Studies on water quality of Son La hydropower reservoir before and after its operatio

Abstract

Son La Hydropower Plant is the biggest hydroelectric project in Vietnam built from 2005 to 2012. The dam for water storage and power generation activities of the plant on Da River was built in 2010. After 9 years of water storage, the Son La hydropower reservoir environment has stabilized, forming a wetland ecosystem - typical reservoir ecosystem in the Northwest, Vietnam. Based on water quality monitoring data of Son La Natural Resources and Environment Monitoring Center and Son La Hydropower Company, this study investigated water quality changes at 03 monitoring sites (upstream of the dam, inside the reservoir and below water gate) of Son La hydropower reservoir before and after its operation. Results showed that there was changes of physical, chemical and biological parameters in the reservoir’s water before and after its operation. Water quality of Son La hydropower reservoir was also found to have seasonal variation. External factors (i.e. natural, economic and social factor) affecting water quality in Son La hydropower reservoir were also evaluated and discussed.