Title: Determining the floodway and flood fringe of the Gamasiab River, Kermanshah, Iran

Authors: Mohammad Mahdi Hosseinzadeh; Somaiyeh Khaleghi; Roya Panahi

Addresses: Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Postal Code: 1983969411, Iran ' Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Postal Code: 1983969411, Iran ' Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Postal Code: 1983969411, Iran

Abstract: All countries have specific rules for flood management and river protection. This study aimed to provide an appropriate solution for defining applicable hydraulic area and flood hazard to determine the floodway and flood fringe of Gamasiab River in Iran using HEC-RAS. The results showed that the floodway limit was corresponding to the old terraces in the reach 1. In the reaches 3 and 4, the floodway has expanded to more than 1200 m on average and most of the rural and urban settlements in Bistoon area have been located in the floodway. Therefore, the water level was changed from 38 cm to 1 m in the reaches 3 and 4. Finally, it is not possible to use a fixed water height for different rivers even in different reaches. Also the designated height was different based on the status of residential areas and topography of floodplains and riverside lands.

Keywords: floodway; flood fringe; encroachment; floodplain; return periods; reach; cross-section; management; HEC-RAS; Gamasiab River.

DOI: 10.1504/IJW.2022.132289

International Journal of Water, 2022 Vol.15 No.2, pp.117 - 130

Received: 30 Sep 2021
Accepted: 02 Jan 2023
Published online: 17 Jul 2023 *

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