Diagnosis of Basin Eco-Hydrological Variation Based on Index Sensitivity of Similar Years: A Case Study in the Hanjiang River Basin

Abstract

The variation of hydrological conditions in the basin affects the original stable state of the basin, and the change of eco-hydrological conditions also plays a decisive role in the stability of the basin. In this manuscript, Indicators of Hydrologic Alteration (IHA) was used to diagnose watershed variation from the eco-hydrological perspective, and a new diagnostic method was proposed in the current study, which was the extraction method of the most relevant eco-hydrological indicators based on a similar year sensitive index and the diagnosis method of variation period. This method used the sensitivity of statistical characteristics between similar years to provide the basis for the selection of the most ecologically-relevant hydrogeological indicators (ERHIs), then selected the strong variation indicators from the most relevant eco-hydrological indicators, and finally used the strong variation indicators to diagnose the watershed variation. The runoff data (1960 to 2020) in the Ankang gauging station of the Hanjiang River were analyzed, and the results showed that the indicators of high variation were the average duration index of low discharge in a year and the minimum discharge index of one day in a year. The variation period was from 1973 to 1986. It was concluded that the diagnosis results from the perspective of eco-hydrology were consistent with the actual hydrological situation changes, and this method had certain reliability.