WATER QUALITY IN WATERCOURSES

Last update
14.09.2012

Key question

Is the quality of water in watercourses, which affects both aquatic organisms and the use of water, improving?

Key message

Since 1993 (or 2000 respectively), average annual concentrations decreased for all of the monitored water quality indicators except chlorophyll (BOD5, CODCr, N-NO3-, Ptotal, cadmium, adsorbable organically bound halogens – AOX and thermotolerant coliform bacteria – FC) in the Elbe and Odra river basins. Most parts of important watercourses are classified in the major indicators as water quality class I to III (according to CSN 75 7221).

In the last decade, the development of water quality in the Elbe and Odra basins has not shown so significant changes as it did in 1990s. There is an increase of the average concentrations of monitored indicators (BOD5, CODCr, Ptotal, chlorophyll) in some places interannually. At present, environmental quality standards (EQS) are exceeded in 39% of the monitored profiles for AOX and in 20% of the profiles for BOD5, CODCr, and Ptotal. Nitrate nitrogen is an exception as it did not comply with the EQS in only 3% of the profiles observed.

Overall assessment	Change since 1990	Change since 2000	Last year-to-year change

The basic requirements for improving water quality are based on the Directive 2000/60/EC of the European Parliament and of the Council of 23rd October 2000 establishing a framework for the Community action in the field of water policy. The Water Framework Directive focuses on the comprehensive protection of the quality and quantity of water, prevention of deterioration and on achieving at least the so-called “good status” of water and related ecosystems, as a basis for sustainable use of water and mitigation of the consequences of floods and drought. The Council Directive 91/676/EEC of 19th December 1991 concerning the protection of waters against pollution caused by nitrates from agricultural sources („the Nitrates Directive“) is very important with regard to diffuse pollution. In order to achieve these objectives, surface water and groundwater administration and the determination of emission and pollution limit values and qualitative objectives are required. Specific objectives and programmes of measures to improve water quality are laid down by the River Basins Management Plans. Transposition of the above-mentioned Water Framework Directive into the Czech legal system is ensured mainly by the Act No. 254/2001 Coll. (The Water Act) which went through an extensive amendment process in 2010. Notable major changes include a new approach to water planning (the 8 river-basin districts that are currently used will be replaced with plans for 10 sub-districts) and support for revitalizing watercourses.

An important instrument for water protection from priority hazardous substances is the Directive 2008/105/EC of the European Parliament and of the Council of 16th December 2008 on environmental quality standards in the field of water policy. The standards have to be achieved by the end of 2015. Indicators reflecting the state of water in a watercourse, EQS and requirements for the use of water are provided for in the Government Regulation No. 23/2011 Coll., amending the Government Regulation No. 61/2003 Coll. on indicators and values of permissible pollution of surface water and waste water, on the requirements for permits of waste water discharge into surface water and sewerage systems and on sensitive areas, as amended by the Government Regulation No. 229/2007 Coll. One of the axes of the National Strategic Plan of Rural Development in the Czech Republic in 2007–2013 also deals with protection of the quality of surface water and groundwater sources through measures related to agricultural activities.

Chart 2: The concentrations of the pollution indicators of watercourses, the Czech Republic [index 1993=100]
Source: The Czech Hydrometeorological Institute

Chart 3: Average nitrate concentrations in the rivers, the Czech Republic [mg/l]
Source: The Czech Hydrometeorological Institute

Chart 4: Average total phosphorus concentrations in the rivers, the Czech Republic [mg/l]
Source: The Czech Hydrometeorological Institute

Chart 5: The concentrations of the pollution indicators of watercourses, the Czech Republic [index 1998=100]
Zdroj: The Czech Hydrometeorological Institute

Figure 1: A comparison of water quality in the watercourses, the Czech Republic, 1991–1992 (upper image) and 2009–2010 (lower image)
Source: The T.G. Masaryk Water Research Institute

