Do something for our planet, print this page only if needed. Even a small action can make an enormous difference when millions of people do it!
3.1 Project MW1 - Water Resources Quality and Quantity. General Approach to Assessment.
This project has the overall objective of describing the detailed monitoring requirements prescribed by existing and proposed EU legislation arising from the European Commission and from International agreements bearing in mind that the EEA Member States comprise those of the EU15, Norway and Iceland. Possible approaches to coordinate and improve the monitoring are identified.
3.1.1 Monitoring requirements
Four types of directive have been employed by the EU to control the pollution of water:
With the exception of the product directives, most require the implementation of monitoring, either routine programmes or preliminary investigations. The extent to which monitoring requirements overlap depends on commonalities between the national implementation of directive requirements and the monitoring undertaken for this purpose will therefore vary from country to country.
The requirements made in the directives have been designed largely independently from each other. The Commission has, however, taken some initiatives to harmonise monitoring and reporting requirements in the Exchange of Information Decision (77/795/EEC as amended by Decision 86/574/EEC) and to harmonise reporting on the implementation of certain directives via questionnaires as specified in Council Decision (92/446/EEC) and laid down in the Reporting Directive (91/692/EEC).
In total, four directives and one proposed directive make requirements for groundwater monitoring (the requirements made in the Dangerous Substances Directive (76/464/EEC) have been superseded by the Groundwater Directive (80/68/EEC)) and there is no overlap in the current monitoring requirements. With regard to surface waters, all monitoring requirements made in EU legislation which apply to rivers, also apply to lakes and reservoirs. Most directives which apply to freshwaters also apply to salt waters. The Shellfish Directive (79/923/EEC) is the only directive which applies to estuaries and coastal waters but not freshwaters.
Of the 15 directives that require monitoring of fresh surface waters, all require water column monitoring. The Dangerous Substances Directives and the Titanium Dioxide Directive (82/883/EEC) also require monitoring of sediment and biota. The Exchange of Information Decisions make the only requirements for flow measurements. There are eight international agreements which also require monitoring of water quantity - flows and levels.
Barriers to the harmonisation of monitoring can be introduced at the sampling, analysis, and reporting stages, and can arise either because requirements differ (i.e. conflicts) or because requirements are not clearly specified (i.e. weaknesses).
3.1.2 Sampling location
The most specific requirements in terms of named water bodies and measuring stations are in the Exchange of Information Decisions. These water bodies are nationally significant rivers and lakes and, as such, are quite likely to be sampled for other national and international obligations (e.g. Rhine and Elbe Conventions). Generally, directives require monitoring in waters designated for specified uses or affected by specified discharges. Thus the scope for overlap in terms of sampling locations is dependent on the degree to which areas where designated use and the presence of specified discharges overlap, which is probably a limited circumstance in many states. Many of the directives allow the competent authority of each Member State to make decisions on such aspects as the exact sampling point, the distance from this point to the nearest point where pollutants are discharged and the depth at which the samples are to be taken but the same sites and depths should be used in all surveys, in relation to physical and temporal conditions.
As the choice of sampling location in some directives is related to areas designated by the Member States rather than by the European Commission, it is unlikely that a comparison of quality across Europe of these designated waters will give a complete picture. The degree of comparability will depend on the interpretation of the designation rules and national differences of how these are implemented. Therefore, the degree of coverage that water quality data encompasses within each country will be determined by national designations and the prevalence of the industries that are required to be regulated.
For international agreements sample location will generally be related to the purpose of the agreement, often being at designated or fixed sites. Other agreements are less specific about sampling location perhaps being determined by the needs of the signatories or monitoring programme objectives.
3.1.3 Sampling frequency and period
The sampling frequency specified in directives and in international agreements is very variable. For some directives, once the fate and behaviour of an effluent is known and the effects have been established, and as long as there is no deterioration, Member States may use a lower sampling frequency than specified in the directive. Sampling period is not usually specified or, if it is, the interpretation of its definition can give rise to differences between countries (for example: bathing season). These imprecise requirements can give rise to different interpretations.
It is not apparent from most of the published directives whether there have been any, or if so, what, statistical considerations when defining the required sampling frequencies or numbers. These aspects have a significant effect on the statistical precision and confidence of the monitoring data produced. The required frequency should be derived with reference to the quantified risks that some waters will be misclassified (against compliance criteria). Furthermore for fairness of comparison the frequency of sampling should be uniform throughout Europe.
