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Journals / Türkiye Uzaktan Algılama Dergisi / 2026 / Volume: 8

Comparative assessment of spectral indices for long-term flood monitoring in poljes using Sentinel-2 data: a case study from Muğla, Türkiye

Haytham Ali(ISTANBUL UNIVERSITY, INSTITUTE OF SOCIAL SCIENCES, GEOGRAPHY (DR))0000-0001-8513-1285
Emre Elbaşı(NEVSEHIR HACI BEKTAS VELI UNIVERSITY)0000-0001-5111-0435
Cihan Bayrakdar(ISTANBUL UNIVERSITY, FACULTY OF LETTERS, DEPARTMENT OF GEOGRAPHY, GEOGRAPHY PR.)0000-0001-5542-700X
Pages
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Publication Date
2026-03-25
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

The Modified Normalized Difference Water Index (MNDWI) achieved the highest performance (97.3% overall accuracy, Kappa 0.945).

📌 3 Key Takeaways

🎯
Objective & Hypothesis:Karst poljes are highly sensitive hydro-geomorphological systems where flooding poses persistent risks to agriculture and settlement.
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Key Findings & Data:This study develops an improved approach by comparing seven spectral indices and designing a thresholding strategy based on representative zones for different flood types.
💡
Conclusion & Impact:The Modified Normalized Difference Water Index (MNDWI) achieved the highest performance (97.3% overall accuracy, Kappa 0.945).
🔬Design:Research Article
📍Scope:2022 Verileri
⚙️Variables:Karst poljes · Flood monitoring · GEE

Abstract

Karst poljes are highly sensitive hydro-geomorphological systems where flooding poses persistent risks to agriculture and settlement. Their distinctive hydrological behavior and vulnerability demand systematic monitoring through remote sensing. However, flood mapping in poljes faces major challenges, including spectral confusion from reflective carbonate rocks, permanent water bodies, shadows, and the selection of appropriate thresholds. This study develops an improved approach by comparing seven spectral indices and designing a thresholding strategy based on representative zones for different flood types. Using Sentinel-2 data processed on GEE, we evaluated a benchmark flood event (14 January 2022) against 182 ground-truth points and PlanetScope imagery. The Modified Normalized Difference Water Index (MNDWI) achieved the highest performance (97.3% overall accuracy, Kappa 0.945). Applying this method to an 8-year series (2018–2025) enabled detection of 12 major floods, precisely delineating their onset and duration, and producing a flood frequency map of recurrently inundated zones. The results demonstrate how spectral index–threshold integration can transform flood monitoring from isolated events into continuous records of flood regimes. This work contributes to the relatively limited body of research on remote sensing–based flood monitoring in Turkish poljes and highlights its value for decision-making in flood risk mitigation and land-use planning.

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Cite This Article

Ali, H., Elbaşı, E., Bayrakdar, C. (2026). Comparative assessment of spectral indices for long-term flood monitoring in poljes using Sentinel-2 data: a case study from Muğla, Türkiye. Türkiye Uzaktan Algılama Dergisi, Volume: 8. https://doi.org/10.51489/tuzal.1770170

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