Effects of Eutrophic Status and Land-use Types on Water Quality in Lake and Reservoir Water Source Reserves

Taking 8 typical lake & reservoir water source reserves in southeast Yunnan as the study area. Based on the water quality data from May to July 2019, combined with 3 land use types of cultivated land, garden land and residential land in the first and second grade protected areas, the influence of different land use types on the quality of water sources in protected areas was explored by correlation analysis, redundancy analysis(RDA). The results showed that Hongqi and Hezuo reservoir did not meet assessment standard(class II water) within sampling period, and the excess factors were TN and TP. The water quality in May and June was better than July. On the whole, all drinking water sources were in poor eutrophication stage. DO was the main driving factor, BOD₅, TN was the potential pollutionindex. There was a significant positive correlation between Res%(percentage of residential land area), Gar%(percentage of garden area) and TN, TP. This indicates agricultural activities are the main factor affecting the water quality of water sources reserve. In RDA analysis, the Gar% and TP or COD_Cr parameters are in the same quadrant, but negatively correlate with DO. Reasonable adjustment of landscape structure and layout has great significance for control non-point source pollution.