This dataset is a subset of the "WFD Classification Status Cycle 2" product. It contains summary data for the element dissolved oxygen (DO) for river water bodies, as used in the classification for Ecological status for the water framework directive (WFD). The DO classification dataset is an element of the physico-chemical group or element set and is used to consider particular phyisco-chemical conditions. Oxygen in rivers is affected by complex interactions between ecological processes, and by anthropogenic pressures. Site classifications are derived from spot sampling monitoring data. The results of which are calculated into percentiles and assessed against two sets of environmental quality standards (EQS), which are derived from site typology. Site classifications for DO use categories of High, Good, Moderate, Poor, and Bad. Attribution statement: © Environment Agency copyright and/or database right 2016. All rights reserved.