Relationship between Hydrological Characteristics and Water Quality of Mountain Streams in Cangshan Mountain, Dali

Mountain streams serve as the primary source for numerous large inland water bodies,including rivers and lakes.To investigate the relationship between flow rate and water quality between different seasons and among rivers with distinct flow rate,weekly samples were collected from Baihe Stream and Heilong Stream in Cangshan Mountain,Dali.Fieldwork was conducted during both the dry and wet seasons in 2019.The DO concentration and the flow rate were measured on-site,while TN and TP concentrations were analyzed in laboratory.The results indicated that the mean value of the flow rate of Baihe Stream in wet season was significantly higher than that of dry season （P<0.05） and the mean value of Heilong Stream in wet season was significantly higher than that of Baihe Stream （P<0.05）.Pearson correlation analysis showed that the flow rate of Baihe Stream was positively correlated with DO concentration （R²=0.522,P<0.05）.The mean TP concentration in Baihe Stream in dry season was higher than that in wet season （P<0.05）,and the mean TP concentration in Baihe Stream in wet season was significantly higher than that in Heilong Stream （P<0.05）.There was no significant difference in TN and DO between rivers in different seasons with different flow rate.In summary,there was a significant positive correlation between flow rate and DO concentration in Cangshan Mountain forest streams.Compared with rivers with low flow rate and the same river in dry season,rivers with high flow rate and rivers in wet season had lower TP concentration.