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Journals / Firat University Journal of Experimental and Computational Engineering / 2026 / Cilt: 5 Sayı: 3

The Impact of Topographic Resolution on Flood Inundation Extent in Narrow Valley Systems: A Case Study of Karakoçan Stream (Elazığ, Türkiye)

Dar Vadi Sistemlerinde Topoğrafik Çözünürlüğün Taşkın Yayılım Alanlarına Etkisi: Karakoçan Deresi (Elazığ-Türkiye) Örneği

Merve Şirinoğulları(FIRAT ÜNİVERSİTESİ)0000-0003-1218-3724
Mustafa Tunç(FIRAT ÜNİVERSİTESİ)0000-0001-9756-8409
Ahmet Toprak(FIRAT ÜNİVERSİTESİ)0000-0001-6790-1856
Pages
701–718
Publication Date
2026-10-25
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AI Summary & Key Takeaways

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

Consequently, these outcomes underscore the imperative need to meticulously select an optimal DEM resolution, carefully balancing site-specific topographic characteristics with data availability.

📌 3 Key Takeaways

🎯
Objective & Hypothesis:Escalating climate change and unregulated riverbed construction have rendered floods the most devastating hydrometeorological hazards worldwide, posing severe threats to lives and infrastructure.
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Key Findings & Data:This study investigates the impact of two distinct DEM datasets, featuring 10-m and 25-m spatial resolutions, on flood inundation mapping across the Karakoçan Stream catchment in Elazığ, Türkiye.
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Conclusion & Impact:Consequently, these outcomes underscore the imperative need to meticulously select an optimal DEM resolution, carefully balancing site-specific topographic characteristics with data availability.
🔬Design:Modeling & Simulation
📍Scope:Comprehensive Sample
⚙️Variables:Taşkın analizi · HEC-RAS · Sayısal yükselti modeli çözünürlüğü

Abstract

Escalating climate change and unregulated riverbed construction have rendered floods the most devastating hydrometeorological hazards worldwide, posing severe threats to lives and infrastructure. The reliability of hydraulic models in predicting flood risks relies heavily upon the spatial resolution of the Digital Elevation Model (DEM) employed to represent terrain topography. This study investigates the impact of two distinct DEM datasets, featuring 10-m and 25-m spatial resolutions, on flood inundation mapping across the Karakoçan Stream catchment in Elazığ, Türkiye. Hydraulic analyses were performed using the HEC-RAS software, and the simulation outcomes were evaluated based on land use impacts and critical hydraulic parameters. The results revealed that coarsening the DEM resolution from 10 m to 25 m expanded the estimated inundation area from 19.36 km² to 48.75 km², representing an artificial overestimation of approximately 152%. Furthermore, the maximum water depth particularly within residential areas dropped significantly from 9.49 m to 2.82 m. This indicates that low-resolution data fails to capture the vertical depth of the flood volume, erroneously dispersing the water horizontally as a shallow layer. These findings demonstrate that DEM resolution is a critical parameter directly influencing the predictive accuracy of flood hazard models. Consequently, these outcomes underscore the imperative need to meticulously select an optimal DEM resolution, carefully balancing site-specific topographic characteristics with data availability.

Özet

Dünya genelinde iklim değişikliği ve dere yataklarında yapılaşma ile taşkın olayları, can ve mal güvenliğini tehdit eden en kritik hidrometeorolojik afetlerin başında gelmektedir. Taşkın risklerinin öngörülebilmesi için kullanılan hidrolik modellerin başarısı, topografyayı temsil eden Sayısal Yükseklik Modeli (DEM) verilerinin çözünürlük hassasiyetine doğrudan bağlıdır. Bu çalışmada, Elazığ ili Karakoçan ilçesinde bulunan Karakoçan Deresi havzasında 10 m ve 25 m çözünürlüğe sahip iki farklı DEM verisinin taşkın yayılımı üzerindeki etkisi incelenmiştir. Hidrolik analizler için HEC-RAS yazılımı kullanılmış elde edilen sonuçlar arazi kullanımı ve hidrolik değişkenler açısından karşılaştırılmıştır. Analiz sonuçları, DEM çözünürlüğü 10 m’den 25 m’ye düştüğünde toplam taşkın alanının 19.36 km2den 48.75 km2ye çıkarak yaklaşık %152 oranında yapay bir genişleme sergilediğini ortaya koymuştur. Özellikle yerleşim alanlarının etkilendiği taşkın analizinde maksimum su derinliğinin 9.49 m’den 2.82 m’ye gerilemesi düşük çözünürlüklü verilerin taşkın hacmini dikey yönde derinleştirmek yerine yatay yönde sığ bir tabaka halinde dağıttığını göstermektedir. Elde edilen bulgular taşkın tehlike analizlerinde kullanılacak DEM verisinin çözünürlüğünün model doğruluğunu doğrudan etkileyen kritik bir parametre olduğunu göstermektedir. Bu bağlamda çalışma alanının özellikleri ve veri olanakları dikkate alınarak uygun çözünürlükte veri seçimi yapılması önerilmektedir.

