Analysis of Channel Form and Evaluation of the Givi Chay River Power (from Givi Dams to the Annex to the Ghezelozan River)

Rivers have different patterns along their path, and understanding these patterns could help researchers understand and predict the responses of human activities and natural factors of the river. In addition, in the morphological analysis, the flow power is one of the most important parameters. Therefore, the purpose of this study was to analyze the channel form and to evaluate the river power in different return periods as well as to estimate the shear stress in the Givi Chay River using Landsat 8 images, topographic maps, geology, hydrological, and field data. Morphological and hydrological indices, as well as methods for analyzing the total river power, river specific power, and shear stress, were used to achieve the purpose of the study. The calculation of the bending coefficient showed that the river pattern was sinusoidal in the first and third intervals and was meandering in the second interval. According to the central angle characteristics, the first and the second intervals were in the highly-developed meandering form and the third interval was in the developed meandering form. Also, according to the results of the study, the highest amount of the total river power was in the first interval at the 4th, 5th, and 6th sections. The specific strength of the river was high in the third intervals and the 2nd, 1st, 5th, and 6th sections. At present, due to the low strength of the lithological formations in these sections, the erosion of the riverbed is observed in these sections. The lowest specific power was due to the high river width and low bed slope at sections 12 and 13. The highest amount of shear stress was in the first interval in sections 5, 6, 2, and the lowest shear stress was in sections 12 and 13. In general, channel formation and channel dynamics in the Givi Chay River were influenced by discharge, lithological resistance of the riverbed, and human interference (encroachment on the riverbed, construction of bridges, and dumping of construction waste and debris).