Spatial-temporal Variation in Water Quality and Its Response to Precipitation and Land Use in Baiyangdian Lake in the Early Stage of the Construction of Xiong'an New Area

Abstract

To assess the water quality of Baiyangdian Lake in the early stage of construction of the Xiong'an New Area, the water quality data in Baiyangdian Lake from December 2020 to November 2021 were collected from five typical monitoring stations. Using the remote-sensing interpretation of land use types, Pearson correlation analysis, comprehensive pollution index, and principal component analysis, the spatial-temporal variation characteristics of the water quality and its response to precipitation and land use structure at different spatial scales were explored in Baiyangdian Lake. The results showed that:① the water quality of Baiyangdian Lake was the best in spring and the worst in summer. Nutrient pollution was the heaviest at Nanliuzhuang, which was greatly affected by the Fuhe River. Organic pollution was the heaviest at Caiputai. ② The comprehensive pollution index of Nanliuzhuang was the highest, followed by that of Shaochedian, Guangdianzhangzhuang, Caiputai, and Quantou. The main excessive pollutant was TN, and the pollution index of 1.55 reached the level of severe pollution. The water quality of Baiyangdian Lake was significantly better than that before the construction of the Xiong'an New Area. ③ The construction land and cropland within the 1.5 km buffer zone had the greatest impact on turbidity, NH4+-N, and TP. While the reed wetland acted as the "sink" for intercepting and absorbing pollutants, it also released nitrogen into the 800 m buffer zone, which was the "source" of the pollutants. ④ The correlation between water quality indicators and land use structure in the rainy season was lower than that in the dry season. This was due to the dilution effect of the upstream reservoir discharging in the rainy season, which weakened the impact of pollutants in the rainfall runoff on the water quality of Baiyangdian Lake.