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Cite This Article

Şirinoğulları, M., Tunç, M., Toprak, A. (2026). The Impact of Topographic Resolution on Flood Inundation Extent in Narrow Valley Systems: A Case Study of Karakoçan Stream (Elazığ, Türkiye). Firat University Journal of Experimental and Computational Engineering, Cilt: 5 Sayı: 3, 701–718. https://doi.org/10.62520/fujece.1952139

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References (36)

  1. Z. W. Kundzewicz et al., “Flood risk and climate change: Global and regional perspectives,” Hydrol. Sci. J., vol. 59, no. 1, pp. 1–28, 2014.
  2. P. D. Bates and A. P. J. De Roo, “A simple raster-based model for flood inundation simulation,” J. Hydrol., vol. 236, nos. 1–2, pp. 54–77, 2000.
  3. U.S. Army Corps of Engineers, HEC-RAS River Analysis System User’s Manual. Hydrologic Engineering Center, 2023.
  4. E. Yalcin, “Assessing the impact of topography and land cover data resolutions on two-dimensional HEC-RAS hydrodynamic model simulations for urban flood hazard analysis,” Nat. Hazards, vol. 101, no. 3, pp. 995–1017, 2020.
  5. M. Durak and İ. Cürebal, “HEC-RAS based 2D flood hazard study: Bahadınlı and Karadere (Burhaniye–Balıkesir),” J. Geomorphol. Res., no. 15, pp. 126–149, 2025.
  6. S. Mirzaei, A. Sadoddin, A. Bahremand, M. Ownegh, and R. Mostafazadeh, “Direct-tangible costs in flood zones simulated using the HEC-RAS 2-D hydraulic model—The Arazkuseh River, Golestan Province,” Water Soil Manag. Model., vol. 5, no. 1, pp. 57–74, 2025.
  7. S. Ogras and F. Onen, “Flood analysis with HEC-RAS: A case study of Tigris River,” Adv. Civ. Eng., vol. 2020, Art. no. 6131982, 2020.
  8. W. G. Namara, T. A. Damisse, and F. G. Tufa, “Application of HEC-RAS and HEC-GeoRAS model for flood inundation mapping, the case of Awash bello flood plain, upper Awash River Basin, oromiya regional state, Ethiopia,” Model. Earth Syst. Environ., vol. 8, no. 2, pp. 1449–1460, 2022.
  9. M. Bozdoğan and E. Canpolat, “Calculation of flood recurrence and modeling with HEC-RAS in Delibekirli Basin (Kırıkhan/Hatay),” J. Nat. Hazards Environ., vol. 10, no. 2, pp. 478–503, 2024.
  10. H. Jafali, A. I. Ceyhunlu, G. Çeribaşı, and T. Akgül, “A one-dimensional hydraulic modeling approach for flood risk management: Bursa Narlıdere Stream case study,” Uludağ Univ. J. Fac. Eng., vol. 30, no. 3, pp. 941–956, 2025.
  11. K. Marks and P. Bates, “Integration of high-resolution topographic data with floodplain flow models,” Hydrol. Process., vol. 14, nos. 11–12, pp. 2109–2122, 2000.
  12. V. T. Chow, D. R. Maidment, and L. W. Mays, Applied Hydrology. New York, NY, USA: McGraw-Hill, 1988.
  13. A. T. Haile and T. H. M. Rientjes, “Effects of LiDAR DEM resolution in flood modelling: A model sensitivity study for the city of Tegucigalpa, Honduras,” in Proc. ISPRS Workshop Laser Scanning 2005, Enschede, The Netherlands, 2005, vol. XXXVI-3/W19, pp. 168–173.
  14. M. S. Horritt and P. D. Bates, “Evaluation of 1D and 2D numerical models for predicting river flood inundation,” J. Hydrol., vol. 268, nos. 1–4, pp. 87–99, 2002.
  15. T. J. Fewtrell, P. D. Bates, M. Horritt, and N. M. Hunter, “Evaluating the effect of scale in flood inundation modelling in urban environments,” Hydrol. Process., vol. 22, no. 26, pp. 5107–5118, 2008.
  16. B. F. Sanders, “Evaluation of on-line DEMs for flood inundation modeling,” Adv. Water Resour., vol. 30, no. 8, pp. 1831–1843, 2007.
  17. A. Cook and V. Merwade, “Effect of topographic data, geometric configuration and modeling approach on flood inundation mapping,” J. Hydrol., vol. 377, nos. 1–2, pp. 131–142, 2009.
