Assessment of Water Quality in the Karun River of Ahvaz City According to Existing Standards

The quality of water available to humans has been seriously threatened due to population growth and the resulting increase in urban and industrial wastewater. To evaluate changes in the water quality of the Karun River in the urban area of Ahvaz, a simulation model was developed and used to assess the river's water quality based on existing standards. Results show that the quality variables of the river are highly dependent on the season of the year, with the largest changes in dissolved oxygen occurring during the driest and wettest seasons. Comparison of the river's current situation with national and international standards indicates that the water quality does not meet most standards, except during the autumn season when the flow rate is highest. Even if all effluents entering the river comply with existing discharge standards, the quality of the river does not meet desired standards. This highlights the importance of considering specific hydraulic conditions and the effect of time on river quality when updating existing standards.