3.1.4 Analysis
Sources of error in the overall assessment of a determinand in a water body would include sampling and analytical errors. The analytical requirements made in directives and in international agreements are generally very basic. Most directives stipulate analytical requirements in terms of performance criteria (i.e. limits of detection, precision and accuracy) and/or by the method. The degree of definition, however, varies greatly from directive to directive. Many directives make very broad requirements to use appropriate methods for pre-treatment and analysis. The performance criteria are the key requirements with regard to analysis. Despite this, several directives, (the Titanium Dioxide Directive and all the use-related directives except the Surface Water through the Sampling Analysis Directive) fail to establish performance requirements for analysis. In addition, the laboratories concerned with applying the directives should be free to use appropriate methods providing they satisfy performance criteria. By comparison, analytical requirements in international agreements are rarely defined in terms of performance criteria.
Probably the most significant omission in requirements for analytical technologies is a requirement for analytical quality control (AQC). Increasingly AQC is being recognised as essential for data from monitoring programmes to be reliable and comparable. Microbiological methods should be standardised for efficiency of recovery and performance (accuracy, specificity, precision) and, for securing harmonisation of results between Member States, single reference procedures should be agreed for each determinand.
3.1.5 Compliance Assessment
Another important aspect of directives, particularly when a comparison of quality across Member States is expressed as a comparison of compliance against limits and standard values (e.g. as in the Bathing Waters Directive), is how the compliance requirements in the directives are expressed, calculated and interpreted. Differences in interpretation of these requirements is another significant barrier to harmonisation of monitoring and the derivation of comparable data across Europe.
3.1.6 Interpretations
As well as the aspects described above, another significant barrier to obtaining valid and quantitative temporal and spatial comparisons of water quality across Europe may arise from differences in how directives are implemented and interpreted at the Member State level. This issue has not been addressed in this project, but it is recommended that such an assessment is undertaken.
3.1.7 Recommendations arising from MW1
A number of deficiencies have been described in the preceding sections which are barriers to obtaining valid and comparative data on a pan-European basis. The primary recommendation arising therefore from this survey would be to focus attention on elimination of these barriers through a systematic approach to removing conflicts between the requirements of the different directives and by introducing clearer, unambiguous, specifications within the directives themselves.
However, we are aware that there are proposed European policy initiatives and possible new directives that will potentially change the needs for national and Europe-wide monitoring. The changes will be aimed at obtaining greater coherence and consistency, the interaction between the quality standards approach and the emission limit values approach, and the links between quality and quantity leading to a greater emphasis on sustainability. The possibility arises of a Framework Water Resource Directive to address these issues through four main elements:
With the baseline reviews arising from projects MW1 and MW2, the Agency, through its Inland Waters Topic Centre, will be well placed to support the Commission and the Environment Committee of the European Parliament in its future deliberations on water policy improvements paying particular attention to the absolute necessity for Member States to deliver high quality, comparative data. The outputs from MW1 and MW2 are also to be used for the basis of monitoring networks to satisfy the needs of the Agency and this is the subject of Project MW3. This is particularly important bearing in mind that the main duties of the EEA are :
The role of the EEA is seen as crucial in relation to the evaluation and dissemination of information, drawing the distinction between real and perceived risks and the provision of a scientific and rational basis for decisions and actions affecting the environment and natural resources. The Agency acts as an interface between scientists, policy makers and the public.
An example of the Agencys role is afforded by the main findings on inland waters reported in the recently published "Europes Environment - The Dobris Assessment" and further supported by the recently published report "Environment in the European Union 1995" which is the Agencys contribution to the review of the 5th Environmental Action Programme:
The drive towards sustainability through initiatives such as the 5th Environmental Action Programme and the Groundwater Action Programme bring together policy and research spanning the agricultural, industrial, regional planning sectors and emphasise the necessity to focus on water quantity as well as quality.
Monitoring activities carried out at national level and assessments at the pan-European level such as those carried out by the EEA provide the necessary feedback on the success or otherwise of integrated policy initiatives. At this point it is worth considering the conclusions of the Agencys review of the 5th Environmental Action Programme which was cited earlier in this section:
"The European Union is making progress in reducing certain pressures on the environment, although this is not enough to improve the general quality of the environment and even less to progress towards sustainability. Without accelerated policies, pressures on the environment will continue to exceed human health standards and the often limited carrying capacity of the environment. Actions taken to date will not lead to full integration of environmental considerations into economic sectors or to sustainable development."
Above all, the Dobris Assessment and the Report on the Environment in the European Union, 1995 have demonstrated that although environmental data have increased in availability as monitoring and research have developed there are significant and serious discrepancies in quality.
