Application of Comprehensive Water Quality Identification Index in Water Quality Assessment of River

Comprehensive water quality identification index, based on single factor water quality identification index, is a new tool for evaluating surface water quality. This evaluation method of water quality can fully depict the general water quality and evaluate water quality qualitatively and quantitatively. We use this method to evaluate the water quality of Dagu River in Laixi area of Qingdao, China, using one year´s monitoring data of three periods including water-deficient period, water-common period and water-rich period. The results show that the water quality of this valley meet the III category of regional water environment domain standards, while the water quality of the water-rich period is the worst and the water quality of lower reaches is worse than upper reaches, which is basically in accordance with the actual situation. This paper shows that the comprehensive water quality identification index is worth using in the river water quality assessment.