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Classification of coastal waters

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Assessment made on  01 May 2004

Generic metadata


Water Water (Primary theme)

Coasts and seas Coasts and seas

DPSIR: State


Indicator codes
  • WEC 2d
Geographic coverage:

Policy issue:  Is good surface water ecological status being achieved?

Key messages

  • Only a few countries in Europe have at present classified their coastlines.


Key assessment

Coast and ocean monitoring is fairly well developed for most of the European countries implementing the WFD. However, most of the monitoring is based on chemical parameters, even though monitoring of biological parameters are increasing (OSPAR, HELCOM, MEDPOL). Only a few countries in Europe have developed classification schemes that have been in use for five years or more. However, all European countries that will implement the Water Framework Directive are developing classification schemes and many of the countries will be testing existing tools and systems in 2003-2004 (Common Implementation Strategy WG 2.4. COAST). An indicator, based on the same principles as the river classification indicator is most likely to be available late 2003 or early 2004.

Examples from some countries based on the CIS WG 2.4 working document are given below. These classification schemes include a combination of biological indicators and, mostly, chemical indicators.

Estuarine water quality in England and Wales has historically been assessed every five years. This is based on an assessment and classification scheme prepared by the Classification of Estuaries Working Party (CEWP) in the 1970s. Estuaries are classified as Good, Fair, Poor or Bad based on three quality elements, biological quality (presence of certain species of fish, aesthetic quality), evidence of aesthetic pollution (sewage-derived litter) and chemical quality (in terms of dissolved oxygen concentrations). A score is allocated for each of these categories according to set criteria and the scores are added to determine the overall class. Assessments were last made in 2000 using a combination of data from statutory monitoring programmes and local knowledge. A new scheme has been under development, based on the Scottish Classification scheme, which should replace the CEWP scheme by 2005. However this has now been abandoned pending the development of the scheme that will be needed to meet the requirements of the EC Water Framework Directive. The existing classification scheme is largely an expert-judgement type system, based on several different and independent aspects of water / environment quality. A simple index for benthos is being developed; nothing further has been established to date, but expert groups on all quality elements are progressing these topics in conjunction with Ireland.

The general classification applied in Finland (National Board of Waters and the Environment 1988, Heinonen and Gerve 1987, Vuoristo 1998) divides waters into five classes. Two approaches are in use to produce the general classification. First, the classes are determined by a counting procedure based on three separate classification criteria describing the suitability of water for water supply, fishing and recreational activities. Second, the concentrations of relevant water quality variables are compared with boundary values, which reflect the overall suitability of waters for the above modes of use. These variables include oxygen, turbidity, chlorophyll a, total phosphorous, colour, transparency, toxic compounds and algal blooms. In uncertain situations, extra support can be found by examining the criteria of the three more specific classifications. The five classes of the general index also have a verbal description to help in separating them from each other. For brackish coastal waters and sea areas the second approach is used.

France is currently developing a water classification system and is planned finalised in 2003.

New legislation was enforced in Italy in 1999 (D.L. 11 May 99, n.152), related to the water protection by pollution in agreement to EC directives 91/271/CEE and 91/676/CEE. The criteria for classification of the state of marine and coastal environment are given. Particularly, the trophic state of marine and coastal waters is characterised through a trophic index (TRIX) based on chlorophyll a, oxygen saturation, mineral nitrogen and total phosphorus. Numerically, the TRIX index is scaled from 2 to 8, covering a range of 4 trophic state. The parameters, to be included in this trophic index, were selected as directly related to eutrophication phenomena. Italy has instituted a new monitoring programme for phytoplankton (qualitative and quantitative), zooplankton (qualitative and quantitative), macroalgae/seagrasses and biocoenoses. Italy is now expanding the application of TRIX from northern to southern Italy.

