Topographical characteristics and evaluating water quality in watershed management

Topographical characteristics and water quality were evaluated at Hacienda Gloria, in Jaboticabal, Sao Paulo State, Brazil. Understanding the relief's morphometric characteristics and the course of the streams in a small watershed supported the hypothesis that land-use affects water quality and helps predict how changes in water-flow and the surrounding landscape occur; areas protected by native forest and those dedicated to agriculture were considered. Water quality was sampled at six sites and physical and chemical changes were analysed. Monthly water samples were collected from the streams on the same day of each month during the course of a year; Horiba equipment was used for recording data. One-way analysis of variance (ANOVA) was used for determining differences between the sites being investigated. Analysing the data revealed significant differences in pH, electric conductivity, turbidity, dissolved oxygen and temperature. Topographical characteristics have been influenced by agricultural activity, thereby having an environmental impact. Surface runoff was predominant on steep slopes, mainly in areas near the top of the watershed. Land-use has had a significant impact on many physical parameters, including stream turbidity and temperature which increased with deforestation. The results indicated the agricultural watershed's fragility to pollutant exposure and/or toxicity, mainly due to turbidity in the streams caused by soil erosion, waste discharge and runoff.