流域水质目标管理的AIZ量化分配技术

“分配影响区”（AIZ）概念是对传统混合区概念及其应用的一次重要补充和修正.它以保持水生态完整性为目的，将分配的概念引入对混合区的管理.AIZ过程涉及的“相对环境价值”、“保护水平”和“毒性质量”等重要概念需要多学科共同研究确定，也是分配过程的关键.在详细介绍了AIZ制定过程的基础上，以大宁河为例说明分配计算过程.采用基于毒性质量的分配方法，结合相关文献资料确定水体用途区和有关参数，计算出各用途区内AIZ的允许面积，该面积即为水体中各排放允许的影响区域.最后给出计算结果说明和管理应用，认为该分配结果要严于一般的“混合区”规定.同时认为该方法是对水体进行综合、量化管理的一个有效手段. 

Management Technology of Water Quality Target for River Basin: Allocation Technique of AIZ

The concept of “Allocated Impact Zone” （AIZ） is an important complement and correction for the conventional “mixing zone” concept. It introduced “allocation” to the management of “mixing zone” in order to achieve ecological integrity. The important parameters of “relative environment value”, “protection level” and “toxic mass” involved in the AIZ procedure need to be determined by multi-discipline collaboration and they are also the key in the procedure. Based on the detailed introduction of the AIZ procedure and related conceptions, an allocation example for the Daning River was illustrated. Designated uses and parameters were determined according to relevant materials, and toxicity mass-based allocation method was used to calculate AIZ area in each designated use. This area is the permitted impact area caused by discharge. The explanation of the calculated results and the managerial application were also presented. It is believed that the result is stricter than that of the conventional “mixing zone” method. It is also believed that the methodology is an integrated and quantitative management tool in water environment protection.