Calculating the Water Deficit and Surplus in the Levels of the Euphrates River Using the Equations of Ivanov and Najib Kharrufa

The science of hydrology focuses on the earth’s waters, including their occurrence, circulation, and distribution, as well as their physical and chemical characteristics and interactions with the surrounding biological and physical environments, including how they react to human activity. Climate is one of the natural factors that directly or indirectly affect the formation of the hydrological characteristics of the Tigris and Euphrates rivers. The data used for the study area included rainfall, evaporation rate, relative humidity, wind speed, length of sunshine hours, Temperature, and water discharge. Data were obtained from NASA, the US National Administration, the Ministry of Water Resources, and the General Authority of Meteorology and Seismic Monitoring from 2013 to 2023. The study area included three stations through which the Euphrates River passes, which is considered one of Iraq’s main rivers. The results obtained using the Ivanov and Najib Kharoufa equations indicate a clear water deficit in the Euphrates River, primarily driven by climatic changes. Notably, reductions in rainfall and increases in evaporation rates have been observed, particularly as the river progresses southward. These climatic changes, such as rising temperatures, increased wind speed and directional variability, higher water surface area exposure, and extended daylight hours, have collectively contributed to significant water losses and a decrease in river discharge. Furthermore, the river’s flow has notably diminished in its southern reaches, where observational stations are located. This is largely due to the region’s low surface gradient, which slows the river’s velocity and exacerbates evaporative losses. In addition to climatic factors, several modern anthropogenic influences have significantly impacted the Euphrates’ flow. Chief among these is the construction of large upstream dams, most notably the Atatürk Dam in Turkey, which has greatly reduced the volume of water reaching downstream countries. The modification and diversion of tributaries and feeder waterways for agricultural irrigation and domestic use have further restricted inflows. Climate change continues to play a critical role by decreasing precipitation and intensifying evaporation, ultimately resulting in substantial losses from both the river and its associated reservoirs. , as it was found that a water deficit occurred in the Hilla, Samawah, and Nasiriyah stations during January, with an average for the period of 10 years and according to the equation Ivanov and respectively -150.5 mm, -166.8 mm and -120.4 mm. The percentage of water deficit, according to the sheep equation for the above stations and for January and the same period, was estimated at -48.5 mm, -46.3 mm, and -41.1 mm, respectively. The primary cause of these water deficits is the high rates of water evaporation observed at the southern stations of the study area, particularly in Samawa and Nasiriya. This is largely attributed to the difference in the angle of incidence of the sun’s rays, which is more oblique in these southern locations compared to the northern stations. Additionally, the increased movement and speed of the wind, particularly in the central and southern regions of the study area, contribute to elevated evaporation rates, leading to higher water losses.