Table 1: Categorization of the profiles of Czech surface waters and groundwater sites on the basis of the time required for overall reduction of the nitrate concentration below a level of 50 mg/l, 2007
Source: Czech Hydrometeorological Institute, Agriculture Water Management Administration (Report of the Czech Republic according to Council Directive 91/676/EEC, 2008)

Chart 6: The average levels of concentrations of pollution indicators in watercourses, a comparison between the Czech Republic and Eastern Europe [mg/l]
Source: Czech Hydrometeorological Institute, EEA

Indicator assessment – text part

Satisfactory water quality in the Czech Republic´s rivers is apparent from of a comparison of maps of water quality, which are drawn up in accordance with the summarising assessment of the basic indicators measured continuously according to CSN 75 7221 since the period 1991-1992. However, it is still possible to record water quality class V in some short sections. Since 2000, there has been primarily a reduction of the sections included in quality class V and an increase of the sections with unpolluted and slightly polluted water. In 2011, total of 6,396 km (11.8%) of watercourses managed by Povodí, State Enterprise were included into the quality classes IV or V. In 2010–2011, according to the maps comparison, the quality of water worsened rather than improved compared to the period 2009–2010 (in all cases, however, by one class only). The deterioration has occurred for example in the rivers Úhlava, Lužnice (below the town of Veselí nad Lužnicí) or Kyjovka. However, most of the watercourses´ sections assessed are classified within water quality classes I through III. Water quality has improved e.g. in the rivers Bílina, Jizera, Malše, Jičínka, Lučina and Lužická Nisa (by two classes). The long-term poor quality of watercourses in southern Moravia (Trkmanka, Kyjovka, Litava) and of some watercourses in the Elbe river basin (Vlkava, Mrlina, Pšovka) is caused by the fact that they contain less water but relatively higher pollution is discharged into them. Therefore, their dilution capacity is decreased, self-purification capacity is lowered by a significant watercourses regulation and there are many places in their catchment areas that are affected by soil erosion (run-off from agricultural land).

Within the indicator, water quality trends are only evaluated for selected profiles within the Eurowaternet network using the average annual concentrations of eight selected basic indicators of pollution (only data from the basins of the Elbe and Odra rivers were available for the evaluation). Organic pollution is expressed using the BOD5 and CODCr indicators, nutrients are represented by N-NO3- and Ptotal, and it was assessed for the basins of the Elbe and Odra rivers. Chlorophyll was selected as a biological indicator and cadmium as a heavy metal indicator, adsorbable organohalogens (AOX) represent the general indicators and thermotolerant (faecal) coliform bacteria (FC) belong to the microbiological indicators. The last four parameters were monitored only in a part of the profiles in the Elbe river basin.

Development of the concentrations of the indicators monitored over the last 20 years largely reflects the development of the quantity of pollution discharged from point sources, access to waste water treatment in the Czech Republic (i.e. the proportion of treated waste water, waste water treatment stages) as well as the socio-economic and political development (restructuring of the industry, growing living standard, joining the EU). Climatic conditions of the given year (amount of water, temperature) play an important role in year-to-year fluctuations, especially in the recent years, when the quantity of pollution discharged does not change significantly. On the regional basis, concentration of industrial activities, existence of old environmental contamination or intensity of agricultural activities are of great importance.

In terms of reducing the amount of pollution discharged from point sources, relatively good progress has been made both in reducing the concentrations and in preventing exceedance of the environmental quality standards for organic pollutants and total phosphorus in the Labe and Odra river basins. In long terms, the BOD5 values have been reduced to 61.1% of the 1993 value and those of CODCr to 68.6%. The average concentrations of organic pollution in the Elbe and Odra basins in 2011 were as follows: BOD5 2.8 mg.l-1, CODCr 19.9 mg.l-1, which represents a slight year-to-year increase.

