This chapter explores the Southeastern Anatolia Development Project (GAP), a transformative yet controversial infrastructure initiative aimed at revitalizing Turkey’s Southeastern Anatolia region. Inspired by U.S. River Basin Planning models like the Tennessee Valley Authority, GAP sought to modernize agriculture, energy production, and social infrastructure through extensive dam construction and irrigation projects. While projects like the Ilisu Dam have contributed to energy generation, they have also resulted in significant cultural, environmental, and social costs, including the flooding of the ancient city of Hasankeyf and strained water-sharing relations with downstream neighbors of Iran and Iraq. The chapter emphasizes how major infrastructure projects often rely on cost calculations that fail to capture the full spectrum of long-term impacts, prompting questions about the trade-offs between nascent economic benefits and preservation in hydrological megaprojects.