The Northern Ireland Estuarine and Coastal Waters Classification Schemes (NIECWCS) were introduced in 1996 and are based upon the Scottish schemes used by the Scottish Environment Protection Agency. These two classification schemes have four class categories; Excellent, Good, Unsatisfactory and Seriously Polluted. The criteria used to classify coastal waters cover aesthetic condition, biological condition, bacteriological condition and chemical condition. Estuary classification is based upon criteria for the following factors: aesthetic condition, biological condition (fish migration, resident biota and/or bioassay, resident fish) and chemical condition (persistent substances based upon the Northern Ireland shellfish water standards, dissolved oxygen (DO) and the UK Red List and EC dangerous substances). The biological classification element is based entirely on expert judgement and looks at a variety of parameters such as diversity, composition, abundance and even-ness of species. Both schemes are default based i.e. the overall class defaults to the worst of the biological / chemical or aesthetic condition for a water body. This approach focuses management attention to the relevant environmental protection issues. A recognised weakness of the scheme is that it does not address eutrophication issues as the biological assessment is based on benthic infauna only. The boundary between coastal waters and estuaries is based upon the limits agreed for the Urban Waste Water Treatment Directive and the scheme extends 12 miles seawards of the territorial waters baseline.

Until the late 1980s, evaluations of environmental conditions in Norwegian fjords and coastal waters were mainly based on comparisons with assumed unpolluted areas. In 1993-94 a system for classification of environmental quality, degree of pollution and suitability for various uses was developed by Norwegian Institute for Water Research (NIVA), and published by the Norwegian State Pollution Control Authority (SPCA) through a series of booklets. The system comprised water quality, metals and organic micropollutants in sediments and biota, soft bottom fauna and suitability for various uses of marine water. The system is developed based on long time monitoring data. Reference values are preferably set at the 90-95 percentiles of results from sites beyond traceable influence from point sources. The final classification of an area is determined based on the parameter that gives the worst score. In 1997 a revised version was presented, using newer data and containing more advice on sampling and calculation of relevant statistical parameters. Norway has started work on classification scheme suitable for WFD based on existing systems and has selected trial "Reference Condition" sites. Norway has carried out a typology exercise and has a monitoring program (>10 years) containing all parameters mandatory in the WFD for southern part of the North Sea, mainly the Skagerrak.

Swedish coasts and oceans are characterised by two very different systems: the brackish Baltic Sea and the northern part of the West Coast, which is a more typical marine system. The system comprises water quality, metals and organic micropollutants in sediments and biota, soft- and hard- bottom flora and fauna. Sweden has established criteria for assessing the environmental status for water and sediments divided into two main areas: the Baltic Sea and the Skagerrak. Sweden has an Environmental Quality Classification System, though this is geared mainly toward eutrophication and does not fulfil WFD requirements at present.

Existing schemes will need expansion to meet WFD requirements in the Netherlands. No formal classification scheme in place, though trend assessment procedure is in use, which uses the concept of "reference level / state". A national "classification" of waterbodies commenced in 1996.

Intensive monitoring and quality assurance schemes are in place in Germany, but no formal classification scheme which would meet requirements of WFD. Projects have commenced which will deliver Typology and Classification.

No formal classification scheme for any of the biological elements is in place in Ireland. Ireland has a chlorophyll/nutrients monitoring programme which provides data for an eutrophication assessment scheme focused on UTTW and nitrates Directives. Only two main categories are provided for: Eutrophic or Non-Eutrophic. A further category of Potentially Eutrophic is largely used where data are insufficient for definitive judgement, and does not correspond to an intermediate status. Similar classification schemes are in place for shellfish and shellfish water quality, but none of these conforms to requirements of WFD. Expert groups on all quality elements are progressing these topics in conjunction with N Ireland / UK.

Portugal has no formal classification scheme. They have a chlorophyll/nutrients monitoring programme and are applying NOAA/NOS scheme. There is also a monitoring programme for toxic algae in shellfish and they have commenced the process of creating a typology, with a basic division into North (similar to NE Atlantic) and South (torrential estuaries). The means for further discrimination being progressed.

The existing Slovenian monitoring scheme covers most parameters, including toxic algae in relation to shellfish quality. Slovenia applies a TRIX scheme, see under Italy.

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