Impact of climate change on evaporation in Mosul Dam reservoir-Iraq

Water resources in Iraq are among the elements most affected by climate change, especially water bodies. One of the most significant losses in semi-arid countries is the evaporation of water from reservoirs. For this reason, studying this issue is essential. In this context, the Mosul Dam Reservoir was selected as a case study to analyze the effects of climate change. The research involved a detailed analysis of climatic data from 1990 to 2020, focusing on the impact of individual climatic variables on evaporation. We developed a mathematical model that incorporates five key climatic variables to estimate evaporation and used it to make projections for the coming years. The results showed that the reservoir loses approximately 0.9 billion cubic meters of water annually due to evaporation. The analysis revealed an increasing trend in evaporation rates, with a 13.6% increase over 30 years. Using the SPSS software, we found that: • Temperature has the strongest direct effect on evaporation, • Humidity has an inverse effect, • Sunshine hours contribute a direct effect, and • Rainfall has a moderate inverse effect. The developed evaporation model for the Mosul Dam Reservoir showed a high level of accuracy, with an R² value of 95.6%. Additionally, the study found that the storage volume of the reservoir has been steadily decreasing over the study period. Given the critical influence of temperature and rainfall, we made future projections using the SDSM program. The model predicts that by 2050, the average temperature will be 0.3°C higher than in 2023. Meanwhile, precipitation levels are expected to continue declining—4.9% lower than in 2023, and approximately 50% lower than in 1990.