e-Digest Statistics about: Inland Water Quality and Use
Freshwater quality
Compliance with the EC Freshwater Fish Directive
The Freshwater Fish Directive (78/659/EEC) was adopted in 1978 and is concerned with the protection and improvement of fresh waters in order to support fish life. It sets water quality standards and monitoring requirements for ensuring the protection of coarse and game fisheries. The Directive requires the designation of appropriate rivers and lakes into two categories of water: those suitable for salmonids (i.e. mainly salmon and trout but also grayling) and those suitable for cyprinids (including carp, tench, bream, roach, chub and minnows). The Directive sets out 14 physical and chemical parameters [7] for which 'imperative' and/or the more rigourous 'guideline' standards are given for the two categories of designation.
By 2005, the UK had designated under the Directive some 34,300 km of river length in England and Wales, 36,650 km in Scotland and 4,280 km in Northern Ireland. Three large lakes totalling some 55,000 hectares were also designated in Northern Ireland. The salmonid waters tend to cover the upper, faster flowing reaches of rivers as well as upland lakes, and cyprinid waters tend to cover lower reaches of rivers and ponds near the bottom of river catchments. 84 per cent of the UK designations of rivers are salmonid, although in England and Wales salmonid designations represent two-thirds of total designated river length.
Table 7a and Table 7b show the length of rivers and additional areas of standing waters which have been designated in England and Wales, under the Directive, together with the corresponding compliance rates over the period 1995 to 2005. Table 7c provides similar analyses for Scotland and Northern Ireland. From 1999 to 2005, failures were mainly caused by low dissolved oxygen concentrations, variations in pH and raised concentrations of total ammonium. The main reasons for these failures were effluent discharges from waste water treatment works, low river flows, algal blooms, and farm run-off. Periodic elevated pH values, attributed to agricultural run-off within the catchment of one of the three designated water bodies, was the main cause of failures for standing waters in Northern Ireland between 1999 and 2005.
Further Information:
Data Tables:
- References, further reading and links to other resources:
- [7] Implementation of the EC Freshwater Fish Directive: Water Quality Requirements for the Support of Fish Life. Water Quality Series No.20. National Rivers Authority, August 1994
- Internet Links:
- For national and local information see:
- England and Wales: Environment Agency - Quality of freshwater fisheries
- Scotland: Scottish Environment Protection Agency
- Northern Ireland: Environment and Heritage Service - Rivers
- Department of the Environment in Northern Ireland
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Page last modified: 20 May 2007
Page published: 24 January 2006