Analysis and Comparison of Uplift Pressure and Seepage Rates in the Shatt al-Hilla Regulator for the Years 2017, 2018, and 2022 under the Influence of Climate Change

Abstract

The reduction in rainfall and increase in temperatures have led to a rise in water evaporation from rivers and fields, reducing water supplies from the upstream countries of the Tigris and Euphrates rivers. This contributed to a reduction in water flowing to the front of the Hindiyah Barrage, affecting the Shatt Al-Hilla regulator, which depends on the barrage's water. This resulted in lowering the up-stream water level of the Hindiyah Barrage from the recommended 31.90 m in the operating manual to 31.40 m. In this study, uplift pressures and seepage rates were compared for the years 2017 and 2018 (at a water level of 31.90 m) and 2022 (at a water level of 31.40 m). Results showed that uplift pressures were unaffected except when the downstream level was reduced below 29 m, which increased uplift pressures under the regulator's foundations. The highest calculated uplift pressures were 6.63, 6.3, and 6.72 ton/m² for the years of 2017, 2018, and 2022, respectively. Piezometers 27 and 28 showed higher values compared with others due to their location below the cutoff wall level. However, the drop in the upstream water level of the Hindiyah Barrage did not affect the structure's stability, as the uplift pressures and seepage rates remained within allowable limits. The Plexis software was used to simulate seepage and calculate the highest seepage rates, which were 2.37×10⁻⁴, 2.18×10⁻⁴, and 3.38×10⁻⁴ m³/s for 2017, 2018, and 2022, respectively, with satisfactory safety factors.