Objective: Transboundary waters in West Asia have, in recent decades, evolved from a purely environmental issue into a major factor shaping the region’s security and defense equations. Turkey’s Southeastern Anatolia Project (GAP), through creating structural asymmetries in the control of the Tigris and Euphrates water resources, has generated extensive environmental and human consequences for downstream states, particularly Iran. This study examines the mechanisms of Turkish hydro-hegemony and its implications for the environmental–defense security of the region with a focus on Iran.
Methodology: The research adopts a qualitative approach based on structural–explanatory foresight. Data were collected and analyzed through systematic content analysis of Turkish water policy documents, international water and environmental law instruments, reports of regional and international organizations, and related scientific studies.
Findings: The findings indicate that Turkey’s hydro-hegemony is reproduced through infrastructural control over water flows, institutional gaps, and the asymmetric transfer of environmental costs. The consequences of this structure—including wetland degradation, desertification, intensified dust storms, and declining water quality—have been transmitted transboundary to Iran and manifested as soft defense risks.
Conclusion: The results suggest that the future of Iran’s environmental–defense security depends on its ability to intervene strategically in hydro-hegemonic structures. Strengthening water diplomacy, regional cooperation, and territorial resilience can play a significant role in reducing security vulnerabilities arising from the regional water crisis.