Since the 1960s, Turkey has placed the management and exploitation of common transboundary waters—such as the Tigris, Euphrates, Orontes, Aras, and other shared basins—at the center of its development policies and foreign relations. Large-scale projects like the Southeastern Anatolia Project (GAP) and Eastern Anatolia Project (DAP) have been designed to secure food production, drinking water supply, industrial growth, and energy production while addressing regional inequalities. These projects, however, coincide with the growing international attention to the scarcity of freshwater and the need for sustainable management of shared resources. As international law evolved through instruments such as the 1966 Helsinki Rules and the 1997 United Nations Watercourses Convention, principles of equitable and reasonable utilization, prevention of significant harm, cooperation, and environmental protection emerged as binding norms guiding states’ conduct. Turkey’s actions—although not based on accession to the 1997 Convention—reflect partial compliance with these norms through bilateral agreements, water release protocols, and gradual alignment with European Union water directives. Yet, tensions remain regarding downstream impacts in Syria, Iraq, Iran, and other riparian states. This article examines whether Turkey’s water policies and infrastructure projects conform to established international legal standards and how they influence Iran’s water security and ecological stability.
Introduction
Water is a vital yet limited resource, and its scarcity has become one of the major drivers of international and regional policies. Turkey, as an upstream country to several major transboundary rivers such as the Tigris, Euphrates, Orontes, Aras, Choruh, and Maritsa, has since the 1960s placed water at the heart of its development agenda. Through large-scale projects like the Southeastern Anatolia Project (GAP) and the Eastern Anatolia Project (DAP), Turkey has sought to increase agricultural production, enhance food security, supply drinking water for rural and urban areas, reduce dependence on imported energy, and address regional socio-economic inequalities. However, these national initiatives inevitably affect downstream countries—such as Syria, Iraq, and Iran—and therefore must be examined against the backdrop of international water law. Over time, the international community has formulated core principles such as equitable and reasonable utilization, the obligation not to cause significant harm, and the duty to cooperate. These principles are embedded in instruments like the 1966 Helsinki Rules and the 1997 UN Convention on the Law of the Non‑Navigational Uses of International Watercourses. This study investigates whether Turkey’s policies and actions conform to these norms and explores their implications for Iran’s water security and ecological balance.
Methodology
The research adopts a descriptive–analytical method with a comparative perspective. First, relevant international legal instruments were reviewed, including historical milestones (Madrid Declaration 1911, Helsinki Rules 1966) and contemporary frameworks (1997 UN Watercourses Convention, 1992 UNECE Water Convention). Next, bilateral agreements and published governmental statements from Turkey were examined to assess their alignment with these norms. Case studies of specific river basins—Tigris, Euphrates, Orontes, Aras, Choruh, and Maritsa—were analyzed to illustrate how Turkey has implemented or deviated from these principles in practice. Academic literature in both international law and hydropolitics, as well as reports by organizations such as the UN and regional research centers, provided context and validation. Special attention was paid to the impact on Iran as a downstream or co‑riparian state, particularly regarding the Aras River and the broader implications of Turkey’s upstream activities.
Results and Discussion
The findings reveal a nuanced picture. Turkey has historically grounded its water policies in the doctrine of absolute territorial sovereignty, asserting full control over resources within its borders. This stance led to tensions with Syria and Iraq over the Euphrates and Tigris, particularly during the construction of massive dams in the 1970s and 1980s. Downstream impacts included reduced flow, ecological stress, and heightened political disputes. In the Aras basin, projects affecting flow and water quality have generated diplomatic concerns in Iran, Azerbaijan, and Armenia. Similar dynamics are evident in the Orontes basin shared with Syria and Lebanon, where Turkey’s control over upstream sections has been contested. However, the research also documents gradual shifts. Turkey has entered into bilateral protocols on water releases, participated in joint technical committees, and increasingly refers to principles resembling equitable use. These measures, while not equivalent to ratification of multilateral conventions, signal partial compliance with customary norms. Furthermore, Turkey’s aspirations for EU membership have driven reforms in its domestic water governance, aligning parts of its legal framework with EU water directives and environmental standards.
The analysis of specific legal instruments shows that although Turkey has not acceded to the 1997 UN Watercourses Convention, many of its principles—such as equitable and reasonable utilization (Articles 5 and 6), the obligation to prevent significant harm (Article 7), cooperation and data exchange (Articles 9 and 10), and protection of ecosystems (Articles 20–23)—are reflected in Turkey’s evolving policies. For example, in managing the Maritsa and Choruh basins, Turkey has demonstrated readiness to coordinate flood management and drought mitigation with Bulgaria, Greece, and Georgia, indicating recognition of mutual interests and shared responsibilities. In contrast, in the Tigris and Euphrates basins, cooperation remains limited and tensions continue, illustrating the gap between legal norms and political realities. For Iran, these findings highlight both risks—such as reduced water inflows and ecological degradation—and opportunities, including potential leverage in advocating for internationally recognized principles.
Conclusion
In conclusion, Turkey’s approach to transboundary water management illustrates the complex interplay between national development priorities and international legal obligations. While historically dominated by a sovereignty-centered perspective, Turkey’s policies have gradually moved toward partial alignment with global norms through bilateral cooperation, institutional reforms, and environmental considerations. Nevertheless, significant challenges remain, particularly in fully embracing multilateral frameworks like the 1997 UN Watercourses Convention, which embodies widely accepted customary principles. For Iran and other co‑riparian states, understanding Turkey’s evolving stance is critical. It offers avenues for constructive dialogue, legal arguments rooted in internationally recognized norms, and frameworks for negotiating future water-sharing agreements. As water scarcity intensifies in the region, the need for comprehensive, legally sound, and environmentally sustainable cooperation becomes ever more urgent, making the lessons from Turkey’s experience highly relevant for policymakers and scholars alike.