1. Researcher, Center of Water Resources and Applied Ecology, Engineering School of São Carlos, Dept. of Hydraulics and Sanitation, Univ. of São Paulo, Av. Trabalhador São Carlense, 400, São Carlos, SP 13566-590, Brazil (corresponding author).
2. Professor, Center of Water Resources and Applied Ecology, Engineering School of São Carlos, Univ. of São Paulo, São Carlos, SP 13566-590, Brazil.