Calculation of River Ecological Flow Based on Multiple Hydrological Methods

Abstract

Under the backdrop of increasing water utilization, river ecosystem problems continue to emerge. Determining the ecological flow of rivers is one of the keys to the comprehensive restoration of river ecosystems. This paper determines the operability of runoff sequences by means of the Mann-Kendal test, quantifies the minimum ecological flow through five representative hydrological methods, including Intra-year distribution (IYD), Flow during curve (FDC), Q90, Monthly minimum average flow (MMAF) and Average flow in the driest month (AFDM), and calculates the suitable ecological flow by the monthly frequency (M-F) method in three different scenarios. In addition, a comprehensive comparison of the methods is made from various aspects to give the recommended methods. Taking the Shaying River basin as the research objects, the AFDM method achieves the best satisfaction in terms of water demand, the Q90 method and the FDC method have the highest satisfaction level, and IYD method best meet the requirements of hydrological rhythms. The suitable ecological flow derived from the M-F method under Scenario a is optimally satisfactory in all respects. It is recommended to determine the minimum and suitable ecological flow processes by IYD method and the result under scenario b, respectively. This study can be used to provide a scientific and effective reference basis for integrated river management.