  18. Y. Wang, J. D. Colby, and K. A. Mulcahy, “An efficient method for mapping flood extent in a coastal floodplain using Landsat TM and DEM data,” Int. J. Remote Sens., vol. 23, no. 18, pp. 3681–3696, 2002.
  19. H. Ozdemir, C. C. Sampson, G. A. de Almeida, and P. D. Bates, “Evaluating scale and roughness effects in urban flood modelling using terrestrial LIDAR data,” Hydrol. Earth Syst. Sci., vol. 17, no. 10, pp. 4015–4030, 2013.
  20. N. A. Muhadi, A. F. Abdullah, S. K. Bejo, M. R. Mahadi, and A. Mijic, “The use of LiDAR-derived DEM in flood applications: A review,” Remote Sens., vol. 12, no. 14, Art. no. 2308, 2020.
  21. E. Huţanu, A. Mihu-Pintilie, A. Urzica, L. E. Paveluc, C. C. Stoleriu, and A. Grozavu, “Using 1D HEC-RAS modeling and LiDAR data to improve flood hazard maps accuracy: A case study from Jijia Floodplain (NE Romania),” Water, vol. 12, no. 6, Art. no. 1624, 2020.
  22. G. Choné, P. M. Biron, T. Buffin-Bélanger, I. Mazgareanu, J. C. Neal, and C. C. Sampson, “An assessment of large-scale flood modelling based on LiDAR data,” Hydrol. Process., vol. 35, no. 8, Art. no. e14293, 2021.
  23. E. Karamuz, R. J. Romanowicz, and J. Doroszkiewicz, “The use of unmanned aerial vehicles in flood hazard assessment,” J. Flood Risk Manag., vol. 13, no. 4, Art. no. e12622, 2020.
  24. E. Yalcin, “Two-dimensional hydrodynamic modelling for urban flood risk assessment using unmanned aerial vehicle imagery: A case study of Kirsehir, Türkiye,” J. Flood Risk Manag., vol. 12, no. 4, Art. no. e12499, 2019.
  25. H. Ozdemir and A. Akbas, “Evaluating the capability of UAV-derived DEMs for flood hazard analysis,” Phys. Geogr., vol. 46, no. 3, pp. 175–195, 2025.
  26. M. Utlu and H. Özdemir, “How much spatial resolution do we need to model a local flood event? Benchmark testing based on UAV data from Biga River (Türkiye),” Arab. J. Geosci., vol. 13, no. 24, Art. no. 1293, 2020.
  27. K. Xu, J. Fang, Y. Fang, S. Sun, Q. Wu, and M. Liu, “The importance of digital elevation model selection in flood simulation and a proposed method to reduce DEM errors: A case study in Shanghai,” Int. J. Disaster Risk Sci., vol. 12, no. 6, pp. 890–902, 2021.
  28. H. Özdemir and A. Akbaş, “Effects of spatial resolution variability in digital elevation models on flood hazard analysis,” J. Geogr., no. 46, pp. 137–156, 2023.
  29. Disaster and Emergency Management Presidency (AFAD), “Elazığ provincial disaster risk reduction plan (IRAP),” Republic of Türkiye Ministry of Interior, Ankara, Türkiye, 2021.
  30. S. Sertel and M. B. Sanyürek, “Disasters occurring in Elazığ (1931–1980),” J. Acad. Soc. Sci., vol. 49, no. 49, pp. 132–162, 2024.
  31. İhlas Haber Ajansı (İHA). Accessed: Apr. 10, 2026. [Online]. Available: https://www.iha.com.tr/haber-karakocanda-yagmur-dereleri-tasirdi-836723
  32. Elazığ Son Söz. Accessed: Apr. 10, 2026. [Online]. Available: https://www.elazigsonsoz.com/elazig-da-su-taskinlarina-karsi-ekipler-calisma-baslatti/10229/
  33. DHA, “Adres Elazığ: Dere taştı, mezra yolu ulaşıma kapandı,” Haber Global, Mar. 31, 2025. Accessed: Apr. 10, 2026. [Online]. Available: https://haberglobal.com/gundem/adres-elazig-dere-tasti-mezra-yolu-ulasima-kapandi-434238
  34. V. T. Chow, Open Channel Hydraulics. New York, NY, USA: McGraw-Hill, 1959.
  35. General Directorate of State Hydraulic Works (DSİ), Guide for Determining Roughness Coefficient for River Beds. Ankara, Türkiye, 2016.
  36. L. Hawker et al., “A 30 m global map of elevation with forests and buildings removed,” Environ. Res. Lett., vol. 17, no. 2, Art. no. 024016, 2022.