SR-34 : Environmental hydrology with special reference to surface water quality modelling

Abstract

Water, air and soil are the three ma jar components of environment. From hydrology point of view, the environment is the science encompasses the behaviour of water as it occurs in the atmosphere, on the earth (soil). Due to the unique properties of water, it gets easily contaminated when passes through its media of trans-port i.e. atmosphere and land. Since, atmosphere is contaminated by our activities, water passes through this media also get contaminated before being dropped on the earth. Due to our revolutionary activities on the surface of the earth the waters transported through surface and sub-surface media, contaminated more, and pollute the bodies of water where it is finally discharged.

Besides indirect pollution of water bodies; streams, lakes, reservoirs, and other water bodies are also polluted by the direct disposal of wastes, solid and liquid, generated from municipal, industrial. agricultural and other sources. Thus, pollution of water bodies have become a common and natural phenomenon. Most of the rivers in the world are victimized of pollution, the same scenario also exists in India.

River(s) which is/are life line of many areas in the country. is/are polluted. Techniques for predicting and forecasting pollution level of river water at different space 8 time have been developed. Numbers of mathematical models with wide range of versatility are available and are successfully being used world wide for water quality modelling. A concise outline of most useful models is given in this report. QUAL-II E has been found the most useful and acceptable model amongst the model developed so far for stream water quality modelling. Due to the varying nature of hydrologic and hydraulic characteristics o f each river, the rate of bio-degradation of water quality variables also varies. thus a model developed based on particular sets of conditions cannot be said unique for all conditions. Moreover. lot of parameters are involved in the reaction process of water quality changes. they also varies with local conditions. Besides these. there are so many variables to be accounted for in the modelling. It is needless to mention that most of the models available for general use even did not apply in the context of Indices problem. The report is mainly focused to the use of QUAL-II E model for stream water quality modelling.