Tahere Taghizade-Firozjaee; Sina Khoshnevisan; Seyedeh Fatemeh Khakzad; Reza Sheikh; Samad Emamgholizadeh
Abstract
This study provides a comprehensive seasonal assessment of the Gorganrood River's water quality in Iran using the IRWQIsc and the NSFWQI, integrated with the novel OPLO-POCOD decision-making model. Water samples from four stations were analyzed for eleven (IRWQIsc) and nine (NSFWQI) physicochemical ...
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This study provides a comprehensive seasonal assessment of the Gorganrood River's water quality in Iran using the IRWQIsc and the NSFWQI, integrated with the novel OPLO-POCOD decision-making model. Water samples from four stations were analyzed for eleven (IRWQIsc) and nine (NSFWQI) physicochemical and biological parameters across all four seasons of 2023. The results revealed significant temporal variations, with the highest water quality observed at the upstream Soosra station in summer and Noudeh in winter, generally categorized as "moderate" to "relatively bad." However, most station-season combinations indicated "bad" to "relatively bad" water quality. Spatially, upstream sites consistently showed better quality than downstream stations, with Araz Koseh and Ghzaghli exhibiting the lowest scores, likely due to accumulated pollution from urban, agricultural, and industrial sources. Shannon entropy analysis identified turbidity, total solids (TS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) as key factors influencing water quality. The OPLO-POCOD method's rankings aligned well with the conventional indices, validating this hybrid approach for detailed water quality evaluation. The findings highlight the urgent need for continuous monitoring and targeted management strategies, including improved wastewater treatment, runoff control, and riparian protection, to preserve the Gorganrood River's ecological health and water supply functions.