In long perspective, the concentration of total phosphorus was reduced most, namely to 0.11 mg.l-1 in 2011, i. e. to 43.7% of the 1993 value. The reason consists in the fact that a big part of it comes from point source pollution, which is better removed and the volume of which is generally reduced. The decline in phosphorus inputs was further supported by restrictions concerning the use of phosphates in laundry detergents beginning from 2006; in the last three years, application of phosphate fertilizers in agriculture has also been declining. Nonetheless, phosphorus remains being the major factor to cause eutrophication. Further significant reduction of phosphorus concentration in surface water is restricted by the relatively high limits for waste water discharge and by the fact that only bigger WWTPs are obliged to reduce phosphorus. A part of phosphorus comes from diffuse pollution sources and this type of pollution is very difficult to remove.

The concentration of nitrate nitrogen, as opposed to phosphorus, decreased only to 76.0% of the 1993 value and in recent years, it has a rather fluctuating trend. The concentration of nitrogen dropped from 3.0 mg.l-1 to 2.7 mg.l-1 on a year-to-year basis. Along with atmospheric deposition and sewage, nitrogen fertilizers are another significant source of nitrogen and, although their consumption is significantly lower in comparison with the period before 1990, there is almost a continuous growth in their consumption in the past twenty years. Along with a slight decrease of inorganic nitrogen discharged from point sources, the above-mentioned facts are the reason why the decline in watercourses pollution with this element is not as significant as it is e.g. for phosphorus. Since diffuse pollution generally covers most of the nitrate-nitrogen pollution, the interannual increase of its concentration in watercourses is partially bound to more watery years because runoff from land is higher. The long-term trend in the reduction of nitrate pollution is related, inter alia, also with the reduction of nitrogen emissions from livestock farming (pigs and poultry breeding attenuation).

After 2000, a significant positive trend was recorded in the Elbe river basin for cadmium (0.06 µg.l-1 in 2011), which belongs to hazardous substances and whose EQS (0.3 μg.l-1) has not been exceeded since 2003. While the average AOX concentrations in the Elbe river basin has basically stagnated since 2000 (24.1 mg.l-1 in 2011), the proportion of profiles which do not comply with the respective EQS (25 µg.l-1) is the highest one (38.9%) of all the indicators monitored. The reason consists in the fact that this pollution, originating in e.g. paper and chemical industries, municipal waste water but partially also in natural resources, is difficult to degrade. Concentrations of thermotolerant coliform bacteria (FC) primarily reflect the level of faecal pollution. Since 2000, FC concentrations have varied considerably in the profiles monitored; climatic conditions in the respective years (temperature, precipitation) have had their influence on the concentrations. During the last two years, they were reduced to 25.3 CFU.ml-1.

The concentration of chlorophyll characterizes the level of primary production in aquatic environment (or eutrophication) and the influence of climatic conditions (precipitation, temperature) is of particular importance in this context. It depends mainly on average temperatures and the course rainfall during the year (or during the growing season). For example, in 2011, high temperatures came very early and despite the below-average temperatures in June and July, the primary production increased which was also supported by the enhanced nutrient supply because of higher summer precipitation. For these reasons, the average concentration in the Elbe river basin is rather fluctuating and generally, it is not reduced. The 2011 value amounted to 23.1 µg.l-1.

On the basis of a comparison of average concentrations of nitrate, phosphorus and BOD5 till 2008 measured in Eurowaternet stations in the Czech Republic and in the states of Eastern Europe (among which the Czech Republic is counted), it is possible to state that the average concentrations of the above indicators are slightly higher in the Czech Republic. However, average concentrations are also influenced by the specific conditions in the watercourses, especially by their flow rate. The declining trend is comparable. Generally, the best quality of waters is found in Northern Europe. Concentrations in the Czech Republic are similar to average concentrations in West European countries.

Data sources

Czech Hydrometeorological Institute
T. G. Masaryk Water Research Institute (a public research institution)
Ministry of Agriculture
European Environment Agency (EEA)

Links to additional information

The European Environment Agency, international indicators (CSI 019, CSI 020)
Report on the state of Water Management in the Czech Republic
IS ARROW – The Czech Hydrometeorological Institute