Effect of Geometric Characteristics of Rivers on Design Discharge in Arid and Semiarid Rivers

Karabi, Ehsan; Majdzadeh Tabatabai, Mohammad Reza; Ghoreishi Najaf Abadi, Seyed Hossain

doi:10.22055/jise.2016.12016

Effect of Geometric Characteristics of Rivers on Design Discharge in Arid and Semiarid Rivers

Document Type : Research Paper

Authors

Ehsan Karabi

Mohammad Reza Majdzadeh Tabatabai

Seyed Hossain Ghoreishi Najaf Abadi

10.22055/jise.2016.12016

Abstract

Appropriate estimates of flows for different return periods are important for floodplain management in designing canal, bridges, culverts and levees. In general, there are two common approaches to determine design flows at ungaged sites: Rainfall-runoff models, which are often costly and time consuming, and regression models, in which design flows of various return periods are related to watershed characteristics such as drainage area, topographic features, soils and climate. In the present study, bankfull-geometry data as well as flashiness index are used as effective independent variables in regression models to evaluate design flows relationships at 41 streamflow-gauging sites in Gara-Gum basin of Khorasan-Razavi province located in an arid and semiarid region. The bankfull geometry regression is found to be useful to predict design flows and comparable with flow estimates developed by traditional approaches for ungaged sites in the same basin. As, in three stations in this study area, the error in computations, compared with the method of frequency analysis, was 8% for bankfull hydraulic geometry relationship.

Keywords

Design flow

Bankfull

River geometry

Flashiness index

Ungaged sites