Historic River Quality Objectives

This record is for Approval for Access product AfA164. The River Quality Objectives (RQO) classification was used for planning water quality improvements until 2006 when the scheme ended. RQOs were assigned to all significantly sized rivers (based on river flow). RQOs were based on the River Ecosystem (RE) Classification Scheme which was introduced in 1994 to replace the National Water Council's methodology. The RE system consists of five classes (1-5) based on the same determinands used in the General Quality Assessment (GQA) chemistry assessment of Biochemical Oxygen Demand (BOD), ammonia and dissolved oxygen but also includes the additional determinands of (free (or un-ionised) ammonia, pH, hardness, dissolved copper and total zinc) that reflect the requirements of a river ecosystem. Chemical samples were taken 12 times a year. Any river quality failures, their reasons and actions to be taken, were stored in separate tables. The national RQO classification scheme ceased at the end of 2006, it is now a fixed table which will not be updated. RQO compliance figures are available for 1997-2006.