Transfering water among basins: an ecological assessment of Northeast Brazilian reservoirs

Abstract

The national project of the São Francisco river integration on northeast basins, lead by the Brazilian Ministry of National Integration, aims to transfer water from this river to different councils of the northeast semiarid region with limited water resources. This study aims to characterize the current ecological status of three northeast reservoirs that will receive water from the São Francisco River. In this work we present results from three monitoring campaigns, in 2009 and 2010, concerning physical-chemical and biological parameters. In relation to physical-chemical and microbiological parameters, the results demonstrated that some of them were in discordance with the legislated standards (total phosphorus, chlorophyll,and some metals). The phytoplankton community was similar in all reservoirs. A high diversity was found in chlorophyceae group, which contrasts with cyanobacteria blooms dominated by Microcystis sp., Anabaena sp. and Cylindrospermopsis raciborskii. In general, the benthic macroinvertebrate community was represented by Mollusca as the predominant group. The Eichhornia crassipes and Eichhornia azurea were the most abundant macrophytes. A global analysis of results showed the existence of contamination problems in all reservoirs, probably due to effluents from domestic and agricultural activities that directly drain to their water bodies.