WATER QUALITY ASSESSMENT AND ANALYSIS FOR THE WEI RIVER BASIN

In this study,water quality in the Wei River basin was assessed with single-factor assessment,comprehensive pollution index and comprehensive water quality identification index,all based on water quality factors at 73 sampling sites in the basin.DO(dissolved oxygen),CODMn(permanganate index),NH3-N(ammonia nitrogen),TN(total nitrogen) and TP(total phosphorus) were chosen as the primary assessment factors.Data showed that water quality in wet seasons was worse than in dry seasons,indicating that non-point pollution contributed more to water quality in the Wei River basin.TN,TP were the primary pollution factors,coming from fertilizers,pesticides,livestock and poultry farming.Water quality showed great spatial discrimination among the three rivers,of which the Wei River was the worst.In the Wei River,water quality in southern tributaries was the best,whereas that in the main stem was the worst,especially in the Guanzhong district.Water quality assessment was helpful to understand pollution situation,and it will be a great reference for pollution management and water quality improvement in the Wei River basin.