Assessment of Physicochemical Characteristics of Surface Water in the Full-Dyke and Semi-Dyke Systems: A Case Study

The present study aimed to assess the physicochemical characteristics of surface water in the full-dyke (FD) and semi-dyke (SD) systems of the An Giang province. Water samples were collected in both seasons in 2019 (1) the first monitoring phase in the dry season (April) and (2) the second monitoring phase in the rainy season (October). At each season, the surface water samples were collected at 15 sites in the FD system and 15 sites in the SD system to analyze the water quality parameters. The results showed that the concentrations of DO, COD, BOD, TSS, NO3-, NH4+, TKN, PO43- and TP parameters in the FD system were higher than in the SD system and there was a significant difference (p<0.05), except the value of pH and DO in the dry season. The DO, COD, BOD5 and TSS concentrations in the FD system tended to exceed the Vietnamese standard threshold (QCVN 08:2015/BTNMT, column B1), but in the SD system, these values were within the allowable limits of Vietnamese Standard. Other parameters, such as NO3-, NH4+, TKN, PO43- and TP exceeded the threshold of the Vietnamese standard in both systems. The results of this study provide the scientific information on water pollution inside the FD system. Therefore, it was expected that the local government of the An Giang province should have long-term strategies to manage the FD system to improve the water quality inside the FD system.