Study on Dynamic Behaviors of Water Quality and Mechanisms of Eutrophication in Kandawgyi Lake, Yangon City, Myanmar

Abstract

Kandawgyi Lake is a famous recreational place in Yangon; however, the water quality deterioration and algae blooming occurred in recent years due to the economic development and people’s unawareness. In this study, the dynamic behaviors of water quality and mechanisms of eutrophication is investigated. During one-year field observation’s results showed that the lake’s water quality had been polluted by domestic wastewater depend on the high value of BOD and COD. Moreover, it was found that the thermal stratification exists about 1.0 meters water depth of the lake and anoxic water mass exists near the bottom of the lake. Besides, the one-year water depth observation showed the seasonal changes of water depth and, the water depth prediction by using the IOM mass balance model indicated better agreements in a dry season than a wet season. From the results of this study, it was thought that internal loading of nutrients could be the main reason of the algae blooms. Therefore, we proposed the bottom sediment removal as the most effective method to improve the water quality. Furthermore, small constructed wetlands at each inlet drains also can be an effective method as a countermeasure for the prevention of the next sediment accumulation.