Aquifer System Urucuia: governance and integrated water management in the São Francisco River Basin - Brazil's Northeast
The San Francisco River basin has 2.696 km and 638.576 km2 of drainage basin, which surrounds parts of of Alagoas, Bahia, Goiás, Minas Gerais, Pernambuco and Sergipe states, plus the Federal District. Most of water withdrawal of 181 m3/s, 63%, is used to irrigation of 500.000 hectares, mainly located in the Middle São Francisco. This region consumes more than half of the flow of irrigation to products fruits and grains (soybeans, cotton and corn) for the foreign market.The region has experienced water stress due to increased demand for water resources, resulting in growing exploitation of groundwater Aquifer System Urucuia (SAU), a regional aquifer which covers an area of ??76,000 km2, ranging from southern Piauí to northwest of Minas Gerais, majority located in western Bahia.The São Francisco River Basin is an example of water conflict due to multiple and tensioning uses. High rates of extracted flow, water pollution, energy production, navigation, prolonged drought effects and, recently, disputes related to water diversion to ensure water security to Northern Northeast constitute a mix of threats and drivers of conflicts. This aquifer has great potential, in part already exploited, to supply the urban and irrigation demands. At the same time it plays an important role in regulating the river flow, especially in periods of drought, which in the region of Sobradinho, for instance, accounts for 90% of the flow.The Urucuia can be described as an open access aquifer, making it vulnerable to contamination by agricultural chemicals and reduction of natural recharge, product of pores compaction that reduces rainwater infiltration. Furthermore the greater part of this aquifer recharge area coincides with new expansion of agriculture irrigated areas. On the other hand, over-pumping is likely to interfere with its contribution to baseflow maintenance to Corrente, Carinhanha and Grande rivers, tributaries of São Francisco River.Between 2003 and 2006 the number of grants of Urucuia water exploitation for irrigation increased by 123%, from 4,500 m3/h to 14,340 m3/s, increasing in 320% the removal flow. It is worth noting that in Brazil there is a serious problem related to illegal wells in operation; it is estimated that for every given well there are other three not granted. This has consequences for the sustainable management of groundwater resources.On the exposed complexity above and considering the climate change consequences, this article uses the concept of governance related to socio-cultural, economic, ecological and institutional. It aims to analyze public, social and private interests to harmonize the proposals of different users in order to permit a sustainable development and use of water resources. In addition, it will be analyzed how the concept of Integrated Water Resources could enhances governance and water security in this basin.