Abstract: Water quality parameter is an important index reflecting the ecological environment of lakes. Traditional random sampling method for the spatial distribution of water quality parameters is restrictive in scale, but the development of geostatistics presents an effective facility to accurately describe the spatial structure of water quality parameters of lake. In order to obtain the spatial distribution of water quality parameters of surface water of Yangzong Lake in summer, we analyzed six water quality parameters (pH value, total chlorophyll-a content, turbidity, dissolved oxygen concentration, electric conductivity, and phycocyanin) by the Kriging interpolation algorithm and the Distance Weighted Inverse (IDW) spatial interpolation algorithm. Results show the surface water of Yangzong Lake in summer experienced a long period of water cycle and a significant spatial heterogeneity of water quality parameters, in particular, total chlorophyll-a content, turbidity and phycocyanin content. The southern area of Yangzong Lake suffers from severe human activity disturbance and pollution, with high concentrations of phycocyanin and dissolved oxygen; while the northern area of Yangzong Lake is more influenced by industrial pollution, with turbidity in this area reaching the peak value. The results of electrical conductivity and pH values are more affected by the ferric salt coagulation of arsenic removal.

Key words: Yangzong Lake, water quality parameters, Kriging interpolation method, inverse distance weighted interpolation, spatial heterogeneity