STATISTICAL RELEASE
Date: 28 August 2007
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River water quality indicator for sustainable development - 2006 final results
The river water quality indicator is one of the 68 indicators of the Government’s Sustainable Development Strategy. It separately measures biological and chemical river water quality on an annual basis and the indicator for each represents the proportion of river water, in terms of river length, which is considered to be of “good” quality.
The main results are as follows:
Biological river water quality
In England
- 71 per cent of river length was of good biological quality in 2006, the same as in 2005, and compared to 67 per cent in 2000 and 60 per cent in 1990
In Wales
- 82 per cent of river length was of good biological quality in 2006, up from 80 per cent in 2005, 78 per cent in 2000 and 79 per cent in 1990
In Northern Ireland
- 54 per cent of river length monitored was of good biological quality in 2006, down from 56 per cent in 2005 and 61 per cent in 2000
- the length of rivers monitored increased greatly between 1995 and 2000, but there was a fall in river length of good quality over this period in those rivers that were monitored in both years.
In Scotland
- comparisons between Scotland and the rest of the UK should be treated with caution as the data are on a different basis (see Notes to Editors).
- 88 per cent of monitored river lengths were of good quality in 2006, up slightly from 87 per cent in 2005, which was the same figure as in 2004 and 2000
- for Scotland, a single combined classification is used which includes chemical, biological, nutrient and aesthetic elements
- changes in river length allocations and the extent of monitoring between 1990 and 2005 mean that it is difficult to draw conclusions about longer term Scottish trends.
For the UK as a whole
- it is estimated that about 76 per cent of rivers were of good biological quality in 2006, the same as in 2005. These estimates are approximate because the classification scheme in Scotland differs from that in England, Wales and Northern Ireland. It is not possible to show reliable trends for the UK because of changes in definitions and the length of river monitored.
Table A: Biological river water quality
Percentage of total river length that is of ‘good’ quality 1
Year |
England |
Wales |
N. Ireland 2 |
Scotland 3 |
1990 4 |
59.7 |
78.5 |
76.1 |
.. |
1995 |
66.3 |
87.0 |
75.4 |
.. |
2000 2 |
67.3 |
78.3 |
66.1 |
86.7 |
2000 2 |
61.5 |
|||
2001 |
.. |
.. |
49.9 |
86.9 |
2002 |
68.0 |
78.5 |
57.3 |
86.2 |
2003 |
69.2 |
79.3 |
56.6 |
87.5 |
2004 |
70.4 |
79.4 |
51.1 |
86.8 |
2005 |
71.0 |
80.0 |
55.7 |
87.2 |
2006 |
71.0 |
82.0 |
53.8 |
87.6 |
Source: Environment Agency, SEPA, EHS |
||||
Chemical river water quality
In England
- 66 per cent of river length was of good chemical quality in 2006, up from 64 per cent in 2005, 64 per cent in 2000 and 43 per cent in 1990
In Wales
- 95 per cent of river length was of good chemical quality in 2006, the same as in 2005, and compared to 93 per cent in 2000 and 86 per cent in 1990
In Northern Ireland
- 74 per cent of river length was of good chemical quality in 2006, a significant increase from 63 per cent in 2005, 55 per cent in 2002 and 44 per cent in 1991
- The length of rivers monitored increased greatly between 1995 and 2000, but there was a fall in river length of good quality over this period in those rivers that were monitored in both years.
In Scotland
- comparisons between Scotland and the rest of the UK should be treated with caution as the data are on a different basis (see Notes to Editors).
- 88 per cent of river length was of good quality in 2006, up slightly from 87 per cent in 2005, which was the same figure as in 2004 and 2000
- for Scotland, a single combined classification is used which includes, chemical, biological, nutrient and aesthetic elements
- changes in river length allocations and the extent of monitoring between 1990 and 2005 mean that it is difficult to draw conclusions about longer term Scottish trends.
For the UK as a whole
- it is estimated that about 76 per cent of rivers were of good chemical quality in 2006. This compares with an estimated figure of 74 per cent in 2005. These estimates are approximate because the classification scheme in Scotland differs from that in England, Wales and Northern Ireland. It is not possible to show reliable trends for the UK because of changes in definitions and the length of river monitored.
- there has been relatively little overall change in the proportion of rivers of good quality in the UK since 2000, but there has been an improvement since 1990. This conclusion is based on a comparison of the trends for individual countries – an exact percentage change cannot be given because of changes in monitoring methods and monitored river networks through the period.
