الملخص
This study aims to assess the Orontes water quality using Water Quality Index (WQI), as an appropriate tool in classifying and studying the impact of spatial and temporal changes on pollution loads, to help in managing the quality of rivers, considering the Orontes River one of the most important water sources that are used in various activities, Hence the importance of identifying the sources of pollution and their type to develop the necessary solutions to address pollution problems. In this research, (11) sampling sites along the River in Homs were selected for the year / 2020 /, and (9) parameters were selected to apply (WQI) to determine the quality of the water, namely: (DO, COD, BOD5, pH, TSS, TDS, FC, PO4, NO3), The results showed that when measuring WQI and classifying its quality based on different conditions, about spatial changes: the water quality in areas (Al-Amiri to the exit of Qattinah Lake) ranges from (60-80)% (very good to good) and is considered relatively pure due to its lack of exposure to pollutants, while the areas (Alsham Road to Ghajar Amir) is from (20-50) and considered highly polluted because it receives large quantities of industrial, human and agricultural pollutants and is considered very polluted, about seasonal changes: the water quality is (61.1) and close to the minimum value for relative purity in "winter" due to rain, while in (spring, summer, and fall) from (45-59) and considered Relatively polluted due to the increase in industrial activity.