Mohammad Bagherian Marzouni - Master Science of Civil & Environmental Eng, Faculty of Water Science Eng, Shahid Chamran University Of Ahwaz
Ali Mohammad Akhoundali - Alimohammad Akhoondali, Professor of Water Eng, Faculty of Water Science Eng, Shahid Chamran University Of Ahwaz
Hadi Moazed - Professor of Civil & Environmental Eng, Faculty of Water Science Eng, Shahid Chamran University Of Ahwaz
Nematollah Jaafarzadeh - Environmental Technology Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran School of Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Karun River is the largest and most watery river in Iran. This river is the longest river which located just inside Iran and Ahvaz Metropolis drinking water supplied from Karun River as well (fa.alalam.ir). Karun River as the main source of water treatment plants in Ahvaz, like most surface waters affected by various contaminants which caused changes in water quality of the river (www.aww.co.ir). Causes such as constructing several dams at upstream river, withdrawalof water from the upstream to the needs of other regions of Iran, exposure of various industries along the river and discharge of industrial and urban sewage into the river, seen that today this river is deteriorating rapidly, qua today is the depth of river reach to 1 m with a highconcentration of pollutants (www.tasnimnews.com). In this study, considering the quality parameters, by using the QUAL2K model and with regard to water quality standards of definedclassification, we defined various scenarios. Then two parameters, BOD and DO were chosen asindicator parameters for assessing these scenarios. Model was calibrated to data from spring 2012 and validation was performed by winter and spring 2013. Then the model was used to take management decisions for critical situation. The results showed that by changing in location ofentry pollutant in the river we achieved water environmental goals. This scenario is also useful for future that flow of river reduced

Karun River, Management Scenario, QUAL2K Model, Water Quality, Simulation