Table B: Chemical river water quality
Percentage of total river length that is of ‘good’ quality 1
Year |
England |
Wales |
N. Ireland 2 |
Scotland 3 |
1990 4 |
43.5 |
86.3 |
44.3 |
.. |
1995 |
55.4 |
93.2 |
44.7 |
.. |
2000 |
64.4 |
93.4 |
58.8 |
86.7 |
2001 |
66.1 |
92.5 |
58.4 |
86.9 |
2002 2 |
65.5 |
92.2 |
58.6 |
86.2 |
2002 2 |
55.4 |
|||
2003 |
61.6 |
92.5 |
57.6 |
87.5 |
2004 |
61.5 |
94.4 |
57.9 |
86.8 |
2005 |
64.2 |
94.7 |
63.4 |
87.2 |
2006 |
66.1 |
95.3 |
74.3 |
87.6 |
Source: Environment Agency, SEPA, EHS |
||||
About the indicator
The river water quality indicator updated here is one of the UK’s Government’s Sustainable Development Indicators, and supports both the UK Government Strategy Securing the future and the UK Framework for Sustainable Development One future – different paths, which is shared with the devolved administrations in Scotland, Wales and Northern Ireland.
Over the next few years, there will be changes in the way that the monitoring process is carried out throughout the UK, and this will eventually result in a change to the way in which the indicator is presented. New monitoring schemes are now in place which will enable the UK, through its separate environmental agencies, to monitor and assess river water quality in accordance with the EU’s Water Framework Directive (WFD), which was adopted by all member states in 2000.
Under this Directive, a “river basin” approach has been introduced to monitoring, in place of the previous regional approach, and greater emphasis has been placed on “ecological” objectives. A target has also been set, with all rivers required to be of “good” quality by 2015, although subject to certain exemptions. Due to the reporting requirements of the WFD, it is not yet possible to produce a stable indicator for UK river water quality. In the interim period, we are intending to continue to present the existing indicator in its current form.
An accompanying note explains more about these changes here:
Notes to editors
-
The river water quality indicator is one of 68 indicators of the UK Government’s Sustainable Development Strategy, published in March 2005. It is also one of 20 indicators outlined in One Future – different paths: The UK’s shared framework for sustainable development, which is shared by the UK government and the devolved administrations of Scotland, Wales and Northern Ireland.
- All 68 indicators are published in a pocket-sized booklet Sustainable development indicators in your pocket 2007, available free of charge from:
Defra Publications, Admail 6000, London, SW1A 2XX
Tel: 08459 556000, Fax: 01709 881673
Email: defra@cambertown.comQuote publication reference PB12683.
A large print A4 version is also available, quote PB12683A.
- More detailed results and descriptions of the current monitoring methods and river networks are available as follows:
- Environment Agency for England and Wales
www.environment-agency.gov.uk/yourenv/eff/1190084/water/213902/?version=1&lang=_e - Scottish Environmental Protection Agency
www.sepa.org.uk/data/classification/ - Northern Ireland Environment and Heritage Service
www.ehsni.gov.uk/environment/waterManage/quality/rivers/river_monitor.shtml - Defra e-Digest of Environmental Statistics (includes England and Wales results summarised at local authority and English Government Office level)
www.defra.gov.uk/environment/statistics/
-
Chemical data from rolling three-year sampling windows are presented to reduce the bias which might be caused by unusual weather conditions in any one year. In Scotland, since 1996, an overall classification has been used combining chemical, biological, nutrient and aesthetic quality. The Scottish classification system and criteria for determining which river lengths should be monitored are different from the other countries. Comparisons between Scotland and other countries should therefore be treated with caution.
-
In England, Wales and Northern Ireland, three measurements are used for chemical quality classification: biochemical oxygen demand, dissolved oxygen and ammonia. Biological testing provides a fuller picture of the health of rivers and canals. Biological grading is based on monitoring tiny animals (i.e. macro-invertebrates) living in or on the river bed. Species groups recorded at a site are compared with those which would be expected to be present in the absence of pollution, allowing for the different environmental characteristics in different parts of the country.
-
In Scotland, iron and pH are also included in chemical monitoring in addition to the other three measurements. Biological (ecological) grading is similar to that used in the other countries. The final allocation of the quality class assigned to a river stretch is based on the lowest class determined from chemical, biological, aesthetic and toxicity assessments available for the associated monitoring point.
-
For this indicator ‘Good’ in England, Wales and Northern Ireland is taken as corresponding to GQA classes A and B. For Scotland, ‘Good’ is taken as corresponding to Scottish Classes A1and A2 plus unclassified river stretches. Unclassified river stretches are mostly located in rural upland catchments, and have been increasingly brought within the scope of monitoring since 2000.
-
Today the Environment Agency for England and Wales also released GQA results for nutrients, together with more detailed chemical and biological results for England and Wales, including figures for river catchment regions and for individual river stretches. These results are published on its web site:
www.environment-agency.gov.uk/yourenv/eff/1190084/water/213902/river_qual/?version=1&lang=_e
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Page published: 28 August 2007