Assessing water quality in the Cai River, Ninh Thuan Province, Vietnam, by field observations

The Cai River is the main river in Ninh Thuan Province, Vietnam, and plays a crucial role as arterial river in the entire province. The Cai River is the main river of the Cai River basin; the Sat, Cho Mo, and Ngang Rivers are located on the left hand side, whereas the Ong, Cha, Than, Quao, and Lu Rivers are located on the right hand side of the basin. In this study, the prevailing water quality of the Cai River basin was evaluated by comparing the observed water quality in the Cai River and at the confluences of its tributaries, and the evaluated water quality of the Cai River was compared with the Vietnamese standards. Several parameters, including the pH, total suspended solids, phosphate, dissolved oxygen, biochemical oxygen demand, and chemical oxygen demand were selected for evaluation. Results show that in comparison with water quality standards of Vietnam for irrigation or other domains with low water quality, the water quality standards in the Cai River and in confluences of its tributaries were not significantly affected by polluting factors.