Much information that is available is inadequate to provide the basis for a rigorous assessment of the state of Europes environment. Improving the quality and comparability of information on the environment is now a major priority to ensure that actions and decisions being taken by policy makers and all sectors of society are in response to the actual rather than the perceived needs. This pressure should provide the stimulus for far greater integration of various policy areas than we have hitherto seen.
3.2 Project MW2 - Inventory of Water Resources Monitoring Networks
Through Project MW1 we have established the monitoring requirements required by EU legislation and international agreements and made some recommendations for improvement and rationalisation. Project MW2 has the objective of determining the extent and structure of current monitoring networks and practices throughout the EEA area and to judge how well they meet the identified requirements. The work was divided into four main tasks:
3.2.1 Inventory of surface water quality monitoring networks
This work was carried out by NERI as a cost-shared project with the Commission of the European Community (DG XI) who have kindly made available the results of the project to the Inland Waters Topic Centre. The task provided an overview of the existing water quality monitoring activities in the EU15 countries plus Norway and Iceland. The study covered all surface waters i.e. rivers, lakes and reservoirs, coastal and open marine waters and provides a description of activities of interest at European, Euro-regional, national and large-regional levels.
The results from these national and large regional monitoring programmes could be the basis for the evaluation of the state and trends in water quality at the EEA level. On the basis of the current report and additional analyses, a European surface water information system could be elaborated, including criteria for incorporating national monitoring sites into the EEA network, proposals for harmonisation and sampling procedures and determinands to be measured, and ideas for information processing from national level to the EEA level.
Conclusions
The report presents summary descriptions of the monitoring activities in each country based on the supplied national descriptions. Generally, the countries have several national monitoring programmes focused on assessment of the environmental state of surface waters. Some countries have a long tradition for national coordination of their monitoring programmes, however, in most of the countries the monitoring of surface waters has traditionally been performed by regional or local organisations. During the 1980s and 1990s the growing need for national information on the environmental state of surface waters made it necessary to work out national coordinated monitoring programmes. In most cases these national programmes are based on the information collected by regional organisations.
Nearly all countries in the EEA area have a national monitoring programme for the purpose of assessing the chemical water quality of rivers. The networks consist generally of more than 100 sampling sites located in all major river systems and rivers in each country. In most of the programmes basic determinands (eg. water flow, temperature, pH, conductivity), organic pollution indicators (eg. BOD5, dissolved oxygen, ammonium), nutrients (nitrogen and phosphorus), specific ions (eg. chloride, sulphate, potassium, calcium) are measured. Heavy metals and organic micropollutants are generally measured at a reduced number of sampling sites the sampling and measuring frequency are generally monthly or more frequent. Most of the countries also have monitoring programmes for the purpose of estimating the riverine loading into coastal areas, or the loading by transboundary rivers. In the Nordic countries programmes have been established for the purpose of monitoring water quality and loading from small catchments. These monitoring programmes generally consist of up to 20 relatively small stream catchments with detailed integrated studies of both river water quality and of the catchment (eg. land use and soil type), the main purpose being to follow reference areas, loading from agricultural land or impact of acid precipitation.
Most European countries have a long tradition for local assessment of river quality based on studies of macroinvertebrates. In some countries these activities have developed into national surveys/classifications of the biological quality of the main rivers. These national surveys are generally based on the results collected by the local organisations and made possible through national harmonisation and standardisation. In some countries (eg. Austria, Germany, Ireland, Luxembourg and the United Kingdom), the national classification has been performed since the 1970s and the countries are generally assessing river quality at two to five year intervals. Some of southern European countries and the Nordic countries have no national programmes for the assessment of biological river quality.
Fewer countries in the EEA area have national monitoring programmes for the assessment of water quality of lakes. Some countries have, however, local monitoring of lakes. The Nordic countries with their many natural lakes generally have one or several lake monitoring programmes. Generally, a "survey-type" monitoring programme including a large number of lakes, which are sampled with intervals of several years (5 -10 years), is supplemented with more intensive programmes with a sampling frequency of several times per year and typically covering a small number of lakes. The lake monitoring programmes usually include measurement of basic determinands (eg. temperature, pH, conductivity, dissolved oxygen), nutrients (nitrogen and phosphorus), specific ions (eg. chloride, sulphate, potassium, calcium). In addition, assessment of biological determinands, especially phytoplankton is also included in many of the lake monitoring programmes.
Norway, Sweden and Finland each have nation-wide surveys in order to assess the extent of acidification. The surveys include national sampling of 200 to more than 1000 water bodies, primarily lakes, and are generally performed at intervals of five to ten years. The Nordic countries and the United Kingdom and Ireland have monitoring programmes involving detailed studies of a few catchments for the purpose of understanding the process of acidification and to analyse trends.
