Drought impacts, social organization, and public policies in northeastern Brazil: a case study of the upper Paraíba River basin.

The upper Paraíba River basin plays a key role in controlling the flow from the Epitácio Pessoa Reservoir, a major reservoir in the semiarid region of Paraíba state. The objective of this study is to analyze historical droughts and public policies and their impacts on the social organization in the upper Paraíba River basin, which is located in the semiarid region of Brazil. In this study, the following methodological procedures were used: (a) historical survey of drought occurrence and dam construction in the semiarid region of Brazil, (b) data processing of hydrologic records (rainfall and streamflow), and (c) field visits to collect and compare data on the changes in the volume of water stored behind dams. The results showed that state intervention in the semiarid region follows a trend based on the characteristics of each historical moment and the interests of the groups that comprise the state sector. It is also observed that the implementation of several public policies, such as social programs, construction of dams, and the transfer of water from the São Francisco River, has resulted in significant changes in the streamflow behavior in this semiarid region. These changes have differed in magnitude depending on the hydrological characteristics of each period (i.e., dry, rainy, or normal). Finally, the use of dams for water management in the semiarid region was identified as the main factor influencing water security and social organization.