Changing properties and causes of the annual maximum flood in the Jialu River Basin

Based on the daily precipitation data from 1969 to 2015 and the flood summary data of the hydrological station in the Jialu River Basin, the annual maximum flood (AMAXF) and extreme precipitation were used to analyze the changing properties and causes of the annual maximum flood. Mann-Kendall test were used to analyze the change characteristics and the correlations between AMAXF and extreme precipitation were analyzed with cross wavelet analysis method. The changes in the NDVI were also analyzed to investigate the reasons for the changes of AMAXF. The results showed that AMAXF series had a significant decreasing trend with an abrupt change point around 1998, and there was no significant change in extreme precipitation. Cross Wavelet Analysis showed the AMAXF had statistically correlations with extreme precipitation in the Jialu River Basin. The decreasing trend in the AMAXF were mainly caused by LUCC.