ABSTRACT
The need for environmental indicators of healthy water resources is based on the requirement of human society for a copious supply of water, which is a necessary component of life and of many human activities, including food production, industry and recreation. Given that there is often limited availability of water, careful management of resources is important. This management includes maintaining high quality of such resources as are available, which requires careful monitoring. The purpose of this chapter is to examine briefly the factors that cause water quality to deteriorate, and to summarize some of the methods used to monitor water quality. Some detail of the background to biological monitoring is given so that the appropriate application of biological techniques may be understood.
