Modelling chloride-discharge relationships in Krishna river basin.

Chloride discharge relationships at several monitoring stations on the River Krishna in South India are investigated, both qualitatively and quantitatively, to identify probable source contributions. The chloride behaviour along the waterway is studied in detail to assess the source contributions at various monitoring stations falling within the study area. Seasonal variations in the intensity of rainfall cause wide variations in the quality of the River Krishna. As there is strong seasonal dependence between the flow in the river and chlorides, seasonal models are developed for prediction of concentrations and loads. Linear regression analysis is carried out to determine the model parameters. The predicted concentrations and loads are in agreement with the observed values within the uncertainty of data. As the area is characterized by distinct dry and wet seasons (based on rainfall distribution over the year), mass balances are used to differentiate between point and non-point source contributions to the river. In large river basins, monitoring all individual sources is difficult and/or impossible and expensive; hence the presented approach based on receiving water quality and flow serves as an alternative for modeling chlorides in the river basin. Results of the study can be used to emphasise water pollution control strategies.