Professor Dr. Saleh Issa Khassaf, a faculty member in the Civil Engineering Department at our college, supervised a doctoral dissertation in Civil Engineering at the College of Engineering, Al-Nahrain University. The dissertation, titled "Improving the Stability of Earth Dams Subject to Leakage Using Various Additives," was co-supervised with a faculty member from the Civil Engineering Department at Al-Nahrain University, specializing in Geotechnical Engineering. The dissertation defense took place on Thursday, February 12, 2026, in the Al-Rafidain Hall at the College of Engineering, Al-Nahrain University. This thesis focuses on improving the sandy soils extracted from Mount Sanam in Basra Governorate by adding various additives. These additives were carefully studied using laboratory physical models and engineering tests, as well as comparisons with numerical models. The results were highly consistent. The researcher concluded that sandy soils can be used in the cores of earth dams by adding lime and fly ash in specific proportions to control seepage, instead of using clay when the material is unavailable at the dam construction site. This is an application of sustainable engineering. After extensive discussion by the examining committee, the thesis was accepted, and the student was awarded a distinction. At the end of the discussion, the Dean of the College of Engineering at Al-Nahrain University presented a letter of thanks and appreciation to Professor Dr. Saleh Issa Khassaf in recognition of his significant scientific efforts in supervising this thesis and for his continued scientific collaboration between different Iraqi universities.