Influence of river cross-section data resolution on flood inundation modeling: Case study of Kashkan river basin in western Iran

Fatemeh Geravand, Seiyed Mossa Hosseini, Behzad Ataie-Ashtiani

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9 Citations (Scopus)

Abstract

In this study, a coupling of a hydrologic and hydraulic model was utilized to assess the impacts of river geometry data resolution on the flood inundation characteristics in a data-scarce environment. Hydrological modeling incorporates soil conservation service curve-number (SCS-CN) and the geomorphologic based instantaneous unit hydrograph model (GIUH) to compute the direct runoff hydrograph in Kashkan river basin located in western Iran. 1D HEC-Geo-RAS model was used and performed to simulate inundation extent of 100-yr floods (~1800 m3/s) along 40 km reach of Kashkan river with a ground survey of river cross-section (2000 cross-sections, each including 500 data-points). The effect of cross-section spacing (20 m to 5000 m) and dataset resolution along cross-section (5–500 points) on 100-yr (~1800 m3/s) flood inundation extent area (FIA), average flow depth (FD), and velocity (FV) in river centerline were scrutinized. Results indicate that coarser cross-section spacing (20–5000 m) showed an overestimating tendency to simulate FIA (~5.75%), FD (391.34%), and FV (31.2%). While increasing grid resolution (5–500 points) on cross-section tends to underestimate of FIA (17.84%),FD (84.13%), and FV (49.12%). The predominant effect of cross-section spacing on FIA, FD, and FV was found compared to the number of data-points on a cross-section. Results of this study could potentially be considered as a baseline for mapping of flood inundation extent in the environment that ground or remotely sensed high-resolution topographic data of river cross-section are scarce while making a trade-off between model accuracy, computational time, and cost of data compilation is crucial.

Original languageEnglish
Article number124743
Number of pages15
JournalJournal of Hydrology
Volume584
DOIs
Publication statusPublished - May 2020

Keywords

  • Cross-section data resolution
  • Data-scarce environment
  • Flood inundation
  • HEC-Geo-RAS
  • River basin modeling

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