Geometric Study of the Lesser Zab River Channel Between Altun-Kupri City and Dibbs Dam, Kirkuk, Northern Iraq

Soran N Sadeq

doi:10.46717/igj.54.1f.4ms-2021-06-24

Abstract

River Lesser Zab in N Iraq flow regime has been changed as a result of building a number of dams across the river course causing the cross-section of the river to vary in time and space. The aim of this study is to investigate the morphological changes for the river channel from AltunKupri City to Dibbs Dam. Five cross-sections were studied to explain the relation between hydraulic geometry parameters (width, depth, and velocity) versus river discharge using linear regression analysis, and the results show that river discharge does have a direct linear relationship with the morphologic parameters of the river channel, and the width-depth ratio has a positive linear relationship with mean flow velocity, and negative nonlinear relationships with cross-section area, indicating widening of river reaches due to the morphological and geologic components of river banks. The meander channel system in the study area can be described as a single phase, irregular width variation with high lateral erosion rate for a meander bend. Also, the river has numerous perennials elongated to subrounded alluvial islands, which are covered by shrubs or houses for local inhabitants. These outcomes are expected to be useful in developing water resources projects in the area.

Highlights

Rivers are considered as the lifelines of human civilization because they have always been essential for various human purposes;
This study shows that the river discharge does have a direct, nonlinear relationship with the morphologic parameters of the river channel
Shape, and geomorphic expression suggest that these islands are unstable, some may disappear, and some will change their dimensions, and the change is in the direction of the movement of water currents. These islands are covered by shrubs or houses for local inhabitants. characterized by woody vegetation or human habitation, they are originated due to many causes; primarily attributed to the river regime, high amount of river sediments load during heavy rainfall season, and human activity throughout the building of several dams across the river course which has a great effect in reserving large quantities of sediments in dam lakes affecting the development of river island

Summary

Introduction

Rivers are considered as the lifelines of human civilization because they have always been essential for various human purposes; (water for domestic, livelihoods, industrial and agricultural purposes). Leopold and Maddock (1953) studied hydraulic geometry analysis of river channels to calculate the relationship between hydraulic variables such as the width of the river channel, average depth, and mean velocity with river discharge changes. Various studies, conducted to predict the morphology of the river and to correlate hydraulic channel geometry variables. They are mathematically interrelated as a power function using the linear regression model. They are mathematically interrelated as a power function using the linear regression model. Rosgen (1994 and 1996) classified the stream system according to several hydrological, geological and hydraulic geometry features of the river basin (Hadadin, 2017). Schumm (1968) evaluates several empirical data taken from sandy bed channels to study the influence of boundary sediments on meander wavelength using an index based on the percent of silt and clay content in the river bed and bank

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Conclusion