Algal bloom control in rivers replenished by reclaimed water has drawn attentions. Aiming at precisely simulating and forecasting the algal density, a typical downstream urban river replenished by reclaimed water was monitored and investigated in aspects of the water quality, algal density, algal community. Parameters of water quality revealed the typical feature of reclaimed water, with high concentration of nitrogen. Algal density dropped gradually from spring to the late autumn, indicating that spring was of high risk of algal bloom. Chlorophyta and Bacillariophyta were identified as the dominant phyla, and Chlorella (belonged to Chlorophyta), Cyclotella (belonged to Bacillariophyta) and Coscinodiscus (belonged to Bacillariophyta) were the dominant species. Both statistical analysis and model simulation revealed that light intensity, nitrogen and metal ions were the influential factors of algal growth in the river. Simulation of the change of algal density using AutoRegressive Integrated Moving Average (ARIMA) model (0, 0, 15) was effective with all the simulated value in the 95% confidence interval, making it feasible to the practical forecast of algal bloom in urban rivers, especially those which are replenished by reclaimed water.

用再生水补充河水中的藻华控制引起了人们的注意。为了精确模拟和预测藻类密度，从水质，藻类密度，藻类群落等方面对典型的下游用再生水补充的城市河流进行了监测和调查。水质参数揭示了再生水的典型特征，其中氮含量很高。从春季到深秋，藻类密度逐渐下降，这表明春季有很高的藻类开花风险。绿藻和硅藻被确定为主要的门类，而小球藻（属于绿藻），小环藻属（属硅藻）和Coscinodiscus（属于Bacillariophyta）是优势种。统计分析和模型模拟均表明，光强度，氮和金属离子是河流中藻类生长的影响因素。使用自回归综合移动平均线（ARIMA）模型（0，0，15）对藻类密度的变化进行模拟是有效的，所有模拟值均在95％置信区间内，这使其对于实际预测城市河流中的藻类开花是可行的，尤其是那些用再生水补充的水。