The General Quality Assessment (GQA) Headline Indicator scheme or GQAHI (previously known as GQA) was the national indicator for water quality in rivers and canals. It was designed to provide an accurate and consistent assessment of the state of water quality and how it changes over time. These assessments were made for Biological, Chemical and Nutrients and undertaken for discrete river stretches. This is now a static dataset and 2009 was the final year of the scheme.
