一是，城市污染物排放量计算；二是，水体水量—水质—生态耦合模型；三是，生态系统良性循环控制目标方程。由这三部分模型方程组合成为“水环境承载能力计算模型”。-One is that urban emissions calculation　Second, water quantity, water quality, water ecology coupling model　Three is that ecosystem benign cycle control target equation. Consists of three parts model equation together as \ water environment carrying capacity calculation model\ .