Effects of land use and seasonality on stream water quality in a small tropical catchment: The headwater of Córrego Água Limpa, São Paulo (Brazil).

摘要: Stream water quality is controlled by the interaction of natural and anthropogenic factors over a range temporal spatial scales. Among these factors, land cover changes at catchment scale can affect stream quality. This work aims to evaluate influence use seasonality on in representative tropical headwater named as Corrego Agua Limpa (Sao Paulo, Brasil), which highly influenced intensive agricultural activities urban areas. Two systematic sampling approach campaigns were implemented with six points along during rainy dry seasons. Three replicates collected each point 2011. Electrical conductivity, nitrates, nitrites, sodium superoxide, Chemical Oxygen Demand (DQO), colour, turbidity, suspended solids, soluble solids total measured. Water parameters differed among points, being lower (0m above sea level), then progressively higher until last downstream (2500m level). For season, mean discharge was 39.5ls-1 (from April September) whereas 113.0ls-1 averaged season October March). In addition, significant differences observed (P<0.05) for fourteen period. The study enhance relationships its effect, showing seasonal between connection, highlighting importance multiple scales understanding impacts human ecosystem services.