e-Digest Statistics about: Inland Water Quality and Use
Freshwater quality
Biological river quality surveys
To provide a more comprehensive picture of the health of rivers and canals than is provided by chemical testing alone, biological testing is also carried out. [4], [5], [6]. Testing throughout the UK has been on an annual basis since 2002.
The biological grading throughout the UK is based on the monitoring of tiny animals (i.e. macro-invertebrates) which live in or on the bed of the river. The number and diversity of freshwater species found in samples can be used to make inferences about water quality, since research has shown that there is a relationship between species composition and water quality. Using a procedure known as the River Invertebrate Prediction and Classification System (RIVPACS), species groups recorded at a site were compared with those which would be expected to be present in the absence of pollution and other harmful substances, allowing for the different physical characteristics in different parts of the country. In England and Wales and in Northern Ireland two different summary statistics, known as ecological quality indices (EQI), were calculated and then the biological quality was assigned to one of six bands based on a combination of these two statistics. In Scotland, a third EQI was also calculated by SEPA and the grading system based on a combination of all three statistics or EQIs.
The biological results for England, Wales and Northern Ireland in 2005 are given in Table 6 and were produced on a consistent basis using the classification developed for GQA.
The River Water Quality Database provides chemical, biological and nutrient data on monitored rivers for each Government Office Region and Local Authority in England and Wales. Biological data are available for 1990, 1995, 2000, 2002 to 2005.
These biological water quality survey assessments have been adopted, along with chemical quality assessments, as part of the river quality framework indicator for sustainable development. The 20 framework indicators associated with the new UK Framework for sustainable development are intended to give an overview of progress on key issues common to the sustainable development strategies of the UK government and the Devolved Administrations. They fulfil a similar role to the former 15 headline indicators of the old sustainable development strategy. The water quality framework indicator is similar to the old water quality headline except that it now focuses on 'good' quality rather than 'good or fair' quality.
For further details of the latest version of the framework indicator, see the press release below, or visit the Sustainable Development web site.
Further Information
- Key Facts:
- Defra data: Biological river water quality
- Defra data: Chemical river water quality
- Sustainable Development Indicators:
- Framework Indicators: River water quality
- Explanation of indicators
- Data Tables:
- Biological water quality of rivers and canals : 1990, 1995, 2000-2006, England, Wales & Northern Ireland XLS
- References, further reading and links to other resources:
- [4] Rivers and Estuaries - A Decade of Improvement. General Quality Assessment of Rivers and Estuary classification in England and Wales 2000. Environment Agency, January 2002
- [5] Improving Scotland's water environment. SEPA State of the Environment Report. The Scottish Environment Protection Agency, 1999
- [6] River Quality in Northern Ireland 1995. Department of the Environment for Northern Ireland, 1997
- Internet Links:
- For further details of national monitoring programmes:
- Environment Agency for England and Wales: River quality
- Scottish Environment Protection Agency Environmental Data : Classification Scheme
- Northern Ireland: Environment and Heritage Service River Water Quality Monitoring
Your questions and comments about information presented on this page are welcome. Contact information and Email . Copyright of data and/or information presented or attached in this document may not reside solely with this Department. Please see guidance on Copyright.
Page last modified: 17 August 2006
Page published: 17 August 2006