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In this study, the environmental condition of the Zayandehrood river was theoretically and experimentally investigated. Therefore, a dynamic mathematical model with multiple pollution sources was formulated to predict the: parameters such as BOD, DO, and temperature of water in the different locations of the river. Also, the water samples were collected from 120 kilometers of the river starting from the south Isfahan municipal wastewater
treatment plant and the BOD, DO, and
temperature of the samples were:: measured in the four seasons of the year 1377. The comparison of the obtained experimental data with the results of computer simulation revealed the extent of accuracy of the model. Using the mathematical simulation, it is possible to predict the Zayandehrood river environmental conditions in future with respect to industrial development and yearly rainfall. Thus by utilizing the model's theoretical results, one is able to make the proper decisions in order to achieve a sustainable development in the Isfahan province.