Abstract
The politics of Transboundary Water Security (TWS) reflect a complex interplay of power, discourse and competing national interests. Focusing on the Nile Basin and the Grand Ethiopian Renaissance Dam (GERD), this paper examines how water security has become a contested political and security concept between upstream and downstream riparian states. Drawing on primary data generated through in-depth and semi-structured interviews with senior Ethiopian officials, GERD negotiators and transboundary water experts, the study offers an empirically grounded and theoretically informed analysis of TWS, an area that remains underexplored within both security studies and transboundary water governance scholarship. The paper conceptualises TWS as an intersubjective field of struggle in which competing hydro-concepts: hydrosovereignty, hydrosecurity, hydrohegemony, hydropolitics and hydrosolidarity/hydroharmony are mobilised to advance divergent political claims. These hydro-concepts correspond to distinct security paradigms, including competitive, cooperative, collective, common and community security, revealing how water governance debates are embedded within broader security imaginaries. The analysis shows that the GERD has intensified these contestations while simultaneously exposing the limits of unilateral and securitised approaches to Nile governance. The paper argues that hydrosolidarity, grounded in cooperative sovereignty, where sovereignty is reimagined as hydrological interdependence rather than absolute territorial control, offers a viable pathway toward the emergence of a transboundary water security community in the Nile Basin.