Complex sentence: Along with the old Aswan Dam, the Assiut Dam today remains in service as the oldest dam on the Nile in Upper Egypt the two other old dams (Naga Hamadi and Isna Barrages) have been rebuilt in the 1990s.
Split into simpler sentences: Along with the old Aswan Dam, the Assiut Dam today remains in service as the oldest dam on the Nile in Upper Egypt. The two other old dams (Naga Hamadi and Isna Barrages) have been rebuilt in the 1990s.