Analysis of the Euphrates River’s movement within Al-Hindiya, Karbala, relative to steady flow conditions using the HEC-RAS model

Abstract

Abstract The steady flow condition is considered to be the dominant case for multiple rivers around the world. River studies thus necessarily focus on this condition, including those in Iraq, which has two rivers running from north to the south. In this study, the HEC–RAS program was applied to steady flow analysis of the Euphrates River within Al-Hindiya in Karbala. The case study was executed for the whole city of Al-Hindiya by selecting 12 km length of the river and dividing it into 30 sections. Field data for 2019 was thus used to develop three profiles for discharge at minimum, normal, and maximum magnitudes, which were 90 m3/sec, 250 m3/sec, and 445 m3/sec, respectively. The results showed that the maximum variation ratios in velocity between sections were 80%, 70%, and 72% for the minimum, normal, and maximum profiles, respectively, with the variation ratios in water level between reach ends being 4%, 6%, and 5% and the slopes of energy grade lines were about 0.009%, 0.015%, and 0.013% for the three profiles respectively. In addition, the regression analysis of the results revealed that the relative energy losses between any two adjacent sections are linked strongly to the relative change in water level for the normal and minimum profiles, with coefficients of determination R2= 0.88 and 0.96 for these profiles, respectively; however, for maximum discharge, the relative energy losses were related to the relative change in both velocity head and water level, with R2 = 0.94.