Environmental flow in the River Ondas basin in Bahia, Brazilian Cerrado

• Published in: Environmental monitoring and assessment 2016, Vol.188 (1), p.68-68, Article 68
• Main Authors: de Souza Castro, Elis Regina Rodrigues, Moreira, Michel Castro, da Silva, Demetrius David
• Format: Article
• Language: English
• Subjects: adults; Atmospheric Protection/Air Quality Control/Air Pollution; Basins; Biodiversity; Brazil; cerrado; Conservation of Natural Resources; Earth and Environmental Science; Ecology; Ecosystem; Ecosystems; Ecotoxicology; Environment; Environmental Management; Environmental monitoring; Environmental Monitoring - methods; habitats; Humans; Hydraulics; Hydrology; Hypostomus; juveniles; Models, Theoretical; Monitoring/Environmental Analysis; probability; Rivers; Software; Stream discharge; Stream flow; Values; Water availability; water management; Water Movements; Water resources management
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-015-5063-8

This paper aimed to estimate the environmental flow of a water basin located in the Brazilian Cerrado using the bidimensional model River2D. The study was carried out in a stretch of the lower portion of the River Ondas in the western part of the state of Bahia, Brazil. To carry out the ecohydrological modeling, the following were used: topobathymetry, hydraulic characterization, the streamflows with the probability of non-exceedances (Q₅₀, Q₆₀, Q₇₀, Q₈₀, Q₉₀, and Q₉₅), and the Habitat Suitability Index for species of the genus Hypostomus. In the River2D, the weighted usable areas (WUAs) pertaining to the streamflows associated with different non-exceedances were simulated for the later construction of optimization and identification matrices of the streamflows that maximize the habitat area throughout the year. For juvenile Hypostomus, WUA increased as streamflow increased, with higher values associated with Q₅₀. For adult specimens, lower WUA values were observed associated with Q₅₀, while higher values were associated with Q₉₅, which shows a preference for lower streamflows. The environmental flows found for the stretch of the River Ondas varied over the course of the year. The lowest environmental flows were observed in September (30.31 m³ s⁻¹) and October (29.98 m³ s⁻¹), while the highest were observed in February (44.22 m³ s⁻¹) and March (43.16 m³ s⁻¹). The environmental flow regime obtained restricts the water availability in the basin, for the purpose of water capture, which shows the importance of ecohydrological studies in forming a basis for water resource management actions.