Classification is a useful way of reporting the health of a river or lake. For a particular point in time a classification will show us where the quality of the water environment is good, and where it may need improving.
The way we classify our waters is changing. For twenty years, we used a General Quality Assessment (GQA) scheme to assess river water quality by looking at chemistry, biology and nutrients. GQA has helped drive environmental improvements by dealing with many of the major point sources of pollutants, such as discharges from sewage treatment works or other industry. The links below explain these classifications.
We now need a more sophisticated way of assessing the whole water environment that will help us direct action to where it is most needed. The European Water Framework Directive (WFD) will give us the means to do this by looking at over 30 measures, grouped into ecological status (this includes biology as well as 'elements' like phosphorus and pH) and chemical status ('priority substances'). The WFD covers estuaries, coastal waters, groundwater and lakes as well as rivers. We have updated our existing assessment techniques and have developed new ones for indicators we have not assessed before.