The recent drastic decrease in the surface water resources quality has limited water resources managers in Great Karun river basin, southwest of Iran. In this research, the effects of water quality on the satisfaction of different demand sits in Great Karun river basin is modeled and studied by dint of systemic analysis principles based on the actual conditions in the river basin. In addition, different scenarios of water resources quality management are defined and the effect of implementing these scenarios on the demand satisfaction criteria is considered. The achieved results indicate the interactive relationship between quality conditions and performance of the system in demand satisfaction. It means that, the applied operating strategies can improve the demand coverage and reliability of the system only if the quality improvement is considered in extracting those strategies. The considered scenarios are able to improve average monthly demand coverage between 0% and 700% for Abadan city as a critical point within the system. Comparison of different quality management scenarios declares that decreasing the amount of agricultural demands has the most impact on reducing the flow contamination and improving the demand satisfaction throughout the basin, especially in downstream areas like Abadan City. This is due to the wide area of agricultural demands within the basin. Reduction of the agricultural demands causes least contaminated return flows on the one hand, and on the other hand it increases the amount of fresh water of river flows.