Comprehensive Evaluation of Spatio-temporal Variation Characteristics of Water Quality in a Large Reservoir in Guangdong Province
To address the lack of long-term,comprehensive analysis of the water quality evaluation of a large reservoir,this paper collected the monthly water quality data from three areas:the river zone(S1),the transition zone(S2)and the lake zone(S3)of the reservoir from 2010 to 2022.Water quality was evaluated using Canadian Council of Ministers of the Environment Water Quality Index(CCME-WQI),and principal component analysis and correlation analysis were employed to explore the spatio-temporal characteristics and influencing factors over the reservoir's long-term operation.The results showed that:(1)On a spatial scale,total nitrogen(TN)and total phosphorus(TP)concentrations were higher at S1,while dissolved oxygen(DO)and chlorophyll-a(Chla)concentrations were higher at S2 and S3,and TP concentrations showed an increasing trend at all monitoring points;(2)On a temporal scale,the WQI at each monitoring point showed an general improvement,especially after 2014;(3)water quality changes at S1 were mainly influenced by pH,ammonia nitrogen(NH3-N)and TN,while S2 and S3 were mainly influenced by pH,five-day biochemical oxygen demand(BOD5),and permanganate index(CODMn).Chla concentrations were highly significantly positively correlated with CODMn,BOD5 and TP concentrations(p＜0.001),but negatively correlated with TN(p＜0.001).Upstream pollutants contributed to higher TN and TP levels at S1,while weaker hydrodynamic conditions at S2 posed a higher risk of algal blooms.After 2014,the effective control of the total amount of pollutants entering the reservoir was the fundamental reason for the improvement in water quality.It is recommended to focus on joint reservoir management,emergency algal bloom responses,and ecological protection and restoration to strengthen the reservoir's capacity for managing water-related risks.
water quality indexprincipal component analysiseutrophicationalgal bloom
万方数据
维普
