Effect of DEM Resolution on Hydraulic Modeling of Flood Inundation Area: Case Study of Gorganrood River, Northeast of Iran

Khojeh, Shokoufeh | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54048 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Ataie Ashtiani, Behzad
  7. Abstract:
  8. Digital Elevation Models (DEM) is a crucial element of hydraulic models, including floods. Due to the lack of high-precision topographic data, including ground-based mapping hydraulic modeling is challenging. In recent years, remote sensing data, extensively used by many researchers in hydraulic modeling due to global coverage and free access. One of the most critical questions in hydraulic modeling is the efficiency of these DEMs in flood simulation. This research focused on using remote-sensing-based DEMs, such as SRTM-30m and 90m, ASTER-30m, and ALOS-12.5m DEMs, on the performance of the HEC-RAS-2D model in the Gorganrood river.The results showed that ALOS and SRTM-30m DEMs' accuracy and capability is higher in flood modeling than other sources. The average error of using these two sources in simulating inundated extent is approximately 50%. According to the results, the ALOS, SRTM-30M, and SRTM-90M DEMs estimate the peak discharge with good accuracy and typically have a 20% error. In Contrast, the ASTER's performance was not satisfactory whether in peak discharge estimation or flood extent determination (in both average errors 70%). According to this study, urban areas, agricultural lands, forests, and bare lands are more vulnerable to floods, respectively. As an overall calculation, one can deduce that ALOS and SRTM-30M are more capable of flood modeling in flat regions for deriving flood inundation mapping, especially in estimation peak flow. Also, according to the better performance of the SRTM-90M than the ASTER, it can be inferred that the use of a different source than the DEM resolution has more effect on the hydraulic model's output
  9. Keywords:
  10. Risk Assessment ; Hydraulic Model ; Flood Zoning ; Gorganrood River ; Digital Elevation Model (DEM)

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