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GQA methodologies for classifying river and estuary quality

Find out about allocating grades to rivers and estuaries under the General Quality Assessment (GQA) scheme and how to determine changes in quality

We monitor the water quality at over 7,000 sites. This represents about:

  • 40,000km of rivers and canals and
  • 2,800km of estuaries in England and Wales.

Find out about the statistical methods used for the:

  • General Quality Assessment scheme for rivers and
  • classification of estuaries.