Information about marine monitoring programmes has been received from ten out of the seventeen countries. Most countries have one general marine monitoring programme, which may be divided into sub-programmes (eg. one programme concentrating on coastal waters and one programme focused on open marine waters). Most of the marine monitoring programmes include measurement of chemical and physical determinands in the water column (basic determinands (eg. temperature and salinity), oxygen condition, and nutrients) and many of the programmes include studies of the biota (phytoplankton, zooplankton, zoobenthos etc.). The sampling networks consist generally of a number of intensive sampling sites, typically less than 20 sites, with frequent sampling (>12/yr) of the water column supplemented with an extensive network including several sampling sites and less frequent sampling (1-4/yr).
Reliable high quality information on the environmental quality of surface waters is essential for water management and the implementation of optimal measures that will improve environmental quality. Greater knowledge of water quality at the regional and European level is essential if the management of surface waters at the European level is to be improved. The considerable information on the state of surface waters collected and reported by various large regional and national authorities may be a valuable input to a European Surface Water Information System. Consistency and comparability of the information processed by the information system would require some harmonisation and standardisation of the regional and national monitoring programmes.
3.2.2 Inventory of surface water quantity monitoring networks.
This work was carried out by IH who issued questionnaires to national institutes (with the kind assistance of National Focal Points) in the 17 countries of the EEA area. All countries provided information with the exception of Belgium, Germany, Norway, Luxembourg and Iceland. A relational database of the information has been constructed. Where possible, maps showing the extent of the monitoring networks have been produced. A technical description of the database is provided including a list of the tables that constitute the database and an entity diagram showing how each table is related.
Conclusions
This report presents a summary of both the extent and quality of surface water quantity monitoring across Europe. The widespread adoption of continuously recording equipment, largely compatible databases and availability of data on floppy disks and magnetic tape encourages transfers of data between countries and between researchers in the same country. This meta-database will facilitate this process by providing:
This meta-database, which will be introduced into the European Topic Centre on Catalogue of Data Sources (ETC/CDS) as a matter of priority, will underpin the efforts of the Agency and the European Commission in bringing together water quantity and quality issues in the drive towards sustainability in resource management.
3.2.3 Inventory of groundwater quality and quantity monitoring networks
This task was led by the Austrian Working Group on Water (AWW). Information was gathered by questionnaires from EEA Member States with the assistance of the National Focal Points. Information was proved by all countries with the exception of Belgium, Iceland and Luxembourg. The information is held as a relational database of meta-data or meta-information rather than the raw numbers. It consists of a number of tables describing: contact names and addresses of responsible and collaborating organisations, information on groundwater regions and the determinands measured and their frequency. The inventory covers both quality and quantity aspects and in a similar way to the surface water inventories described above provides a description of the fundamental sources of data that are essential for the derivation of an effective pan-European network aimed at bringing groundwater quality and quantity issues together in a systematic and managed way.
3.3 Project MW3 - Design of a freshwater monitoring network for the EEA area.
This project uses the findings of Projects MW1 and MW2 to address the design and development of a pan-European water quality and quantity monitoring network based where possible on existing programmes in order to provide high quality, representative, reliable and comparable data relevant at the European level aimed at sustaining the EEAs objectives and needs.
The Project was divided into 3 Sub-projects:
There were a number of Tasks associated with these Sub-projects and these have been reported to the Agency:
Surface water quality
Surface water quantity
Groundwater quality
Groundwater quantity
Surface water quality
Surface water quantity
Groundwater quality
Groundwater quantity
Surface water quality
Surface water quantity
Groundwater quality
Groundwater quantity
Surface water quality
Surface water quantity
Groundwater quality
Groundwater quantity
Surface water quality
Surface water quantity
Groundwater quality
Groundwater quantity
3.3.1 The design of a freshwater monitoring network for the EEA area
The overall objective of the monitoring network is defined as:
"To obtain timely, quantitative and comparable information on the status of inland waters (groundwater, lakes/reservoirs, rivers and estuaries) from all EEA member states so that valid temporal and spatial comparisons can be made, and so that key environmental problems associated with Europes inland waters can be defined, quantified and monitored".
To meet this objective there is an explicit need to try and relate differences in water quality and quantity to human activities in catchments, and thereby try to demonstrate cause/effect relationships. The addition of the supportive information on catchment characteristics and human activities will add a further layer of difficulty to implementing the network. There will, therefore, be determinands (primary and secondary) that will provide the information to address the questions. There is potential for collaboration with work to be undertaken by other Topic Centres, for example those on Catalogue of Data Sources and on Land Cover. Because of this, certain aspects of the monitoring and reporting network have not been finalised until feedback can be obtained from these sources.
