This book examines Nile water security through the morphology of the river: it uses the always changing form of the river as a theoretical and empirical device to map and understand how infrastructures and discourses dynamically interact with the Nile. By bringing a history of two centuries of dam development on the Nile in relation with the drainage of a hill slope in Ethiopia on the one hand and irrigation reform in Sudan on the other, the author shows how the scales, units and ‘populations’ figuring in projects to securitize the river emerge through the rearrangement of its water and sediments. The analysis of ‘Making water security’ is more than yet another story of how modern projects of water security have legitimized often violent dispossessions of Nile land and water. It shows how no water user is confined by the roles assigned by project engineers and planners. As ongoing modern ‘development’ of the river reduces the prospects for new large diversions of water, the targeted subjects of development and modernization make use of newly opened spaces to carve out their own projects. They creatively mobilize old irrigation and drainage infrastructures in ways that escape the universal logic of water security.