The rivers rejuvenate themselves by traveling over a distance thereby they assimilate the pollution load and cause their own self-cleansing, also termed ‘Self-purification capacity’. To ascertain such assimilative capacity of the river system, various water quality models (WQMs) were studied. Out of numerous WQMs, six models including QUAL2Kw, WASP, SWAT, SIMCAT, MIKE-11, and CE-QUAL-W2 were selected and studied on basis of their development, characteristics, capabilities and strengths, model input, governing equations, application, assumptions and limitations. A comparison based on such a study showing input variables and data, assumptions and limitations, strengths, and specific characteristics has been carried out and tabulated. While the selection of a model is based on the problem for which the decision-making is to be done. Of all the models, QUAL2Kw and WASP have been found to be advantageous over the rest. For a complex river system, a single model may not work and in such cases, a combination may be tried. A model finally selected for a problem must be calibrated so as to have minimum errors and maximum accuracy.

  • Sustaining river water quality is essential for the entire river ecosystem.

  • The assimilative capacity of the rivers defines its limit to absorb pollution load.

  • Dissolved oxygen (DO) content is a key indicator of the health of the river.

  • Mathematical modeling support in estimation of pollution loads of the river.

  • Water quality models serve as an effective tool in Environmental Impact Assessment.

Graphical Abstract

Graphical Abstract
Graphical Abstract
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