Spatial and Seasonal Assessment of Water Quality in the Lobo Stream River Basin, Brazil Using Multivariate Statistical Techniques

Abstract

In view of the complexity of the processes associated to water quality, this study objective is to identify the main factors related to spatial and seasonal variability in water courses of the Lobo Stream River Basin. To this, multivariate statistical techniques were used. Data collection for water quality and streamfl ow variables were carried out monthly, from May 2018 to April 2019, at 10 monitoring points along basin's tributaries. The results show that, during the dry season, the main causes for water quality decrease are related to erosion process on the river margins, which is intensifi ed by inadequate handling in livestock activities in some monitoring points. In the rainy season, the main causes are related to soil leaching in agricultural areas that increases the nitrogen compounds concentration and reduces water quality. However, in addition to this, it was noted that regardless the environmental conditions, the most impactful factor is the point pollution from the effl uent discharge of Itirapina City sewage treatment plant, responsible for nutrient concentration increase, organic contamination, OD reduction, and, consequently, water quality deterioration. With this, the study shows how multivariate statistical analysis enables more relevant evaluation of water quality data variability and supports further studies in the basin.

Enhancing Water Ecosystem Services Using Environmental Zoning in Land Use Planning

“…In the JGRB, precipitation during the rainy months represents 80% of the total annual precipitation volume [49]. Intense precipitation during this period promotes higher sediment and nutrient exports due to surface runoff and leaching from agricultural areas [94]. Therefore, additional studies at finer scales may be necessary to complement our findings and quantify the seasonal effects of land use changes on WESs in the studied watershed.…”

Integrated use of SAR and Optical data in mapping native vegetation: a study in a transitional Brazilian Cerrado-Atlantic Forest interface

“…Constructed in 1936 to generate electricity, the Lobo Reservoir is currently used for irrigation, tourism, and research. One of Brazil's most studied reservoirs, it is known worldwide as the Broa model, reflecting the scientific research it has generated since the 1970s as a strategic project of two major universities, the University of São Paulo, and the Federal University of São Carlos [2][3][4]14,25]. The reservoir is primarily formed by contributions of the Itaqueri river and the Lobo stream, augmented by contributions from the Água Branca, Geraldo, Limoeiro, and Perdizes streams.…”

“…The spatial composition of the basin's native vegetation is formed by permanent protection areas, consisting of fragments of the Atlantic Forest in regions of rivers and streams, close to springs and the region comprising the Ecological Station of Itirapina composed of vegetation characteristic of the typical savannah and grassland Brazilian Cerrado biome. The study further contributes to national and international research, as the basin is part of the long-term ecological research program of the National Council for Scientific and Technological Development, which promotes advances in environmental and ecological research [2][3][4]8,14,25,26].…”

“…Alterations in land use and land cover (LULC) arising from anthropic activities are one of the principal environmental problems studied by scientists [1][2][3][4][5][6]. Adverse changes in conservation areas cause environmental damage and harm our quality of life, such as reduction in the available water for human consumption, or reduction in soil nutrients for food production.…”

“…Without adequate LULC management focused on sustainability, regional river basins suffer persistent alterations. The Lobo Reservoir Hydrographic Basin (LRHB), hereafter basin, is formed by streams and rivers that contribute to the reservoir [2][3][4]14]. It lies in the center-west of the state of São Paulo, Brazil, a transitional region between the Brazilian Cerrado and the Atlantic Forest, over 200 km from the city of São Paulo, one of the principal financial, corporate, and commercial centers of South America [4,14].…”