Research on response of water quality to land use pattern in nine plateau lake watersheds of Yunnan Province, China

To study how water quality responds to land use types is of great significance in realizing effective control of non-point source pollution. This study built a response model of water quality to land use. The research results are as follows. First, the proportion of farmland is positively correlated to the total phosphorus (TP) value and biochemical oxygen demand (BOD) value, which indicates that the water quality deteriorates as the area of farmland increases. Second, the proportion of woodland is negatively correlated to the permanganate index, the trophic state index, total nitrogen (TN) value, TP value and BOD value, which means the water quality improves as the area of woodland increases. Third, the proportion of grassland is negatively correlated to the water quality indices and the correlation coefficient is large, which indicates that the water quality improves as the area of grassland increases. Fourth, the proportion of land used for buildings is positively correlated to the trophic state index and the chemical oxygen demand (COD) value at the 0.05 significance level, which means that the water quality deteriorates as the area of land for buildings increases. This study is expected to provide a basis for optimization of the land use and effective pollution control in the nine plateau lake watersheds.