Land use and its impacts on the water quality of the Cachoeirinha Invernada Watershed, Guarulhos (SP)

Abstract

The urbanization process through which large urban centers have been passing has drastically affected the availability and especially the quality of water. The Cachoeirinha Invernada Watershed (CIW), located in the municipality of Guarulhos (State of São Paulo, Brazil), includes areas with different land use classes. This paper aims to correlate the spatial and temporal effects of land use and land cover on the water quality of the Cachoeirinha Invernada Watershed. In a period of 12 months and at six sampling points along the watershed, the physicochemical parameters temperature (T), pH, turbidity (TU), total solids (TS), electrical conductivity (EC), total phosphorus (TP), biochemical oxygen demand (BOD), as well as microbiological analysis (E. coli) were measured. Water quality was assessed using a modified version (WQIM) of the Water Quality Index (WQI) and the Trophic State Index (TSI). The areas surrounded by urban development presented a marked worsening in water quality, with the downstream point most affected and ranked as 'POOR'. From the evaluated parameters, what contributed most to water quality degradation of the Cachoeirinha Invernada Watershed (CIW) was E. coli, followed by BOD, and TP, all parameters related to the presence of sewage in the water. The need for the construction of sewerage and waste treatment, protection and recovery of riparian forests, and environmental education regarding waste disposal are necessary to significantly improve the environmental quality of the Cachoeirinha Invernada Watershed. correlacionar os efeitos espaciais e temporais do uso da terra e da cobertura do solo na qualidade da água dessa bacia hidrográfica.. Foram analisados, em um período de 12 meses e em seis pontos de amostragem na área da bacia hidrográfica, parâmetros físico-químicos como a temperatura (T), pH, turbidez (TU), sólidos totais (ST), condutividade elétrica (CE), fósforo total (FT), demanda bioquímica de oxigênio (DBO), bem como análise microbiológica (E. coli). A qualidade da água foi avaliada usando uma versão modificada (WQIM) do Índice de Qualidade da Água (IQA) e do Índice do Estado Trófico (IET). As áreas cercadas pelo desenvolvimento urbano apresentaram um acentuado agravamento na qualidade da água, com o ponto a jusante mais afetado e classificado como 'POBRE'. A partir dos parâmetros avaliados, o que mais contribuiu para a degradação da qualidade da água da BHCI foi E. coli, seguido de DBO e FT, parâmetros esses relacionados à presença de esgoto na água. A necessidade de construção de esgoto e tratamento de resíduos, proteção e recuperação de matas ciliares e educação ambiental com foco na eliminação de resíduos são necessárias para melhorar significativamente a qualidade ambiental da bacia hidrográfica Cachoeirinha Invernada.Palavras-chave: degradação ambiental, eutrofização, águas urbanas, poluição da água.

Land use and water quality in watersheds in the State of São Paulo, based on GIS and SWAT data

“…In both areas, the surface runoff rates were higher in the subwatersheds in which there was a predominance of exposed soil and agricultural activity. A similar result was obtained by Oliveira et al (2018a) which identified that deforestation and agricultural use increase peak flows at the same time as percolation decreases; these alterations can result in degradation of source water quality. Armas et al (2007) found that the presence of pesticides in surface waters in the Piracicaba River watershed was related to aspects of land use, mainly to the predominance of sugarcane cultivation.…”

Analysis of Socio-Environmental, Economic and Sanitary Aspects of an Informal Settlement in the Municipality of Guarulhos, Sp

“…Guarulhos has 47 neighborhoods and an estimated population of 1,349,113 inhabitants, according to the Brazilian Institute of Geography and Statistics -IBGE (2017). It is the second most populous city in the state of São Paulo, the 13 th most populous municipality in Brazil and the first among those that are not a state capital (OLIVEIRA et al, 2010, NOVAES, 2012, VARGAS et al, 2018, PREFEITURA DE GUARULHOS, 2019.…”

“…Unfortunately, this economic potential has not being converted into a better quality of life for the larger part of its population. This is mostly due to the inefficiency of urban planning (NOVAES, 2012;OLIVEIRA et al, 2018;VARGAS et al, 2018).…”

“…Its rapid urban expansion forced the poorest population to develop informal settlements in the outskirts of Guarulhos. The first favela dates from 1970 and there were 343 in 2002, which are occupying environmentally protected areas on the native forested hillsides and along watercourses (NOVAES, 2012;OLIVEIRA et al, 2018;VARGAS et al, 2018).…”

“…The process of urban growth requires new land for building, but it does not justify the degradation of the vegetation, soil and water courses. This environment degradation ends up directly affecting the quality of human life regarding health, safety and well-being (NASCIMENTO, 2007;CORAZZA et al, 2018, VARGAS et al, 2018. Jacobi et al (2015a) remind us of the importance of implementing programs to recover urban streams and rivers because of their ecosystem services, such as water supply as well as aesthetic, cultural and leisure aspects, favoring a better quality of life for the population.…”