| Remote Sensing Monitoring of Seasonal Drawdown in Latyan Dam Reservoir Using Sentinel-2 Imagery |
| کد مقاله : 1202-IWWA |
| نویسندگان |
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فاطمه وثوقی *1، محمد مهدی شرفی2 1گروه آب- دانشکده کشاورزی- دانشگاه تبریز- تبریز- ایران 2تهران |
| چکیده مقاله |
| Latyan Dam Reservoir, a vital source of drinking water for Tehran, faces severe water level fluctuations due to its dependence on seasonal precipitation and high evaporation. This study monitors water level dynamics using remote sensing and assesses seasonal stress severity. Sentinel-2 Level-2A imagery was used over four years (2023–2026) during three summer months (July to September). Water surface area was extracted using the Modified Normalized Difference Water Index (MNDWI) and Otsu adaptive thresholding. A new index called the “Relative Drawdown Index” (RDI) was defined to quantify summer drawdown severity. Results showed that the mean extraction error using adaptive thresholding compared to fixed thresholding was less than 3%. The reservoir area fluctuated between 0.95 and 2.22 km². Maximum extent (2.22 km²) was recorded in July 2026 and minimum (0.95 km²) in September 2025, indicating a 57% decline relative to the peak level. The years 2023 and 2025, with RDI values of 0.52 and 0.49 respectively, experienced nearly 50% area loss during summer, while this value was only 0.21 in 2024. The year 2026 showed intermediate behavior (RDI ≈ 0.345); despite recording the maximum July extent, it lost a considerable portion of its surface by September. Spatial analyses showed that this reduction was mainly concentrated in shallow upstream arms, and permanent water was limited solely to the main deep channel near the dam body. Overall, the RDI is introduced as a simple, independent, and efficient tool for operational reservoir stress monitoring, with high potential for supporting water resource management . |
| کلیدواژه ها |
| Remote Sensing, Latyan Dam, MNDWI, Relative Drawdown Index (RDI), Water Resource Resilience. |
| وضعیت: پذیرفته شده برای ارسال فایل های ارائه پوستر |