The clear understanding is that the monitoring network will be based where possible on existing national and international networks, use existing sources of monitoring information and create, only if necessary, an EEA database of meta-data rather than of non-aggregated data.
There will clearly be danger in the Agency taking monitoring information at face value. There will need to be validation on key aspects such as statistical confidence, sampling windows and frequencies, sampling methodologies and analysis (e.g. performance, quality assurance, limits of detection), so that judgements can be made on the validity of comparisons and differences. These aspects have been addressed in this report. Guidance is also given on how stations (and hence information) might be selected from current national monitoring programmes so that a representative view of water resources can be obtained. To this end water bodies/stations might be stratified in terms of the information required such as on reference or baseline conditions, fluxes and the impact of human activities.
There are a number of options on how the network can be developed:
The first three options would not necessarily give a representative view of Europes water resources, and method and data comparability would be an important issue to address. The latter option is the preferred one and is recommended for acceptance by the EEA Member States.
There is a need for different types of monitoring stations to be included in the networks. In rivers these would be:
Similarly the network for lakes and reservoirs would comprise reference, representative and impacted lakes. The largest and most important rivers and lakes in the EEA area should also be included.
For groundwater there should be a reference network that would deliver general information about the quality and quantity of groundwater and cover the entire area of each Member State. Reference stations should be established in areas not influenced by groundwater pumping and other anthropogenic activities. All major national aquifers should be included. In some areas within the EEA (small countries or in densely populated areas) it will not be possible to establish such stations. There should also be an impact network with stations selected in areas with different types and sources of contamination for example with different land use. Even though sample station density should be based on national geological conditions and variability in measured determinands, it is proposed that for the implementation/testing stages the impact network should consist of on average 1 station per 25 km2 of aquifer, with the reference stations representatively selected from all major national aquifers that meet the required criteria. It will be important to confirm that the monitoring wells, which are chosen for the EEA network, should have been designed and constructed in a similar way so it will be possible to compare the results from the network in all the member states.
In summary, it is recommended that the sampling stations to be included into the EEA network should be selected from the sampling stations in national monitoring programmes supplemented by additional stations to meet specific requirements of the EEA.
In cases where no national monitoring programmes exist, the stations to be included will, if possible, be selected from regional sampling stations. The network should be a representative sub-sample of the inland water bodies of the EEA area and the sampling stations to be included in the network should be selected so that they are representative of:
Sampling frequency should be based on an assessment of determinand variability and the desired level of precision in the information. These aspects will be looked at in the pilot project and during the subsequent progressive implementation of the network.
In the interim it is recommended that the summary information for rivers should, where possible, be based on an annual assessment of at least monthly samples, for lakes 8 samples a year, and for groundwater two samples a year, (one each during high and low ground water levels) should be adequate. When deeper groundwater reservoirs occur at the same sampling station they should be sampled at the same time as the shallower ones.
Groups of primary and secondary determinands have been identified for surface and groundwater. Substances such as pesticides, other synthetic organic substances and heavy metals should be selected on the basis of their use in the catchment of interest. In addition supportive data on catchment characteristics and land use will be required and should be collected in comparable ways.
The Topic Centre on Catalogue of Data Sources is currently working on many aspects of the environmental information network and there will need to be close liaison with the Topic Centre on Inland Waters. For example, there must be a common language for determinands, sampled media and units, usually codified in a data dictionary. Details of analytical procedures, methods, limits of detection, quality control may also have to be transferred to the Agency. Monitoring meta-data should also be made available to the Agency in the form of summary statistics and measures of data variability to allow assessments of data quality and comparability.
A preliminary assessment of the differences between current national and international monitoring networks and the requirements of the EEA network has been undertaken. One difference identified is that many of the river quality stations in national monitoring programmes are not located at or near gauging stations, and the requirement for water flow data may reduce the number of possible stations, especially in the case of small rivers and reference stations. In terms of water quality determinands in surface waters, the Nordic countries measure COD instead of BOD, and dissolved oxygen is not routinely measured. In addition, BOD and COD are analysed by many different methods. Some standardisation will be necessary to ensure that these data are comparable at an EEA level. In addition, in some countries total nitrogen is measured instead of nitrate, especially in the Nordic countries with relatively low nitrate levels and relatively high organic nitrogen levels. In some countries soluble reactive phosphate (SRP) is measured instead of total phosphorus.
