Relating land-use/land-cover patterns to water quality in watersheds based on the structural equation modeling

Abstract Understanding the relationships between land-use/land-cover (LULC) patterns in watersheds and water quality is of great significance for exploring the causes of non-point source pollution and scientific planning of land use. Multivariate regression methods have often been used to examine the response of specific water contaminants to LULC patterns. However, this also resulted in overlooking the ecological process and biased parameter estimates caused by redundancy where some landscape metrics are strongly correlated. In this study, based on “source-sink” landscape theory, Redundancy Analysis (RDA) and Partial Least Squares Structural Equation Modeling (PLS-SEM) were used to investigate the relationship between LULC patterns and water quality in the surrounding sub-watersheds of the Danjiangkou Reservoir in the dry and rainy seasons. The results showed that water quality parameters were characterized by seasonal differences. In the dry season, only the proportion of the watershed occupied by urban landscapes (P_Urban) had a significant impact on water quality in watersheds (β = 0.835, p