e-Digest Statistics about: Inland Water Quality and Use
Freshwater quality
Harmonised monitoring scheme
The Harmonised Monitoring Scheme (HMS) was established to provide a archive of water quality data for Great Britain. It is used to provide information for international obligations, including the long-term trends of some determinands and the estimation of riverborne input of selected determinands to the sea.
The HMS commenced in 1974 and has been administrated and maintained by the Environment Agency since 1998. The sampling network includes 230 sites, which are mainly located at the tidal limits of major rivers or at the points of confluence of significant tributaries.
Data from the HMS can be found in Table 8a to Table 11 (except 9d). For each determinand in Table 8a, Table 8b, Table 8c, Table 9b and Table 9c, annual mean concentrations have been calculated for each HMS site. The tables show the annual averages of the site means in each region, with each site given equal weight irrespective of the number of samples taken - an average of all the samples would give a greater weight to the sites at which samples are most frequently taken. In order to give an indication of the range of values at different sites within each region, figures are also given for the maximum and minimum site mean for each region. The tables also includes for the Great Britain average, the 10th percentile and the 90th percentile of the site means for the whole of Great Britain.for each determinand in each year and the 10-percentile and the 90-percentile of the site means in each region.
In Detail:
Further Information:
Data Tables:
- Internet Links:
- For national and local information see:
- England and Wales, Water Quality: Environment Agency
- Scotland: Scottish Environment Protection Agency - Harmonised Monitoring Data
- Northern Ireland: Environment and Heritage Service
- Department of the Environment in Northern Ireland
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Page last modified: 31 January 2006
Page published: 7 December 2004