Rivers have got very important place in Indian culture and tradition. They are the lifeline of majority of population in cities, towns and villages and most of these are considered sacred. During festivals people take holy dip in rivers. Every river stretch has a distinct water use like bathing, drinking, municipal supply, navigation, irrigation and fishing. Simultaneously, it is also used as a receptacle for discharge of industrial effluent, municipal sewage and dumping of solid wastes. The Water (Prevention and Control of Pollution) Act, 1974 is aimed to support the water quality of various designated best-uses of water bodies. The Water Quality Atlas of the Indian River System was prepared on the basis of five major uses of river water such as;

(a) Drinking water source without conventional treatment but after disinfection;

(b) Outdoor bathing organized;

(c) Drinking water source with conventional treatment followed by disinfection;

(d) Propagation of wild life, fisheries;

(e) Irrigation, industrial cooling, controlled waste disposal.

Thus, the concept of water quality mapping in India, has been initiated with the identification of beneficial uses of water in terms of primary water quality criteria. For maintaining the quality of river water, the pollution levels in rivers have been detected by monitoring limited number of the physico-chemical parameters, which could only determine the changes in chemical characteristics of water bodies. Deterioration in water quality, over the past several years has gradually rendered the river water quality unsuitable for various beneficial purposes. Moreover, the objective of The Water Act, 1974 is maintain and restore the wholesomeness of river water in terms of their ecological sustainability is increasingly realized. The concept of bio-mapping originated from use of biological system as a biological water quality criteria. The concept of biomapping has been introduced by CPCB for the prediction and detection of ecological effects and to protect rare and endangered biotic species surviving in surface water from evergrowing pollution problem.