ABSTRACT
The measurement and management of water quality in a river is an important task within hydrology. To carry this out, a knowledge of the pollution type, pollution source (assuming it is not natural) and pathways leading into the stream are important. Equally, it is important to know the flow regime of any receiving river so that dilution rates can be assessed. There are methods available to control water quality, whether through treatment at point sources (e.g. waste water treatment) or control throughout a catchment using land use planning. This chapter sets out the principal water quality parameters and sampling and measurement techniques, including proxy measures. A number of case studies illustrate the global challenges in managing and improving water quality.
