基于青草沙水库取水口2010—2019年这10年的日监测数据, 对水质的主要理化指标进行了年际和季节性变化趋势分析, 并探讨了理化指标间的关联关系. 结果表明: ①青草沙水库取水口溶解氧浓度始终保持较高水平, pH值呈现弱碱性; ②取水口氨氮浓度较低, 硝酸盐氮浓度介于1.2 ~ 2.0 mg/L, 总磷浓度为0.1 ~ 0.2 mg/L, 高锰酸盐指数浓度为2.0 ~ 4.0 mg/L, 且这4项指标从2015年开始均呈下降趋势, 表明来水水质进一步变好; ③溶解氧浓度、水温和pH值存在明显的四季变化, 而总硬度、永久硬度、电导率和氯化物这4项指标受海水入侵影响且季节变化基本一致, 其余指标随季节变化差异不明显; ④总磷浓度、高锰酸盐指数浓度随浊度的升高而升高, 总磷浓度和硝酸盐氮浓度随着大通流量的增加而呈现下降趋势.

Based on daily monitoring data of the Qingcaosha Reservoir water intake from 2010 to 2019, this paper analyzes the interannual and seasonal variation trends in the main physical and chemical water quality indicators, and explores the correlation between these indicators. The results show that: ① The dissolved oxygen at the intake of Qingcaosha Reservoir was consistently high, and the pH value was slightly alkaline. ② The concentration of ammonia nitrogen was low at the intake of Qingcaosha Reservoir, the concentration of nitrate-nitrogen was between 1.2 and 2.0 mg/L, the concentration of total phosphorus was between 0.1 and 0.2 mg/L, and the permanganate index was between 2.0 and 4.0 mg/L. These indexes, furthermore, all showed a downward trend after 2015, suggesting that the quality of incoming water subsequently improved. ③ Dissolved oxygen concentration, water temperature, and pH exhibited obvious seasonal variations, while total hardness, permanent hardness, conductivity, and chloride showed consistent variations under the influence of seawater intrusion. There was no significant seasonal variation in the other indicators. ④ The concentration of total phosphorus and the permanganate index increased with turbidity. The concentration of total phosphorus and nitrate nitrogen, moreover, decreased with an increase in water discharge at Datong.