In several countries there is no national lake/reservoir monitoring programme. However, in some of these countries local authorities monitor the water quality of lakes/reservoirs, and it should be possible to select the required number of water bodies for the EEA network from the local networks.
It is recommended that the suggested networks are piloted in a few selected countries during the first half of 1996, and subsequently, progressively implemented throughout the EEA area in a planned and programmed way later in 1996 and in subsequent years.
For the pilot project, station selection will be undertaken using the proposed criteria and procedures, and non-aggregated data will be needed to test and assess intra- and inter-strata variability, and to investigate optimum sample station densities and sample frequencies. In addition, probably in the second half of 1996 and in subsequent years, analytical and sampling methodology will be examined in detail to identify further potential barriers to harmonisation. Finally, the meta-data transfer process to the Agency will be tested once data dictionaries and formats have been developed and finalised. Support will also be required from other Topic Centres on the catchment and human activity information that will be required. All these activities are scheduled into the work programme of the Agency under the control of the Project and Programme Manager.
3.3.2 The development of an EEA database
A number of databases have been identified in the review carried out by the Topic Centre (MW3-Task11). A meta-database is under construction. Programmes fall into 3 main categories:
Four different sources of information were used to compile the database:
This activity is supplemented by the databases built up in Projects MW2 and MW3 by the partners of the ETC/IW involved in specific tasks. We are currently awaiting guidance from the EEA and collaboration with the ETC on Catalogue of Data Sources on the appropriate standardised format for these databases.
3.3.3 Analysis of data from large rivers
This work was carried out by NERI and WRc under a contract from the Commission of the European Community (DG XI). With the agreement of DG XI and the EEA the Project was assimilated into the work programme of the Topic Centre and its scope was enlarged.
For DG XI, the work focused on Council Decision 77/795/EEC. According to this Decision the Member States measured 18 specified determinands at 126 stations, located mainly in the large rivers of Europe. This information is to be provided to the Commission on an annual basis who publish summaries of the data every three years. The project assessed the degree to which Member States have complied with the requirements of the Decision in the period 1990 - 1992 and describes, as far as the data allows, temporal and spatial trends in water quality.
The report is divided into two main parts. The first part describes the reporting of Member States and the compliance in relation to the Decision. The second part is an assessment of water quality reported at 126 stations. This section describes for each of the 18 determinands summary statistics and frequency distribution, and for selected determinands, the temporal trend in annual average concentrated is evaluated.
For the Agency, a database of the Exchange of Information data was established in fulfilment of MW3 Task 12. The database was a merging of the DG XI data with data from the EEA Task Force database on rivers. Task 15 of MW3 required an evaluation and analysis of data and a report relating water quality in large rivers to the dominating human activities in their catchments. This report has been produced and is divided into two parts. First, a general characterisation of the major rivers in the EEA area including size of catchment areas, water flow, population density and land-use. The second part is an assessment of water quality at downstream stations in the large rivers (water quality data from around 35 of the 126 EU stations as well as water quality data from stations in Norway, Sweden and Finland are used). In addition, the water quality data were related to human activities in the catchments of the major rivers from information provided by the Topic Centre partners and collated by NERI.
Conclusions
There are 15 rivers with a catchment area greater than 50,000 km2 draining the EEA area. The largest of these, the Danube, discharges into the Black Sea and only a small part of its catchment lies within the EEA area. Of the other 14, the most noticeable feature is the dominance of a westerly or northwesterly flow direction with only three of the major rivers, the Rhône, the Ebro and the Po discharging into the Mediterranean. In total the study covers around 50 large rivers in the EEA area (the majority of rivers with catchments greater than 20,000 km2 although some smaller ones are included because of their great significance nationally).
Large regional variations in the annual run-off were found. Large rivers with their source in the Alps and rivers draining the north and Northwest Europe generally have an annual run-off greater than 500mm, while the rivers draining the southern part of Iberia have an annual run-off less than 200mm.
The catchment area of the large rivers in Norway, Sweden and Finland generally have a population density of less than 10 inhabitants per km2. Several of the large rivers in the south-western part of the region have population densities between 40 to 100 inhabitants per km2. In the central part of the EEA area the rivers generally have population densities greater than 100 inhabitants per km2, with the highest densities being observed in the rivers draining northern France and the Benelux countries, in Italian rivers, the Rhine and the large rivers in the southern part of England. The amount of water per inhabitant ranges from less than 1000 m3 per inhabitant per year in the most densely populated rivers to more than 20,000 m3 per inhabitant per year in the most sparsely populated rivers in the northern part of the EEA area.
