Calculation Method of River Ecological Water Demand Based on Variable Interval Threshold Method

In view of the different characteristics of the natural river runoff,a calculation method of ecological water demand,which takes into account the variation of annual runoff,is put forward,the upper and lower thresholds shall be set at the same time in flood seasons. Compared with Tennant method and distributed flow method,the results show that the performance of variable interval threshold method is not inferior to that of distributed flow method,and the distribution of noninferior solution set is more uniform than that of Tennant method,it is beneficial to resist the invasion of the saltwater tide,the discharge of the reservoir is larger in March and May,which is beneficial to the ecological environment and the spawning period of the fishes,and the dependence of the runoff data in the dry season is reduced,which is easy to calculate. It enriches the existing calculation methods of ecological water requirement and provides technical support and reference for related research.