Background and Purpose: Today, by increasing different pollutants, the continuous monitoring of surface waters is essential. Dorudzan Dam is one of the main sources of surface water in Fars Province, Iran; hence, the current study investigated the quality  of Dorudzan Reservoir for drinking and irrigation consumptions.

Materials and Methods: In this study, various physicochemical parameters [pH, total dissolved salt (TDS), Ca, Mg, electrical conductivity (EC), HCO3, CO3, Na, Cl, NO2, NO3, F, SO4, K, PO4, TH, sodium adsorption ratio, temperature, and turbidity] were measured. Besides, to determine the water quality in the studied water supply, 31 samples (18 samples in the cold seasons and 13 samples in the warm seasons) were taken from the reservoir outlet. For analyzing the gathered data, Canadian Water Quality Index was utilized.

Results: The irrigation water quality in the reservoir was determined between 73 and 78 (good) in cold, warm, and all seasons together, and for drinking consumption, the value was 89-90 (very good). The model showed that TDS (480.03 ± 59.14) and HCO3 (206.71 ± 23.75) in the irrigation consumption and EC (693.00 ± 94.11) and turbidity (1.10 ± 0.23) in the drinking consumption had the greatest contributions in reducing the quality of the water source.

Conclusion: The results revealed that generally the physicochemical quality of the reservoir’s water was more suitable for drinking consumption in compare to irrigation use. Nevertheless, based on the used model, its quality for irrigation is also desirable.