多年调节水库调节的周期取决於水库的有效库容以及河流天然水量的变迁情况,少则三年五年,多则十年八年,甚至更长。但是,过去河流的水文资料记录时间都很短暂。在苏联一些较大的通航河道,也只有六,七十年的流量记录,只有一条河有一百三十年的流量记录。在我国这方面情况更差,历史比较长的 The period for adjusting the reservoir regulation for many years depends on the effective storage capacity of the reservoir and the evolution of the natural water volume of rivers, ranging from three to five years to as many as ten years and eight years or even longer. However, in the past, the hydrological records of rivers were short-lived. In some of the larger rivers in the Soviet Union, there were only six or seventy years of traffic records, and only one river had a one-hundred-thirty-year flow record. In China, the situation is even worse, and the history is longer.