2) Water resources in the Brazilian Northeast; brief history

In ancient times the Brazilian Northeast was inhabited by numerous indigenous societies among which the largest were the tupinamba, the potiguara, the caete, the tapuia, the tupina and the tupinikin. These nations mainly dedicated to fishingⁱ and roça farmingⁱⁱ . According to historical chronicles and documents the population for the whole region at that time could be estimated at several millionⁱⁱⁱ.

The arrival of Portuguese navigators took place during the late fifteenth and early sixteenth century (Alvaro Cabral arrived by “accident” in 1497). In 1532, Martin Afonso de Sousa established two colonies in the island of São Vicente and in Piratininga (present São Paulo). Two years later King João III divided the coast in 14 hereditary captaincies, most of which were not occupied immediately. The Northeastern Captaincies were Maranhão, Pernambuco, Bahia and Ilheus).

In 1535, the city of Olinda was founded (in the territory of present Pernambuco), and in 1537, the city of Recife, also in Pernambuco, was established. In 1549 was founded Salvador in the Itaparica bay, and at a later date, João Pessoa (1585), Natal (1599), Fortaleza (1611) and São Luis (1612). During the sixteenth and seventeenth century the economy focused on sugar cane production, based on native slave labor. During that period indigenous people were captured and forced to work in the plantations. Mistreatment, disruption of communities and families, and repression, reduced native population dramatically and to compensate for the lack of labourers, African slaves were brought (also by force) from Africa to do the plantation work.

Descendants from those native populations and African forced migrants (including many who managed to escape and establish rebel communities or quilombos in the interior) represent the majority of the population in contemporary Brazilian Northeastern urban and rural societies.

The extremely unequal distribution of land property, as a result of concentrated grants by the Portuguese and Brazilian Crowns, which continued without major changes in the Republic period, as well as the highly inappropriate management of native ecosystems (logging and burning of primary forests and bush-lands, inadequate farming, over-grazing, over-irrigation) produced a badly degraded landscape.

During colonial times, the largest river of the region, the São Francisco, became the main route of penetration into the continent from the coastal Atlantic settlements. Bandeirantes (slave raiders) would navigate the river to capture slaves for the sugar cane plantations, and at a later date (early XVIII century) miners and other adventurers used the river to reach the gold producing areas of Minas Gerais (Ouro Preto).

During the nineteenth century the São Francisco became a transportation route for people and for merchandises produced in the interior.

The historical importance of the river São Francisco cannot be underestimated. Because it is the only river entering deeply into the continent from the Atlantic façade, it has been the backbone of many historical and political events in Brazil. It is called “the river of Brazilian unity”, and, in fact, it crosses vast expanses of the Brazilian interior and, in that way, provided one unique route for exchange and communication between communities, cities, producing areas and commercial centers.

However, the heavy exploitation of the basin, mainly through extensive processes of deforestation, produced deep changes in river dynamics and water quality. Droughts and floods became more prevalent, run-off rates and erosion augmented, and consequently, river water, presently loaded with sediments (i.e. clay and silt, even sand and pebbles) and increased turbidity, has lost a great deal of its original biological productivity.

During the twentieth century, several large water projects were developed in the basin, including the three largest dams (Tres Marias, Sobradinho and Itaparica) and numerous irrigation schemes. The dams produced a mixed balance: on the one hand, they reduced the sediment load arriving to the lower basin and regularized the flow, on the other hand there was increased evaporation in the lakes and consequently decrease in the average water available in the lower stretches of the river. Also, the lakes were utilized as sources of water for several irrigation projects in Minas Gerais, Bahia and Pernambuco introducing additional modifications to the São Francisco hydro-system.

Lately, a project of water transposition was proposed to deviate water from the São Francisco dams of Sobradinho and Itapacarica, towards several northeastern basins in the Northeast (i.e. Jaguaribe, Acodi, Piranhas and Paraiba rivers) and to smaller basins in Central and Western Pernambuco. This issue is explored in section 6 of this paper.

i Potiguara means “shrimp eaters”

ii Roça planting is done through partial logging and burning. Main crops included manioc, corn, sweet potato and tobacco.

iii It is difficult to know the exact numbers. Alfonso Braz wrote in 1551: “There are so many of them and land is so good and their increasing in such numbers, that if they weren’t constantly in war and eating each other the land couldn’t contain them” Source: “Red Gold” from John Hemming, 1978