ARCHIVE: 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:
Oxygen and ammonia
Nutrients
List II metals
Pesticides
Further Information:
Data Tables:
Table
No.
Title Download file type
8a Annual average, highest and lowest mean concentrations of water quality determinands by region: 1980-2005 (Dissolved oxygen), Great Britain
8b Annual average, highest and lowest mean concentrations of water quality determinands by region: 1980-2005 (Biochemical Oxygen Demand), Great Britain
8c Annual average, highest and lowest mean concentrations of water quality determinands by: 1980-2005 (Ammoniacal nitrogen), Great Britain
9a Annual average concentrations of nitrates and orthophosphates by landscape type: 1980-2005, Great Britain
9b Annual average, highest and lowest mean concentrations of nitrates by region: 1980-2005, Great Britain
9c Annual average, highest and lowest mean concentrations of orthophosphates by region: 1980, 1990-2005, Great Britain
10 Annual average concentrations of selected determinands of river water quality, by river location: 1980, 1990 and 1995-2005, Great Britain
11 Distribution of annual site mean concentrations of certain heavy metals in rivers: 1980-2005, Great Britain
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