degrees in recent decades.
Adsorbable organically-bound halogens (AOX) and total nitrogen are seen as representative of the chemical pollution of Germany’s watercourses. These summary indicators are used mainly to record industrial pollution from point sources (AOX) and diffuse pollution from agriculture (total nitrogen). Total nitrogen is also a significant indicator of pollution of the oceans via rivers. However, it should be made clear that while both groups of substances are important for characterising water quality, they by no means cover all aspects of the state of the water. They also do not reflect the considerable negative impact on ecological water quality caused by man-made changes to the structure of water-bodies.
Between 1996 and 2007 there was a slight improvement in water quality as regards AOX, though with considerable fluctuations: the proportion of monitored watercourses meeting the Class II chemical water quality target of 25 µg/l rose from an average of 39 % for 1996-1998 to an average of 47 % for 2005-2007.
For total nitrogen the pollution levels were higher: an average of only 13 % of monitoring stations met the Class II water quality requirement for total nitrogen of 3 mg/l between 1996 and 2007. Since 1996 the annual achievement has ranged from 11 % of monitoring stations (1999, 2004, and 2006) to 16 % (1997), while the most recent figure (2007) was 14 %. This shows that in future water pollution controls will be particularly needed in areas with diffuse pollutant discharges, particularly from agriculture. Intensive fertilisation and excessive concentrations of livestock produce an average annual nitrogen surplus of some 105 kg per hectare. The distribution of water quality classes for total nitrogen at the same 133 monitoring stations for 1996-2007 has seen a slight reduction in monitoring stations with high levels of pollution (Class III and worse), thanks mainly to improvements in wastewater treatment by municipal treatment plants and industry.
Structural changes to watercourses
Only 21 % of Germany’s rivers and streams – most of them in less populated areas – are still in a near-natural condition, meaning that they have undergone little or only moderate levels of man-made change. A total of 33 000 km of watercourses were surveyed and classified into seven grades – from Class I = unchanged to Class 7 = completely changed – according to the system used by the LAWA. The major rivers have generally been fitted with defences and locks for shipping and hydroelectric power generation. Large areas of their floodplains have also been cut off from the rivers and narrowed by flood embankments. This explains their considerable structural problems and why the vast majority were classified as substantially to completely changed. The Ems, Danube, Oder and Weser are graded as Class 6 or 7 for 50 % of their length while the intensive use of the Rhine and its surrounding area means that as much as 80 % of its length from Lake Constance to the Netherlands also falls into these classes.
In contrast, between the Central Uplands (Mittelgebirge) and the Geesthacht weir, the Elbe has sections that are clearly still structure-rich (Classes 3 and 4). Only the Tidal Elbe and the more densely populated stretches along the Upper Elbe are structure-poor and thus graded in Classes 6 and 7. This underlines the fact that near-natural sections of the major rivers, such as the free-flowing section of the Danube below the confluence with the Isar and the middle section of the Elbe, are rare and worth protecting.
Most of the smaller rivers and streams in the Central Uplands, the hill country and the North German Plain have also been altered for hydroelectric power generation, to protect areas of settlement and transport routes or for agricultural use including land improvement. They are regularly maintained, which tends to prevent morpho-dynamic processes, in other words natural development. These water bodies are mostly classified as distinctly changed – Class 4 – to completely changed – Class 7.
Nitrate in groundwater
The Länder have set up theirs own individual monitoring networks to monitor groundwater quality. Nitrate levels are regularly tested at almost all the sites in the networks. For their regular reports to the European Environment Agency (EEA), the Länder chose representative sites and combined them to form what is known as the EEA groundwater monitoring network. The following chart gives an overview of nitrate pollution in the groundwater in 2007 based on the 683 sampling sites in this network where the groundwater nitrate content was determined.
Nitrate pollution depends to a large extent on land use in the catchment area of a station. Regional hydro-geological conditions such as depth to the water table and flow speed, as well as the underground hydro-chemical conditions, play an important role.
Concentrations are < 25 mg/l at 67.3 % of the stations. At 14.1%, however, the 50 mg/l limit for nitrate laid down in the EU- Drinking Water Directive is exceeded, sometimes considerably. In many cases this results from intensive agriculture in the catchment area in question. Under the terms of the EU’s Water Framework Directive the groundwater here is of poor quality and measures must be taken to improve it.
Quality of natural bathing water
Bathing water quality in Germany is monitored under Länder-level regulations that apply the values for excellent, good and sufficient bathing water quality as laid down in the EU Directive 2006/7/EC. This Directive replaces the 1975 Directive 76/160/ EEC. Since the 2008 bathing season, bathing waters are monitored under the new Directive. Classification requires data from four bathing seasons, and will only be available after the 2011 bathing season. Transitional rules apply until then.
In 2008 a total of 2 263 bathing waters in Germany were monitored under the new Directive, 373 of which were on the coast.
From 1992 to 2001 there was a steady reduction in non-compliance with the guide and imperative values. Since 2001 bathing water quality has been consistently high – on average 94 % of freshwater bathing places met the microbiological requirements, and 78 % the stricter guide values for good water quality. For coastal bathing waters the figures were 98 % and 87 % respectively.
With the new monitoring parameters in the 2008 bathing season an improvement in the quality of the freshwater bathing waters was observed. Considerably fewer of the coastal waters, however, were classified as good. This was partly because of a new classification for the estuary areas of the major coastal rivers such as the Elbe which usually do not have very good water quality. In line with the Water Framework Directive these have been classified as coastal waters instead of freshwater since the 2008 bathing season.
Only around 1 % of the 2 263 bathing waters had poor water quality in the 2008 bathing season.
For references, please go to http://www.eea.europa.eu/soer/countries/de/freshwater-state-and-impacts-germany or scan the QR code.
PDF generated on 08 Dec 2016, 03:51 AM