The São Francisco river crosses some of the driest parts of the Brazilian Semi-arid Region and brings life to ecosystems and to millions of people. Droughts are a recurrent problem in the basin. Since the second part of the twentieth century, several dams, irrigation projects, and water and sanitation systems have been built, and these developments have impacted river conditions, such as stream flows, sedimentation, silting, and water quality. The development of the river, and its engineering solutions, have prioritized the hydroelectric and agricultural sectors. This has started to change with the new water law of 1997 and the creation of the National Water Agency (ANA) in 2000. This chapter reviews current water management and use in the basin as well as the scenarios, which indicate that, in the future, precipitation and stream flows may be reduced significantly due to climate change while water demand will increase due to population growth and development.

On top of dealing with climate change impacts on rainfall and temperature, and rising populations and development, the Euphrates–Tigris basin also faces conflict and instability. The Syrian Civil War, the presence of many nonstate armed groups, and the lack of coordination between Turkey, Syria, and Iraq to manage the water resources can lead to continued political confrontation and economic disintegration. This complicates the existent issue of nexus in the Euphrates–Tigris basin. The conflicting needs of energy, water, and food require more coordination not just between countries but between sectors within the countries. Each sector must be allocated a certain amount of water based on the needs it fulfills for the country. If violence continues and instability in the region is not resolved, these demands may increase and further pressure the basin.