The large rivers in Norway, Sweden and Finland generally have less than 10% agricultural land in their catchment, with most of the catchment dominated by natural landscape and forest. In the central and southern parts of the EEA area the large rivers generally have between 40 to 50% agricultural land in their catchments and the percentage of forest and natural land (eg mountains, wetlands, arid land) varies between 10% to 50%. A more detailed categorisation of the agricultural land (eg in arable land, rough grassing and permanent crops) has not been possible at this stage.
The large rivers have been divided into three regions: The northern region: large rivers draining Norway, Sweden, Finland and Scotland; the central region: large rivers draining Northern France, Denmark, Germany, the Benelux countries, Ireland and the UK; and the southern region; large rivers draining Southern France, the Iberian Peninsula, Italy and Greece. The annual average water temperature was generally between 11-14oC in the large rivers in the central region and between 14-18oC in the rivers in the southern region. The pH was markedly lower in the northern rivers, while most of the rivers in the central and southern regions had annual average pH levels between 7.5 and 8. The conductivity levels were lowest in the northern rivers, medium in the southern rivers and highest in the rivers in the central region.
The level of organic matter (BOD5) was quite similar in the central and southern large rivers (there were no BOD5 data from the northern region). The ammonium level is an order of magnitude lower in the northern rivers, medium in the southern rivers and highest in the rivers draining the central part of the EEA area. An increasing ammonium concentration was found with increasing population density in the river catchments.
During the last 15-20 years biological treatment of domestic and industrial waste waters has intensified, and organic matter loading has consequently decreased in many parts of Europe. This reduction in organic loading of the rivers is reflected in a similar reduction in the concentration of BOD5 in many of the large rivers. A comparison of organic matter levels (BOD5) at 101 river stations in large rivers in the EU12 Member States (no BOD5 data from Norway, Sweden and Finland) reveals signs of improving conditions. From the period around 1980 to 1990-1992, the organic matter concentration decreased at almost 72% of the river stations. The improvement was greatest in the rivers in the north-western Member States, while in the southern Member States 15 stations had decreasing concentrations and 16 stations increasing BOD5 levels. A similar reduction in the ammonium concentration was observed. The ammonium concentration decreased at 65% of the 130 river stations at large rivers in the EEA area between the beginning of the 1980s and 1990-92.
The levels of nutrients were an order of magnitude lower in the large rivers of the northern region compared to the other large rivers in the EEA area. The phosphorus concentrations were generally higher in the more densely populated central region than in the large southern rivers. There is a positive correlation between the population density and annual average river water phosphorus concentration.
A markedly higher nitrate concentration was observed in the large rivers of the central region compared to the large rivers of the southern region. The nitrate concentration is significantly correlated to the percentage of farmland in the river catchments. In rivers with the percentage of agricultural land greater than 40%, the nitrate level was about double in the large rivers draining the central part of the EEA area compared to the large rivers in the southern part. These regional differences in the nitrate levels can be explained by differences in agricultural intensity. In both the central and the southern region the percentage of farmland is around 60%, however, in the central region the usage of nitrogen fertilisers is about double the usage in the southern region.
The concentration of phosphorus decreased from the beginning of the early 1980s to 1990-1992 in the majority of the large rivers. In contrast, the nitrate level in the large rivers has generally been increasing the last 10-15 years. Thus, the nitrate levels increased between the beginning of the 1980s and 1990-92 in nearly three quarters of 120 river stations.
3.4 Project MW4 - Development and Establishment of the European Water Quality Monitoring Network and Databases.
The initial work on this project has focused on reservoirs, their usage and associated water quality problems The work has been carried out by IOW with the support of IFEN (Institut Français de lEnvironnement). The objectives were as follows:
The project has initially concentrated attention on reservoir issues most prominent in semi-arid areas with water scarcity problems. Original data were based on the information held by the International Committee on Large Dams (ICOLD) but an important feature was the gathering of data using questionnaires with the assistance of National Focal Points.
Conclusions
At this stage, the lack of available data means that no definite conclusions can be drawn. However, this report has been able to outline the main issues concerning major reservoir monitoring. Two of the most important issues are discussed below.
Firstly, the availability of reservoir data and the mobilisation of existing data within a short timespan are both very limited. With the exception of Portugal and Ireland, none of the National Focal Points has been able to complete the questionnaires within the originally-proposed timescale. These two countries were able to provide almost all of the requested data, since the information was already organised into national databases or because of previous comprehensive surveys of a reduced set of reservoirs.
