Shahid Beheshti University Sustainable Earth Trends 3060-6225 6 1 2026 01 01 Modeling Water Quality of Chitgar Lake: Evaluation of the Effectiveness of Various Water Treatment Scenarios on Lake Water Quality 35 44 105226 10.48308/set.2025.237670.1086 EN Javad Bayat Department of Environmental Pollutants Research, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran 0000-0002-2544-6805 Masoud Entezari Department of Environmental Pollutants Research, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran Behrooz Bagheri Sanian Department of Geography and Urban Planning, Faculty of Humanities, Payame Noor University of Karaj, Alborz, Iran Maryam Rouhi Department of Environment, Natural Resources Faculty, Isfahan University of Technology, Isfahan, Iran HamidReza Heidari Department of Environmental Science, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran Mehdi Karami Department of Environmental Pollutants Research, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran Journal Article 2024 11 23 Chitgar Lake in Tehran city faces challenges in maintaining water quality due to nutrient loading and potential eutrophication. A water treatment plant (WTP) established in 2016 plays a crucial role in improving Chitgar Lake's water quality. The treatment process involves screening, coagulation, filtration, and disinfection, reducing TP to below 0.02 mg/L before releasing the water into the lake. A water quality model was developed to assess the impacts of external and internal nutrient and organic loading on lake management. This study investigates the impact of different WTP operational scenarios on water quality parameters using a water quality model. The results show that the lake experiences water quality issues, with a minimum DO level of 3.96 mg/L and maximum TP and Chl-a levels exceeding standard levels. The river water undergoes significant improvements after treatment, with nutrient reductions, Chl-a, and turbidity. The study highlights the critical need for continuous monitoring and effective treatment strategies to maintain Chitgar Lake's water quality well above standard conditions. The model serves as a valuable tool for assessing management strategies and optimizing water treatment plant operations, helping to control eutrophication and preserve the lake's recreational value. The simulation scenarios indicate that the most effective strategy for maintaining water quality in Chitgar Lake is the continuous operation of the water treatment plant during both the refilling and recycling periods. This approach successfully keeps key parameters, such as Chl-a and TP, within acceptable limits, effectively preventing eutrophication and ensuring the lake's suitability for recreational activities. https://sustainearth.sbu.ac.ir/article_105226_a531799953d47b75a4fa884d9f47ad34.pdf