Modeling and management of the river water quality for aquatic life using a source control approach (case study:The Zarrineh River)

Protection and management of water quality of rivers, as one of the valuable natural resources, is of high importance, especially where the sacristy of water resources matter too. In the present study, in addition to identifying contamination resources, it was surveyed different sceneries of controlling the major pollutants of the Zarrineh River in order to meet the water quality standards for aquatic life. To achieve the research objectives water quality sampling, monitoring of the contamination resources and plant coverage, along the river were conducted during the three seasons in 2016. A river water quality and hydraulic model was implemented, calibrated and confirmed by using the data in QUAL2KW. Evaluation of the hydraulic behavior and river water quality indicate that during the dry seasons, both reaction and advection affect the variations in water quality parameters, whereas during the wet periods, advection dominants. Subsequently, analysis of the river water quality pollutants reveals that the distributed sources like pile of trashes and animal wastes at the river bank have the largest share in contamination (Nutrients) of the Zarrineh River and among the point source pollution and agricultural pollutants, the largest share in contamination during summer and fall seasons belongs to the point source and during the spring season belongs to agricultural pollutants. In the present condition, evaluation of water quality management sceneries during the fall season, shows that restricting Sugar Factory Sewage BOD5 to 210(mg/l) gives rise to keeping standard amount of BOD for the aquatic life.