Trophic state in the Catolé Grande River under different streamflow rates

Luciano Vieira Barreto; Micael de Souza Fraga; Flávia Mariani Barros; Felizardo Adenilson Rocha; Jhones da Silva Amorim; Stênio Rocha de Carvalho; Paulo Bonomo; Danilo Paulúcio da Silva

Luciano Vieira Barreto Universidade Estadual do Sudoeste da Bahia
Micael de Souza Fraga Universidade Federal de Viçosa
Flávia Mariani Barros Universidade Estadual do Sudoeste da Bahia
Felizardo Adenilson Rocha Instituto Federal da Bahia
Jhones da Silva Amorim Universidade Estadual do Sudoeste da Bahia
Stênio Rocha de Carvalho Universidade Estadual do Sudoeste da Bahia
Paulo Bonomo Universidade Estadual do Sudoeste da Bahia
Danilo Paulúcio da Silva Universidade Estadual do Sudoeste da Bahia

Keywords: monitoring, water quality, eutrofization

Abstract

This study evaluated the trophic state of Catolé Grande River under different streamflow levels in a cross section near the uptake point for the water supply of the town of Itapetinga, in Bahia State, Brazil. Water samples were collected in different months, corresponding to different streamflow levels. The Catolé Grande River’s trophic state classification was performed using two distinct methodologies, both based on phosphorus content. The streamflow was calculated by the product of velocity by cross section area. The results showed very high trophic classifications at the evaluated section, with the high levels of trophic status associated with high streamflows. The water classification at this section was hypertrophic between January and July of 2011, by both methodologies; however, from August to November of the same year, there were differences in trophic classification. Considering the average of the entire study period, the section was classified as hypereutrophic, regardless of the methodology used.