RELATIONSHIP BETWEEN PRECIPITATION AND TURBIDITY IN WATER COURSES IN THE HOLY SPIRIT
Name: PEDRO HENRIQUE SILVA PENEDO
Publication date: 28/08/2015
Advisor:
Name |
Role |
|---|---|
| GIOVANNI DE OLIVEIRA GARCIA | Advisor * |
| ROBERTO AVELINO CECÍLIO | Co-advisor * |
| SIDNEY SARA ZANETTI | Co-advisor * |
Examining board:
| Name |
Role |
|---|---|
| CAMILA APARECIDA DA SILVA MARTINS | External Examiner * |
| GIOVANNI DE OLIVEIRA GARCIA | Advisor * |
| ROBERTO AVELINO CECÍLIO | Co advisor * |
Summary: The aim of this study was to evaluate the relationship between turbidity, morphometric characteristics and land use characteristics in 50 watersheds in the Espirito Santo state, Brazil. 50 points of water uptake operated by Companhia Espírito Santense de Saneamento (CESAN) for treatment and supply to the public network, were selected. Turbidity data are collected periodically by CESAN to control the treatment process and reagents dosage. This study used monthly average turbidity of 48 months, from January 2006 to December 2009. The watersheds were delimited using a hydrologically consisted digital elevation model obtained in GIS environment, and their morphometric characteristics. The average monthly rainfall data for the period from rainfall gauges were spatialized using a geostatistical technique ordinary kriging. The land use data came from Instituto Estadual do Meio Ambiente IEMA database, and Espirito Santos state geographical database - Geobases. Regression analysis between turbidity and precipitation in all the basins was performed, resulting in equations with an R2 ranging between 0.90 and 0.015. The removal of highly correlated independent variables was done to reduce multicollinearity. A hierarchical cluster analysis technique was applied to group the watersheds of similar morphometric characteristics and similar land use. A partial correlation analysis was performed between the variables in the obtained groups, to assess its influence on turbidity. Multiple regression analysis was performed between the variables and the turbidity in the obtained groups, resulting in adjusted equations with R2 between 0.68 and 0.16. Interaction variations of the precipitation, morphometric characteristics and land use with turbidity levels occurring in sub-monthly scale could not be observed, which may have contributed to the inaccuracy of the adjusted models.
Keywords: watersheds; cluster analysis; partial correlations.