In France, the absence of a centralised survey organisation and the large number of independent dam owners required that a questionnaire survey be dispatched by post, which yielded a good questionnaire response rate, but demonstrated a significant lack of water quality monitoring. The situation is similar in Norway, but for different reasons.
Amongst the five other countries with large numbers of dams (>100), it appears that three of them (Great Britain, Germany and Sweden) are not able at present to provide data about their dams and reservoirs, nor carry out a validation of the initial data taken from the ICOLD World Register of Dams. It is understood that Italy and Austria will be in a position to provide data in the next few months.
However, the problem is not necessarily the large number of dams included in the questionnaire: data has not been received from several countries with small numbers of dams (Belgium, Greece, the Netherlands and Luxembourg).
One of the main results of this project is, therefore, that substantial time lags between the questionnaire and its response are unavoidable in data collection. This should lead to a more realistic timetabling of future surveys related to still waters. In practice, closer co-operation between the European Topic Centre on Inland Waters and the National Focal Points should be initiated to evaluate which data sources can be mobilised in each country, including privately-owned, unofficial sources of data.
With regard to the objectives of the EEA, it should be noted that the choice of a standard nomenclature for rivers, catchments and administrative bodies is still pending. In the meantime, a data conceptual model is being developed in order to provide the EEA with a sound data description which will serve for the continuation of the project. This conceptual model and the associated software development will be available in the coming months.
Last but not least, the data obtained revealed a wide range of situations which have been used to develop an approach to environmental issues concerning dams across Europe. The following points are for discussion purposes and should be considered as purely tentative, since insufficient data is currently available.
Dam construction has a very long history, dating back to periods when environmental considerations were not foremost. So, most works lack the facilities which would permit their operation in an environmentally-friendly way. This should be evaluated when sufficient data concerning dam equipment are available (sluices, bottom outlets, fish ladders etc.).
Roughly speaking, reservoirs devoted to water supply are principally distributed to the west of a diagonal Northwest-Southwest line across Europe. Two main groups of water bodies are of interest:
Both types can suffer from eutrophication phenomena partly due to long renewal times and nutrient accumulation, but their evaluation could be approached differently. Eutrophication of the largest reservoirs can be considered by aerial surveys, for the others only an analytical approach is suitable. In both cases, the main issue is the requirement for a high standard of water quality.
In the rest of the considered part of Europe, most reservoirs are used for hydropower production. The environmental effects suspected are principally related to flow regime. The evaluation of such effects requires a merging of data from different sources, in particular river-related data.
3.5 Project MW5 - Key Water Resource Issues
This project has started with a review of the issues in arid and semi-arid areas carried out by CEDEX, INAG and ITGE. The objectives were to review the key water resource issues in arid and semi-arid/water scarcity regions of the EEA area.
Conclusions
Final conclusions and proposed future technical activity will be made in the final report, where it is expected to incorporate data from Greece and other regions of Italy and also comments the present draft from other countries.
However, some recommendations for possible future technical activities can be anticipated:
In order to harmonise data it would be suitable to map the mean annual values for precipitation, potential evapotranspiration and runoff on a pan-European scale, with the same methodologies for all the countries.
Synthesis studies of hydrological regimes (quantity and quality) with the same methodology on a pan-European scale will also improve our understanding of the different problems associated to water resources.
Erosion is an important issue in southern Europe and it would be important to know the most affected areas and relate them with hydrological changes (increase of peak flows and decrease of time of concentration).
It is important to characterise water quality problems and the main sources of contamination in southern Europe and its relationships with the potential water resources.
The development of guidelines for environmental impact analysis, management tools, etc for the conjunctive use of surface and groundwater resources should be made.
The setting up of criteria for the determination of ecological flows for semi-arid areas of EEA is considered to be of paramount importance.
It is necessary to characterise drought affected areas in southern Europe and to map some of the drought qualifiers as drought risk, resilience and vulnerability. Analysis of long series of precipitation and river discharges would clarify these drought studies.
Studies on a pan-European scale related to the social, economical and environmental impacts of extremes events (droughts and floods) would give a good idea of the scope of these problems.
The possible effects of climate change upon the quantity and quality of water resources, especially in the semi-arid regions where the effects can be more adverse, should be investigated.
For references, please go to https://eea.europa.eu./publications/92-9167-005-7/page004.html or scan the QR code.
PDF generated on 23 Nov 2024, 01:24 PM
Engineered by: EEA Web Team
Software updated on 26 September 2023 08:13 from version 23.8.18
Software version: EEA Plone KGS 23.9.14
Document Actions
Share with others