Historic UK Water Quality: Harmonised Monitoring Scheme Summary

United Kingdom water quality data from the Harmonised Monitoring Scheme (HMS) covers 230 sampling sites, primarily at tidal limits and major river confluences, from 1975 onward. The dataset provides annual summary statistics, including means, maximums, minimums, and percentiles for determinands like oxygen, ammonia, nutrients, metals, and pesticides. It serves as an archive for assessing long-term trends and fulfilling international environmental reporting obligations.

Use Cases

• Analyzing long-term trends in nutrient and metal concentrations across UK regions.
• Assessing compliance with environmental regulations for riverborne inputs to the sea.
• Comparing regional water quality using annual mean, maximum, and minimum site statistics.
• Calculating national and regional percentiles for specific water quality determinands.

Strengths

• Provides a long-term archive with data starting from 1975, enabling trend analysis.
• Covers a defined network of 230 strategically located sampling sites across the UK.
• Includes calculated annual summary statistics (means, percentiles) to facilitate regional and national comparisons.

Limitations

• The dataset is noted as retired and superseded by another record, indicating it may not be the current version.
• Specific column names, row counts, and file sizes are not provided in the available metadata.
• The license and detailed authorship information are not explicitly stated in the provided sources.

Provenance

Source

Environment Agency (UK), collected under the Harmonised Monitoring Scheme.

Collection Method

Water quality sampling at a fixed network of monitoring sites, with annual statistical aggregation.

Time Range

1975 onward

Freshness

Last updated metadata date is 2026-07-17, but the underlying data is historic and the record is retired.

Geography

United Kingdom, focusing on major rivers and their tidal limits.